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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Goodheart B, Creel S, Vinks MA, Banda K, Reyes de Merkle J, Kusler A, Dart C, Banda K, Becker MS, Indala P, Simukonda C, Kaluka A. African wild dog movements show contrasting responses to long and short term risk of encountering lions: analysis using dynamic Brownian bridge movement models. Mov Ecol 2022; 10:16. [PMID: 35361272 PMCID: PMC8974231 DOI: 10.1186/s40462-022-00316-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Prey depletion is a threat to the world's large carnivores, and is likely to affect subordinate competitors within the large carnivore guild disproportionately. African lions limit African wild dog populations through interference competition and intraguild predation. When lion density is reduced as a result of prey depletion, wild dogs are not competitively released, and their population density remains low. Research examining distributions has demonstrated spatial avoidance of lions by wild dogs, but the effects of lions on patterns of movement have not been tested. Movement is one of the most energetically costly activities for many species and is particularly costly for cursorial hunters like wild dogs. Therefore, testing how top-down, bottom-up, and anthropogenic variables affect movement patterns can provide insight into mechanisms that limit wild dogs (and other subordinate competitors) in resource-depleted ecosystems. METHODS We measured movement rates using the motion variance from dynamic Brownian Bridge Movement Models (dBBMMs) fit to data from GPS-collared wild dogs, then used a generalized linear model to test for effects on movement of predation risk from lions, predictors of prey density, and anthropogenic and seasonal variables. RESULTS Wild dogs proactively reduced movement in areas with high lion density, but reactively increased movement when lions were immediately nearby. Predictors of prey density had consistently weaker effects on movement than lions did, but movements were reduced in the wet season and when dependent offspring were present. CONCLUSION Wild dogs alter their patterns of movement in response to lions in ways that are likely to have important energetic consequences. Our results support the recent suggestion that competitive limitation of wild dogs by lions remains strong in ecosystems where lion and wild dog densities are both low as a result of anthropogenic prey depletion. Our results reinforce an emerging pattern that movements often show contrasting responses to long-term and short-term variation in predation risk.
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Affiliation(s)
- Ben Goodheart
- Department of Ecology, Montana State University, 310 Lewis Hall, Bozeman, MT, 59717, USA.
- Zambian Carnivore Programme, PO Box 80, Mfuwe, Eastern Province, Zambia.
| | - Scott Creel
- Department of Ecology, Montana State University, 310 Lewis Hall, Bozeman, MT, 59717, USA
- Zambian Carnivore Programme, PO Box 80, Mfuwe, Eastern Province, Zambia
- Insitutioned För Vilt, Fisk Och Miljö, Sveriges lantbruksuniversitet, Umeå, Sweden
| | - Milan A Vinks
- Zambian Carnivore Programme, PO Box 80, Mfuwe, Eastern Province, Zambia
- Montana Fish Wildlife and Parks, 490 North Meridian Road, Kalispell, MT, 59901, USA
| | - Kambwiri Banda
- Department of Ecology, Montana State University, 310 Lewis Hall, Bozeman, MT, 59717, USA
- Zambian Carnivore Programme, PO Box 80, Mfuwe, Eastern Province, Zambia
| | - Johnathan Reyes de Merkle
- Department of Ecology, Montana State University, 310 Lewis Hall, Bozeman, MT, 59717, USA
- Zambian Carnivore Programme, PO Box 80, Mfuwe, Eastern Province, Zambia
| | - Anna Kusler
- Zambian Carnivore Programme, PO Box 80, Mfuwe, Eastern Province, Zambia
| | - Chase Dart
- Zambian Carnivore Programme, PO Box 80, Mfuwe, Eastern Province, Zambia
| | - Kachama Banda
- Zambian Carnivore Programme, PO Box 80, Mfuwe, Eastern Province, Zambia
| | - Matthew S Becker
- Department of Ecology, Montana State University, 310 Lewis Hall, Bozeman, MT, 59717, USA
- Zambian Carnivore Programme, PO Box 80, Mfuwe, Eastern Province, Zambia
| | - Peter Indala
- Zambia Department of National Parks and Wildlife, Private Bag 80, Lusaka, Zambia
| | - Chuma Simukonda
- Zambia Department of National Parks and Wildlife, Private Bag 80, Lusaka, Zambia
| | - Adrian Kaluka
- Zambia Department of National Parks and Wildlife, Private Bag 80, Lusaka, Zambia
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Vinks MA, Creel S, Schuette P, Becker MS, Rosenblatt E, Sanguinetti C, Banda K, Goodheart B, Young-Overton K, Stevens X, Chifunte C, Midlane N, Simukonda C. Response of lion demography and dynamics to the loss of preferred larger prey. Ecol Appl 2021; 31:e02298. [PMID: 33434324 DOI: 10.1002/eap.2298] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 10/07/2020] [Accepted: 10/27/2020] [Indexed: 06/12/2023]
Abstract
Large carnivores are experiencing range contraction and population declines globally. Prey depletion due to illegal offtake is considered a major contributor, but the effects of prey depletion on large carnivore demography are rarely tested. We measured African lion density and tested the factors that affect survival using mark-recapture models fit to six years of data from known individuals in Kafue National Park (KNP), Zambia. KNP is affected by prey depletion, particularly for large herbivores that were preferred prey for KNP lions a half-century ago. This provides a unique opportunity to test whether variables that explain local prey density also affect lion survival. Average lion density within our study area was 3.43 individuals/100 km2 (95% CI, 2.79-4.23), which was much lower than lion density reported for another miombo ecosystem with similar vegetation structure and rainfall that was less affected by prey depletion. Despite this, comparison to other lion populations showed that age- and sex-specific survival rates for KNP lions were generally good, and factors known to correlate with local prey density had small effects on lion survival. In contrast, recruitment of cubs was poor and average pride size was small. In particular, the proportion of the population comprised of second-year cubs was low, indicating that few cubs are recruited into the subadult age class. Our findings suggest that low recruitment might be a better signal of low prey density than survival. Thus, describing a lion population's age structure in addition to average pride size may be a simple and effective method of initially evaluating whether a lion population is affected by prey depletion. These dynamics should be evaluated for other lion populations and other large carnivore species. Increased resource protection and reducing the underlying drivers of prey depletion are urgent conservation needs for lions and other large carnivores as their conservation is increasingly threatened by range contraction and population declines.
