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Oltra J, García J, Carbonell I, Jambas J, Álvarez E, Iglesias‐Lebrija JJ, Gil‐Carrera A, Pérez‐García JM, Frías Ó, González del Barrio JL, Blanco G, Carrete M. Early life movements and mortality of Egyptian vultures: Implications for transcontinental conservation. Ecol Evol 2024; 14:e70291. [PMID: 39279788 PMCID: PMC11402506 DOI: 10.1002/ece3.70291] [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: 06/04/2024] [Revised: 08/06/2024] [Accepted: 08/16/2024] [Indexed: 09/18/2024] Open
Abstract
Understanding the movements and mortality of individuals across different life stages is crucial for the effective conservation of wild populations. We used data from 32 Egyptian vultures (Neophron percnopterus) tagged with GPS transmitters as nestlings in three Iberian breeding areas to study their dependence period, migration routes, movements in Africa, and mortality at each stage. Our results show no significant differences in the timing of nest departure or the duration of the dependence period between individuals of different sexes or breeding nuclei. Most juveniles migrated to sub-Saharan Africa in their first year, but some (3 of 32, 9.4%) remained in the Iberian Peninsula. Individuals that migrated to Africa did so annually, while those remaining in Iberia never migrated to the Sahel, indicating distinct migratory and non-migratory strategies. Non-migratory individuals consistently moved northward during the breeding season to their natal territories. Siblings did not coordinate their migration strategy or timing. All juveniles showed extensive overlap in the vast areas used in Africa, where females arrived before males, and in the Iberian Peninsula. Our study also revealed that no juveniles died immediately after fledging, but that none of the tagged individuals lived more than 7 years or were recruited as breeders. Although most casualties occurred during the longer stay in the Sahel, the mortality rate was highest during the few days of the first migration. Our results show that despite small variations in movement patterns between breeding nuclei and sexes, Egyptian vultures face similar challenges during the years before recruitment as breeders, mostly determined by their migratory strategy. These findings are relevant for designing conservation strategies, both in breeding areas and, more importantly, in wintering areas and along migration pathways. Such strategies will significantly impact the entire Iberian population of this endangered species.
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Affiliation(s)
- Juan Oltra
- Department of Physical, Chemical and Natural SystemsUniversidad Pablo de OlavideSevillaSpain
| | | | | | - José Jambas
- Oriolus Ambiente e Eco Turismo LDAOportoPortugal
| | - Ernesto Álvarez
- Grupo de Rehabilitación de la Fauna Autóctona y su Hábitat (GREFA)MajadahondaSpain
| | | | | | | | - Óscar Frías
- Department of Physical, Chemical and Natural SystemsUniversidad Pablo de OlavideSevillaSpain
| | | | - Guillermo Blanco
- Department of Evolutionary EcologyMuseo Nacional de Ciencias Naturales (CSIC)MadridSpain
| | - Martina Carrete
- Department of Physical, Chemical and Natural SystemsUniversidad Pablo de OlavideSevillaSpain
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Tarabai H, Krejci S, Karyakin I, Bitar I, Literak I, Dolejska M. Clinically relevant antibiotic resistance in Escherichia coli from black kites in southwestern Siberia: a genetic and phenotypic investigation. mSphere 2023; 8:e0009923. [PMID: 37310717 PMCID: PMC10449506 DOI: 10.1128/msphere.00099-23] [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: 02/24/2023] [Accepted: 04/27/2023] [Indexed: 06/14/2023] Open
Abstract
Wild birds including raptors can act as vectors of clinically relevant bacteria with antibiotic resistance. The aim of this study was to investigate the occurrence of antibiotic-resistant Escherichia coli in black kites (Milvus migrans) inhabiting localities in proximity to human-influenced environments in southwestern Siberia and investigate their virulence and plasmid contents. A total of 51 E. coli isolates mostly with multidrug resistance (MDR) profiles were obtained from cloacal swabs of 35 (64%, n = 55) kites. Genomic analyses of 36 whole genome sequenced E. coli isolates showed: (i) high prevalence and diversity of their antibiotic resistance genes (ARGs) and common association with ESBL/AmpC production (27/36, 75%), (ii) carriage of mcr-1 for colistin resistance on IncI2 plasmids in kites residing in proximity of two large cities, (iii) frequent association with class one integrase (IntI1, 22/36, 61%), and (iv) presence of sequence types (STs) linked to avian-pathogenic (APEC) and extra-intestinal pathogenic E. coli (ExPEC). Notably, numerous isolates had significant virulence content. One E. coli with APEC-associated ST354 carried qnrE1 encoding fluoroquinolone resistance on IncHI2-ST3 plasmid, the first detection of such a gene in E. coli from wildlife. Our results implicate black kites in southwestern Siberia as reservoirs for antibiotic-resistant E. coli. It also highlights the existing link between proximity of wildlife to human activities and their carriage of MDR bacteria including pathogenic STs with significant and clinically relevant antibiotic resistance determinants. IMPORTANCE Migratory birds have the potential to acquire and disperse clinically relevant antibiotic-resistant bacteria (ARB) and their associated antibiotic resistance genes (ARGs) through vast geographical regions. The opportunistic feeding behavior associated with some raptors including black kites and the growing anthropogenic influence on their natural habitats increase the transmission risk of multidrug resistance (MDR) and pathogenic bacteria from human and agricultural sources into the environment and wildlife. Thus, monitoring studies investigating antibiotic resistance in raptors may provide essential data that facilitate understanding the fate and evolution of ARB and ARGs in the environment and possible health risks for humans and animals associated with the acquisition of these resistance determinants by wildlife.
