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Creel S, Reyes de Merkle J, Goodheart B, Mweetwa T, Mwape H, Simpamba T, Becker MS. An integrated population model reveals source-sink dynamics for competitively subordinate African wild dogs linked to anthropogenic prey depletion. J Anim Ecol 2024; 93:417-427. [PMID: 38311822 DOI: 10.1111/1365-2656.14052] [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: 06/08/2023] [Accepted: 01/04/2024] [Indexed: 02/06/2024]
Abstract
Many African large carnivore populations are declining due to decline of the herbivore populations on which they depend. The densities of apex carnivores like the lion and spotted hyena correlate strongly with prey density, but competitively subordinate carnivores like the African wild dog benefit from competitive release when the density of apex carnivores is low, so the expected effect of a simultaneous decrease in resources and dominant competitors is not obvious. Wild dogs in Zambia's South Luangwa Valley Ecosystem occupy four ecologically similar areas with well-described differences in the densities of prey and dominant competitors due to spatial variation in illegal offtake. We used long-term monitoring data to fit a Bayesian integrated population model (IPM) of the demography and dynamics of wild dogs in these four regions. The IPM used Leslie projection to link a Cormack-Jolly-Seber model of area-specific survival (allowing for individual heterogeneity in detection), a zero-inflated Poisson model of area-specific fecundity and a state-space model of population size that used estimates from a closed mark-capture model as the counts from which (latent) population size was estimated. The IPM showed that both survival and reproduction were lowest in the region with the lowest density of preferred prey (puku, Kobus vardonii and impala, Aepyceros melampus), despite little use of this area by lions. Survival and reproduction were highest in the region with the highest prey density and intermediate in the two regions with intermediate prey density. The population growth rate (λ ) was positive for the population as a whole, strongly positive in the region with the highest prey density and strongly negative in the region with the lowest prey density. It has long been thought that the benefits of competitive release protect African wild dogs from the costs of low prey density. Our results show that the costs of prey depletion overwhelm the benefits of competitive release and cause local population decline where anthropogenic prey depletion is strong. Because competition is important in many guilds and humans are affecting resources of many types, it is likely that similarly fundamental shifts in population limitation are arising in many systems.
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Affiliation(s)
- Scott Creel
- Department of Ecology, Montana State University, Bozeman, Montana, USA
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
| | - Johnathan Reyes de Merkle
- Department of Ecology, Montana State University, Bozeman, Montana, USA
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
| | - Ben Goodheart
- Department of Ecology, Montana State University, Bozeman, Montana, USA
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
| | | | - Henry Mwape
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
| | - Twakundine Simpamba
- Department of National Parks and Wildlife, South Luangwa Area Management Unit, Mfuwe, Eastern Province, Zambia
| | - Matthew S Becker
- Department of Ecology, Montana State University, Bozeman, Montana, USA
- Zambian Carnivore Programme, Mfuwe, Eastern Province, Zambia
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2
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Behr DM, Hodel FH, Cozzi G, McNutt JW, Ozgul A. Higher Mortality Is Not a Universal Cost of Dispersal: A Case Study in African Wild Dogs. Am Nat 2023; 202:616-629. [PMID: 37963118 DOI: 10.1086/726220] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
AbstractMortality is considered one of the main costs of dispersal. A reliable evaluation of mortality, however, is often hindered by a lack of information about the fate of individuals that disappear under unexplained circumstances (i.e., missing individuals). Here, we addressed this uncertainty by applying a Bayesian mortality analysis that inferred the fate of missing individuals according to information from individuals with known fate. Specifically, we tested the hypothesis that mortality during dispersal is higher than mortality among nondispersers using 32 years of mark-resighting data from a free-ranging population of the endangered African wild dog (Lycaon pictus) in northern Botswana. Contrary to expectations, we found that mortality during dispersal was lower than mortality among nondispersers, indicating that higher mortality is not a universal cost of dispersal. Our findings suggest that group living can incur costs for certain age classes, such as limited access to resources as group density increases, that exceed the mortality costs associated with dispersal. By challenging the accepted expectation of higher mortality during dispersal, we urge for further investigations of this key life history trait and propose a robust statistical approach to reduce bias in mortality estimates.
