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Núñez CL, Clark JS, Poulsen JR. Disturbance sensitivity shapes patterns of tree species distribution in Afrotropical lowland rainforests more than climate or soil. Ecol Evol 2024; 14:e11329. [PMID: 38698930 PMCID: PMC11063613 DOI: 10.1002/ece3.11329] [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: 09/19/2023] [Revised: 02/20/2024] [Accepted: 04/07/2024] [Indexed: 05/05/2024] Open
Abstract
Understanding how tropical forests respond to abiotic environmental changes is critical for preserving biodiversity, mitigating climate change, and maintaining ecosystem services in the coming century. To evaluate the relative roles of the abiotic environment and human disturbance on Central African tree community composition, we employ tree inventory data, remotely sensed climatic data, and soil nutrient data collected from 30 1-ha plots distributed across a large-scale observational experiment in forests that had been differently impacted by logging and hunting in northern Republic of Congo. We show that the composition of Afrotropical plant communities at this scale responds to human disturbance more than to climate, with particular sensitivities to hunting and distance to the nearest village (a proxy for other human activities, including tree-cutting and gathering). These findings contrast neotropical predictions, highlighting the unique ecological, evolutionary, and anthropogenic history of Afrotropical forests.
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Affiliation(s)
- Chase L. Núñez
- Department for the Ecology of Animal SocietiesMax Planck Institute of Animal BehaviorKonstanzGermany
- Centre for the Advanced Study of Collective BehaviourUniversity of KonstanzKonstanzGermany
- Department of BiologyUniversity of KonstanzKonstanzGermany
- University Program in EcologyDuke UniversityDurhamNorth CarolinaUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
| | - James S. Clark
- University Program in EcologyDuke UniversityDurhamNorth CarolinaUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
| | - John R. Poulsen
- University Program in EcologyDuke UniversityDurhamNorth CarolinaUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
- The Nature ConservancyBoulderColoradoUSA
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Tsunamoto Y, Tsuruga H, Kobayashi K, Sukegawa T, Asakura T. Seed dispersal function of the brown bear Ursus arctos on Hokkaido Island in northern Japan: gut passage time, dispersal distance, germination, and effects of remaining pulp. Oecologia 2024; 204:505-515. [PMID: 38265600 DOI: 10.1007/s00442-024-05510-5] [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: 10/04/2023] [Accepted: 01/05/2024] [Indexed: 01/25/2024]
Abstract
Megafauna are important seed dispersers because they can disperse large quantities of seeds over long distances. In Hokkaido, Japan, the largest terrestrial animal is the brown bear (Ursus arctos) and other megafauna seed dispersers are lacking. Thus, brown bears are expected to have an important function as seed dispersers in Hokkaido. In this study, we, for the first time, evaluated the seed dispersal function of brown bears in Hokkaido using three fleshy-fruited trees and studied: (1) gut passage time (GPT) in feeding experiments, (2) seed dispersal distance using tracking data of wild bears, and (3) the effect of gut passage and pulp removal on germination rate. Most seeds were defecated intact, and less than 6% were broken. The average GPT without pulp was 3 h and 56 min to 6 h and 13 min, depending on the plant and trial. Each plant's average simulated seed dispersal distance was 202-512 m. The dispersal distance of Actinidia arguta seeds with pulp was significantly longer than those without pulp because of their longer GPT. The germination rate of defecated seeds without pulp was 19-51%, depending on the plant, and was significantly higher or not different comparing with that of seeds with pulp. We concluded that brown bears in Hokkaido are effective seed dispersers. In managing brown bears in Hokkaido, such ecological functions should be considered along with conserving the bear population and reducing human-bear conflicts.
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Affiliation(s)
- Yoshihiro Tsunamoto
- Hokkaido Research Organization, Research Institute of Energy, Environment and Geology, Kita 19 Nishi 12, Kita-ku, Sapporo, Hokkaido, 060-0819, Japan.
