1
|
Agnetta D, Badalamenti F, Sweeting CJ, D'Anna G, Libralato S, Pipitone C. Erosion of fish trophic position: an indirect effect of fishing on food webs elucidated by stable isotopes. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230167. [PMID: 39034698 PMCID: PMC11293850 DOI: 10.1098/rstb.2023.0167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 01/08/2024] [Accepted: 01/23/2024] [Indexed: 07/23/2024] Open
Abstract
Fishing has significant trophodynamic impacts on marine communities, including reductions in the mean trophic position (TP) of the ecosystem resulting from a decrease in the abundance and size of species and individuals with high TPs. This study demonstrates the erosion of fish TP, an additional process that results in lower TP of individuals of a given size, which may exacerbate the effects of fishing on the food web. A stable isotope approach based on the tRophicPosition Bayesian method was used to quantify the TP of 12 target marine species at a given length, and compare their TP between fishery-restricted areas and trawled areas. The results show a difference in the TP of six benthic and apical nekto-benthic predators, which feed in the median at about 0.5 TP lower in trawled areas. It appears that current 'fishing down marine food webs' analyses may underestimate the trophic effects of fishing. Accounting for changes in trophodynamics of individuals at a given size is important to detect indirect effects through food web interactions. The application of a trawling ban may lead to the restoration of lost trophic structure; however, trophic changes may occur more slowly than changes in biomass. This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.
Collapse
Affiliation(s)
- Davide Agnetta
- National Institute of Oceanography and Applied Geophysics (OGS), Trieste34151, Italy
- NBFC, National Biodiversity Future Center, Palermo90133, Italy
| | - Fabio Badalamenti
- NBFC, National Biodiversity Future Center, Palermo90133, Italy
- CNR-IAS, Lungomare Cristoforo Colombo 4521, Palermo90149, Italy
- School of Geosciences, University of Edinburgh, The King’s Buildings, EdinburghEH9 3FE, UK
| | - Christopher J. Sweeting
- Marine Management Organisation Lancaster House, Newcastle Business Park, Newcastle Upon TyneNE4 7YH, UK
| | - Giovanni D'Anna
- NBFC, National Biodiversity Future Center, Palermo90133, Italy
- CNR-IAS, Via Giovanni da Verrazzano 17, Castellammare91014, Italy
| | - Simone Libralato
- National Institute of Oceanography and Applied Geophysics (OGS), Trieste34151, Italy
| | - Carlo Pipitone
- NBFC, National Biodiversity Future Center, Palermo90133, Italy
- CNR-IAS, Lungomare Cristoforo Colombo 4521, Palermo90149, Italy
| |
Collapse
|
2
|
Ogino M, Farine DR. Collective intelligence facilitates emergent resource partitioning through frequency-dependent learning. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230177. [PMID: 39034703 PMCID: PMC11293853 DOI: 10.1098/rstb.2023.0177] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 07/23/2024] Open
Abstract
Deciding where to forage must not only account for variations in habitat quality but also where others might forage. Recent studies have suggested that when individuals remember recent foraging outcomes, negative frequency-dependent learning can allow them to avoid resources exploited by others (indirect competition). This process can drive the emergence of consistent differences in resource use (resource partitioning) at the population level. However, indirect cues of competition can be difficult for individuals to sense. Here, we propose that information pooling through collective decision-making-i.e. collective intelligence-can allow populations of group-living animals to more effectively partition resources relative to populations of solitary animals. We test this hypothesis by simulating (i) individuals preferring to forage where they were recently successful and (ii) cohesive groups that choose one resource using a majority rule. While solitary animals can partially avoid indirect competition through negative frequency-dependent learning, resource partitioning is more likely to emerge in populations of group-living animals. Populations of larger groups also better partition resources than populations of smaller groups, especially in environments with more choices. Our results give insight into the value of long- versus short-term memory, home range sizes and the evolution of specialization, optimal group sizes and territoriality. This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.
Collapse
Affiliation(s)
- Mina Ogino
- Department of Evolutionary Biology and Environmental Science, University of Zurich, ZurichWinterthurerstrasse 190, 8057, Switzerland
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, KonstanzAm Obstberg 1, 78315 Radolfzell, Germany
| | - Damien R. Farine
- Department of Evolutionary Biology and Environmental Science, University of Zurich, ZurichWinterthurerstrasse 190, 8057, Switzerland
- Department of Collective Behaviour, Max Planck Institute of Animal Behavior, KonstanzAm Obstberg 1, 78315 Radolfzell, Germany
- Division of Ecology and Evolution, Research School of Biology, Australian National University, 46 Sullivans Creek Road, CanberraACT 2600, Australia
| |
Collapse
|
3
|
de Camargo NF, de Oliveira HFM, Ribeiro JF, de Camargo AJA, Vieira EM. Morphological traits explain the individual position within resource-consumer networks of a Neotropical marsupial. Curr Zool 2024; 70:453-464. [PMID: 39176064 PMCID: PMC11336675 DOI: 10.1093/cz/zoad023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 06/13/2023] [Indexed: 08/24/2024] Open
Abstract
Knowledge regarding the influence of individual traits on interaction patterns in nature can help understand the topological role of individuals within a network of intrapopulation interactions. We tested hypotheses on the relationships between individuals' positions within networks (specialization and centrality) of 4 populations of the mouse opossum Gracilinanus agilis and their traits (i.e., body length, body condition, tail length relative to body length, sex, reproductive condition, and botfly parasitism) and also seasonal effects in the Brazilian savanna. Individuals with lower body length, better body condition, and relatively shorter tail were more specialized (i.e., less connected within the network). Individuals were also more specialized and less connected during the warm-wet season. The relationship between individuals' position in the network and body traits, however, was independent of season. We propose that specialization may arise not only as a result of preferred feeding strategies by more capable individuals (i.e., those with better body condition and potentially prone to defend and access high-quality food resources) but also because of morphological constraints. Smaller/younger individuals (consequently with less experience in foraging) and short-tailed individuals (less skilled to explore the vertical strata of the vegetation) would feed only on a subset of the available food resources and consequently become more specialized. Moreover, individuals are more specialized during the warm-wet season because of high competition (population-dense period) and higher ecological opportunities (resource-rich period). Therefore, our study reveals the relevance of individual traits in shaping interaction patterns and specialization in populations.
Collapse
Affiliation(s)
- Nícholas F de Camargo
- Laboratório de Ecologia de Vertebrados, Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, CP 04457, Brasília, DF, 70910-900, Brazil
| | - Hernani F M de Oliveira
- Departamento de Zoologia, Setor de Ciências Biológicas, Universidade Federal do Paraná, Avenida Coronel Francisco Heráclito dos Santos100, Curitiba, PR, 81531980, Brazil
| | - Juliana F Ribeiro
- Laboratório de Ecologia de Vertebrados, Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, CP 04457, Brasília, DF, 70910-900, Brazil
| | | | - Emerson M Vieira
- Laboratório de Ecologia de Vertebrados, Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, CP 04457, Brasília, DF, 70910-900, Brazil
| |
Collapse
|
4
|
Inzani E, Kelley L, Thomas R, Boogert NJ. Early-life diet does not affect preference for fish in herring gulls ( Larus argentatus). PeerJ 2024; 12:e17565. [PMID: 39006022 PMCID: PMC11246621 DOI: 10.7717/peerj.17565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 05/22/2024] [Indexed: 07/16/2024] Open
Abstract
Urban populations of herring gulls (Larus argentatus) are increasing and causing human-wildlife conflict by exploiting anthropogenic resources. Gulls that breed in urban areas rely on varying amounts of terrestrial anthropogenic foods (e.g., domestic refuse, agricultural and commercial waste) to feed themselves. However, with the onset of hatching, many parent gulls switch to sourcing more marine than anthropogenic or terrestrial foods to provision their chicks. Although anthropogenic foods may meet chick calorific requirements for growth and development, some such foods (e.g., bread) may have lower levels of protein and other key nutrients compared to marine foods. However, whether this parental switch in chick diet is driven by chicks' preference for marine foods, or whether chicks' food preferences are shaped by the food types provisioned by their parents, remains untested. This study tests whether chick food preferences can be influenced by their provisioned diet by experimentally manipulating the ratio of time for which anthropogenic and marine foods were available (80:20 and vice versa) in the rearing diets of two treatment groups of rescued herring gull chicks. Each diet was randomly assigned to each of the 27 captive-reared chicks for the duration of the study. We tested chicks' individual food preferences throughout their development in captivity using food arrays with four food choices (fish, cat food, mussels and brown bread). Regardless of the dietary treatment group, we found that all chicks preferred fish and almost all refused to eat most of the bread offered. Our findings suggest that early-life diet, manipulated by the ratio of time the different foods were available, did not influence gull chicks' food preferences. Instead, chicks developed a strong and persistent preference for marine foods, which appears to match adult gulls' dietary switch to marine foods upon chick hatching and may reinforce the provisioning of marine foods during chick development. However, whether chicks in the wild would refuse provisioned foods, and to a sufficient extent to influence parental provisioning, requires further study. Longitudinal studies of urban animal populations that track wild individuals' food preferences and foraging specialisations throughout life are required to shed light on the development and use of anthropogenic resource exploitation.
Collapse
Affiliation(s)
- Emma Inzani
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, United Kingdom
| | - Laura Kelley
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, United Kingdom
| | - Robert Thomas
- Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Neeltje J. Boogert
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, United Kingdom
| |
Collapse
|
5
|
Jensen AJ, Muthersbaugh M, Ruth CR, Butfiloski JW, Cantrell J, Adams J, Waits L, Kilgo JC, Jachowski DS. Resource pulses shape seasonal and individual variation in the diet of an omnivorous carnivore. Ecol Evol 2024; 14:e11632. [PMID: 38966241 PMCID: PMC11222735 DOI: 10.1002/ece3.11632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 06/01/2024] [Accepted: 06/06/2024] [Indexed: 07/06/2024] Open
Abstract
Resource pulses are ecologically important phenomenon that occur in most ecosystems globally. Following optimal foraging theory, many consumers switch to pulsatile foods when available, examples of which include fruit mast and vulnerable young prey. Yet how the availability of resource pulses shapes the ecology of predators is still an emerging area of research; and how much individual variation there is in response to pulses is not well understood. We hypothesized that resource pulses would lead to dietary convergence in our population, which we tested by tracking both population-level and individual coyote diets for 3 years in South Carolina, USA. We (1) described seasonal dietary shifts in relation to resource pulses; (2) compared male and female diets across seasons; and (3) tested this dietary convergence hypothesis by quantifying individual dietary variation both across and within periods when resource pulses were available. We found that pulses of white-tailed deer fawns and blackberries composed over half of coyote diet in summer, and persimmon fruits were an important component in fall. Male and female coyotes generally had similar diets, but males consumed more deer in fall, perhaps driven by scavenging more. We found support for our dietary convergence hypothesis, where individuals had more similar diets during resource pulses compared to a non-pulse period. We also found that this convergence happened before peak availability, suggesting a non-symmetric response to pulse availability. We show that nearly all coyotes eat fawns, suggesting that targeted efforts to remove "fawn killers" would be in vain. Instead, given how quickly coyotes collectively converge on resource pulses, our findings show that resource pulses could potentially be used by managers to alter the behavior of apex predators. More broadly, we open a new line of inquiry into how variation in individual foraging decisions scales up to shape the effects of resource pulses on ecological communities.
Collapse
Affiliation(s)
- Alex J. Jensen
- Department of Forestry and Environmental ConservationClemson UniversityClemsonSouth CarolinaUSA
- North Carolina Museum of Natural SciencesRaleighNorth CarolinaUSA
| | - Michael Muthersbaugh
- Department of Forestry and Environmental ConservationClemson UniversityClemsonSouth CarolinaUSA
| | - Charles R. Ruth
- South Carolina Department of Natural ResourcesColumbiaSouth CarolinaUSA
| | | | - Jay Cantrell
- South Carolina Department of Natural ResourcesColumbiaSouth CarolinaUSA
| | - Jennifer Adams
- Department of Fish and Wildlife SciencesUniversity of IdahoMoscowIdahoUSA
| | - Lisette Waits
- Department of Fish and Wildlife SciencesUniversity of IdahoMoscowIdahoUSA
| | - John C. Kilgo
- United States Forest Service Southern Research StationNew EllentonSouth CarolinaUSA
| | - David S. Jachowski
- Department of Forestry and Environmental ConservationClemson UniversityClemsonSouth CarolinaUSA
| |
Collapse
|
6
|
Marcuk V, Piña-Ortiz A, Castillo-Guerrero JA, Masello JF, Bustamante P, Griep S, Quillfeldt P. Trophic plasticity of a tropical seabird revealed through DNA metabarcoding and stable isotope analyses. MARINE ENVIRONMENTAL RESEARCH 2024; 199:106627. [PMID: 38968803 DOI: 10.1016/j.marenvres.2024.106627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Revised: 06/19/2024] [Accepted: 06/28/2024] [Indexed: 07/07/2024]
Abstract
DNA metabarcoding and stable isotope analysis have significantly advanced our understanding of marine trophic ecology, aiding systematic research on foraging habits and species conservation. In this study, we employed these methods to analyse faecal and blood samples, respectively, to compare the trophic ecology of two Red-billed Tropicbird (Phaethonaethereus; Linnaeus, 1758) colonies on Mexican islands in the Pacific. Trophic patterns among different breeding stages were also examined at both colonies. Dietary analysis reveals a preference for epipelagic fish, cephalopods, and small crustaceans, with variations between colonies and breeding stages. Isotopic values (δ15N and δ13C) align with DNA metabarcoding results, with wider niches during incubation stages. Differences in diet are linked to environmental conditions and trophic plasticity among breeding stages, influenced by changing physiological requirements and prey availability. Variations in dietary profiles reflect contrasting environmental conditions affecting local prey availability.