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3
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Hofmann DD, Cozzi G, McNutt JW, Ozgul A, Behr DM. A three-step approach for assessing landscape connectivity via simulated dispersal: African wild dog case study. LANDSCAPE ECOLOGY 2023; 38:981-998. [PMID: 36941928 PMCID: PMC10020313 DOI: 10.1007/s10980-023-01602-4] [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: 04/07/2022] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
CONTEXT Dispersal of individuals contributes to long-term population persistence, yet requires a sufficient degree of landscape connectivity. To date, connectivity has mainly been investigated using least-cost analysis and circuit theory, two methods that make assumptions that are hardly applicable to dispersal. While these assumptions can be relaxed by explicitly simulating dispersal trajectories across the landscape, a unified approach for such simulations is lacking. OBJECTIVES Here, we propose and apply a simple three-step approach to simulate dispersal and to assess connectivity using empirical GPS movement data and a set of habitat covariates. METHODS In step one of the proposed approach, we use integrated step-selection functions to fit a mechanistic movement model describing habitat and movement preferences of dispersing individuals. In step two, we apply the parameterized model to simulate dispersal across the study area. In step three, we derive three complementary connectivity maps; a heatmap highlighting frequently traversed areas, a betweenness map pinpointing dispersal corridors, and a map of inter-patch connectivity indicating the presence and intensity of functional links between habitat patches. We demonstrate the applicability of the proposed three-step approach in a case study in which we use GPS data collected on dispersing African wild dogs (Lycaon pictus) inhabiting northern Botswana. RESULTS Using step-selection functions we successfully parametrized a detailed dispersal model that described dispersing individuals' habitat and movement preferences, as well as potential interactions among the two. The model substantially outperformed a model that omitted such interactions and enabled us to simulate 80,000 dispersal trajectories across the study area. CONCLUSION By explicitly simulating dispersal trajectories, our approach not only requires fewer unrealistic assumptions about dispersal, but also permits the calculation of multiple connectivity metrics that together provide a comprehensive view of landscape connectivity. In our case study, the three derived connectivity maps revealed several wild dog dispersal hotspots and corridors across the extent of our study area. Each map highlighted a different aspect of landscape connectivity, thus emphasizing their complementary nature. Overall, our case study demonstrates that a simulation-based approach offers a simple yet powerful alternative to traditional connectivity modeling techniques. It is therefore useful for a variety of applications in ecological, evolutionary, and conservation research. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10980-023-01602-4.
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Affiliation(s)
- David D. Hofmann
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Botswana Predator Conservation Program, Wild Entrust, Private Bag 13, Maun, Botswana
| | - Gabriele Cozzi
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Botswana Predator Conservation Program, Wild Entrust, Private Bag 13, Maun, Botswana
| | - John W. McNutt
- Botswana Predator Conservation Program, Wild Entrust, Private Bag 13, Maun, Botswana
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Dominik M. Behr
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Botswana Predator Conservation Program, Wild Entrust, Private Bag 13, Maun, Botswana
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4
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Hodel FH, Behr DM, Cozzi G, Ozgul A. A hierarchical approach for estimating state‐specific mortality and state transition in dispersing animals with incomplete death records. Methods Ecol Evol 2023. [DOI: 10.1111/2041-210x.14069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Florian H. Hodel
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
- Department of Fisheries and Wildlife Michigan State University East Lansing Michigan USA
| | - Dominik M. Behr
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Gabriele Cozzi
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
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5
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Nordli K, Wabakken P, Eriksen A, Sand H, Wikenros C, Maartmann E, Zimmermann B. Spatial and temporal cohesion of parents and offspring in a social large carnivore. Anim Behav 2023. [DOI: 10.1016/j.anbehav.2022.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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6
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Rutherford KL, Cottenie K, Denomme-Brown ST. To go or not to go: variable density-dependent dispersal in small mammals. J Mammal 2022. [DOI: 10.1093/jmammal/gyac117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Abstract
Population density has been widely understood to be a key influencer of dispersal behavior; however, the generality of density-dependent (DD) dispersal in vertebrates is unclear. We conducted a review of the available empirical data on small mammal DD dispersal, distinguishing between the three dispersal stages: emigration, immigration, and transience (dispersal distance). We focused on small mammals because they are a well-studied, functionally similar group of vertebrates, with a distinct ecological importance. We also examined the effect of season, body mass, study length, and study type on the strength and direction of DD dispersal. The majority of emigration and dispersal distance studies reported negative density dependence, while immigration was mostly independent of density. No correlative patterns were detected; however, interpretation of the available data was hindered by inconsistencies in experimental and analytical approach across studies. Our results suggest that the three phases of the dispersal process may be influenced differently by density and highlight the importance of distinguishing between emigration, immigration, and transience when considering the effects of density dependence. As well, our study identifies several limitations with the current available data which limit the ability to compare DD dispersal behavior across systems, and calls for future investigations that consider all three phases of dispersal in the same system.