| | - Hifumi Tsuruga
- Hokkaido Research Organization, Research Institute of Energy, Environment and Geology, Kita 19 Nishi 12, Kita-ku, Sapporo, Hokkaido, 060-0819, Japan
| | - Konomi Kobayashi
- Sapporo Maruyama Zoo, 3-1 Miyagaoka, Chuo-ku, Sapporo, Hokkaido, Japan
| | - Takeshi Sukegawa
- Sapporo Maruyama Zoo, 3-1 Miyagaoka, Chuo-ku, Sapporo, Hokkaido, Japan
| | - Takuya Asakura
- Sapporo Maruyama Zoo, 3-1 Miyagaoka, Chuo-ku, Sapporo, Hokkaido, Japan
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Fell A, Silva T, Duthie AB, Dent D. A global systematic review of frugivorous animal tracking studies and the estimation of seed dispersal distances. Ecol Evol 2023; 13:e10638. [PMID: 37915807 PMCID: PMC10616751 DOI: 10.1002/ece3.10638] [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: 06/13/2023] [Revised: 09/25/2023] [Accepted: 10/08/2023] [Indexed: 11/03/2023] Open
Abstract
Seed dispersal is one of the most important ecosystem functions globally. It shapes plant populations, enhances forest succession, and has multiple, indirect benefits for humans, yet it is one of the most threatened processes in plant regeneration, worldwide. Seed dispersal distances are determined by the diets, seed retention times and movements of frugivorous animals. Hence, understanding how we can most effectively describe frugivore movement and behaviour with rapidly developing animal tracking technology is key to quantifying seed dispersal. To assess the current use of animal tracking in frugivory studies and to provide a baseline for future studies, we provide a comprehensive review and synthesis on the existing primary literature of global tracking studies that monitor movement of frugivorous animals. Specifically, we identify studies that estimate dispersal distances and how they vary with body mass and environmental traits. We show that over the last two decades there has been a large increase in frugivore tracking studies that determine seed dispersal distances. However, some taxa (e.g. reptiles) and geographic locations (e.g. Africa and Central Asia) are poorly studied. Furthermore, we found that certain morphological and environmental traits can be used to predict seed dispersal distances. We demonstrate that flight ability and increased body mass both significantly increase estimated seed dispersal mean and maximum distances. Our results also suggest that protected areas have a positive effect on mean seed dispersal distances when compared to unprotected areas. We anticipate that this review will act as a reference for future frugivore tracking studies, specifically to target current taxonomic and geographic data gaps, and to further explore how seed dispersal relates to key frugivore and fruit traits.
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Affiliation(s)
- Adam Fell
- Biological and Environmental SciencesUniversity of StirlingStirlingUK
| | - Thiago Silva
- Biological and Environmental SciencesUniversity of StirlingStirlingUK
| | - A. Bradley Duthie
- Biological and Environmental SciencesUniversity of StirlingStirlingUK
| | - Daisy Dent
- Department of Environmental Systems ScienceInstitute of Integrative Biology, ETH ZurichZurichSwitzerland
- Max Planck Institute for Animal BehaviourKonstanzGermany
- Smithsonian Tropical Research InstituteBalboaPanama
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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.
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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
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Poulsen JR, Beirne C, Rundel C, Baldino M, Kim S, Knorr J, Minich T, Jin L, Núñez CL, Xiao S, Mbamy W, Obiang GN, Masseloux J, Nkoghe T, Ebanega MO, Clark CJ, Fay MJ, Morkel P, Okouyi J, White LJT, Wright JP. Long Distance Seed Dispersal by Forest Elephants. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.789264] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
By dispersing seeds long distances, large, fruit-eating animals influence plant population spread and community dynamics. After fruit consumption, animal gut passage time and movement determine seed dispersal patterns and distances. These, in turn, are influenced by extrinsic, environmental variables and intrinsic, individual-level variables. We simulated seed dispersal by forest elephants (Loxodonta cyclotis) by integrating gut passage data from wild elephants with movement data from 96 individuals. On average, elephants dispersed seeds 5.3 km, with 89% of seeds dispersed farther than 1 km. The longest simulated seed dispersal distance was 101 km, with an average maximum dispersal distance of 40.1 km. Seed dispersal distances varied among national parks, perhaps due to unmeasured environmental differences such as habitat heterogeneity and configuration, but not with human disturbance or habitat openness. On average, male elephants dispersed seeds farther than females. Elephant behavioral traits strongly influenced dispersal distances, with bold, exploratory elephants dispersing seeds 1.1 km farther than shy, idler elephants. Protection of forest elephants, particularly males and highly mobile, exploratory individuals, is critical to maintaining long distance seed dispersal services that shape plant communities and tropical forest habitat.
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Sandhage-Hofmann A, Linstädter A, Kindermann L, Angombe S, Amelung W. Conservation with elevated elephant densities sequesters carbon in soils despite losses of woody biomass. GLOBAL CHANGE BIOLOGY 2021; 27:4601-4614. [PMID: 34197679 DOI: 10.1111/gcb.15779] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 06/14/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Nature conservation and restoration in terrestrial ecosystems is often focused on increasing the numbers of megafauna, expecting them to have positive impacts on ecological self-regulation processes and biodiversity. In sub-Saharan Africa, conservation efforts also aspire to protect and enhance biodiversity with particular focus on elephants. However, elephant browsing carries the risk of woody biomass losses. In this context, little is known about how increasing elephant numbers affects carbon stocks in soils, including the subsoils. We hypothesized that (1) increasing numbers of elephants reduce tree biomass, and thus the amount of C stored therein, resulting (2) in a loss of soil organic carbon (SOC). If true, a negative carbon footprint could limit the sustainability of elephant conservation from a global carbon perspective. To test these hypotheses, we selected plots of low, medium, and high elephant densities in two national parks and adjacent conservancies in the Namibian component of the Kavango Zambezi Transfrontier Area (KAZA), and quantified carbon storage in both woody vegetation and soils (1 m). Analyses were supplemented by the assessment of soil carbon isotopic composition. We found that increasing elephant densities resulted in a loss of tree carbon storage by 6.4 t ha-1 . However, and in contrast to our second hypothesis, SOC stocks increased by 4.7 t ha-1 with increasing elephant densities. These higher SOC stocks were mainly found in the topsoil (0-30 cm) and were largely due to the formation of SOC from woody biomass. A second carbon input source into the soils was megaherbivore dung, which contributed with 0.02-0.323 t C ha-1 year-1 to ecosystem carbon storage in the low and high elephant density plots, respectively. Consequently, increasing elephant density does not necessarily lead to a negative C footprint, as soil carbon sequestration and transient C storage in dung almost compensate for losses in tree biomass.