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Affiliation(s)
- Hassan Tarabai
- Central European Institute of Technology (CEITEC), University of Veterinary Sciences, Brno, Czech Republic
- Department of Parasitology, Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Simon Krejci
- Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic
| | | | - Ibrahim Bitar
- Biomedical Center, Charles University, Prague, Czech Republic
| | - Ivan Literak
- Central European Institute of Technology (CEITEC), University of Veterinary Sciences, Brno, Czech Republic
- Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic
| | - Monika Dolejska
- Central European Institute of Technology (CEITEC), University of Veterinary Sciences, Brno, Czech Republic
- Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic
- Biomedical Center, Charles University, Prague, Czech Republic
- Department of Clinical Microbiology and Immunology, Institute of Laboratory Medicine, The University Hospital, Brno, Czech Republic
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Cerecedo-Iglesias C, Bartumeus F, Cortés-Avizanda A, Pretus JL, Hernández-Matías A, Real J. Resource predictability modulates spatial-use networks in an endangered scavenger species. MOVEMENT ECOLOGY 2023; 11:22. [PMID: 37081522 PMCID: PMC10120099 DOI: 10.1186/s40462-023-00383-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/03/2023] [Indexed: 05/03/2023]
Abstract
BACKGROUND Changes in human-induced resource availability can alter the behaviour of free-living species and affect their foraging strategies. The future European Landfill Waste Directive and Circular Economy Action Plan will reduce the number of predictable anthropogenic food subsidies (PAFS), above all, by closing landfills to preclude negative effects on human health. Obligate avian scavengers, the most threatened group of birds worldwide, are the most likely group of species that will be forced to change their behaviour and use of space in response to landfill site closures. Here, we examine the possible consequences of these management decisions on the foraging patterns of Egyptian vultures (Neophron percnopterus) in an expanding population in the Iberian Peninsula. METHODS We tracked 16 individuals in 2018-2021, including breeders and non-breeders, and, using a combination of spatial-use and spatial-network modelling, assessed landscape connectivity between key resources based on movement patterns. We then carried out simulations of future scenarios based on the loss of PAFS to predict likely changes in the movement patterns of both non-breeders and breeders. RESULTS Our results show that foraging strategies in non-breeders and breeders differ significantly: non-breeders performed more dispersal movements than breeding birds across a spatial-use network. Non-breeding and breeding networks were found to be vulnerable to the removal of central foraging areas containing landfill sites, a highly predictable resource, while perturbation analysis showed dissimilar foraging responses to the gradual reduction of other predictable resources. Under a context of the non-availability of landfills for breeders and non-breeders, vultures will increase their use of extensive livestock as a trophic resource. CONCLUSIONS Future environmental policies should thus extend the areas used by scavengers in which livestock carcasses are allowed to remain in the wild, a strategy that will also mitigate the lack of food caused by any reduction in available waste if landfills close. In general, our results emphasize the capabilities of a spatial network approaches to address questions on movement ecology. They can be used to infer the behavioural response of animal species and, also demonstrate the importance of applying such approaches to endangered species conservation within a context of changing humanized scenarios.
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Affiliation(s)
- Catuxa Cerecedo-Iglesias
- Equip de Biologia de la Conservació, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia and Institut de la Recerca de la Biodiversitat (IRBIO), Universitat de Barcelona, Diagonal 643, 08028 Barcelona, Catalonia Spain
| | - Frederic Bartumeus
- Centre d’Estudis Avançats de Blanes (CEAB), CSIC, Accés a la Cala Sant Francesc, 17300 Blanes, Girona, Spain
- Centre de Recerca Ecològica i Aplicacions Forestals, CREAF, Campus Bellaterra, 17300 Cerdanyola del Vallès, Spain
- Institució Catalana de Recerca i Estudis Avançats, ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Ainara Cortés-Avizanda
- Department of Plant Biology and Ecology, Faculty of Biology, University of Seville, Avda. Reina Mercedes 6, 41012 Seville, Spain
| | - Joan Ll. Pretus
- Equip de Biologia de la Conservació, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia and Institut de la Recerca de la Biodiversitat (IRBIO), Universitat de Barcelona, Diagonal 643, 08028 Barcelona, Catalonia Spain
| | - Antonio Hernández-Matías
- Equip de Biologia de la Conservació, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia and Institut de la Recerca de la Biodiversitat (IRBIO), Universitat de Barcelona, Diagonal 643, 08028 Barcelona, Catalonia Spain
| | - Joan Real
- Equip de Biologia de la Conservació, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia and Institut de la Recerca de la Biodiversitat (IRBIO), Universitat de Barcelona, Diagonal 643, 08028 Barcelona, Catalonia Spain
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Black Kites on a flyway between Western Siberia and the Indian Subcontinent. Sci Rep 2022; 12:5581. [PMID: 35368027 PMCID: PMC8976839 DOI: 10.1038/s41598-022-09246-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 03/11/2022] [Indexed: 11/18/2022] Open
Abstract