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Affiliation(s)
- Kate L Rutherford
- Department of Integrative Biology, University of Guelph , 50 Stone Road East, Guelph, Ontario N1G 2W1 , Canada
| | - Karl Cottenie
- Department of Integrative Biology, University of Guelph , 50 Stone Road East, Guelph, Ontario N1G 2W1 , Canada
| | - Simon T Denomme-Brown
- Department of Integrative Biology, University of Guelph , 50 Stone Road East, Guelph, Ontario N1G 2W1 , Canada
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Emmet RL, Augustine BC, Abrahms B, Rich LN, Gardner B. A spatial capture-recapture model for group-living species. Ecology 2022; 103:e3576. [PMID: 34714927 DOI: 10.1002/ecy.3576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/09/2021] [Accepted: 08/24/2021] [Indexed: 12/13/2022]
Abstract
Group living in species can have complex consequences for individuals, populations, and ecosystems. Therefore, estimating group density and size is often essential for understanding population dynamics, interspecific interactions, and conservation needs of group-living species. Spatial capture-recapture (SCR) has been used to model both individual and group density in group-living species, but modeling either individual-level or group-level detection results in different biases due to common characteristics of group-living species, such as highly cohesive movement or variation in group size. Furthermore, no SCR method currently estimates group density, individual density, and group size jointly. Using clustered point processes, we developed a cluster SCR model to estimate group density, individual density, and group size. We compared the model to standard SCR models using both a simulation study and a data set of detections of African wild dogs (Lycaon pictus), a group-living carnivore, on camera traps in northern Botswana. We then tested the model's performance under various scenarios of group movement in a separate simulation study. We found that the cluster SCR model outperformed a standard group-level SCR model when fitted to data generated with varying group sizes, and mostly recovered previous estimates of wild dog group density, individual density, and group size. We also found that the cluster SCR model performs better as individuals' movements become more correlated with their groups' movements. The cluster SCR model offers opportunities to investigate ecological hypotheses relating group size to population dynamics while accounting for cohesive movement behaviors in group-living species.
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Affiliation(s)
- Robert L Emmet
- Quantitative Ecology and Resource Management, University of Washington, Seattle, Washington, USA
| | - Ben C Augustine
- Department of Natural Resources and the Environment, Cornell University, Ithaca, New York, USA
| | - Briana Abrahms
- Department of Biology, Center for Ecosystem Sentinels, University of Washington, Seattle, Washington, USA
| | - Lindsey N Rich
- California Department of Fish and Wildlife, Wildlife Diversity Program, West Sacramento, California, USA
| | - Beth Gardner
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
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8
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Effects of early-life experience on innovation and problem-solving in captive coyotes. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03251-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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9
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Addis BR, Lowe WH. Environmentally associated variation in dispersal distance affects inbreeding risk in a stream salamander. Am Nat 2022; 200:802-814. [DOI: 10.1086/721763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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10
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Should I stay or should I go now: dispersal decisions and reproductive success in male white-faced capuchins (Cebus imitator). Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03197-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Priority of access to food and its influence on social dynamics of an endangered carnivore. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-021-03115-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Dupont P, Allainé D, Ferrandiz-Rovira M, Pradel R. Efficient spatial multi-state capture-recapture model to study natal dispersal: An application to the Alpine marmot. J Anim Ecol 2021; 91:266-278. [PMID: 34743354 DOI: 10.1111/1365-2656.13629] [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: 03/17/2021] [Accepted: 10/21/2021] [Indexed: 11/30/2022]
Abstract
Studying natal dispersal in natural populations using capture-recapture data is challenging as an unknown proportion of individuals leaves the study area when dispersing and are never recaptured. Most dispersal (and survival) estimates from capture-recapture studies are thus biased and only reflect what happens within the study area, not the population. Here, we elaborate on recent methodological advances to build a spatially explicit multi-state capture-recapture model to study natal dispersal in a territorial mammal while accounting for imperfect detection and movement in and out of the study area. We validate our model using a simulation study where we compare it to a non-spatial multi-state capture-recapture model. We then apply it to a long-term individual-based dataset on Alpine marmot Marmota marmota. Our model was able to accurately estimate natal dispersal and survival probabilities, as well as mean dispersal distance for a large range of dispersal patterns. By contrast, the non-spatial multi-state estimates underestimated both survival and natal dispersal even for short dispersal distances relative to the study area size. We discuss the application of our approach to other species and monitoring setups. We estimated higher inheritance probabilities of female Alpine marmots, which suggests higher levels of philopatry, although the probability to become dominant after dispersal did not differ between sexes. Nonetheless, the lower survival of young adult males suggests higher costs of dispersal for males. We further discuss the implications of our findings in light of the life history of the species.