Collapse
Affiliation(s)
- Vladislav Marcuk
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26, 35392, Giessen, Germany.
| | - Alberto Piña-Ortiz
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26, 35392, Giessen, Germany.
| | - José Alfredo Castillo-Guerrero
- Departamento de Estudios para el Desarrollo Sustentable de la Zona Costera, Centro Universitario de la Costa Sur, Universidad de Guadalajara, Gómez Farías 82, San Patricio-Melaque, Municipio de Cihuatlán, Jalisco, C.P. 48980, Mexico.
| | - Juan F Masello
- Department of Animal Behaviour, Bielefeld University, Germany; Department of Biological Sciences, University of Venda, Private Bag X5050, Thohoyandou, 0950, South Africa.
| | - Paco Bustamante
- LIttoral, Environnement et Societés (LIENSs), UMR 7266 CNRS - La Rochelle Université, 17000, La Rochelle, France.
| | - Sven Griep
- Institute for Bioinformatics and Systems Biology, Justus Liebig University Giessen, Heinrich-Buff-Ring 58, D-35392, Giessen, Germany.
| | - Petra Quillfeldt
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26, 35392, Giessen, Germany.
| |
Collapse
|
7
|
Medo A, Ohte N, Doi H, Kamdee K, Koba K, Arai N, Mitsunaga Y, Kume M, Kojima D, Nose T, Yokoyama A, Viputhanumas T, Mitamura H. Trophic niche partitioning and intraspecific variation in food resource use in the genus Pangasianodon in a reservoir revealed by stable isotope analysis of multiple tissues. JOURNAL OF FISH BIOLOGY 2024. [PMID: 38880940 DOI: 10.1111/jfb.15842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/20/2024] [Accepted: 05/28/2024] [Indexed: 06/18/2024]
Abstract
Understanding the mechanism by which non-native fish species integrate into native communities is crucial for evaluating the possibility of their establishment success. The genus Pangasianodon, comprising Pangasianodon gigas and Pangasianodon hypophthalmus, has been introduced into reservoirs, which are non-native habitats, for fishery stock enhancement. P. gigas and P. hypophthalmus often successfully establish and co-occur in several Thai reservoirs, but there is little information on differences in food resource use between the two species. To investigate the trophic niche width of P. gigas and P. hypophthalmus in a Thai reservoir, we conducted stable carbon and nitrogen ratio (δ13C and δ15N) analyses. We examined the degree of individual specialization in both species using the δ13C and δ15N values of muscle and liver tissues, which provides long- and short-term diet information. The isotopic niches did not overlap between P. gigas and P. hypophthalmus. The δ15N value of P. gigas was significantly higher than that of P. hypophthalmus, whereas the δ13C value did not significantly differ between the two species. The isotopic niche sizes were larger in P. hypophthalmus than in P. gigas. Individual specialization was observed in P. hypophthalmus but not in P. gigas, indicating that intraspecific variation in food resource use was larger in P. hypophthalmus compared to P. gigas. These findings suggest that trophic niche partitioning was one of the factors facilitating the establishment success of P. gigas and P. hypophthalmus in a reservoir, but the establishment process may differ between the two species.
Collapse
Affiliation(s)
- Ayano Medo
- Graduate School of Informatics, Kyoto University, Kyoto, Japan
- Center for Ecological Research, Kyoto University, Otsu, Japan
| | - Nobuhito Ohte
- Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | - Hideyuki Doi
- Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | | | - Keisuke Koba
- Center for Ecological Research, Kyoto University, Otsu, Japan
| | - Nobuaki Arai
- Field Science Education and Research Center, Kyoto University, Kyoto, Japan
| | | | - Manabu Kume
- Field Science Education and Research Center, Kyoto University, Kyoto, Japan
| | - Daichi Kojima
- Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | - Takashi Nose
- Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | - Ayako Yokoyama
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Thavee Viputhanumas
- Inland Aquaculture Research and Development Division, Department of Fisheries, Bangkok, Thailand
| | - Hiromichi Mitamura
- Field Science Education and Research Center, Kyoto University, Kyoto, Japan
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| |
Collapse
|
8
|
Zhang C, Lin Y, Xue Q, Mo X, He M, Liu J. Nitrogen supply neutralizes the nanoplastic-plant interaction in a coastal wetland. ENVIRONMENTAL RESEARCH 2024; 251:118572. [PMID: 38437902 DOI: 10.1016/j.envres.2024.118572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/25/2024] [Accepted: 02/26/2024] [Indexed: 03/06/2024]
Abstract
The presence of nanoplastics posed a potential threat to coastal saline-alkaline wetlands where nitrogen (N) fertilizer is being implemented as an important ecological restoration measure. Notwithstanding, the effects of N inputs on plant community in polypropylene-nanoplastics (PP-NPs) coexistence environments are largely unknown. To address this, we investigated the effects of PP-NPs addition alone or combined N supply on community aboveground biomass, morphological traits, diversity, composition, niche differentiation, interspecific interactions, and assembly. Our results showed that the PP-NPs addition alone reduced community aboveground biomass and morphological traits. However, the addition of high concentration (0.5%) PP-NPs alone favored community α-diversity and reduced community stability, which could be weakened through combined N supply. Overall, the effect of PP-NPs addition alone on plant community composition was greater than that of combined N supply. We also demonstrated PP-NPs addition alone and combined N supply reduced the niche breadth of the plant community and affected the niche overlap of dominant species. In the assembly of plant communities, stochastic processes played a dominant role. We conclude that N fertilization can amend the terrestrial nanoplastics pollution, thus mitigating the effects of PP-NPs on the plant community.
Collapse
Affiliation(s)
- Chunping Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Center for Grassland Microbiome, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China
| | - Yingchao Lin
- Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, National & Local Joint Engineering Research Center on Biomass Resource Utilization, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Qing Xue
- School of Geographic and Environmental Science, Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin, 300387, China
| | - Xunqiang Mo
- School of Geographic and Environmental Science, Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin, 300387, China
| | - Mengxuan He
- School of Geographic and Environmental Science, Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin, 300387, China.
| | - Jie Liu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Center for Grassland Microbiome, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China; Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, National & Local Joint Engineering Research Center on Biomass Resource Utilization, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China.
| |
Collapse
|
9
|
Borkowski A. The Relationships between the Population Density of Fir Bark Beetles and Niche Breadth. INSECTS 2024; 15:422. [PMID: 38921137 PMCID: PMC11204340 DOI: 10.3390/insects15060422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 05/29/2024] [Accepted: 05/31/2024] [Indexed: 06/27/2024]
Abstract
Bark beetles are a significant link in the chain of diseases that lead to the accelerated dying of firs (Abies alba Mill.), a key species in the cultivation of stable mixed-tree stands. The aim of this work was to evaluate biotic interactions in populations of bark beetles that colonised natural traps made from firs. The tested hypothesis was that the niche breadth of the species increases with the increasing density of the population. The research was carried out in near-natural forests containing fir, growing in the Suchedniów-Oblęgorek Landscape Park in central Poland. Data were collected from 30 traps trees and 30 windfalls in the years 2010-2023. Cryphalus piceae Ratz. prefers heavily weakened trees, as shown by the fact that it colonised all of the natural traps, which lack any defensive reactions. The sampling method used in the study proved effective, as confirmed by the segregation of the niches of all of the bark beetles. Using nonlinear regression (linearisable model and piecewise linear regression), models were constructed that describe the niche breadths of the bark beetles. The niche parameter is correlated with the density of colonisation. The derived models explain around 77-84% of the variation in the niche breadth of bark beetles on natural traps. The mean relative errors of estimation do not exceed 20%. The niche breadth parameter obtained from the derived regression equations may be used in models that describe-for example-the impact of observed climate change on the population dynamics of bark beetles.
Collapse
Affiliation(s)
- Andrzej Borkowski
- Department of Environmental Biology, Institute of Biology, Jan Kochanowski University, Uniwersytecka 7 Str, 25-406 Kielce, Poland
| |
Collapse
|
10
|
Abrham M, Norén K, Bartolomé Filella J, Angerbjörn A, Lecomte N, Pečnerová P, Freire S, Dalerum F. Properties of vertebrate predator-prey networks in the high Arctic. Ecol Evol 2024; 14:e11470. [PMID: 38826159 PMCID: PMC11137350 DOI: 10.1002/ece3.11470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 04/17/2024] [Accepted: 05/10/2024] [Indexed: 06/04/2024] Open
Abstract
Predation is an important ecological process that can significantly impact the maintenance of ecosystem services. In arctic environments, the relative ecological importance of predation is thought to be increasing due to climate change, partly because of increased productivity with rising temperatures. Therefore, understanding predator-prey interactions in arctic ecosystems is vital for the sustainable management of these northern regions. Network theory provides a framework for quantifying the structures of ecological interactions. In this study, we use dietary observations on mammalian and avian predators in a high arctic region, including isolated peninsulas on Ellesmere Island and north Greenland, to construct bipartite trophic networks. We quantify the complexity, specialization, and nested as well as modular structures of these networks and also determine if these properties varied among the peninsulas. Mammal prey remains were the dominant diet item for all predators, but there was spatial variation in diet composition among peninsulas. The predator-prey networks were less complex, had more specialized interactions, and were more nested and more modular than random expectations. However, the networks displayed only moderate levels of modularity. Predator species had less specialized interactions with prey than prey had with predators. All network properties differed among the peninsulas, which highlights that ecosystems often show complex responses to environmental characteristics. We suggest that gaining knowledge about spatial variation in the characteristics of predator-prey interactions can enhance our ability to manage ecosystems exposed to environmental perturbations, particularly in high arctic environments subject to rapid environmental change.
Collapse
Affiliation(s)
- Muzit Abrham
- Department of ZoologyStockholm UniversityStockholmSweden
| | - Karin Norén
- Department of ZoologyStockholm UniversityStockholmSweden
| | | | | | - Nicolas Lecomte
- Department of BiologyUniversity of MonctonMonctonNew BrunswickCanada
| | | | - Susana Freire
- Biodiversity Research InstituteCSIC‐Univ. Oviedo‐PrincMieresSpain
- Biodiversity Research InstituteMieresSpain
| | - Fredrik Dalerum
- Department of ZoologyStockholm UniversityStockholmSweden
- Biodiversity Research InstituteCSIC‐Univ. Oviedo‐PrincMieresSpain
- Biodiversity Research InstituteMieresSpain
- Mammal Research Institute, Department of Zoology and EntomologyUniversity of PretoriaPretoriaSouth Africa
| |
Collapse
|
11
|
Barros HKS, Barbosa TAP, Prudente BDS. Feeding ecology of Moenkhausia collettii (Steindachner, 1882) (Characiformes: Characidae) in streams in the eastern Amazon: Environmental factors and body size. JOURNAL OF FISH BIOLOGY 2024; 104:2008-2021. [PMID: 38561933 DOI: 10.1111/jfb.15743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 03/12/2024] [Accepted: 03/17/2024] [Indexed: 04/04/2024]
Abstract
The present study aimed to characterize the diet of Moenkhausia collettii and investigate possible changes due to environmental variations and its body size in streams in the eastern Amazon. The specimens were sampled monthly between April 2019 and March 2020. They were measured for standard length (SL) and total mass (Tm) and eviscerated for analysis of stomach contents. Food items were identified and grouped into categories. Dietary aspects such as food importance index (AI%), trophic niche width, and stomach repletion index (SRI%) were evaluated. Furthermore, generalized linear models (GLMs) were used to evaluate the relation between diet and the SL, as well as between diet and the environmental variables of streams. A total of 355 specimens with SL ranging from 11.06 to 46.03 mm and weight ranging from 0.020 to 2.373 g were evaluated. Out of the 355 stomachs analysed, 88 contained material in an advanced stage of decomposition and 12 were empty. The diet of M. collettii was considered omnivorous, with a tendency toward insectivory. Formicidae was the most important category in the diet of the species, followed by immature Diptera and plant material. The GLMs showed a relationship between the diet and a set of environmental variables such as dissolved oxygen, conductivity, flow, width, depth, wood, leaf bank, and SL. The trophic niche width and feeding intensity increased with the length of the species, as well as in the period of higher precipitation, reinforcing trophic opportunism for M. collettii. Therefore, new studies that combine the traditional method of stomach content analysis, the use of stable isotopes, as well as ecomorphological attributes, are crucial for a profound understanding of the trophic ecology of the ichthyofauna in the face of natural changes occurring in their environment.