The Black Kite (Milvus migrans) is one of the most widespread raptors in the world. The Palaearctic is populated by two migrating subspecies, Milvus migrans migrans and Milvus migrans lineatus, in the western and eastern part of this realm, respectively. There is a large intergradation zone of M. m. migrans/M. m. lineatus in-between. Although the migration routes of M. m. migrans from Europe to Sub-Saharan Africa and the Middle East are well known, detailed information about migration routes of Black Kites from intergradation zone are missing. Using satellite telemetry we are able to fill this gap in our knowledge of these birds. We tagged with GPS/SMS/GPRS telemetry loggers 13 and 6 Black Kite pulli in lowland around Biysk (Altai Krai, Russia) and in mountains around Kosh-Agach (Altai Republic, Russia), respectively. After fledging, Black Kites from both subpopulations stayed in a small, non-overlapping areas and then migrated to southern Asia through narrow corridors. Black Kites originating from Biysk migrated through the Western Circum-Himalayan Corridor. Black Kites originating from Kosh-Agach used the Trans-Himalayan Corridor crossing the Himalayas in altitudes of up to 6256 m asl. The average total distance travelled of Black Kites from both subpopulations was 9166 km without any significant differences between these subpopulations. Timing of both spring and autumn migration did not vary along different age groups. Black Kites from both subpopulations wintered in low elevations of Pakistan and India. Birds wintered on average for 190 days, and the mean area of individual home ranges in winter was 4704 km2. During the breeding period, birds dwelled in south-western Siberia, where they spent on average 125 days with an average home range size 3537 km2. We found that ontogenetic shifts in migratory behaviour of Black Kites from Eastern Russia differ from those in population/subspecies in Europe. Black Kites crossing the Himalayas fly and, moreover, stay for hours resting at night in the environment of mountains at altitudes over 5000 m.
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Hill JE, Holland AE, Brohl LK, Kluever BM, Pfeiffer MB, DeVault TL, Belant JL. Diets of Black Vultures and Turkey Vultures in Coastal South Carolina, USA with a Review of Species' Dietary Information. SOUTHEAST NAT 2022. [DOI: 10.1656/058.021.0102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Jacob E. Hill
- University of Georgia, Savannah River Ecology Laboratory, PO Drawer E, Aiken, SC 29802
| | - Amanda E. Holland
- Global Wildlife Conservation Center, State University of New York College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210
| | - Lisa K. Brohl
- Lake Erie Islands Conservancy, P.O. Box 461, Put-in-Bay, OH 43456
| | - Bryan M. Kluever
- United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Florida Field Station, 2820 East University Avenue, Gainesville, FL 32641
| | - Morgan B. Pfeiffer
- United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Ohio Field Station, 6100 Columbus Avenue, Sandusky, OH 44870
| | - Travis L. DeVault
- University of Georgia, Savannah River Ecology Laboratory, PO Drawer E, Aiken, SC 29802
| | - Jerrold L. Belant
- Global Wildlife Conservation Center, State University of New York College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210
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Patterson SK, Strum SC, Silk JB. Early life adversity has long-term effects on sociality and interaction style in female baboons. Proc Biol Sci 2022; 289:20212244. [PMID: 35105243 PMCID: PMC8808103 DOI: 10.1098/rspb.2021.2244] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Social bonds enhance fitness in many group-living animals, generating interest in the processes that create individual variation in sociality. Previous work on female baboons shows that early life adversity and temperament both influence social connectedness in adulthood. Early life adversity might shape sociality by reducing ability to invest in social relationships or through effects on attractiveness as a social partner. We examine how females' early life adversity predicts sociality and temperament in wild olive baboons, and evaluate whether temperament mediates the relationship between early life adversity and sociality. We use behavioural data on 31 females to quantify sociality. We measure interaction style as the tendency to produce grunts (signals of benign intent) in contexts in which the vocalization does not produce immediate benefits to the actor. Early life adversity was negatively correlated with overall sociality, but was a stronger predictor of social behaviours received than behaviours initiated. Females who experienced less early life adversity had more benign interaction styles and benign interaction styles were associated with receiving more social behaviours. Interaction style may partially mediate the association between early life adversity and sociality. These analyses add to our growing understanding of the processes connecting early life experiences to adult sociality.
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Affiliation(s)
- Sam K. Patterson
- Department of Anthropology, New York University, New York, NY, USA
| | - Shirley C. Strum
- Department of Anthropology, University of California, San Diego, CA, USA,Uaso Ngiro Baboon Project, Nairobi, Kenya
| | - Joan B. Silk
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA,Institute for Human Origins, Arizona State University, Tempe, AZ, USA
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Chakraborty B, Baek H, Bairagi N. Diffusion-induced regular and chaotic patterns in a ratio-dependent predator-prey model with fear factor and prey refuge. CHAOS (WOODBURY, N.Y.) 2021; 31:033128. [PMID: 33810757 DOI: 10.1063/5.0035130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
Population distribution of interacting species in a large scale natural system is heterogeneous and subject to change for various reasons. Here, we explore how behavioral modification in prey species due to fear of predator and mutual interference between predators can create different spatiotemporal patterns in population distribution. We show that the fear factor and diffusion in a ratio-dependent predator-prey model may show more complex dynamics than observed earlier. It is shown that when prey diffusivity is low, prey remains concentrated at different patches throughout the domain. However, prey density becomes low at the patches as they disperse at a higher rate. Mixed and stripe patterns are observed during the transition from a hot spot pattern at the lower prey diffusivity to a cold spot pattern at its higher value. Pattern transition is, however, completely opposite if the antipredator behavior is gradually increased. Our simulation results reveal that the spatiotemporal chaotic pattern may also be observed in the Hopf-Turing region of instability provided prey shows a higher level of antipredator behavior. The chaotic pattern of the Hopf-Turing region may be shifted to a spot type pattern of the Turing region depending on the refuge level of the habitat.