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Affiliation(s)
- Pierre Dupont
- Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Évolutive, Villeurbanne, France.,Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Dominique Allainé
- Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Évolutive, Villeurbanne, France
| | - Mariona Ferrandiz-Rovira
- CREAF, Cerdanyola del Vallès, Catalonia, Spain.,BABVE, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalonia, Spain
| | - Roger Pradel
- CEFE, CNRS, University of Montpellier, University of Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
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13
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Van Belle S, Di Fiore A. Dispersal patterns in black howler monkeys (Alouatta pigra): Integrating multiyear demographic and molecular data. Mol Ecol 2021; 31:391-406. [PMID: 34661321 DOI: 10.1111/mec.16227] [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: 06/27/2021] [Revised: 10/03/2021] [Accepted: 10/11/2021] [Indexed: 11/29/2022]
Abstract
Dispersal is a fundamental process in the functioning of animal societies as it regulates the degree to which closely related individuals are spatially concentrated. A species' dispersal pattern can be complex as it emerges from individuals' decisions shaped by the cost-benefit tradeoffs associated with either remaining in the natal group or dispersing. Given the potential complexity, combining long-term demographic information with molecular data can provide important insights into dispersal patterns of a species. Based on a 15-year study that integrates multiyear demographic data on six groups with longitudinal and cross-sectional genetic sampling of 20 groups (N = 169 individuals, N = 21 polymorphic microsatellite loci), we describe the various dispersal strategies of male and female black howler monkeys (Alouatta pigra) inhabiting Palenque National Park, Mexico. Genetically confirmed dispersal events (N = 21 of 59 males; N = 6 of 65 females) together with spatial autocorrelation analyses revealed that the dispersal pattern of black howlers is bisexual with strong sex-biases in both dispersal rate (males disperse more often than females) and dispersal distance (females disperse farther than males). Observational and genetic data confirm that both males and females can successfully immigrate into established groups, as well as form new groups with other dispersing individuals. Additionally, both males and females may disperse singly, as well as in pairs, and both may also disperse secondarily. Overall, our findings suggest multiple dispersal trajectories for black howler males and females, and longer multiyear studies are needed to unravel which demographic, ecological and social factors underlie individuals' decisions about whether to disperse and which dispersal options to take.
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Affiliation(s)
- Sarie Van Belle
- Department of Anthropology, The University of Texas at Austin, Austin, Texas, USA
| | - Anthony Di Fiore
- Department of Anthropology, The University of Texas at Austin, Austin, Texas, USA.,Tiputini Biodiversity Station, College of Biological and Environmental Sciences, Universidad San Francisco de Quito, Cumbayá, Ecuador
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14
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Rabaiotti D, Groom R, McNutt JW, Watermeyer J, O'Neill HMK, Woodroffe R. High temperatures and human pressures interact to influence mortality in an African carnivore. Ecol Evol 2021; 11:8495-8506. [PMID: 34257912 PMCID: PMC8258213 DOI: 10.1002/ece3.7601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 03/12/2021] [Accepted: 03/26/2021] [Indexed: 12/05/2022] Open
Abstract
The impacts of high ambient temperatures on mortality in humans and domestic animals are well-understood. However much less is known about how hot weather affects mortality in wild animals. High ambient temperatures have been associated with African wild dog Lycaon pictus pup mortality, suggesting that high temperatures might also be linked to high adult mortality.We analyzed mortality patterns in African wild dogs radio-collared in Kenya (0°N), Botswana (20°S), and Zimbabwe (20°S), to examine whether ambient temperature was associated with adult mortality.We found that high ambient temperatures were associated with increased adult wild dog mortality at the Kenya site, and there was some evidence for temperature associations with mortality at the Botswana and Zimbabwe sites.At the Kenya study site, which had the highest human impact, high ambient temperatures were associated with increased risks of wild dogs being killed by people, and by domestic dog diseases. In contrast, temperature was not associated with the risk of snare-related mortality at the Zimbabwe site, which had the second-highest human impact. Causes of death varied markedly between sites.Pack size was positively associated with survival at all three sites.These findings suggest that while climate change may not lead to new causes of mortality, rising temperatures may exacerbate existing anthropogenic threats to this endangered species, with implications for conservation. This evidence suggests that temperature-related mortality, including interactions between temperature and other anthropogenic threats, should be investigated in a greater number of species to understand and mitigate likely impacts of climate change. .