Collapse
|
12
|
Bastos RF, Condini MV, Barbosa EF, Oliveira RL, Almeida LL, Garcia AM, Hostim-Silva M. Seeing further into the early steps of the endangered atlantic goliath grouper (Epinephelus itajara): Eye lenses high resolution isotopic profiles reveal ontogenetic trophic and habitat shifts. MARINE ENVIRONMENTAL RESEARCH 2024; 198:106517. [PMID: 38657369 DOI: 10.1016/j.marenvres.2024.106517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/12/2024] [Accepted: 04/15/2024] [Indexed: 04/26/2024]
Abstract
Estuarine mangroves are often considered nurseries for the Atlantic Goliath grouper juveniles. Yet, the contributions of different estuarine primary producers and habitats as sources of organic matter during early ontogenetic development remain unclear. Given the species' critically endangered status and protection in Brazil, obtaining biological samples from recently settled recruits in estuaries is challenging. In this study, we leveraged a local partnership with fishers and used stable isotope (C and N) profiles from the eye lenses of stranded individuals or incidentally caught by fishery to reconstruct the trophic and habitat changes of small juveniles. The eye lens grows by the apposition of protein-rich layers. Once these layers are formed, they become inert, allowing to make inferences on the trophic ecology and habitat use along the development of the individual until its capture. We used correlations between fish size and the entire eye lens size, along with estuarine baselines, to reconstruct the fish size and trophic positions for each of the lens layers obtained. We then used dominant primary producers and basal sources from mangrove sheltered, exposed estuarine and marine habitats to construct an ontogenetic model of trophic and habitat support changes since maternal origins. Our model revealed marine support before the juveniles reached 25 mm (standard length), followed by a rapid increase in reliance on mangrove sheltered sources, coinciding with the expected size at settlement. After reaching 60 mm, individuals began to show variability. Some remained primarily supported by the mangrove sheltered area, while others shifted to rely more on the exposed estuarine area around 150 mm. Our findings indicate that while mangroves are critical for settlement, as Goliath grouper juveniles grow, they can utilize organic matter produced throughout the estuary. This underscores the need for conservation strategies that focus on seascape connectivity, as protecting just one discrete habitat may not be sufficient to preserve this endangered species and safeguard its ecosystem functions.
Collapse
Affiliation(s)
- Rodrigo F Bastos
- Laboratório de Ecologia de Peixes Marinhos/LEPMAR, Departamento de Ciências Agrárias e Biológicas, CEUNES, Universidade Federal do Espírito Santo, BR-101, Km 60, Litorâneo, São Mateus, ES, 29932-540, Brazil; Programa de Pós-graduação Em Oceanografia Ambiental, Universidade Federal Do Espírito Santo - Av. Fernando Ferrari, 514 - Goiabeiras, Vitória, ES, 29075-910, Brazil.
| | - Mario V Condini
- Laboratório de Ecologia de Peixes Marinhos/LEPMAR, Departamento de Ciências Agrárias e Biológicas, CEUNES, Universidade Federal do Espírito Santo, BR-101, Km 60, Litorâneo, São Mateus, ES, 29932-540, Brazil; Programa de Pós-graduação Em Oceanografia Ambiental, Universidade Federal Do Espírito Santo - Av. Fernando Ferrari, 514 - Goiabeiras, Vitória, ES, 29075-910, Brazil
| | - Ester F Barbosa
- Laboratório de Ecologia de Peixes Marinhos/LEPMAR, Departamento de Ciências Agrárias e Biológicas, CEUNES, Universidade Federal do Espírito Santo, BR-101, Km 60, Litorâneo, São Mateus, ES, 29932-540, Brazil
| | - Rafael L Oliveira
- Laboratório de Ecologia de Peixes Marinhos/LEPMAR, Departamento de Ciências Agrárias e Biológicas, CEUNES, Universidade Federal do Espírito Santo, BR-101, Km 60, Litorâneo, São Mateus, ES, 29932-540, Brazil; Programa de Pós-Graduação Em Ciências Biológicas (Biologia Animal - PPGBAN), Departamento de Ciências Biológicas, Universidade Federal Do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, CEP: 29055-460, Vitória, ES, Brazil
| | - Lorena L Almeida
- Laboratório de Ecologia de Peixes Marinhos/LEPMAR, Departamento de Ciências Agrárias e Biológicas, CEUNES, Universidade Federal do Espírito Santo, BR-101, Km 60, Litorâneo, São Mateus, ES, 29932-540, Brazil; Instituto Meros Do Brasil, Rua Benjamin Constant 67, Conj. 1104, CEP: 80060-020, Curitiba, PR, Brazil
| | - Alexandre M Garcia
- Laboratório de Ictiologia, Instituto de Oceanografia, Universidade Federal Do Rio Grande, Av. Itália Km 8, Carreiros. 96.201-900, Rio Grande, RS, Brazil
| | - Maurício Hostim-Silva
- Laboratório de Ecologia de Peixes Marinhos/LEPMAR, Departamento de Ciências Agrárias e Biológicas, CEUNES, Universidade Federal do Espírito Santo, BR-101, Km 60, Litorâneo, São Mateus, ES, 29932-540, Brazil; Programa de Pós-graduação Em Oceanografia Ambiental, Universidade Federal Do Espírito Santo - Av. Fernando Ferrari, 514 - Goiabeiras, Vitória, ES, 29075-910, Brazil; Programa de Pós-Graduação Em Ciências Biológicas (Biologia Animal - PPGBAN), Departamento de Ciências Biológicas, Universidade Federal Do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, CEP: 29055-460, Vitória, ES, Brazil; Instituto Meros Do Brasil, Rua Benjamin Constant 67, Conj. 1104, CEP: 80060-020, Curitiba, PR, Brazil
| |
Collapse
|
13
|
Costa-Pereira R, Shaner PJL. The spatiotemporal context of individual specialization in resource use and environmental associations. J Anim Ecol 2024. [PMID: 38706400 DOI: 10.1111/1365-2656.14090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/14/2024] [Indexed: 05/07/2024]
Abstract
1. Individual niche specialization is widespread in natural populations and has key implications for higher levels of biological organization. This phenomenon, however, has been primarily quantified in resource niche axes, overlooking individual variation in environmental associations (i.e. abiotic conditions organisms experience). 2. Here, we explore what we can learn from a multidimensional perspective of individual niche specialization that integrates resource use and environmental associations into a common framework. 3. By combining predictions from theory and simple simulations, we illustrate how (i) multidimensional intraspecific niche variation and (ii) the spatiotemporal context of interactions between conspecifics scale up to shape emergent patterns of the population niche. 4. Contemplating individual specialization as a multidimensional, unifying concept across biotic and abiotic niche axes is a fundamental step towards bringing this concept closer to the n-dimensional niche envisioned by Hutchinson.
Collapse
Affiliation(s)
- Raul Costa-Pereira
- Department of Animal Biology, Institute of Biology, Universidade Estadual de Campinas (Unicamp), Campinas, Brazil
| | - Pei-Jen Lee Shaner
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
- Department of Natural Resources and Environmental Studies, National Dong Hwa University, Hualien, Taiwan
| |
Collapse
|
14
|
Pereira JM, Ramos JA, Ceia FR, Krüger L, Marques AM, Paiva VH. Boldness predicts foraging behaviour, habitat use and chick growth in a central place marine predator. Oecologia 2024; 205:135-147. [PMID: 38739168 PMCID: PMC11144154 DOI: 10.1007/s00442-024-05557-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 04/17/2024] [Indexed: 05/14/2024]
Abstract
Animal personality can shape individual's fitness. Yet, the mechanistic relationship by which individual's personality traits lead to variations in fitness remains largely underexplored. Here, we used novel object tests to measure boldness of chick-provisioning Cory's shearwaters (Calonectris borealis) from a coastal colony off west Portugal, and deployed GPS loggers to study their at-sea behaviour and distribution. We then tested whether boldness predicts individual differences in adult's trophic ecology and variations in chick growth, to assess potential implications of personality-specific foraging behaviours. Foraging effort was higher for shyer than for bolder individuals, which, during short forays, exhibited larger foraging ranges, and foraged in regions of higher and more variable bathymetry. This suggests that nearby the colony bolder individuals expanded their foraging area to maximize resource acquisition and increase the probability of foraging success. When endeavouring to longer distances, bolder individuals exhibited comparably shorter foraging ranges and targeted low bathymetry regions, likely with enhanced prey availability, while shyer individuals exhibited much larger foraging ranges indicating greater flexibility when foraging in oceanic realms. Despite such differences between bolder and shyer individuals their isotopic niches were similar. Yet, chicks raised by bolder parents grew at a faster rate than those raised by shyer parents. Together, our results suggest that differences in resource acquisition strategies could play a key role through which individual's boldness may influence breeding performance, even when individuals have similar isotopic preferences.
Collapse
Affiliation(s)
- Jorge M Pereira
- Department of Life Sciences, University of Coimbra, MARE - Marine and Environmental Sciences Centre / ARNET - Aquatic Research Network, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.
| | - Jaime A Ramos
- Department of Life Sciences, University of Coimbra, MARE - Marine and Environmental Sciences Centre / ARNET - Aquatic Research Network, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Filipe R Ceia
- Department of Life Sciences, University of Coimbra, MARE - Marine and Environmental Sciences Centre / ARNET - Aquatic Research Network, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Lucas Krüger
- Instituto Antártico Chileno, Plaza Muñoz Gamero 1055, 620 000, Punta Arenas, Chile
- Instituto Milenio Biodiversidad de Ecosistemas Antárticos y Subantárticos (BASE), Las Palmeras 3425, Ñuñoa, Santiago, Chile
| | - Ana M Marques
- Department of Life Sciences, University of Coimbra, MARE - Marine and Environmental Sciences Centre / ARNET - Aquatic Research Network, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Vitor H Paiva
- Department of Life Sciences, University of Coimbra, MARE - Marine and Environmental Sciences Centre / ARNET - Aquatic Research Network, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| |
Collapse
|
15
|
Salton M, Raoult V, Jonsen I, Harcourt R. Niche partitioning and individual specialisation in resources and space use of sympatric fur seals at their range margin. Oecologia 2024; 204:815-832. [PMID: 38568471 PMCID: PMC11062968 DOI: 10.1007/s00442-024-05537-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 03/03/2024] [Indexed: 05/02/2024]
Abstract
Ecological theory predicts niche partitioning between high-level predators living in sympatry as a mechanism to minimise the selective pressure of competition. Accordingly, male Australian fur seals Arctocephalus pusillus doriferus and New Zealand fur seals A. forsteri that live in sympatry should exhibit partitioning in their broad niches (in habitat and trophic dimensions) in order to coexist. However, at the northern end of their distributions in Australia, both are recolonising their historic range after a long absence due to over-exploitation, and their small population sizes suggest competition should be weak and may allow overlap in niche space. We found some niche overlap, yet clear partitioning in diet trophic level (δ15N values from vibrissae), spatial niche space (horizontal and vertical telemetry data) and circadian activity patterns (timing of dives) between males of each species, suggesting competition may remain an active driver of niche partitioning amongst individuals even in small, peripheral populations. Consistent with individual specialisation theory, broad niches of populations were associated with high levels of individual specialisation for both species, despite putative low competition. Specialists in isotopic space were not necessarily specialists in spatial niche space, further emphasising their diverse individual strategies for niche partitioning. Males of each species displayed distinct foraging modes, with Australian fur seals primarily benthic and New Zealand fur seals primarily epipelagic, though unexpectedly high individual specialisation for New Zealand fur seals might suggest marginal populations provide exceptions to the pattern generally observed amongst other fur seals.
Collapse
Affiliation(s)
- Marcus Salton
- School of Natural Sciences, Macquarie University, North Ryde, NSW, 2109, Australia.
- Australian Antarctic Division, Department of Climate Change, Energy, the Environment and Water, Kingston, TAS, 7050, Australia.
| | - Vincent Raoult
- School of Natural Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
- School of Environmental and Life Sciences, University of Newcastle, Ourimbah, 2258, Australia
| | - Ian Jonsen
- School of Natural Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Robert Harcourt
- School of Natural Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| |
Collapse
|
16
|
Gangoso L, Viana DS, Merchán M, Figuerola J. A new trophic specialization buffers a top predator against climate-driven resource instability. Behav Ecol 2024; 35:arae005. [PMID: 38287939 PMCID: PMC10824164 DOI: 10.1093/beheco/arae005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/22/2023] [Accepted: 01/15/2024] [Indexed: 01/31/2024] Open
Abstract
Intraspecific phenotypic variability is key to respond to environmental changes and anomalies. However, documenting the emergence of behavioral diversification in natural populations has remained elusive due to the difficulty of observing such a phenomenon at the right time and place. Here, we investigated how the emergence of a new trophic strategy in a population subjected to high fluctuations in the availability of its main trophic resource (migrating songbirds) affected the breeding performance, population structure, and population fitness of a specialized color polymorphic predator, the Eleonora's falcon from the Canary Islands. Using long-term data (2007-2022), we found that the exploitation of an alternative prey (a local petrel species) was associated with the growth of a previously residual falcon colony. Pairs in this colony laid earlier and raised more fledglings than in the other established colonies. The specialization on petrels increased over time, independently of annual fluctuations in prey availability. Importantly, however, the positive effect of petrel consumption on productivity was stronger in years with lower food availability. This trophic diversification was further associated with the genetically determined color morph, with dark individuals preying more frequently on petrels than pale ones, which might promote the long-term maintenance of genotypic and phenotypic diversity. We empirically demonstrate how the emergence of an alternative trophic strategy can buffer populations against harsh environmental fluctuations by stabilizing their productivity.