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Affiliation(s)
- Milan A Vinks
- Department of Ecology, Montana State University, Bozeman, Montana, 59717, USA
- Zambian Carnivore Programme, Mfuwe, Zambia
| | - Scott Creel
- Department of Ecology, Montana State University, Bozeman, Montana, 59717, USA
- Zambian Carnivore Programme, Mfuwe, Zambia
- Institut för Vilt, Fisk Och Miljö, Sveriges Lantbruksuniversitet, Umeå, Sweden
| | - Paul Schuette
- Marine Mammals Management, U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, Alaska, 99503, USA
| | - Matthew S Becker
- Department of Ecology, Montana State University, Bozeman, Montana, 59717, USA
- Zambian Carnivore Programme, Mfuwe, Zambia
| | - Elias Rosenblatt
- Rubenstein School of Environment and Natural Resources, Aiken Center, University of Vermont, Burlington, Vermont, 05405, USA
| | | | | | - Ben Goodheart
- Department of Ecology, Montana State University, Bozeman, Montana, 59717, USA
- Zambian Carnivore Programme, Mfuwe, Zambia
| | - Kim Young-Overton
- Panthera, 8 West 40 Street, Floor 18, New York, New York, 10018, USA
| | - Xia Stevens
- Panthera, 8 West 40 Street, Floor 18, New York, New York, 10018, USA
| | - Clive Chifunte
- Institut för Vilt, Fisk Och Miljö, Sveriges Lantbruksuniversitet, Umeå, Sweden
- Zambia Department of National Parks and Wildlife, Chilanga, Zambia
| | - Neil Midlane
- Wilderness Safaris, Block H, The Terraces, Steenberg Office Park, 1 Silverwood Close, Tokai, Cape Town, South Africa
| | - Chuma Simukonda
- Zambia Department of National Parks and Wildlife, Chilanga, Zambia
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Vinks MA, Creel S, Schuette P, Rosenblatt E, Matandiko W, Sanguinetti C, Banda K, Goodheart B, Becker M, Chifunte C, Simukonda C. Testing the effects of anthropogenic pressures on a diverse African herbivore community. Ecosphere 2020. [DOI: 10.1002/ecs2.3067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Milan A. Vinks
- Conservation Biology and Ecology Program Department of Ecology Montana State University Bozeman Montana59717USA
- Zambian Carnivore Programme Mfuwe Zambia
| | - Scott Creel
- Conservation Biology and Ecology Program Department of Ecology Montana State University Bozeman Montana59717USA
- Zambian Carnivore Programme Mfuwe Zambia
- Department of Wildlife Fish and Environmental Studies Sveriges Lantbruksuniversitet Umeå90183Sweden
| | - Paul Schuette
- Zambian Carnivore Programme Mfuwe Zambia
- Alaska Center for Conservation Science University of Alaska Anchorage Anchorage Alaska99508USA
| | - Elias Rosenblatt
- Rubenstein School of Environment and Natural Resources Aiken Center University of Vermont Burlington Vermont05405USA
| | - Wigganson Matandiko
- Conservation Biology and Ecology Program Department of Ecology Montana State University Bozeman Montana59717USA
- Zambian Carnivore Programme Mfuwe Zambia
| | | | | | - Ben Goodheart
- Conservation Biology and Ecology Program Department of Ecology Montana State University Bozeman Montana59717USA
- Zambian Carnivore Programme Mfuwe Zambia
| | | | - Clive Chifunte
- Department of Wildlife Fish and Environmental Studies Sveriges Lantbruksuniversitet Umeå90183Sweden
- Zambia Department of National Parks and Wildlife Lusaka Zambia
| | - Chuma Simukonda
- Zambia Department of National Parks and Wildlife Lusaka Zambia
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