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Affiliation(s)
- Daniella Rabaiotti
- Institute of ZoologyZoological Society of LondonLondonUK
- Division of BiosciencesDepartment of Genetics, Evolution and EnvironmentCentre for Biodiversity and Environment ResearchUniversity College LondonLondonUK
| | - Rosemary Groom
- Institute of ZoologyZoological Society of LondonLondonUK
- African Wildlife Conservation FundChishakwe RanchZimbabwe
| | | | | | - Helen M. K. O'Neill
- Durrell Institute of Conservation and EcologySchool of Anthropology and ConservationUniversity of KentKentUK
| | - Rosie Woodroffe
- Institute of ZoologyZoological Society of LondonLondonUK
- Division of BiosciencesDepartment of Genetics, Evolution and EnvironmentCentre for Biodiversity and Environment ResearchUniversity College LondonLondonUK
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15
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Layton-Matthews K, Griesser M, Coste CFD, Ozgul A. Forest management affects seasonal source-sink dynamics in a territorial, group-living bird. Oecologia 2021; 196:399-412. [PMID: 34061249 PMCID: PMC8241677 DOI: 10.1007/s00442-021-04935-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 05/03/2021] [Indexed: 12/03/2022]
Abstract
The persistence of wildlife populations is under threat as a consequence of human activities, which are degrading natural ecosystems. Commercial forestry is the greatest threat to biodiversity in boreal forests. Forestry practices have degraded most available habitat, threatening the persistence of natural populations. Understanding population responses is, therefore, critical for their conservation. Population viability analyses are effective tools to predict population persistence under forestry management. However, quantifying the mechanisms driving population responses is complex as population dynamics vary temporally and spatially. Metapopulation dynamics are governed by local dynamics and spatial factors, potentially mediating the impacts of forestry e.g., through dispersal. Here, we performed a seasonal, spatially explicit population viability analysis, using long-term data from a group-living territorial bird (Siberian jay, Perisoreus infaustus). We quantified the effects of forest management on metapopulation dynamics, via forest type-specific demography and spatially explicit dispersal, and how forestry impacted the stability of metapopulation dynamics. Forestry reduced metapopulation growth and stability, through negative effects on reproduction and survival. Territories in higher quality natural forest contributed more to metapopulation dynamics than managed forests, largely through demographic processes rather than dispersal. Metapopulation dynamics in managed forest were also less resilient to disturbances and consequently, may be more vulnerable to environmental change. Seasonal differences in source-sink dynamics observed in managed forest, but not natural forests, were caused by associated seasonal differences in dispersal. As shown here, capturing seasonal source-sink dynamics allows us to predict population persistence under human disturbance and to provide targeted conservation recommendations.
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Affiliation(s)
- Kate Layton-Matthews
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
- Norwegian Institute for Nature Research, Tromsø, Norway.
| | - Michael Griesser
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Department of Anthropology, University of Zurich, Zurich, Switzerland
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Christophe F D Coste
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
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16
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Individual differences in dominance-related traits drive dispersal and settlement in hatchery-reared juvenile brown trout. Sci Rep 2021; 11:7277. [PMID: 33790366 PMCID: PMC8012712 DOI: 10.1038/s41598-021-86613-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 03/15/2021] [Indexed: 11/30/2022] Open
Abstract
Effective management of exploited populations is based on an understanding of population dynamics and evolutionary processes. In spatially structured populations, dispersal is a central process that ultimately can affect population growth and viability. It can be influenced by environmental conditions, individual phenotypes, and stochastic factors. However, we have a limited knowledge of the relative contribution of these components and its interactions, and which traits can be used as reliable predictors of the dispersal ability. Here, we conducted a longitudinal field experiment aimed to identify traits which can be used as proxy for dispersal in juvenile brown trout (Salmo trutta L.). We measured body size and standard metabolic rates, and estimated body shapes for 212 hatchery-reared juvenile fish that were marked with individual codes and released in a small coastal stream in northwest Spain. We registered fish positions and distances to the releasing point after 19, 41, 60 and 158 days in the stream. We detected a high autocorrelation of dispersal distances, demonstrating that most individuals settle down relatively soon and then hold stable positions over the study period. Body size and fish shape were reliable predictors of dispersal, with bigger and more robust-set individuals being more likely to settle closer to the release site than smaller and more elongated fish. In addition, the analysis of spacing and spatial patterns indicated that the dispersal of introduced fish could affect the distribution of resident conspecifics. All together, these results suggest that stocking programs aimed to the enhancement of overexploited populations at fine spatial scales can be optimized by adjusting the size and shape of the introduced fish to specific management targets and environmental conditions.