Collapse
Affiliation(s)
- Laura Gangoso
- Department of Biodiversity, Ecology and Evolution, Faculty of Biological Sciences, Complutense University of Madrid, C/Antonio Novais 12, 28040, Madrid, Spain
| | - Duarte S Viana
- Estación Biológica de Doñana, CSIC, C/Américo Vespucio 26, 41092, Sevilla, Spain
| | - Marina Merchán
- Estación Biológica de Doñana, CSIC, C/Américo Vespucio 26, 41092, Sevilla, Spain
| | - Jordi Figuerola
- Estación Biológica de Doñana, CSIC, C/Américo Vespucio 26, 41092, Sevilla, Spain
| |
Collapse
|
17
|
Härer A, Rennison DJ. Gut Microbiota Uniqueness Is Associated with Lake Size, a Proxy for Diet Diversity, in Stickleback Fish. Am Nat 2024; 203:284-291. [PMID: 38306277 DOI: 10.1086/727703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
AbstractOrganismal divergence can be driven by differential resource use and adaptation to different trophic niches. Variation in diet is a major factor shaping the gut microbiota, which is crucial for many aspects of their hosts' biology. However, it remains largely unknown how host diet diversity affects the gut microbiota, and it could be hypothesized that trophic niche width is positively associated with gut microbiota diversity. To test this idea, we sequenced the 16S ribosomal RNA gene from intestinal tissue of 14 threespine stickleback populations from lakes of varying size on Vancouver Island, Canada, that have been shown to differ in trophic niche width. Using lake size as a proxy for trophic ecology, we found evidence for higher gut microbiota uniqueness among individuals from populations with broader trophic niches. While these results suggest that diet diversity might promote gut microbiota diversity, additional work investigating diet and gut microbiota variation of the same host organisms will be necessary. Yet our results motivate the question of how host population diversity (e.g., ecological, morphological, genetic) might interact with the gut microbiota during the adaptation to ecological niches.
Collapse
|
18
|
Ebersole A, Bunker ME, Weiss SL, Fox-Dobbs K. Inter- and intrapopulation resource use variation of marine subsidized western fence lizards. Oecologia 2024; 204:1-11. [PMID: 38244058 PMCID: PMC10830707 DOI: 10.1007/s00442-023-05496-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 12/04/2023] [Indexed: 01/22/2024]
Abstract
Marine resource subsidies alter consumer dynamics of recipient populations in coastal systems. The response to these subsidies by generalist consumers is often not uniform, creating inter- and intrapopulation diet variation and niche diversification that may be intensified across heterogeneous landscapes. We sampled western fence lizards, Sceloporus occidentalis, from Puget Sound beaches and coastal and inland forest habitats, in addition to the lizards' marine and terrestrial prey items to quantify marine and terrestrial resource use with stable isotope analysis and mixing models. Beach lizards had higher average δ13C and δ15N values compared to coastal and inland forest lizards, exhibiting a strong mixing line between marine and terrestrial prey items. Across five beach sites, lizard populations received 20-51% of their diet from marine resources, on average, with individual lizards ranging between 7 and 86% marine diet. The hillslope of the transition zone between marine and terrestrial environments at beach sites was positively associated with marine-based diets, as the steepest sloped beach sites had the highest percent marine diets. Within-beach variation in transition zone slope was positively correlated with the isotopic niche space of beach lizard populations. These results demonstrate that physiography of transitional landscapes can mediate resource flow between environments, and variable habitat topography promotes niche diversification within lizard populations. Marine resource subsidization of Puget Sound beach S. occidentalis populations may facilitate occupation of the northwesternmost edge of the species range. Shoreline restoration and driftwood beach habitat conservation are important to support the unique ecology of Puget Sound S. occidentalis.
Collapse
Affiliation(s)
- Alexi Ebersole
- Department of Biology, University of Puget Sound, Tacoma, WA, 98416, USA.
| | - Marie E Bunker
- Department of Biology, University of Puget Sound, Tacoma, WA, 98416, USA
| | - Stacey L Weiss
- Department of Biology, University of Puget Sound, Tacoma, WA, 98416, USA
| | - Kena Fox-Dobbs
- Department of Geology, University of Puget Sound, Tacoma, WA, 98416, USA
| |
Collapse
|
19
|
Lubich C, Aguiar-Santos J, Corrêa F, Freitas CEC, Siqueira-Souza FK. Trophic ecology of Acestrorhynchus falcirostris Cuvier, 1819 in island lakes on the lower stretch of the Solimões River, Amazon Basin. BRAZ J BIOL 2024; 84:e253852. [DOI: 10.1590/1519-6984.253852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/18/2021] [Indexed: 11/22/2022] Open
Abstract
Abstract The aim objective of this study was to determine the trophic ecology of juvenile and adult Acestrorhynchus falcirostris during the rising and flood (high-water) period in six island lakes adjacent to the Solimões River. As such, we investigated: i) the trophic position, through the fractional trophic niche; ii) the niche breadth; iii) niche overlap and iv) the food strategy of the species. The specimens were collected during the years 2014 to 2017, using gillnets with mesh sizes ranging from 30 to 120mm between opposite knots. Through the analysis of stomach contents, the preference in the consumption of items of animal origin was observed. Juveniles consumed insects in greater proportions (IAi% = 50%), while adults consumed fish (IAi%=99,98%). Despite the large supply of food items available in the high-water period, juveniles were the only ones to consume items of allochthonous origin, such as insects. Juveniles presented a different dietary strategy and dietary composition to adults. Juveniles were omnivores with a generalist strategy, while adults were piscivores with a specialist strategy. Thus, the food composition, niche breadth, trophic position and feeding strategy of Acestrorhynchus falcirostris change due to the stage of development.
Collapse
Affiliation(s)
- C. Lubich
- Universidade Federal do Amazonas, Brasil
| | | | - F. Corrêa
- Universidade do Estado de Mato Grosso, Brasil
| | | | | |
Collapse
|
20
|
Rivas-Salvador J, Reif J. Species-specific traits affect bird species' susceptibility to global change. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2023; 110:54. [PMID: 37957333 DOI: 10.1007/s00114-023-01883-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/15/2023]
Abstract
The current ecological crisis has risen extinction rates to similar levels of ancient mass extinctions. However, it seems to not be acting uniformly across all species but affecting species differentially. This suggests that species' susceptibility to the extinction process is mediated by specific traits. Since understanding this response mechanism at large scales will benefit conservation effort around the world, we used the IUCN global threat status and population trends of 8281 extant bird species as proxies of the extinction risk to identify the species-specific traits affecting their susceptibility to extinction within the biogeographic regions and at the global scale. Using linear mixed effect models and multinomial models, we related the global threat status and the population trends with the following traits: migratory strategy, habitat and diet specialization, body size, and generation length. According to our results and independently of the proxy used, more vulnerable species are sedentary and have larger body size, longer generation time, and higher degree of habitat specialization. These relationships apply globally and show little variation across biogeographic regions. We suggest that such concordant patterns might be caused either by a widespread occurrence of the same threats such as habitat modification or by a uniform capacity of some traits to reflect the impact of different local threats. Regardless of the cause of this pattern, our study identified the traits that affect species' response capability to the current ecological crisis. Conservation effort should focus on the species with trait values indicating the limited response capacity to overcome this crisis.
Collapse
Affiliation(s)
- Javier Rivas-Salvador
- Institute of Environmental Studies, Faculty of Science, Charles University, Prague, Czech Republic.
- PECBMS Group, Czech Society for Ornithology, Prague, Czech Republic.
| | - Jiři Reif
- Institute of Environmental Studies, Faculty of Science, Charles University, Prague, Czech Republic
- Department of Zoology, Faculty of Science, Palacky University, Olomouc, Czech Republic
| |
Collapse
|
21
|
Power M, Thorstad EB, Forseth T, Fiske P. Temporal shifts in the marine feeding of individual Atlantic salmon inferred from scale isotope ratios. Ecol Evol 2023; 13:e10656. [PMID: 37920771 PMCID: PMC10618632 DOI: 10.1002/ece3.10656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 07/10/2023] [Accepted: 09/27/2023] [Indexed: 11/04/2023] Open
Abstract
Given the limited information on prey use during the marine residency period for Atlantic salmon, scales were collected from salmon at return to the River Namsen (Norway) for spawning after 1 year at sea, and scale material from the first and second summer marine feeding periods was analysed using stable isotope methods to understand dynamics of their trophic ecology. As the salmon increased in size from the first to second summer, they reduced their feeding niche and specialised more (narrowed the δ13C range) and increased their dependency on higher tropic level (δ15N) prey, likely fish. Changes in δ13C indicated a consistent pattern of movement towards the north and west between summer feeding periods. Hence, salmon during their first year at sea may have a migration route roughly resembling that of previous spawners, as inferred from earlier tagging studies. Feeding conditions and nutrient composition during the last summer at sea, i.e. in the months before returning to the river for spawning, impacted final body size and within-season timing of return. Fish undergoing the largest trophic niche shift (δ13C and δ15N combined) between summer feeding periods, returned earliest. The earliest returning fish had the fastest specific growth rates at sea. Hence, salmon encountering abundant high-quality fish food during the marine migration, particularly during the last months, may reach a size and energetic state whereby it is better to return early to a safer environment in freshwater than risk being eaten by a big predator at sea. Both trophic status (δ15N), resource use (δ13C) and growth rates were significantly correlated between feeding periods. Nutrient composition during the first summer at sea did not impact the fish body length after the following winter, but growth conditions during the first summer evidenced carry-over effects from the first to the second summer of feeding.
Collapse
Affiliation(s)
- Michael Power
- Department of BiologyUniversity of WaterlooWaterlooOntarioCanada
| | - Eva B. Thorstad
- Aquatic Ecology DepartmentNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Torbjørn Forseth
- Aquatic Ecology DepartmentNorwegian Institute for Nature Research (NINA)TrondheimNorway
| | - Peder Fiske
- Aquatic Ecology DepartmentNorwegian Institute for Nature Research (NINA)TrondheimNorway
| |
Collapse
|
22
|
Prigent I, Mullon C. The molding of intraspecific trait variation by selection under ecological inheritance. Evolution 2023; 77:2144-2161. [PMID: 37459126 DOI: 10.1093/evolut/qpad124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 05/04/2023] [Accepted: 05/29/2023] [Indexed: 10/05/2023]
Abstract
Organisms continuously modify their environment, often impacting the fitness of future conspecifics due to ecological inheritance. When this inheritance is biased toward kin, selection favors modifications that increase the fitness of downstream individuals. How such selection shapes trait variation within populations remains poorly understood. Using mathematical modelling, we investigate the coevolution of multiple traits in a group-structured population when these traits affect the group environment, which is then bequeathed to future generations. We examine when such coevolution favors polymorphism as well as the resulting associations among traits. We find in particular that two traits become associated when one trait affects the environment while the other influences the likelihood that future kin experience this environment. To illustrate this, we model the coevolution of (a) the attack rate on a local renewable resource, which deteriorates environmental conditions, with (b) dispersal between groups, which reduces the likelihood that kin suffers from such deterioration. We show this often leads to the emergence of two highly differentiated morphs: one that readily disperses and depletes local resources, and another that maintains these resources and tends to remain philopatric. More broadly, we suggest that ecological inheritance can contribute to phenotypic diversity and lead to complex polymorphism.
Collapse
Affiliation(s)
- Iris Prigent
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - Charles Mullon
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| |
Collapse
|
23
|
Mason C, Hobday AJ, Lea M, Alderman R. Individual consistency in the localised foraging behaviour of shy albatross ( Thalassarche cauta). Ecol Evol 2023; 13:e10644. [PMID: 37881226 PMCID: PMC10594074 DOI: 10.1002/ece3.10644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/28/2023] [Accepted: 10/09/2023] [Indexed: 10/27/2023] Open
Abstract
Quantifying the intra- and interindividual variation that exists within a population can provide meaningful insights into a population's vulnerability and response to rapid environmental change. We characterise the foraging behaviour of 308 trips taken by 96 shy albatross (Thalassarche cauta) from Albatross Island across seven consecutive years. At a population level, incubating shy albatross exploited a consistent area within ca. 500 km radius of their breeding colony. During half of the trips, individuals utilised the closest shelf break to the west of the colony, where upwelling events have been reported. The other half of the trips were exclusively within the neritic zone, utilising a variety of locations within the Bass Strait. Furthermore, we found evidence of individual consistency to geographic locations, with subsequent trips by an individual more similar than random trips from all individuals in our data, both within and between years (G-test, p < .05). Between-individual variation in foraging behaviour was not meaningfully explained by age (linear regression, p > .05) or sex (t-test, p > .05) for any metric, suggesting that other intrinsic individual factors are accounting for between-individual variation in foraging trips. A localised foraging distribution is unusual for albatross, which, combined with high variation in space use between individuals demonstrated here, suggests that this species is accessing adequate resources near the colony. Overall, these findings suggest that incubating shy albatross from Albatross Island exhibit tendencies of a generalist population comprised of uniquely specialised individuals. These results suggest that this species is operating below its biological capacity in this fast-warming area and provide a baseline from which to assess future change.