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Affiliation(s)
- Bhaskar Chakraborty
- Centre for Mathematical Biology and Ecology, Department of Mathematics, Jadavpur University, Kolkata 700032, India
| | - Hunki Baek
- Department of Mathematics Education, Catholic University of Daegu, Gyeongsan, Gyeongbuk 712-702, South Korea
| | - Nandadulal Bairagi
- Centre for Mathematical Biology and Ecology, Department of Mathematics, Jadavpur University, Kolkata 700032, India
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Blanco G, López-Hernández I, Morinha F, López-Cerero L. Intensive farming as a source of bacterial resistance to antimicrobial agents in sedentary and migratory vultures: Implications for local and transboundary spread. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 739:140356. [PMID: 32758969 DOI: 10.1016/j.scitotenv.2020.140356] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/16/2020] [Accepted: 06/17/2020] [Indexed: 06/11/2023]
Abstract
The role of wild birds in the carriage and transmission of human and food animal bacteria with resistant genotypes has repeatedly been highlighted. However, few studies have focussed on the specific exposure sources and places of acquisition and selection for antimicrobial-resistant bacteria in vultures relying on livestock carcasses across large areas and different continents. The occurrence of bacterial resistance to antimicrobial agents was assessed in the faecal microbiota of sedentary Griffon vultures (Gyps fulvus) and trans-Saharan migratory Egyptian vultures (Neophron percnopterus) in central Spain. High rates (generally >50%) of resistant Escherichia coli and other enterobacteria to amoxicillin, cotrimoxazole and tetracycline were found. About 25-30% of samples were colonised by extended-spectrum beta-lactamases (ESBL) producing bacteria, while 5-17% were positive for plasmid mediated quinolone resistance (PMQR) phenotypes, depending on vulture species and age. In total, nine ESBL types were recorded (7 in griffon vultures and 5 in Egyptian vultures), with CTX-M-1 the most prevalent in both species. The most prevalent PMQR was mediated by qnrS genes. We found no clear differences in the occurrence of antimicrobial resistance in adult vultures of each species, or between nestling and adult Egyptian vultures. This supports the hypothesis that antimicrobial resistance is acquired in the European breeding areas of both species. Bacterial resistance can directly be driven by the regular ingestion of multiple active antimicrobials found in medicated livestock carcasses from factory farms, which should be not neglected as a contributor to the emergence of novel resistance clones. The One Health framework should consider the potential transboundary carriage and spread of epidemic resistance from high-income European to low-income African countries via migratory birds.
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Affiliation(s)
- Guillermo Blanco
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain.
| | - Inmaculada López-Hernández
- Unidad de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain
| | - Francisco Morinha
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - Lorena López-Cerero
- Unidad de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain
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Mbizah MM, Farine DR, Valeix M, Hunt JE, Macdonald DW, Loveridge AJ. Effect of ecological factors on fine-scale patterns of social structure in African lions. J Anim Ecol 2020; 89:2665-2676. [PMID: 32895921 DOI: 10.1111/1365-2656.13334] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/07/2020] [Indexed: 01/21/2023]
Abstract
Environmental variations can influence the extent to which individuals interact with other individuals by changing the value of grouping. It is well known that many species can form and disband groups, often in response to the distribution and abundance of resources. While previous studies showed that resources influence the broad-scale structure of animal groups, knowledge gaps remain on whether they affect fine-scale patterns of association among individuals within groups. We quantify association patterns in African lions while simultaneously monitoring the abundance and distribution of prey. We test how social and ecological factors, including individual trait (age, sex, reproductive state) similarity and prey availability (prey abundance, dispersion, herd size and body size) affect within-pride social structure in African lions. We found that individual decisions about associates depended on resource availability with individuals associating equally across all members of the pride when prey herds were scarce, aggregated or large bodied, and associating more exclusively (in subgroups of preferred associates) when prey herds were abundant, dispersed or small bodied. Individuals within lion prides seemed to be buffering against changes in prey availability by modulating their strength and density of connections with conspecifics when prides split into subgroups. The strength and density of connections among individuals within subgroups was greater when prey herds were large and lower when prey herds were dispersed or are large bodied. Our findings suggest that individual lions are making social decisions at both the subgroup level and the pride level, with decisions representing putatively fitness-enhancing strategies. Individuals were typically shifting between having few strong connections and having many weaker connections depending on prevailing ecological conditions, with prey abundance, dispersion and body size having the greatest impact on decisions about splitting into subgroups. The maintenance of connections within prides and subgroups in the face of ecological change suggests that the fission-fusion nature of lion prides might be essential for the long-term maintenance of social connections even when short-term conditions do not allow them. More broadly, our study reveals how fission-fusion dynamics and ecological factors can simultaneously have an effect on animals across multiple levels of sociality.
