African wild dog movements show contrasting responses to long and short term risk of encountering lions: analysis using dynamic Brownian bridge movement models

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.

Spatial co-occurrence patterns of sympatric large carnivores in a multi-use African system

“…These findings add to the growing body of literature suggesting spatial displacement of wild dog from areas of high lion density [5,20,67,69,70]. However, as the models employed cannot directly infer the mechanisms of the underlying ecological interactions [42], the observed effects could, at least in part, be a result of wild dog being unable to persist in areas of high lion use due to increased mortality, rather than solely avoidance [20,26,27].…”

Long‐term data reveal fitness costs of anthropogenic prey depletion for a subordinate competitor, the African wild dog (Lycaon pictus)

“…Following methods from Goodheart et al. (2022) for data from the same radiocollars on African wild dogs, the window size was set to 15 fixes, margin size to 3 fixes, and location error to 1 m (Goodheart et al., 2022). We estimated density ($$$ \hat{D} $$$) using the dBBMM‐based estimate of area in only 4 years (2016, 2018, 2019, and 2020) for which we had GPS collar data for all groups in all four regions of the focal study area.…”

“…Cheetahs, African wild dogs, and dholes are notable exceptions to this rule because they are competitively subordinate within their guilds (Creel & Creel, 1996 ; Durant, 2000 ; Steinmetz et al., 2013 ). Top‐down forces due to intraguild predation and kleptoparasitism by larger carnivores (e.g., tigers, lions, and spotted hyenas) have strong effects on their population dynamics and densities (Hairston et al., 1960 ; Palomares & Caro, 1999 ; Polis et al., 1989 ), and (as it is typical of subordinate competitors) they use a combination of dietary, spatial, and temporal niche partitioning to coexist with dominant competitors (Bhandari et al., 2021 ; Broekhuis et al., 2013 ; Dröge et al., 2017 ; Fedriani et al., 2000 ; Goodheart et al., 2022 ; Hayward & Slotow, 2009 ; Karanth & Sunquist, 2000 ; Vanak et al., 2013 ). True apex carnivores like the lion typically exploit areas with high prey density (Carbone et al., 2011 ; Carbone & Gittleman, 2002 ; Karanth, 1999 ), so competitive subordinates must optimize a trade‐off between avoiding dominant competitors and maintaining access to prey (Bhandari et al., 2021 ; Creel & Creel, 1996 ; Durant, 2000 ; Laurenson, 1995 ; Swanson et al., 2014 ).…”

An integrated population model reveals source‐sink dynamics for competitively subordinate African wild dogs linked to anthropogenic prey depletion

“…Below the tipping point, wild dog density should decrease as prey density decreases, because the costs of prey depletion must eventually outweigh the benefits of competitive release. A recent meta-analysis supports this tippingpoint hypothesis (Creel et al, 2023), and recent field studies suggest that prey density has dropped below the tipping point in some ecosystems, for example in the Greater Kafue Ecosystem, where wild dog density is very low (<1/100 km 2 ) even though the density of dominant competitors is also low, as a consequence of prey depletion (Creel et al, 2018;Goodheart et al, 2021Goodheart et al, , 2022Vinks et al, 2020).…”