Collapse
Affiliation(s)
- Claire Mason
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaBattery PointTasmaniaAustralia
- CSIRO EnvironmentBattery PointTasmaniaAustralia
| | | | - Mary‐Anne Lea
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaBattery PointTasmaniaAustralia
| | - Rachael Alderman
- Department of Natural Resources and EnvironmentTasmanian GovernmentTasmaniaHobartAustralia
| |
Collapse
|
24
|
Dubois F. Skill trade-offs promote persistent individual differences and specialized tactics. Ecol Evol 2023; 13:e10578. [PMID: 37809359 PMCID: PMC10550786 DOI: 10.1002/ece3.10578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 10/10/2023] Open
Abstract
Individuals generally differ in their ability to perform challenging behaviours, but the causes of such variability remain incompletely understood. Because animals can usually use different behavioural tactics to achieve their goals, we might expect individual differences in skill to be maintained when the available tactics require different abilities to perform well. To explore this idea, I used the producer-scrounger (PS) paradigm, which considers interactions between foragers that may either invest effort in searching for resources (i.e. produce) or exploit others' discoveries (i.e. scrounge). Specifically, I tested whether individual differences in cognitive traits (i.e. the ability to find food) might result from a trade-off with competitiveness (i.e. the ability to steal food) that would exert disruptive selection pressure and, as such, might explain the coexistence of condition-dependent foraging tactics. If individuals differ in their competitiveness, with strong contestants being better able to monopolize food resources (and hence to scrounge), the model predicts that strong and weak competitors should rely more on scrounging and producing, respectively, especially when the finder's advantage is low. These findings indicate that the existence of individual differences in competitive abilities may be sufficient to explain short-term individual foraging tactic specialization. Yet, the degree of behavioural specialization is expected to depend on both the social and ecological context. Furthermore, persistent phenotypic differences, that are necessary for stable individual specialization, require the existence of a trade-off between competitive abilities that enable greater success as scroungers and cognitive abilities that are associated with better efficiency to detect and/or capture prey and, as such, enable greater success as producers. Therefore, this study further highlights the importance of considering the existence of alternative tactics to measure and predict the evolution of traits, including cognitive traits, within populations.
Collapse
Affiliation(s)
- Frédérique Dubois
- Département de Sciences BiologiquesUniversité de MontréalMontrealQuebecCanada
| |
Collapse
|
25
|
Badger JJ, Bowen WD, den Heyer CE, Breed GA. Individual Quality Drives Life History Variation in a Long-Lived Marine Predator. Am Nat 2023; 202:351-367. [PMID: 37606942 DOI: 10.1086/725451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
AbstractIndividual quality and environmental conditions may mask or interact with energetic trade-offs in life history evolution. Deconstructing these sources of variation is especially difficult in long-lived species that are rarely observed on timescales long enough to disentangle these effects. Here, we investigated relative support for variation in female quality and costs of reproduction as factors shaping differences in life history trajectories using a 32-year dataset of repeated reproductive measurements from 273 marked, known-age female gray seals (Halichoerus grypus). We defined individual reproductive investment using two traits, reproductive frequency (a female's probability of breeding) and provisioning performance (offspring weaning mass). Fitted hierarchical Bayesian models identified individual investment relative to conspecifics (over a female's entire life and in three age classes) and subsequently estimated how these investment metrics and the Atlantic Multidecadal Oscillation are associated with longevity. Individual differences (i.e., quality) contributed a large portion of the variance in reproductive traits. Females that consistently invest well in their offspring relative to other females survive longer. The best-supported model estimated survival as a function of age class-specific provisioning performance, where late-life performance was particularly variable and had the greatest impact on survival, possibly indicating individual variation in senescence. There was no evidence to support a trade-off in reproductive performance and survival at the individual level. Overall, these results suggest that in gray seals, individual quality is a stronger driver in life history variation than individual strategies resulting from energetic trade-offs.
Collapse
|
26
|
Rosenblatt AE, Greco R, Beal E, Colbert J, Moore Y, Baglin V, Nifong JC. Golf course living leads to a diet shift for American alligators. Ecol Evol 2023; 13:e10495. [PMID: 37664492 PMCID: PMC10468965 DOI: 10.1002/ece3.10495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/31/2023] [Accepted: 08/11/2023] [Indexed: 09/05/2023] Open
Abstract
Human-driven land use change can fundamentally alter ecological communities, especially the diversity and abundance of large-bodied predators. Yet, despite the important roles large-bodied predators play in structuring communities through feeding, there have been only a few investigations of how the feeding patterns of large-bodied predators change in human-dominated landscapes. One group of large-bodied predators that has been largely overlooked in the context of land use change is the crocodilians. To help fill these gaps, we studied the feeding patterns of juvenile American alligators (Alligator mississippiensis) on neighboring barrier islands on the southeast coast of Georgia, USA. Jekyll Island has multiple golf courses and substantial amounts of human activity, while Sapelo Island does not have any golf courses and a much smaller amount of human activity. We found that juvenile alligator populations on both islands ate the same types of prey but in vastly different quantities. Sapelo Island alligators primarily consumed crustaceans while alligators that lived on Jekyll Island's golf courses ate mostly insects/arachnids. Furthermore, the Jekyll Island alligators exhibited a much more generalist feeding pattern (individuals mostly ate the same types of prey in the same quantities) than the more specialized Sapelo Island alligators (diets were more varied across individuals). The most likely explanation for our results is that alligators living on golf courses have different habitat use patterns and have access to different prey communities relative to alligators in more natural habitats. Thus, land use change can strongly alter the feeding patterns of large-bodied predators and, as a result, may affect their body condition, exposure to human-made chemicals, and role within ecological communities.
Collapse
Affiliation(s)
| | - Robert Greco
- University of North FloridaJacksonvilleFloridaUSA
| | - Eli Beal
- University of North FloridaJacksonvilleFloridaUSA
| | | | - Yank Moore
- Jekyll Island AuthorityJekyll IslandGeorgiaUSA
| | | | | |
Collapse
|
27
|
Iozia LM, Varone L. Tackling local ecological homogeneity: Finding intraspecific trait variability in local populations of Mediterranean plants. Ecol Evol 2023; 13:e10550. [PMID: 37732284 PMCID: PMC10507572 DOI: 10.1002/ece3.10550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 07/26/2023] [Accepted: 08/31/2023] [Indexed: 09/22/2023] Open
Abstract
Local homogeneity, in ecology, is the often undisclosed assumption that variability within populations is negligible or mostly distributed evenly. In large areas, this can lead to the aggregation of different populations without regard for their unique needs and characteristics, such as drought sensitivity and functional trait distributions. Here, we discuss whether this assumption can be justified, and we hypothesize that discerning the source of variation between plasticity and adaptation could be a feasible approach to formulate an informed decision. We test this hypothesis on plants, resorting to a common garden experiment to determine the source of variation of several plant functional traits at a local scale (~60 km) of three wild species: Quercus ilex, Pistacia lentiscus, and Cistus salviifolius. Individuals of each species were sourced from three key sites chosen along a local aridity gradient. Our approach led to the rejection of the local homogeneity assumption for Q. ilex and C. salviifolius at this scale due to the adaptive divergence observed among neighboring populations. This case study provides evidence that addressing local homogeneity can highlight diverging populations in a relatively simple way. We conclude that gathering empirical evidence on intraspecific variability is a feasible approach that can provide researchers with solid bases to decide whether to adopt the local homogeneity assumption or not.
Collapse
Affiliation(s)
| | - Laura Varone
- Department of Environmental BiologySapienza University of RomeRomeItaly
| |
Collapse
|
28
|
Pereira AC, Nardoto GB, Colli GR. Sources of intraspecific variation in the isotopic niche of a semi-aquatic predator in a human-modified landscape. PeerJ 2023; 11:e15915. [PMID: 37663285 PMCID: PMC10474837 DOI: 10.7717/peerj.15915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 07/26/2023] [Indexed: 09/05/2023] Open
Abstract
Intraspecific variation modulates patterns of resource use by species, potentially affecting the structure and stability of food webs. In human-modified landscapes, habitat disturbance modifies trophic interactions and intraspecific niche variation, impacting population persistence. Here, we investigated the relationship of sex, ontogeny, and habitat factors with the trophic niche of Caiman crocodilus in an agricultural landscape. We evaluated temporal variation in the trophic niche parameters using carbon and nitrogen stable isotope analysis from different body tissues. We found that caimans exploit the same carbon and nitrogen pools through time, with low isotopic variability between seasons, partly due to the slow isotope turnover rates of tissues in crocodilians. Conversely, the trophic niche of caimans varied across habitats, but with no evidence of a difference between natural and anthropogenic habitats. It apparently results from the influence of habitat suitability, connectivity, and caiman movements during the foraging. Our findings highlight the broader niches of juvenile caimans relative to adults, possibly in response of territorialism and opportunistic foraging strategy. Although using similar resources, females had a larger niche than males, probably associated with foraging strategies during nesting. Considering the sex and body size categories, caimans occupied distinct isotopic regions in some habitats, indicating apparent niche segregation. Ontogenetic trophic shifts in the isotopes (δ13C and δ15N) depended on sex, leading to resource partitioning that can potentially reduce intraspecific competition. Decision-makers and stakeholders should consider the trophic dynamics of sex and body size groups for the sustainable management and conservation of caiman populations, which implies in the maintenance of wetland habitats and landscape heterogeneity in the Formoso River floodplain.
Collapse
Affiliation(s)
- André Costa Pereira
- Departamento de Zoologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasilia, Distrito Federal, Brazil
- Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasilia, Distrito Federal, Brazil
| | - Gabriela Bielefeld Nardoto
- Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasilia, Distrito Federal, Brazil
| | - Guarino Rinaldi Colli
- Departamento de Zoologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasilia, Distrito Federal, Brazil
| |
Collapse
|
29
|
Vejřík L, Vejříková I, Blabolil P, Sajdlová Z, Kočvara L, Kolařík T, Bartoň D, Jůza T, Šmejkal M, Peterka J, Čech M. Trophic Position of the Species and Site Trophic State Affect Diet Niche and Individual Specialization: From Apex Predator to Herbivore. BIOLOGY 2023; 12:1113. [PMID: 37626997 PMCID: PMC10452534 DOI: 10.3390/biology12081113] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 07/31/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023]
Abstract
Intra-species variability in isotopic niches, specifically isotopic total niche width (ITNW), isotopic individual niche width (IINW), and isotopic individual specialization (IIS), was studied using an innovative approach without sacrificing the vertebrates. Stable isotopes (δ13C, δ15N) in four body tissues differing in isotopic half-life were analyzed from four freshwater fish species representing different trophic positions. ITNW was widest for the apex predator (European catfish) and narrowest for the obligate predator (Northern pike). IINW exhibited a polynomial trend for the European catfish, Northern pike, and Eurasian perch (mesopredator), decreasing with body mass and increasing again after exceeding a certain species-dependent body mass threshold. Thus, for ectotherms, apex predator status is linked rather to its size than to the species. In herbivores (rudd), IINW increased with body mass. The IIS of predators negatively correlated with site trophic state. Therefore, eutrophication can significantly change the foraging behavior of certain species. We assume that the observed trends will occur in other species at similar trophic positions in either aquatic or terrestrial systems. For confirmation, we recommend conducting a similar study on other species in different habitats.
Collapse
Affiliation(s)
- Lukáš Vejřík
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| | - Ivana Vejříková
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| | - Petr Blabolil
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
- Faculty of Science, University of South Bohemia in České Budějovice, Branišovská 31, 37005 České Budějovice, Czech Republic
| | - Zuzana Sajdlová
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| | - Luboš Kočvara
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| | - Tomáš Kolařík
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| | - Daniel Bartoň
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| | - Tomáš Jůza
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| | - Marek Šmejkal
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| | - Jiří Peterka
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| | - Martin Čech
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 7, 37005 České Budějovice, Czech Republic; (L.V.); (P.B.); (Z.S.); (L.K.); (T.K.); (D.B.); (T.J.); (M.Š.); (J.P.); (M.Č.)
| |
Collapse
|
30
|
Gill BA, Wittemyer G, Cerling TE, Musili PM, Kartzinel TR. Foraging history of individual elephants using DNA metabarcoding. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230337. [PMID: 37416829 PMCID: PMC10320352 DOI: 10.1098/rsos.230337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 06/07/2023] [Indexed: 07/08/2023]
Abstract
Individual animals should adjust diets according to food availability. We used DNA metabarcoding to construct individual-level dietary timeseries for elephants from two family groups in Kenya varying in habitat use, social position and reproductive status. We detected at least 367 dietary plant taxa, with up to 137 unique plant sequences in one fecal sample. Results matched well-established trends: elephants tended to eat more grass when it rained and other plants when dry. Nested within these switches from 'grazing' to 'browsing' strategies, dietary DNA revealed seasonal shifts in food richness, composition and overlap between individuals. Elephants of both families converged on relatively cohesive diets in dry seasons but varied in their maintenance of cohesion during wet seasons. Dietary cohesion throughout the timeseries of the subdominant 'Artists' family was stronger and more consistently positive compared to the dominant 'Royals' family. The greater degree of individuality within the dominant family's timeseries could reflect more divergent nutritional requirements associated with calf dependency and/or priority access to preferred habitats. Whereas theory predicts that individuals should specialize on different foods under resource scarcity, our data suggest family bonds may promote cohesion and foster the emergence of diverse feeding cultures reflecting links between social behaviour and nutrition.