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Affiliation(s)
- Moreangels M Mbizah
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK
| | - Damien R Farine
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany.,Edward Grey Institute, Department of Zoology, University of Oxford, Oxford, UK
| | - Marion Valeix
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK.,Laboratoire de Biométrie et Biologie Evolutive, UMR 5558, CNRS, Université de Lyon, Université Lyon 1, Villeurbanne, France.,LTSER France, Zone Atelier "Hwange", CNRS HERD (Hwange Environmental Research Development) Program, Dete, Zimbabwe
| | - Jane E Hunt
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK
| | - Andrew J Loveridge
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK
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Blanco G, Sergio F, Frías Ó, Salinas P, Tanferna A, Hiraldo F, Barceló D, Eljarrat E. Integrating population connectivity into pollution assessment: Overwintering mixing reveals flame retardant contamination in breeding areas in a migratory raptor. ENVIRONMENTAL RESEARCH 2018; 166:553-561. [PMID: 29960221 DOI: 10.1016/j.envres.2018.06.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/22/2018] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
Determining the exposure and magnitude at which various pollutants are differentially assimilated at the breeding and non-breeding grounds of migratory wildlife is challenging. Here, the possibility of applying the migratory connectivity framework to understanding contamination in birds is illustrated by considering flame retardants in inviable eggs of a migratory raptor, the black kite (Milvus migrans). The occurrence and concentration of legacy and emerging compounds in eggs from the southeastern peri-urban area of Madrid city, central Spain, were compared with those from Doñana National Park in southern Spain. A much higher occurrence and concentration of multiple polybrominated diphenyl ethers and Dechlorane 602 were found in Madrid than Doñana, but the opposite patterns were found for Dechlorane Plus. Individuals from these and other breeding areas in western Europe showed a strong intermixing pattern over widespread wintering areas in Africa, as assessed by ringing recoveries and movements tracked by satellite devices. This diffuse migratory connectivity reveals breeding areas as the main contamination grounds. High contamination burdens sequestered in eggs point to rapid assimilation of these compounds before laying, associated with important emission sources in Madrid, especially landfills of partially incinerated urban refuse, and other anthropogenic operations. Diet composition regarding aquatic vs. terrestrial prey, and bioaccumulation and biomagnification processes are suggested to explain differential assimilation of some compounds, especially Dechlorane Plus in Doñana, although a local emission source polluting this area cannot be ruled out. Insight from the migratory connectivity framework can help to disentangle large-scale patterns of contaminant uptake and refocus attention on key regions and potential causes of chemical hazards in declining migratory species and human populations.
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Affiliation(s)
- Guillermo Blanco
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, 28006 Madrid, Spain.
| | - Fabrizio Sergio
- Department of Conservation Biology, Estacion Biologica de Doñana CSIC, C/ Americo Vespucio 26, 41092 Sevilla, Spain
| | - Óscar Frías
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - Pablo Salinas
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - Alessandro Tanferna
- Department of Conservation Biology, Estacion Biologica de Doñana CSIC, C/ Americo Vespucio 26, 41092 Sevilla, Spain
| | - Fernando Hiraldo
- Department of Conservation Biology, Estacion Biologica de Doñana CSIC, C/ Americo Vespucio 26, 41092 Sevilla, Spain
| | - Damià Barceló
- Water and Soil Quality Research Group, Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona, 18-26, 08034 Barcelona, Spain
| | - Ethel Eljarrat
- Water and Soil Quality Research Group, Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona, 18-26, 08034 Barcelona, Spain
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Krauel J, Ratcliffe J, Westbrook J, McCracken G. Brazilian free-tailed bats (Tadarida brasiliensis) adjust foraging behaviour in response to migratory moths. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0284] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insect migrations represent large movements of resources across a landscape, which are attractive to predators capable of detecting and catching them. Brazilian free-tailed bats (Tadarida brasiliensis (I. Geoffroy, 1824)) consume migratory noctuid moths, which concentrate in favourable winds resulting in aggregations of prey that attract bats hundreds of metres above ground. Although T. brasiliensis are known to feed on these aggregations of migratory moths, changes in their foraging behaviours have not been linked to moth migration events. We investigated possible shifts in the bats’ foraging behaviours when moths are migrating with respect to altitude and moth abundance. We recorded 1104 echolocation call passes of T. brasiliensis at ground level and at altitudes of ∼100 and ∼200 m above ground level. We found proportionally more bat activity at higher altitudes when migratory moth abundance was high. We also found that bats decreased call frequency and bandwidth and increased call duration at higher altitudes and behaved similarly with increasing moth abundance even at ground level. Our results support predictions that bats change foraging behaviour in response to seasonal availability of migratory moths and document alterations in echolocation call parameters that are consistent with optimizing prey detection.
