Assessing carnivore spatial co‐occurrence and temporal overlap in the face of human interference in a semiarid forest

Abstract

Apex predators drive top-down effects in ecosystems and the loss of such species can trigger mesopredator release. This ecological process has been well documented in humanmodified small areas, but for management and conservation of ecological communities, it is important to know which human factors affect apex predator occurrence and which mediate mesopredators release at large scales. We hypothesized that mesopredators would avoid spatial and temporal overlap with the apex predator, the puma; but that human perturbations (i.e., cattle raising and trophy hunting) would dampen top-down effects and mediate habitat use. We installed 16 camera traps in each of 45, 10 × 10 km grid cells in the Caldén forest region of central Argentina resulting in 706 total stations covering 61,611 km 2 . We used single-season occupancy and two-species co-occurrence models and calculated the species interaction factor (SIF) to explore the contributions of habitat, biotic, and anthropic variables in explaining cooccurrence between carnivore pairs. We also used kernel density estimation techniques to analyze temporal overlap in activity patterns of the carnivore guild. We found that puma habitat use increased with abundance of large prey and with proximity to protected areas. Geoffroy's cats and skunks spatially avoided pumas and this effect was strong and mediated by distance to protected areas and game reserves, but pumas did not influence pampas fox and pampas cat space use. At medium and low levels of puma occupancy, we found evidence of spatial avoidance between three pairs of mesocarnivores. All predators were mostly nocturnal and crepuscular across seasons and mesopredators showed little consistent evidence of changing activity patterns with varying levels of puma occupancy or human interference. We found potential for mesopredator release at large scale, especially on the spatial niche axis. Our results suggest that a combination of interacting factors, in conjunction with habitat features and intervening human activities, may make mesopredator release unlikely or difficult to discern at broad scales. Overall, we believe that promoting the creation of new protected areas linked by small forest patches would likely lead to increased predator and prey abundances, as well as the interactions among carnivores inside and outside of protected areas.

Top-down and bottom-up effects modulate species co-existence in a context of top predator restoration

“…Although previous research has revealed that several species can modify their temporal activity patterns according to factors such as predation risk or human disturbance 22,39 , the circadian rhythms of genets and martens were predominately nocturnal and consistent among predation risk scenarios and seasons 23,40 . However, these mesocarnivores showed temporal segregation with the Iberian lynx, in contrast to Sarmento et al 33 findings for a more diurnal and adaptable mesopredator, the red fox.…”

Habitat partitioning among sympatric tinamous in semiarid woodlands of central Argentina

“…The presence of predators, or greater use of preferred sites, could reduce the likelihood of prey occurrence, or alter prey co-occurrence patterns according to species-specific responses to increased predation risk [28,30]. In the calde ´n woodland region, tinamou species share similar predators [50]. We found that the distribution of each tinamou species could be related to the presence of one or two predator species.…”

“…We installed 16 single, remote cameras (Digital Moultrie Game Spy 4.0 Camera, EBSCO Industries) at regular intervals (2-3 km) in a 4×4 array within each selected 10×10 km square (Fig 1 ) between September 2010 and March 2013, for a total of 720 sites. Although the distance between cameras was relatively long for our study organisms, this sampling design allowed us to record large carnivores and better estimate the occurrence of potential tinamou predators [50]. We installed and georeferenced the cameras along dirt roads, wildlife and cattle trails, following standard practices [20,24,51], operating four grids simultaneously.…”

“…The cameras functioned 24 h per day for an average of 31 days, taking a photograph with a minimum 5-min delay between triggering events. We did not use a shorter delay (e.g., 15-30 s) as in other studies due to the large number of cattle in the area that might cause memory cards to fill [50].…”

Livestock activity shifts large herbivore temporal distributions to their crepuscular edges

“…In theory, these shifts allow species to utilize the same spaces and resources they would have otherwise abandoned, allowing for greater coexistence (Carter & Linnell, 2016), though responses likely vary by species and community assemblage. High human densities can alter predator community structures through mesopredator and prey release from top‐down pressures (Shamoon et al., 2018; Wang et al., 2019; Zanón Martínez et al., 2022). In some instances, human activity may create spatial refuges for prey (Muhly et al., 2011), and prey may deliberately select locations with high human densities to shield themselves from apex predators (Gordon et al., 2015).…”