Collapse
Affiliation(s)
- Brian A. Gill
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA
- Institute at Brown for Environment and Society, Brown University, Providence, RI 02912, USA
| | - George Wittemyer
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA
- Save the Elephants, Nairobi, Kenya
| | - Thure E. Cerling
- Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, USA
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Paul M. Musili
- Botany Department, East African Herbarium, National Museums of Kenya, Nairobi, Kenya
| | - Tyler R. Kartzinel
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA
- Institute at Brown for Environment and Society, Brown University, Providence, RI 02912, USA
| |
Collapse
|
31
|
Fraleigh DC, Archer FI, Williard AS, Hückstädt LA, Fleming AH. Possible niche compression and individual specialization in Pacific Arctic beluga ( Delphinapterus leucas) from the 19th to 20th century. Ecol Evol 2023; 13:e10230. [PMID: 37408623 PMCID: PMC10318618 DOI: 10.1002/ece3.10230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 06/08/2023] [Accepted: 06/14/2023] [Indexed: 07/07/2023] Open
Abstract
Cetaceans have shown a potential to be used as sentinel species for tracking environmental change in marine ecosystems, yet our assessment of change is typically limited to recent decades and lacks ecological baselines. Using historical museum specimens, we compared community niche metrics and degree of individual dietary specialization in groups of Pacific Arctic beluga (Delphinapterus leucas) from the 1800s (n = 5) to 1900s (n = 10) using stable carbon and nitrogen isotopes drilled from teeth. Beluga occupied a broader trophic niche and demonstrated a higher degree of individual specialization in the 1800s than in the 1900s. The cause of this shift is difficult to confirm given long timescales and constraints of specimen-based research but could indicate changes in the prey base or competition. The scale and nature of this detected shift provide perspective for continued research on these climate-vulnerable species.
Collapse
Affiliation(s)
- Devin C. Fraleigh
- Center for Marine ScienceUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
| | - Frederick I. Archer
- Southwest Fisheries Science CenterNational Marine Fisheries Service, National Oceanic and Atmospheric AdministrationLa JollaCaliforniaUSA
| | - Amanda S. Williard
- Department of Biology and Marine BiologyUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
| | - Luis A. Hückstädt
- Department of Biology and Marine BiologyUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
- Centre for Ecology and ConservationUniversity of ExeterCornwallUK
| | - Alyson H. Fleming
- Center for Marine ScienceUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
- Department of Forest & Wildlife EcologyUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
- National Museum of Natural HistorySmithsonian InstitutionWashingtonDistrict of ColumbiaUSA
| |
Collapse
|
32
|
Romero-Vidal P, Luna Á, Fernández-Gómez L, Navarro J, Palma A, Tella JL, Carrete M. Intraspecific competition and individual behaviour but not urbanization affect the dietary patterns of a generalist avian predator. Sci Rep 2023; 13:10255. [PMID: 37355736 PMCID: PMC10290650 DOI: 10.1038/s41598-023-37026-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 06/14/2023] [Indexed: 06/26/2023] Open
Abstract
Urbanization has reshaped ecosystems and changed natural processes, driving an intense transformation of biomes, biotic community composition and diversity. Despite the growing interest in studying urban ecology over the last decades, the consequences of these changes on species occupying these ecosystems are not yet fully understood. Trophic generalism and tolerance to human disturbance have been proposed as two key traits in the colonization of urban environments. However, most studies focused on species' average traits, paying less attention to the potential role of inter-individual variability. Here, we examined diet specialization in urban and rural breeding pairs, as well as its relationship with individual behaviour and intraspecific competition, using the burrowing owl as a study model. Our results show that both urban and rural breeding pairs behaved as trophic specialists. The diet of burrowing owl breeding pairs followed a gradient from coleopteran- to micromammal-dominated, which is related to individual behaviour (bolder individuals consuming more coleopterans than shyer ones). Besides, pairs distant from others showed a more diverse diet than those experiencing higher levels of intraspecific competition. Models fitted separately for each habitat showed that the proportion of micromammals in the diet of urban breeding pairs was related to their behavior, while the diet of rural pairs was not affected by individual behavior but by intraspecific competition. However, despite the strong selection of tame and more explorative individuals in urban environments and the higher density they reach in this habitat type, they did not differ in their degree of diet specialization from rural conspecifics. Although it would be necessary to evaluate prey availability on a small scale, our results suggest that burrowing owl breeding pairs behave as specialists, despite the generalist character of the species, and that this specialization is not affected by the occupation of urban environments but to individual behaviour and intraspecific competition.
Collapse
Affiliation(s)
- Pedro Romero-Vidal
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Seville, Spain.
- Department of Conservation Biology, Estación Biológica de Doñana (CSIC), Seville, Spain.
| | - Álvaro Luna
- Department of Health Sciences, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Madrid, Spain
| | - Lola Fernández-Gómez
- Department of Applied Biology, Centro de Investigación e Innovación Alimentaria (CIAGRO-UMH), Universidad Miguel Hernández, Elche, Spain
| | - Joan Navarro
- Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain
| | - Antonio Palma
- Department of Conservation Biology, Estación Biológica de Doñana (CSIC), Seville, Spain
| | - José L Tella
- Department of Conservation Biology, Estación Biológica de Doñana (CSIC), Seville, Spain
| | - Martina Carrete
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Seville, Spain
| |
Collapse
|
33
|
Wang Z, Gong L, Huang Z, Geng Y, Zhang W, Si M, Wu H, Feng J, Jiang T. Linking changes in individual specialization and population niche of space use across seasons in the great evening bat (Ia io). MOVEMENT ECOLOGY 2023; 11:32. [PMID: 37287053 DOI: 10.1186/s40462-023-00394-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/16/2023] [Indexed: 06/09/2023]
Abstract
BACKGROUND The niche breadth of an animal population comprises both within-individual and between-individual variation (individual specialization). Both components can be used to explain changes in population niche breadth, and this has been extensively investigated in dietary niche dimension studies. However, little is known about how changes in food resources or environmental factors across seasons affect changes in individual and population space use within the same population. METHODS In this study, we used micro-GPS loggers to capture the space use of individuals and of a population of the great evening bat (Ia io) in summer and autumn. We used I. io as a model to investigate how individual spatial niche breadth and spatial individual specialization affect changes in population niche breadth (home range and core area sizes) across seasons. Additionally, we explored the drivers of individual spatial specialization. RESULTS We found that the population home range and the core area of I. io did not increase in autumn when insect resources were reduced. Moreover, I. io showed different specialization strategies in the two seasons: higher spatial individual specialization in summer and lower individual specialization but broader individual niche breadth in autumn. This trade-off may maintain the dynamic stability of the population spatial niche breadth across seasons and facilitate the population response to changes in food resources and environmental factors. CONCLUSIONS Like diet, spatial niche breadth of a population also may be determined by a combination of individual niche breadth and individual specialization. Our work provides new insights into the evolution of niche breadth from the spatial dimension.
Collapse
Affiliation(s)
- Zhiqiang Wang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Lixin Gong
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Zhenglanyi Huang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Yang Geng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Wenjun Zhang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Man Si
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Hui Wu
- College of Life Science, Jilin Agricultural University, 2888 Xincheng Street, Changchun, 130118, China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.
- College of Life Science, Jilin Agricultural University, 2888 Xincheng Street, Changchun, 130118, China.
| | - Tinglei Jiang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.
| |
Collapse
|
34
|
Arrondo E, Sebastián-González E, Moleón M, Morales-Reyes Z, María Gil-Sánchez J, Cortés-Avizanda A, Ceballos O, Donázar JA, Sánchez-Zapata JA. Vulture culture: dietary specialization of an obligate scavenger. Proc Biol Sci 2023; 290:20221951. [PMID: 37132232 PMCID: PMC10154924 DOI: 10.1098/rspb.2022.1951] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 04/06/2023] [Indexed: 05/04/2023] Open
Abstract
Individual dietary variation has important ecological and evolutionary consequences. However, it has been overlooked in many taxa that are thought to have homogeneous diets. This is the case of vultures, considered merely as 'carrion eaters'. Given their high degree of sociality, vultures are an excellent model to investigate how inter-individual transmissible behaviours drive individual dietary variation. Here, we combine GPS-tracking and accelerometers with an exhaustive fieldwork campaign to identify the individual diet of 55 griffon vultures (Gyps fulvus) from two Spanish populations that partially overlap in their foraging areas. We found that individuals from the more humanized population consumed more anthropic resources (e.g. stabled livestock or rubbish), resulting in more homogeneous diets. By contrast, individuals from the wilder population consumed more wild ungulates, increasing their dietary variability. Between sexes, we found that males consumed anthropic resources more than females did. Interestingly, in the shared foraging area, vultures retained the dietary preference of their original population, highlighting a strong cultural component. Overall, these results expand the role of cultural traits in shaping key behaviours and call for the need of including cultural traits in Optimal Foraging models, especially in those species that strongly rely on social information while foraging.
Collapse
Affiliation(s)
- Eneko Arrondo
- Centro de Investigación e Innovación Agroalimentaria y Agroambiental (CIAGRO-UMH), Miguel Hernández University, Elche 03312, Spain
- Department of Conservation Biology, Estación Biológica de Doñana (CSIC), Cartuja TA-10, Edificio I, C. Américo Vespucio, s/n, 41092 Sevilla, Spain
- Department of Zoology, University of Granada, Granada 18003, Spain
| | | | - Marcos Moleón
- Department of Zoology, University of Granada, Granada 18003, Spain
| | - Zebensui Morales-Reyes
- Instituto de Estudios Sociales Avanzados (IESA), CSIC, Campo Santo de los Mártires, 7, 14004 Córdoba, Spain
| | | | - Ainara Cortés-Avizanda
- Department of Conservation Biology, Estación Biológica de Doñana (CSIC), Cartuja TA-10, Edificio I, C. Américo Vespucio, s/n, 41092 Sevilla, Spain
- Department of Plant Biology and Ecology, Faculty of Biology, University of Seville, Avda. Reina Mercedes s/n, 41012, Seville, Spain
| | | | - José Antonio Donázar
- Department of Conservation Biology, Estación Biológica de Doñana (CSIC), Cartuja TA-10, Edificio I, C. Américo Vespucio, s/n, 41092 Sevilla, Spain
| | - José Antonio Sánchez-Zapata
- Centro de Investigación e Innovación Agroalimentaria y Agroambiental (CIAGRO-UMH), Miguel Hernández University, Elche 03312, Spain
| |
Collapse
|
35
|
Hämäläinen R, Kajanus MH, Forsman JT, Kivelä SM, Seppänen JT, Loukola OJ. Ecological and evolutionary consequences of selective interspecific information use. Ecol Lett 2023; 26:490-503. [PMID: 36849224 DOI: 10.1111/ele.14184] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 02/02/2023] [Accepted: 02/04/2023] [Indexed: 03/01/2023]
Abstract
Recent work has shown that animals frequently use social information from individuals of their own species as well as from other species; however, the ecological and evolutionary consequences of this social information use remain poorly understood. Additionally, information users may be selective in their social information use, deciding from whom and how to use information, but this has been overlooked in an interspecific context. In particular, the intentional decision to reject a behaviour observed via social information has received less attention, although recent work has indicated its presence in various taxa. Based on existing literature, we explore in which circumstances selective interspecific information use may lead to different ecological and coevolutionary outcomes between two species, such as explaining observed co-occurrences of putative competitors. The initial ecological differences and the balance between the costs of competition and the benefits of social information use potentially determine whether selection may lead to trait divergence, convergence or coevolutionary arms race between two species. We propose that selective social information use, including adoption and rejection of behaviours, may have far-reaching fitness consequences, potentially leading to community-level eco-evolutionary outcomes. We argue that these consequences of selective interspecific information use may be much more widespread than has thus far been considered.
Collapse
Affiliation(s)
| | - Mira H Kajanus
- Ecology and Genetics, University of Oulu, Oulu, Finland
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | | | - Sami M Kivelä
- Ecology and Genetics, University of Oulu, Oulu, Finland
| | | | | |
Collapse
|
36
|
Wickman J, Koffel T, Klausmeier CA. A Theoretical Framework for Trait-Based Eco-Evolutionary Dynamics: Population Structure, Intraspecific Variation, and Community Assembly. Am Nat 2023; 201:501-522. [PMID: 36958005 DOI: 10.1086/723406] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
AbstractHow is trait diversity in a community apportioned between and within coevolving species? Disruptive selection may result in either a few species with large intraspecific trait variation (ITV) or many species with different mean traits but little ITV. Similar questions arise in spatially structured communities: heterogeneous environments could result in either a few species that exhibit local adaptation or many species with different mean traits but little local adaptation. To date, theory has been well-equipped to either include ITV or to dynamically determine the number of coexisting species, but not both. Here, we devise a theoretical framework that combines these facets and apply it to the above questions of how trait variation is apportioned within and between species in unstructured and structured populations, using two simple models of Lotka-Volterra competition. For unstructured communities, we find that as the breadth of the resource spectrum increases, ITV goes from being unimportant to crucial for characterizing the community. For spatially structured communities on two patches, we find no local adaptation, symmetric local adaptation, or asymmetric local adaptation, depending on how much the patches differ. Our framework provides a general approach to incorporate ITV in models of eco-evolutionary community assembly.