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Affiliation(s)
- J.J. Krauel
- Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN 37996, USA
| | - J.M. Ratcliffe
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2, Canada
| | - J.K. Westbrook
- USDA Agricultural Research Service, 2771 F and B Road, College Station, TX 77845, USA
| | - G.F. McCracken
- Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN 37996, USA
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12
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Sanz-Aguilar A, Cortés-Avizanda A, Serrano D, Blanco G, Ceballos O, Grande JM, Tella JL, Donázar JA. Sex- and age-dependent patterns of survival and breeding success in a long-lived endangered avian scavenger. Sci Rep 2017; 7:40204. [PMID: 28074860 PMCID: PMC5225485 DOI: 10.1038/srep40204] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 12/05/2016] [Indexed: 11/09/2022] Open
Abstract
In long-lived species, the age-, stage- and/or sex-dependent patterns of survival and reproduction determine the evolution of life history strategies, the shape of the reproductive value, and ultimately population dynamics. We evaluate the combined effects of age and sex in recruitment, breeder survival and breeding success of the globally endangered Egyptian vulture (Neophron percnopterus), using 31-years of exhaustive data on marked individuals in Spain. Mean age of first reproduction was 7-yrs for both sexes, but females showed an earlier median and a larger variance than males. We found an age-related improvement in breeding success at the population level responding to the selective appearance and disappearance of phenotypes of different quality but unrelated to within-individual aging effects. Old males (≥8 yrs) showed a higher survival than both young males (≤7 yrs) and females, these later in turn not showing aging effects. Evolutionary trade-offs between age of recruitment and fitness (probably related to costs of territory acquisition and defense) as well as human-related mortality may explain these findings. Sex- and age-related differences in foraging strategies and susceptibility to toxics could be behind the relatively low survival of females and young males, adding a new concern for the conservation of this endangered species.
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Affiliation(s)
- Ana Sanz-Aguilar
- Department of Conservation Biology, Estación Biológica de Doñana, CSIC. Americo Vespucio s/n, Isla La Cartuja E-41092 Sevilla, Spain
- Population Ecology Group, Instituto Mediterráneo de Estudios Avanzados (CSIC-UIB), Miquel Marqués 21, E-07190 Esporles, Islas Baleares, Spain
- Ecology Area, Department of Applied Biology, Miguel Hernández University. Avda. de la Universidad s/n, E-03202 Elche, Alicante, Spain
| | - Ainara Cortés-Avizanda
- Department of Conservation Biology, Estación Biológica de Doñana, CSIC. Americo Vespucio s/n, Isla La Cartuja E-41092 Sevilla, Spain
- Infraestruturas de Portugal Biodiversity Chair CIBIO/InBIO. Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto. Campus Agrário de Vairão, 4485-661 Vairão, Portugal
- CEABN/InBio, Centro de Ecologia Aplicada “Professor Baeta Neves”, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal
| | - David Serrano
- Department of Conservation Biology, Estación Biológica de Doñana, CSIC. Americo Vespucio s/n, Isla La Cartuja E-41092 Sevilla, Spain
| | - Guillermo Blanco
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | | | - Juan M. Grande
- Instituto de Ciencias de la Tierra y Ambientales de La Pampa, CONICET, Avda. Uruguay 151, 6300 Santa Rosa, La Pampa, Argentina
- Centro para el Estudio y Conservación de las Aves Rapaces en Argentina, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, Avda. Uruguay 151, 6300 Santa Rosa, La Pampa, Argentina
| | - José L. Tella
- Department of Conservation Biology, Estación Biológica de Doñana, CSIC. Americo Vespucio s/n, Isla La Cartuja E-41092 Sevilla, Spain
| | - José A. Donázar
- Department of Conservation Biology, Estación Biológica de Doñana, CSIC. Americo Vespucio s/n, Isla La Cartuja E-41092 Sevilla, Spain
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13
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Blendinger PG, Jiménez J, Macchi L, Martín E, Sánchez MS, Ayup MM. Scale-Dependent Spatial Match between Fruits and Fruit-eating Birds during the Breeding Season in Yungas Andean Forests. Biotropica 2015. [DOI: 10.1111/btp.12247] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Pedro G. Blendinger
- Instituto de Ecología Regional; Universidad Nacional de Tucumán; CC 34 4107 Tucumán Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas; Crisóstomo Álvarez 722 4000 Tucumán Argentina
| | - Julieta Jiménez
- Instituto de Ecología Regional; Universidad Nacional de Tucumán; CC 34 4107 Tucumán Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas; Crisóstomo Álvarez 722 4000 Tucumán Argentina
| | - Leandro Macchi
- Instituto de Ecología Regional; Universidad Nacional de Tucumán; CC 34 4107 Tucumán Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas; Crisóstomo Álvarez 722 4000 Tucumán Argentina
| | - Eduardo Martín
- Fundación Miguel Lillo; Miguel Lillo 205 4000 Tucumán Argentina
| | - Mariano S. Sánchez
- Consejo Nacional de Investigaciones Científicas y Técnicas; Crisóstomo Álvarez 722 4000 Tucumán Argentina
- Facultad de Ciencias Naturales e Instituto Miguel Lillo; Universidad Nacional de Tucumán; Miguel Lillo 205 4000 Tucumán Argentina
| | - María Marta Ayup
- Instituto de Ecología Regional; Universidad Nacional de Tucumán; CC 34 4107 Tucumán Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas; Crisóstomo Álvarez 722 4000 Tucumán Argentina
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14
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Macdonald DW, Johnson DDP. Patchwork planet: the resource dispersion hypothesis, society, and the ecology of life. J Zool (1987) 2015. [DOI: 10.1111/jzo.12202] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- D. W. Macdonald
- Wildlife Conservation Research Unit; The Recanati-Kaplan Centre; Department of Zoology; University of Oxford; UK
| | - D. D. P. Johnson
- Department of Politics and International Relations; University of Oxford; UK
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15
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Takeda KF, Hiraiwa-Hasegawa M, Kutsukake N. Arch displays signal threat intentions in a fission–fusion flock of the red-crowned crane. BEHAVIOUR 2015. [DOI: 10.1163/1568539x-00003304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ritualised displays are used by group-living animals in various contexts, such as when individuals join a group or flock. Only a few quantitative studies of the function of displays in species with fission–fusion social dynamics have been conducted to date. Here, we examined the arch display in red-crowned cranes (Grus japonensis) immediately after joining a flock. Behavioural observations indicated that the arch functions as a signal of both threat motivation and individual strength. Singletons had disadvantages in terms of competition over resources and were, therefore, expected to have higher threat motivation than pairs or families. Indeed, singletons performed the arch more frequently than did pairs or families. Performance of the arch was related to dominance: males and adults were more likely to perform the arch than females and sub-adults. The likelihood of performing the arch was positively associated with local group density, indicating that joiners arched in more competitive situations. Contextual analyses indicated that subsequent behaviour by a joiner was more aggressive and that nearby individuals more frequently showed behavioural responses when a joiner arched than when it did not. Together, this study shows that cranes demonstrate functional displays to potential competitors, and represents a rare example of the functional analysis of ritualised signals in non-songbird species with fission–fusion social dynamics.