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Affiliation(s)
- Alexandra Sandhage-Hofmann
- Institute of Crop Science and Resource Conservation, Soil Science and Soil Ecology, University of Bonn, Bonn, Germany
| | - Anja Linstädter
- Institute of Crop Science and Resource Conservation, Section Grassland Ecology and Management, University of Bonn, Bonn, Germany
- Institute of Biochemistry and Biology, Biodiversity and Systematic Botany, University of Potsdam, Potsdam, Germany
| | - Liana Kindermann
- Institute of Crop Science and Resource Conservation, Section Grassland Ecology and Management, University of Bonn, Bonn, Germany
- Institute of Biochemistry and Biology, Biodiversity and Systematic Botany, University of Potsdam, Potsdam, Germany
| | - Simon Angombe
- Faculty of Agriculture & Natural Resources, Neudamm Campus, University of Namibia, Windhoek, Namibia
| | - Wulf Amelung
- Institute of Crop Science and Resource Conservation, Soil Science and Soil Ecology, University of Bonn, Bonn, Germany
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Abraham AJ, Prys‐Jones TO, De Cuyper A, Ridenour C, Hempson GP, Hocking T, Clauss M, Doughty CE. Improved estimation of gut passage time considerably affects trait‐based dispersal models. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13726] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Andrew J. Abraham
- School of Informatics, Computing and Cyber Systems Northern Arizona University Flagstaff AZ USA
- Environmental Change Institute School of Geography and the Environment University of Oxford Oxford UK
| | - Tomos O. Prys‐Jones
- School of Informatics, Computing and Cyber Systems Northern Arizona University Flagstaff AZ USA
| | - Annelies De Cuyper
- Department of Nutrition, Genetics and Ethology Faculty of Veterinary Medicine Ghent University Merelbeke Belgium
| | - Chase Ridenour
- School of Informatics, Computing and Cyber Systems Northern Arizona University Flagstaff AZ USA
| | - Gareth P. Hempson
- Centre for African Ecology School of Animal, Plant and Environmental Sciences University of the Witwatersrand Johannesburg South Africa
| | - Toby Hocking
- School of Informatics, Computing and Cyber Systems Northern Arizona University Flagstaff AZ USA
| | - Marcus Clauss
- Clinic for Zoo Animals Exotic Pets and Wildlife Vetsuisse Faculty University of Zurich Zurich Switzerland
| | - Christopher E. Doughty
- School of Informatics, Computing and Cyber Systems Northern Arizona University Flagstaff AZ USA
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Yang Y, Lin Y, Shi L. The effect of lizards on the dispersal and germination of Capparis spinosa (Capparaceae). PLoS One 2021; 16:e0247585. [PMID: 33635876 PMCID: PMC7909692 DOI: 10.1371/journal.pone.0247585] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 02/10/2021] [Indexed: 11/19/2022] Open
Abstract
Seed dispersal is a key component of the interactions between plants and animals. There is little research on the effects of lizard seed dispersal, which is more common on islands than elsewhere. In this study, the effects of the passage of Capparis spinosa seeds through Teratoscincus roborowskii lizard digestive tracts on the seed coats, water uptake rates and germination rates were investigated. In addition, the spatial patterns of fecal deposition by lizards in various microhabitats were assessed. Our results showed that the mean retention time (MRT) of mealworms was significantly longer than that of C. spinosa seeds in both adult and juvenile lizards. The defecation rate of C. spinosa tended to be lower than that of mealworms, which might be beneficial for seed dispersal. It was determined that the longer MRT of C. spinosa seeds enhanced the permeability of the seed coats, which promoted fast water uptake, broke seed dormancy and increased the seed germination rate. Furthermore, the seeds that passed through the digestive tracts of lizards were deposited in favorable germination microhabitats. By enhancing seed germination and depositing intact and viable seeds in safe potential recruitment sites, the lizard T. roborowskii acts, at least qualitatively, as an effective disperser of C. spinosa.
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Affiliation(s)
- Yi Yang
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Yingying Lin
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Lei Shi
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China
- * E-mail:
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