Collapse
|
37
|
Reidy R, Gauthier S, Doniol-Valcroze T, Lemay MA, Clemente-Carvalho RBG, Cowen LLE, Juanes F. Integrating technologies provides insight into the subsurface foraging behaviour of a humpback whale (Megaptera novaeangliae) feeding on walleye pollock (Gadus chalcogrammus) in Juan de Fuca Strait, Canada. PLoS One 2023; 18:e0282651. [PMID: 36877706 PMCID: PMC9987809 DOI: 10.1371/journal.pone.0282651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 02/19/2023] [Indexed: 03/07/2023] Open
Abstract
Subsurface foraging is an important proportion of the activity budget of rorqual whales, yet information on their behaviour underwater remains challenging to obtain. Rorquals are assumed to feed throughout the water column and to select prey as a function of depth, availability and density, but there remain limitations in the precise identification of targeted prey. Current data on rorqual foraging in western Canadian waters have thus been limited to observations of prey species amenable to surface feeding, such as euphausiids and Pacific herring (Clupea pallasii), with no information on deeper alternative prey sources. We measured the foraging behaviour of a humpback whale (Megaptera novaeangliae) in Juan de Fuca Strait, British Columbia, using three complimentary methods: whale-borne tag data, acoustic prey mapping, and fecal sub-sampling. Acoustically detected prey layers were near the seafloor and consistent with dense schools of walleye pollock (Gadus chalcogrammus) distributed above more diffuse aggregations of pollock. Analysis of a fecal sample from the tagged whale confirmed that it had been feeding on pollock. Integrating the dive profile with the prey data revealed that the whale's foraging effort followed the general pattern of areal prey density, wherein the whale had a higher lunge-feeding rate at the highest prey abundance and stopped feeding when prey became limited. Our findings of a humpback whale feeding on seasonally energy-dense fish like walleye pollock, which are potentially abundant in British Columbia, suggests that pollock may be an important prey source for this rapidly growing whale population. This result is informative when assessing regional fishing activities for semi-pelagic species as well as the whales' vulnerability to fishing gear entanglements and feeding disturbances during a narrow window of prey acquisition.
Collapse
Affiliation(s)
- Rhonda Reidy
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Stéphane Gauthier
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
- Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia, Canada
| | - Thomas Doniol-Valcroze
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Matthew A. Lemay
- Hakai Institute Genomics Laboratory, Quadra Island, British Columbia, Canada
| | | | - Laura L. E. Cowen
- Department of Mathematics and Statistics, University of Victoria, Victoria, British Columbia, Canada
| | - Francis Juanes
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| |
Collapse
|
38
|
Stallings CD, Nelson JA, Peebles EB, Ellis G, Goddard EA, Jue NK, Mickle A, Tzadik OE, Koenig CC. Trophic ontogeny of a generalist predator is conserved across space. Oecologia 2023; 201:721-732. [PMID: 36843229 DOI: 10.1007/s00442-023-05337-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 02/12/2023] [Indexed: 02/28/2023]
Abstract
Consumers can influence ecological patterns and processes through their trophic roles and contributions to the flow of energy through ecosystems. However, the diet and associated trophic roles of consumers commonly change during ontogeny. Despite the prevalence of ontogenetic variation in trophic roles of most animals, we lack an understanding of whether they change consistently across local populations and broad geographic gradients. We examined how the diet and trophic position of a generalist marine predator varied with ontogeny across seven broadly separated locations (~ 750 km). We observed a high degree of heterogeneity in prey consumed without evidence of spatial structuring in this variability. However, compound-specific isotope analysis of amino acids revealed remarkably consistent patterns of increasing trophic position through ontogeny across local populations, suggesting that the roles of this generalist predator scaled with its body size across space. Given the high degree of diet heterogeneity we observed, this finding suggests that even though the dietary patterns differed, the underlying food web architecture transcended variation in prey species across locations for this generalist consumer. Our research addresses a gap in empirical field work regarding the interplay between stage-structured populations and food webs, and suggests ontogenetic changes in trophic position can be consistent in generalist consumers.
Collapse
Affiliation(s)
| | - James A Nelson
- Department of Biology, University of Louisiana Lafayette, Lafayette, LA, USA
| | - Ernst B Peebles
- College of Marine Science, University of South Florida, St. Petersburg, FL, USA
| | - Gregory Ellis
- College of Marine Science, University of South Florida, St. Petersburg, FL, USA
- Johns Hopkins All Children's Hospital, St Petersburg, FL, USA
| | - Ethan A Goddard
- College of Marine Science, University of South Florida, St. Petersburg, FL, USA
| | - Nathaniel K Jue
- Department of Biology and Chemistry, California State University, Monterey Bay, Seaside, CA, USA
| | - Alejandra Mickle
- Department of Biology, Florida State University, Tallahassee, FL, USA
- Office of Habitat Conservation-Restoration Center, NOAA Fisheries, Silver Spring, MD, USA
| | - Orian E Tzadik
- College of Marine Science, University of South Florida, St. Petersburg, FL, USA
| | | |
Collapse
|
39
|
Valenzuela-Toro AM, Mehta R, Pyenson ND, Costa DP, Koch PL. Feeding morphology and body size shape resource partitioning in an eared seal community. Biol Lett 2023; 19:20220534. [PMID: 36883314 PMCID: PMC9993223 DOI: 10.1098/rsbl.2022.0534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
Body size and feeding morphology influence how animals partition themselves within communities. We tested the relationships among sex, body size, skull morphology and foraging in sympatric otariids (eared seals) from the eastern North Pacific Ocean, the most diverse otariid community in the world. We recorded skull measurements and stable carbon (δ13C) and nitrogen (δ15N) isotope values (proxies for foraging) from museum specimens in four sympatric species: California sea lions (Zalophus californianus), Steller sea lions (Eumetopias jubatus), northern fur seals (Callorhinus ursinus) and Guadalupe fur seals (Arctocephalus townsendi). Species and sexes had statistical differences in size, skull morphology and foraging significantly affecting the δ13C values. Sea lions had higher δ13C values than fur seals, and males of all species had higher values than females. The δ15N values were correlated with species and feeding morphology; individuals with stronger bite forces had higher δ15N values. We also found a significant community-wide correlation between skull length (indicator of body length), and foraging, with larger individuals having nearshore habitat preferences, and consuming higher trophic level prey than smaller individuals. Still, there was no consistent association between these traits at the intraspecific level, indicating that other factors might account for foraging variability.
Collapse
Affiliation(s)
- Ana M Valenzuela-Toro
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA.,Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
| | - Rita Mehta
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Nicholas D Pyenson
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA.,Department of Paleontology and Geology, Burke Museum of Natural History and Culture, Seattle, WA 98105, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA.,Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Paul L Koch
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| |
Collapse
|
40
|
Emer C, Memmott J. Intraspecific variation of invaded pollination networks – the role of pollen-transport, pollen-transfer and different levels of biological organization. Perspect Ecol Conserv 2023. [DOI: 10.1016/j.pecon.2023.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
|
41
|
Gong L, Gu H, Chang Y, Wang Z, Shi B, Lin A, Wu H, Feng J, Jiang T. Seasonal variation of population and individual dietary niche in the avivorous bat, Ia io. Oecologia 2023; 201:733-747. [PMID: 36929223 DOI: 10.1007/s00442-023-05346-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 02/28/2023] [Indexed: 03/18/2023]
Abstract
The variation in niche breadth can affect how species respond to environmental and resource changes. However, there is still no clear understanding of how seasonal variability in food resources impacts the variation of individual dietary diversity, thereby affecting the dynamics of a population's dietary niche breadth. Optimal foraging theory (OFT) and the niche variation hypothesis (NVH) predict that when food resources are limited, the population niche breadth will widen or narrow due to increased within-individual dietary diversity and individual specialization or reduced within-individual dietary diversity, respectively. Here, we used DNA metabarcoding to examine the composition and seasonality of diets of the avivorous bat Ia io. Furthermore, we investigated how the dietary niches changed among seasons and how the population niche breadth changed when the availability of insect resources was reduced in autumn. We found that there was differentiation in dietary niches among seasons and a low degree of overlap, and the decrease of insect resource availability and the emergence of ecological opportunities of nocturnal migratory birds might drive dietary niche shifts toward birds in I. io. However, the population's dietary niche breadth did not broaden by increasing the within-individual dietary diversity or individual specialization, but rather became narrower by reducing dietary diversity via predation on bird resources that served as an ecological opportunity when insect resources were scarce in autumn. Our findings were consistent with the predictions of OFT, because birds as prey for bats provided extremely different resources from those of insects in size and nutritional value. Our work highlights the importance of size and quality of prey resources along with other factors (i.e., physiological, behavioral, and life-history traits) in dietary niche variation.
Collapse
Affiliation(s)
- Lixin Gong
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Hao Gu
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Yang Chang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Zhiqiang Wang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Biye Shi
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Aiqing Lin
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China
| | - Hui Wu
- College of Life Science, Jilin Agricultural University, 2888 Xincheng Street, Changchun, 130118, China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.
- College of Life Science, Jilin Agricultural University, 2888 Xincheng Street, Changchun, 130118, China.
| | - Tinglei Jiang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.
- Key Laboratory of Vegetation Ecology of Education Ministry, Institute of Grassland Science, Northeast Normal University, 2555 Jingyue Street, Changchun, 130117, China.
| |
Collapse
|
42
|
Mureb LS, Rocha-Santos L, Cassano CR, da Silva Lopes G, Rosa B, Miranda FR, Miranda CRR, Giné GAF. Tree diversity mediates individual diet specialization of the maned sloth (Bradypus torquatus). Mamm Biol 2023. [DOI: 10.1007/s42991-023-00348-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
|
43
|
Botha JA, Trueman CN, Kirkman SP, Arnould JPY, Lombard AT, Connan M, Hofmeyr GJG, Seakamela SM, Pistorius PA. Geographical, temporal, and individual-based differences in the trophic ecology of female Cape fur seals. Ecol Evol 2023; 13:e9790. [PMID: 36789339 PMCID: PMC9909003 DOI: 10.1002/ece3.9790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 02/11/2023] Open
Abstract
Information on resource use and trophic dynamics of marine predators is important for understanding their role in ecosystem functioning and predicting population-level responses to environmental change. Where separate populations experience different local environmental conditions, geographic variability in their foraging ecology is often expected. Within populations, individuals also vary in morphology, physiology, and experience, resulting in specialization in resource use. In this context, isotopic compositions of incrementally grown tissues such as keratinous hairs offer a valuable opportunity to study long-term variation in resource and habitat use. We investigated the trophic ecology of female Cape fur seals (Arctocephalus pusillus pusillus) using carbon and nitrogen isotopic compositions of serially sampled whiskers collected at four breeding sites along the coast of South Africa. Drawing on over 900 isotopic measurements, we assessed geographic variability in isotopic niche width between colonies and the degree of individual specialization. We found slight, but clear geographic differences in isotopic ratios and isotopic niche widths, seemingly related to ecological setting, with niche widths being proportional to the area of available shelf and shelf-slope habitat surrounding the colony. We further identified periodic oscillations in isotopic ratios, which likely reflect temporal patterns in foraging distribution and prey type, linked to shifts in the availability of prey resources and their interaction with constraints on individual females throughout their breeding cycle. Finally, individual specialization indices revealed that each of the study populations contain specialist individuals that utilize only a small subset of the total population niche width. The degree of individual specialization was, however, not consistent across colonies and may reflect an interactive influence between density-dependent effects and habitat heterogeneity. Overall, this study provides important information on the trophic ecology of Cape fur seals breeding in South Africa and highlights the need to consider geographic and individual variability when assessing the foraging ecology of marine predators.
Collapse
Affiliation(s)
- Jonathan A. Botha
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - Clive N. Trueman
- Ocean and Earth Science, SouthamptonUniversity of SouthamptonSouthamptonUK
| | - Stephen P. Kirkman
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
- Oceans and Coast Research, Department of ForestryFisheries and the EnvironmentCape TownSouth Africa
| | - John P. Y. Arnould
- Faculty of Science, Engineering and Built EnvironmentDeakin UniversityBurwoodVictoriaAustralia
| | - Amanda T. Lombard
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - Maëlle Connan
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - G. J. Greg Hofmeyr
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
- Port Elizabeth Museum at BayworldGqeberhaSouth Africa
| | - S. Mduduzi Seakamela
- Oceans and Coast Research, Department of ForestryFisheries and the EnvironmentCape TownSouth Africa
| | - Pierre A. Pistorius
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| |
Collapse
|
44
|
Booth CG, Guilpin M, Darias-O’Hara AK, Ransijn JM, Ryder M, Rosen D, Pirotta E, Smout S, McHuron EA, Nabe-Nielsen J, Costa DP. Estimating energetic intake for marine mammal bioenergetic models. CONSERVATION PHYSIOLOGY 2023; 11:coac083. [PMID: 36756464 PMCID: PMC9900471 DOI: 10.1093/conphys/coac083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 11/08/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
Bioenergetics is the study of how animals achieve energetic balance. Energetic balance results from the energetic expenditure of an individual and the energy they extract from their environment. Ingested energy depends on several extrinsic (e.g prey species, nutritional value and composition, prey density and availability) and intrinsic factors (e.g. foraging effort, success at catching prey, digestive processes and associated energy losses, and digestive capacity). While the focus in bioenergetic modelling is often on the energetic costs an animal incurs, the robust estimation of an individual's energy intake is equally critical for producing meaningful predictions. Here, we review the components and processes that affect energy intake from ingested gross energy to biologically useful net energy (NE). The current state of knowledge of each parameter is reviewed, shedding light on research gaps to advance this field. The review highlighted that the foraging behaviour of many marine mammals is relatively well studied via biologging tags, with estimates of success rate typically assumed for most species. However, actual prey capture success rates are often only assumed, although we note studies that provide approaches for its estimation using current techniques. A comprehensive collation of the nutritional content of marine mammal prey species revealed a robust foundation from which prey quality (comprising prey species, size and energy density) can be assessed, though data remain unavailable for many prey species. Empirical information on various energy losses following ingestion of prey was unbalanced among marine mammal species, with considerably more literature available for pinnipeds. An increased understanding and accurate estimate of each of the components that comprise a species NE intake are an integral part of bioenergetics. Such models provide a key tool to investigate the effects of disturbance on marine mammals at an individual and population level and to support effective conservation and management.