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Affiliation(s)
- Kohei F. Takeda
- Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, SOKENDAI (The Graduate University for Advanced Studies), Japan
| | - Mariko Hiraiwa-Hasegawa
- Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, SOKENDAI (The Graduate University for Advanced Studies), Japan
| | - Nobuyuki Kutsukake
- Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, SOKENDAI (The Graduate University for Advanced Studies), Japan
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16
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López-López P, García-Ripollés C, Urios V. Food predictability determines space use of endangered vultures: implications for management of supplementary feeding. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2014; 24:938-49. [PMID: 25154088 DOI: 10.1890/13-2000.1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Understanding space use of free-living endangered animals is key to informing management decisions for conservation planning. Like most scavengers, vultures have evolved under a context of unpredictability of food resources (i.e., exploiting scattered carcasses that are intermittently available). However, the role of predictable sources of food in shaping spatial ecology of vultures has seldom been studied in detail. Here, we quantify the home range of the Egyptian Vulture (Neophron percnopterus), a long-lived raptor that has experienced severe population decline throughout its range and is qualified as endangered worldwide. To this end, six adults were tracked by satellite telemetry in Spain during the breeding season, from 2007 to 2012, recording 10360 GPS locations. Using Resource Utilization Functions, we assessed the topology of the Utilization Distribution, a three-dimensional measure that shows the probability of finding an animal within the home range. Our results showed how food availability, and principally, how food predictability, determines ranging behavior of this species. Egyptian Vultures showed consistent site fidelity across years, measured as the two- and three-dimensional overlap in their home ranges. Space use varied considerably within the home range and remarkably, places located far from nesting sites were used more frequently than some areas located closer. Therefore, traditional conservation measures based on establishing restrictive rules within a fixed radius around nesting sites could be biologically meaningless if other areas within the home range are not protected too. Finally, our results emphasize the importance of anthropogenic predictable sources of food (mainly vulture restaurants) in shaping the space use of scavengers, which is in agreement with recent findings. Hence, measures aimed at ensuring food availability are essential to preserve this endangered vulture, especially in the present context of limiting carrion dumping in the field due to sanitary regulations according to European legislation.
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17
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Cardador L, Sardà-Palomera F, Carrete M, Mañosa S. Incorporating spatial constraints in different periods of the annual cycle improves species distribution model performance for a highly mobile bird species. DIVERS DISTRIB 2013. [DOI: 10.1111/ddi.12156] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Laura Cardador
- Departament de Biologia Animal; Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona; Facultat de Biologia; Avinguda Diagonal 643 08028 Barcelona Spain
- Forest Sciences Center of Catalonia (CTFC); Crta. de Sant Llorenç de Morunys Km 2 25280 Solsona Spain
| | - Francesc Sardà-Palomera
- Forest Sciences Center of Catalonia (CTFC); Crta. de Sant Llorenç de Morunys Km 2 25280 Solsona Spain
- Catalan Ornithological Institute (ICO); Museu de Zoologia; Passeig Picasso s/n 08003 Barcelona Spain
| | - Martina Carrete
- Department of Physical; Chemical and Natural Systems; Universidad Pablo de Olavide; Ctra. Utrera km 1 41013 Sevilla Spain
- Estación Biológica de Doñana (CSIC); Américo Vespucio s/n E-41092 Sevilla Spain
| | - Santi Mañosa
- Departament de Biologia Animal; Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona; Facultat de Biologia; Avinguda Diagonal 643 08028 Barcelona Spain
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18
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Panuccio M, Agostini N, Mellone U, Bogliani G. Circannual variation in movement patterns of the Black Kite (Milvus migrans migrans): a review. ETHOL ECOL EVOL 2013. [DOI: 10.1080/03949370.2013.812147] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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19
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López-López P, Benavent-Corai J, García-Ripollés C, Urios V. Scavengers on the move: behavioural changes in foraging search patterns during the annual cycle. PLoS One 2013; 8:e54352. [PMID: 23372712 PMCID: PMC3553087 DOI: 10.1371/journal.pone.0054352] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 12/12/2012] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Optimal foraging theory predicts that animals will tend to maximize foraging success by optimizing search strategies. However, how organisms detect sparsely distributed food resources remains an open question. When targets are sparse and unpredictably distributed, a Lévy strategy should maximize foraging success. By contrast, when resources are abundant and regularly distributed, simple brownian random movement should be sufficient. Although very different groups of organisms exhibit Lévy motion, the