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Abstract Droughts are increasing in frequency and severity globally due to climate change, leading to changes in resource availability that may have cascading effects on animal ecology. Resource availability is a key driver of animal space use, which in turn influences interspecific interactions like intraguild competition. Understanding how climate‐induced changes in resource availability influence animal space use, and how species‐specific responses scale up to affect intraguild dynamics, is necessary for predicting broader community‐level responses to climatic changes.Although several studies have demonstrated the ecological impacts of drought, the behavioural responses of individuals that scale up to these broader‐scale effects are not well known, particularly among animals in top trophic levels like large carnivores. Furthermore, we currently lack understanding of how the impacts of climate variability on individual carnivore behaviour are linked to intraguild dynamics, in part because multi‐species datasets collected at timescales relevant to climatic changes are rare.Using 11 years of GPS data from four sympatric large carnivore species in southern Africa—lions (Panthera leo), leopards (Panthera pardus), African wild dogs (Lycaon pictus) and cheetahs (Acinonyx jubatus)—spanning 4 severe drought events, we test whether drought conditions impact (1) large carnivore space use, (2) broad‐scale intraguild spatial overlap and (3) fine‐scale intraguild interactions.Drought conditions expanded space use across species, with carnivores increasing their monthly home range sizes by 35% (wild dogs) to 66% (leopards). Drought conditions increased the amount of spatial overlap between lions and subordinate felids (cheetahs and leopards) by up to 119%, but only lion‐cheetah encounter rates were affected by these changes, declining in response to drought.Our findings reveal that drought has a clear signature on the space use of multiple sympatric large carnivore species, which can alter spatiotemporal partitioning between competing species. Our study thereby illuminates the links between environmental change, animal behaviour and intraguild dynamics. While fine‐scale avoidance strategies may facilitate intraguild coexistence during periodic droughts, large carnivore conservation may require considerable expansion of protected areas or revised human‐carnivore coexistence strategies to accommodate the likely long‐term increased space demands of large carnivores under projected increases in drought intensity.
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A taste of space: Remote animal observations and discrete‐choice models provide new insights into foraging and density dynamics for a large subarctic herbivore
Competition for resources and space can drive forage selection of large herbivores from the bite through the landscape scale. Animal behaviour and foraging patterns are also influenced by abiotic and biotic factors. Fine‐scale mechanisms of density‐dependent foraging at the bite scale are likely consistent with density‐dependent behavioural patterns observed at broader scales, but few studies have directly tested this assertion. Here, we tested if space use intensity, a proxy of spatiotemporal density, affects foraging mechanisms at fine spatial scales similarly to density‐dependent effects observed at broader scales in caribou. We specifically assessed how behavioural choices are affected by space use intensity and environmental processes using behavioural state and forage selection data from caribou (Rangifer tarandus granti) observed from GPS video‐camera collars using a multivariate discrete‐choice modelling framework. We found that the probability of eating shrubs increased with increasing caribou space use intensity and cover of Salix spp. shrubs, whereas the probability of eating lichen decreased. Insects also affected fine‐scale foraging behaviour by reducing the overall probability of eating. Strong eastward winds mitigated negative effects of insects and resulted in higher probabilities of eating lichen. At last, caribou exhibited foraging functional responses wherein their probability of selecting each food type increased as the availability (% cover) of that food increased. Space use intensity signals of fine‐scale foraging were consistent with density‐dependent responses observed at larger scales and with recent evidence suggesting declining reproductive rates in the same caribou population. Our results highlight potential risks of overgrazing on sensitive forage species such as lichen. Remote investigation of the functional responses of foraging behaviours provides exciting future applications where spatial models can identify high‐quality habitats for conservation.
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- PAR ID:
- 10553093
- Publisher / Repository:
- British Ecological Society
- Date Published:
- Journal Name:
- Journal of Animal Ecology
- Volume:
- 93
- Issue:
- 7
- ISSN:
- 0021-8790
- Page Range / eLocation ID:
- 891 to 905
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1111/1365-2656.14109