Collapse
Affiliation(s)
- Cormac G Booth
- Corresponding author: SMRU Consulting, Scottish Oceans Institute, University of St Andrews, East Sands, St Andrews, KY16 8LB, UK.
| | | | - Aimee-Kate Darias-O’Hara
- SMRU Consulting, Scottish Oceans Institute, University of St Andrews, East Sands, St Andrews, KY16 8LB, UK
| | - Janneke M Ransijn
- Sea Mammal Research Unit, Scottish Oceans Institute, East Sands, University of St. Andrews, St. Andrews, KY16 8LB, UK
| | - Megan Ryder
- SMRU Consulting, Scottish Oceans Institute, University of St Andrews, East Sands, St Andrews, KY16 8LB, UK
| | - Dave Rosen
- Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall,
Vancouver, BC V6T 1Z4, Canada
| | - Enrico Pirotta
- Centre for Research into Ecological and Environmental Modelling,
The Observatory, Buchanan
Gardens, University of St. Andrews, St. Andrews,
KY16 9LZ, UK
| | - Sophie Smout
- Sea Mammal Research Unit, Scottish Oceans Institute, East Sands, University of St. Andrews, St. Andrews, KY16 8LB, UK
| | - Elizabeth A McHuron
- Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, 3737 Brooklyn Ave NE, Seattle, WA, 98105, USA
| | - Jacob Nabe-Nielsen
- Marine Mammal Research, Department of Ecoscience, Aarhus University, Aarhus, DK-4000
Roskilde, Denmark
| | - Daniel P Costa
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, 130
McAlister Way, Santa Cruz, CA, 95064, USA
| |
Collapse
|
45
|
Teixeira CR, Botta S, Cremer MJ, Marcondes MCC, Pereira LB, Newsome SD, Jorge FGD, Simões-Lopes PC. Ecologically driven differences in individual diet specialization across three populations of Guiana dolphin. Oecologia 2023; 201:397-408. [PMID: 36650314 DOI: 10.1007/s00442-022-05312-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/29/2022] [Indexed: 01/19/2023]
Abstract
Populations usually considered foraging generalists may include specialized individuals that feed on a restricted subset of the prey spectrum consumed by the population. By analyzing the time series of δ13C and δ15N values in sequential growth layer groups within tooth dentin, we measured population- and individual-level variation in resource use of three populations of Guiana dolphins (Sotalia guianensis)-Caravelas River, Babitonga Bay, and Norte Bay-along a latitudinal gradient in the southwestern Atlantic Ocean. We show that the Guiana dolphin at Caravelas River is a generalist population consisting of individual dietary specialists, likely due to the absence of other resident dolphin populations thus allowing individuals to target prey across a wide range of habitats. The Babitonga Bay population is also composed of individual specialists potentially due to the selective foraging behavior of some individuals on high-quality prey sources within and near the bay. In contrast, the Norte Bay population comprises individual generalists, which likely reflects its distinctive cohesive social organization, coexistence with two other dolphin species, and an opportunistic foraging strategy in response to resource fluctuations inherent to the southern limit of the species distribution. Although the Guiana dolphin is generally considered to be a dietary generalist at the population level, our findings reveal that the total niche width of populations and the degree of individual diet specialization are highly context dependent, suggesting dietary plasticity that may be related to a latitudinal gradient in resource availability and environmental conditions.
Collapse
Affiliation(s)
- Clarissa R Teixeira
- Laboratório de Mamíferos Aquáticos (LAMAQ), Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil. .,Department of Fisheries, Wildlife, and Conservation Sciences, Marine Mammal Institute, Oregon State University, Newport, OR, USA.
| | - Silvina Botta
- Laboratório de Ecologia e Conservação da Megafauna Marinha (ECOMEGA), Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Brazil
| | - Marta J Cremer
- Laboratório de Ecologia e Conservação de Tetrápodes Marinhos e Costeiros (TetraMar), Unidade São Francisco do Sul, Universidade da Região de Joinville, São Francisco do Sul, Santa Catarina, Brazil
| | | | - Luiza B Pereira
- Laboratório de Mamíferos Aquáticos (LAMAQ), Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Fábio G Daura Jorge
- Laboratório de Mamíferos Aquáticos (LAMAQ), Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Paulo C Simões-Lopes
- Laboratório de Mamíferos Aquáticos (LAMAQ), Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| |
Collapse
|
46
|
Walker RH, Hutchinson MC, Potter AB, Becker JA, Long RA, Pringle RM. Mechanisms of individual variation in large herbivore diets: Roles of spatial heterogeneity and state-dependent foraging. Ecology 2023; 104:e3921. [PMID: 36415899 PMCID: PMC10078531 DOI: 10.1002/ecy.3921] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/24/2022]
Abstract
Many populations of consumers consist of relatively specialized individuals that eat only a subset of the foods consumed by the population at large. Although the ecological significance of individual-level diet variation is recognized, such variation is difficult to document, and its underlying mechanisms are poorly understood. Optimal foraging theory provides a useful framework for predicting how individuals might select different diets, positing that animals balance the "opportunity cost" of stopping to eat an available food item against the cost of searching for something more nutritious; diet composition should be contingent on the distribution of food, and individual foragers should be more selective when they have greater energy reserves to invest in searching for high-quality foods. We tested these predicted mechanisms of individual niche differentiation by quantifying environmental (resource heterogeneity) and organismal (nutritional condition) determinants of diet in a widespread browsing antelope (bushbuck, Tragelaphus sylvaticus) in an African floodplain-savanna ecosystem. We quantified individuals' realized dietary niches (taxonomic richness and composition) using DNA metabarcoding of fecal samples collected repeatedly from 15 GPS-collared animals (range 6-14 samples per individual, median 12). Bushbuck diets were structured by spatial heterogeneity and constrained by individual condition. We observed significant individual-level partitioning of food plants by bushbuck both within and between two adjacent habitat types (floodplain and woodland). Individuals with home ranges that were closer together and/or had similar vegetation structure (measured using LiDAR) ate more similar diets, supporting the prediction that heterogeneous resource distribution promotes individual differentiation. Individuals in good nutritional condition had significantly narrower diets (fewer plant taxa), searched their home ranges more intensively (intensity-of-use index), and had higher-quality diets (percent digestible protein) than those in poor condition, supporting the prediction that animals with greater endogenous reserves have narrower realized niches because they can invest more time in searching for nutritious foods. Our results support predictions from optimal foraging theory about the energetic basis of individual-level dietary variation and provide a potentially generalizable framework for understanding how individuals' realized niche width is governed by animal behavior and physiology in heterogeneous landscapes.
Collapse
Affiliation(s)
- Reena H Walker
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, USA
| | - Matthew C Hutchinson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Arjun B Potter
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Justine A Becker
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| | - Ryan A Long
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, USA
| | - Robert M Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| |
Collapse
|
47
|
Sex-mediated changes in foraging behaviour according to breeding stage in a monomorphic seabird adapted to rural habitats. Anim Behav 2023. [DOI: 10.1016/j.anbehav.2023.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
|
48
|
Cogoni R, Di Gregorio M, Cianferoni F, Lunghi E. Monitoring of the Endangered Cave Salamander Speleomantes sarrabusensis. Animals (Basel) 2023; 13:ani13030391. [PMID: 36766280 PMCID: PMC9913285 DOI: 10.3390/ani13030391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/11/2023] [Accepted: 01/20/2023] [Indexed: 01/27/2023] Open
Abstract
In this study, we performed the first monitoring activities on one of the most endangered amphibians in Europe, the Sette Fratelli cave salamander Speleomantes sarrabusensis. The data presented here are derived from two monitoring activities aiming to assess the status and abundance of four populations of S. sarrabusensis. With the first monitoring, we surveyed the well-known population occurring within artificial springs during the period 2015-2018, providing monthly data on the number of active individuals. With the second monitoring performed during spring to early summer of 2022, we surveyed four populations at three time points (the one from artificial springs and three from forested areas) and we provided the first estimation of the populations' abundance. Furthermore, we analyzed for the first time the stomach contents from a population of S. sarrabusensis only occurring in forested environments. With our study, we provided the first information on the abundance of different populations of S. sarrabusensis, representing the starting point for future status assessments for this endangered species.
Collapse
Affiliation(s)
- Roberto Cogoni
- Unione Speleologica Cagliaritana, Quartu Sant’Elena, 09045 Cagliari, Italy
| | - Milos Di Gregorio
- Dipartimento di Biologia, Università degli Studi di Pisa, 56126 Pisa, Italy
- Correspondence:
| | - Fabio Cianferoni
- Istituto di Ricerca sugli Ecosistemi Terrestri (IRET), Consiglio Nazionale delle Ricerche (CNR), Sesto Fiorentino, 50019 Firenze, Italy
- Museo di Storia Naturale dell’Università degli Studi di Firenze, “La Specola”, 50125 Firenze, Italy
| | - Enrico Lunghi
- Dipartimento di Medicina Clinica, Sanità Pubblica, Scienze Della Vita e dell’ambiente (MeSVA), Universià degli Studi dell’Aquila, 67100 L’Aquila, Italy
- Associazione Natural Oasis, 59100 Prato, Italy
- Unione Speleologica Calenzano, 50041 Calenzano, Italy
| |
Collapse
|
49
|
Horka P, Musilova Z, Holubova K, Jandova K, Kukla J, Rutkayova J, Jones JI. Anthropogenic nutrient loading affects both individual species and the trophic structure of river fish communities. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2022.1076451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Although the concept of trophic interactions has been used for a long time, there are still considerable gaps in our understanding of the effect of various environmental factors on trophic interactions within river fish assemblages. Carbon (δ13C) and nitrogen (δ15N) stable isotope ratios of 20 species of fish belonging to both eurytopic and rheophilic ecological groups from a large temperate rivers were used to evaluate overall trophic niche use and trophic position of species, and to find out how environmental variability associated with nutrient loading affects individual and community-wide aspects of trophic structure. The study was carried out at 11 sites along the European rivers Vltava and Elbe, representing a continuous gradient of pollution and habitat degradation. Corrected Standard Ellipse Area (SEAc) was significantly larger for the group of eurytopic ecological species than for rheophilic species. Despite narrower isotopic niche space, rheophilic fish species occupied a higher trophic position, suggesting that these species use resources more enriched in 15N. Of the 11 environmental variables tested, nutrients had a significant effect on trophic niche area of species (SEAc), indicating that eutrophication is of critical importance for fish assemblages. Isotopic niche area of species was found to be positively influenced by total phosphorus, and negatively affected by concentrations of nitrate (N-NO3−) and ammonia (N-NH4+). A negative association between oxygen demand and a measure of trophic diversity - mean distance to centroid (CD)- and a measure of density and clustering of species - mean nearest neighbor distance (MNND)- were found, indicating that the oxygen demand is a key factor influencing community trophic structure. An observed pattern where nutrient loading influenced both individual species and trophic structure of the fish assemblage provides strong support for an anthropogenic influence on riverine food webs.
Collapse
|
50
|
Berman TS, Inbar M. Molecular identification of individual and seasonal variation in incidental ingestion of arthropods by free-ranging goats. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2022.1070088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The extent of direct interactions between large mammalian herbivores (LMH) and plant-dwelling arthropods (PDA), i.e., the ingestion of PDA by LMH, remains largely unexplored. Grazing LMH may ingest a variety of PDA, yet, it is unknown how different foraging strategies (i.e., browsing, grazing, etc.) influence the ingestion of PDA or whether individual variation within herds affects it. Here we examine how individual variation within a herd of browsing LMH impacts PDA ingestion. This was done using a DNA metabarcoding analysis on feces collected monthly from marked individuals within a herd of free-ranging goats. We found that goats frequently ingest PDA while feeding (all samples contains PDA), including a complex food-chain of herbivores, predators and parasites, which differed over the season and among individual goats. In total, 63 families of insects and 9 families of arachnids from 15 orders were ingested by the goats. Most ingested PDA were herbivores with reduced mobility, such as immature or sessile species. Highly mobile and noxious PDA were rarely detected. We show for the first time that ingestion of PDA by LMH is influenced by seasonal and individual variation within the herd and that it is common among LMH, regardless of feeding strategy or habitat.
Collapse
|