shift from a Lévy to a brownian search strategy has been suggested to depend on internal and external factors such as sex, prey density, or environmental context. However, animal response at the individual level has received little attention. METHODOLOGY/PRINCIPAL FINDINGS We used GPS satellite-telemetry data of Egyptian vultures Neophron percnopterus to examine movement patterns at the individual level during consecutive years, with particular interest in the variations in foraging search patterns during the different periods of the annual cycle (i.e. breeding vs. non-breeding). Our results show that vultures followed a brownian search strategy in their wintering sojourn in Africa, whereas they exhibited a more complex foraging search pattern at breeding grounds in Europe, including Lévy motion. Interestingly, our results showed that individuals shifted between search strategies within the same period of the annual cycle in successive years. CONCLUSIONS/SIGNIFICANCE Results could be primarily explained by the different environmental conditions in which foraging activities occur. However, the high degree of behavioural flexibility exhibited during the breeding period in contrast to the non-breeding period is challenging, suggesting that not only environmental conditions explain individuals' behaviour but also individuals' cognitive abilities (e.g., memory effects) could play an important role. Our results support the growing awareness about the role of behavioural flexibility at the individual level, adding new empirical evidence about how animals in general, and particularly scavengers, solve the problem of efficiently finding food resources.
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Affiliation(s)
- Pascual López-López
- Vertebrates Zoology Research Group, CIBIO Research Institute, University of Alicante, Alicante, Spain.
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20
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Carrete M, Bortolotti GR, Sánchez-Zapata JA, Delgado A, Cortés-Avizanda A, Grande JM, Donázar JA. Stressful conditions experienced by endangered Egyptian vultures on African wintering areas. Anim Conserv 2012. [DOI: 10.1111/acv.12001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Carrete
- Department of Physical, Chemical and Natural Systems; University Pablo de Olavide; Seville; Spain
| | - G. R. Bortolotti
- Department of Biology; University of Saskatchewan; Saskatoon; Saskatchewan; Canada
| | - J. A. Sánchez-Zapata
- Department of Applied Biology; University Miguel Hernández; Orihuela; Alicante; Spain
| | - A. Delgado
- Laboratorio de Biogeoquímica de Isótopos Estables; Instituto Andaluz de Ciencias de la Tierra; Armilla; Granada; Spain
| | - A. Cortés-Avizanda
- Department of Conservation Biology; Estación Biológica de Doñana (CSIC); Seville; Spain
| | | | - J. A. Donázar
- Department of Conservation Biology; Estación Biológica de Doñana (CSIC); Seville; Spain
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21
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Månsson J, Bunnefeld N, Andrén H, Ericsson G. Spatial and temporal predictions of moose winter distribution. Oecologia 2012; 170:411-9. [PMID: 22437909 DOI: 10.1007/s00442-012-2305-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 03/06/2012] [Indexed: 11/25/2022]
Affiliation(s)
- J Månsson
- Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden.
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22
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Margalida A, Oro D, Cortés-Avizanda A, Heredia R, Donázar JA. Misleading population estimates: biases and consistency of visual surveys and matrix modelling in the endangered bearded vulture. PLoS One 2011; 6:e26784. [PMID: 22039550 PMCID: PMC3198840 DOI: 10.1371/journal.pone.0026784] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 10/04/2011] [Indexed: 11/24/2022] Open
Abstract
Conservation strategies for long-lived vertebrates require accurate estimates of parameters relative to the populations' size, numbers of non-breeding individuals (the “cryptic” fraction of the population) and the age structure. Frequently, visual survey techniques are used to make these estimates but the accuracy of these approaches is questionable, mainly because of the existence of numerous potential biases. Here we compare data on population trends and age structure in a bearded vulture (Gypaetus barbatus) population from visual surveys performed at supplementary feeding stations with data derived from population matrix-modelling approximations. Our results suggest that visual surveys overestimate the number of immature (<2 years old) birds, whereas subadults (3–5 y.o.) and adults (>6 y.o.) were underestimated in comparison with the predictions of a population model using a stable-age distribution. In addition, we found that visual surveys did not provide conclusive information on true variations in the size of the focal population. Our results suggest that although long-term studies (i.e. population matrix modelling based on capture-recapture procedures) are a more time-consuming method, they provide more reliable and robust estimates of population parameters needed in designing and applying conservation strategies. The findings shown here are likely transferable to the management and conservation of other long-lived vertebrate populations that share similar life-history traits and ecological requirements.
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Affiliation(s)
- Antoni Margalida
- Bearded Vulture Study and Protection Group, El Pont de Suert, Lleida, Spain.
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