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17
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Hewison AJM, Gaillard JM, Morellet N, Cagnacci F, Debeffe L, Cargnelutti B, Gehr B, Kröschel M, Heurich M, Coulon A, Kjellander P, Börger L, Focardi S. Sex differences in condition dependence of natal dispersal in a large herbivore: dispersal propensity and distance are decoupled. Proc Biol Sci 2021; 288:20202947. [PMID: 33715424 PMCID: PMC7944087 DOI: 10.1098/rspb.2020.2947] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/12/2021] [Indexed: 11/12/2022] Open
Abstract
Evolution should favour plasticity in dispersal decisions in response to spatial heterogeneity in social and environmental contexts. Sex differences in individual optimization of dispersal decisions are poorly documented in mammals, because species where both sexes commonly disperse are rare. To elucidate the sex-specific drivers governing dispersal, we investigated sex differences in condition dependence in the propensity and distance of natal dispersal in one such species, the roe deer, using fine-scale monitoring of 146 GPS-collared juveniles in an intensively monitored population in southwest France. Dispersal propensity increased with body mass in males such that 36% of light individuals dispersed, whereas 62% of heavy individuals did so, but there was no evidence for condition dependence in dispersal propensity among females. By contrast, dispersal distance increased with body mass at a similar rate in both sexes such that heavy dispersers travelled around twice as far as light dispersers. Sex differences in the strength of condition-dependent dispersal may result from different selection pressures acting on the behaviour of males and females. We suggest that females disperse prior to habitat saturation being reached, likely in relation to the risk of inbreeding. By contrast, natal dispersal in males is likely governed by competitive exclusion through male-male competition for breeding opportunities in this strongly territorial mammal. Our study is, to our knowledge, a first demonstration that condition dependence in dispersal propensity and dispersal distance may be decoupled, indicating contrasting selection pressures drive the behavioural decisions of whether or not to leave the natal range, and where to settle.
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Affiliation(s)
- A. J. M. Hewison
- Université de Toulouse, INRAE, CEFS, 31326 Castanet Tolosan, France; and LTSER ZA PYRénées GARonne, 31320 Auzeville Tolosane, France
| | - J.-M. Gaillard
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR5558, F-69622 Villeurbanne, France
| | - N. Morellet
- Université de Toulouse, INRAE, CEFS, 31326 Castanet Tolosan, France; and LTSER ZA PYRénées GARonne, 31320 Auzeville Tolosane, France
| | - F. Cagnacci
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Trentino, Italy
| | - L. Debeffe
- Université de Toulouse, INRAE, CEFS, 31326 Castanet Tolosan, France; and LTSER ZA PYRénées GARonne, 31320 Auzeville Tolosane, France
| | - B. Cargnelutti
- Université de Toulouse, INRAE, CEFS, 31326 Castanet Tolosan, France; and LTSER ZA PYRénées GARonne, 31320 Auzeville Tolosane, France
| | - B. Gehr
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - M. Kröschel
- Forest Research Institute of Baden-Wuerttemberg, FVA-Wildlife Institute, Wonnhaldestraße 4, 79100 Freiburg; and University of Freiburg, Faculty of Environment and Natural Resources, Chair of Wildlife Ecology and Management, Tennenbacher Straße 4, Freiburg, DE 79106, Germany
| | - M. Heurich
- Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany
| | - A. Coulon
- Centre d'Ecologie et des Sciences de la Conservation (CESCO), Muséum national d'Histoire naturelle, Centre National de la Recherche Scientifique, Sorbonne Université, CP 135, 57 rue Cuvier 75005 Paris, France
- CEFE, Univ Montpellier, CNRS, EPHE-Université PSL, IRD, Univ Paul Valéry Montpellier 3, MNHN, Montpellier, France
| | - P. Kjellander
- Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - L. Börger
- Department of Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - S. Focardi
- Istituto dei Sistemi Complessi, CNR, via Madonna del Piano 10, Sesto Fiorentino 50019, Italy
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