Niche partitioning among neotropical felids

Understanding how sympatric predators coexist remains a central question in community ecology, particularly when those species are phylogenetically related obligate carnivores with similar body sizes and trophic roles. In the neotropics this challenge is particularly salient because jaguars (Panthera onca), pumas (Puma concolor), ocelots (Leopardus pardalis) and margays (Leopardus wiedii) are broadly sympatric pairs of large- and medium-bodied hypercarnivores in apparent violation of the principle of limiting similarity. We conducted a comprehensive multi-dimensional analysis of coexistence mechanisms among two large-bodied (jaguars and pumas) and two medium-bodied (ocelots and margays) felids by quantifying spatial, temporal, and dietary niche partitioning in the Maya Biosphere Reserve, Guatemala. To do so, we integrated high-resolution fecal DNA metabarcoding using extant and novel assays, ground and arboreal camera trapping and abundance-mediated species interaction models. Contrary to expectations, we found little evidence for body size-based prey partitioning among pairs of similarly sized felids. Instead, vertical dietary partitioning driven by selection of arboreal versus terrestrial prey emerged as the dominant axis of niche differentiation. Jaguars specialized on large terrestrial prey-notably peccaries-and armadillos, while pumas exhibited high consumption of arboreal primates. Among smaller felids, despite high uncertainty, margays appeared to more strongly select arboreal prey. Also contrary to expectations, we found little evidence for spatial segregation, even among species with potential for interference competition. Despite high rates of intraguild predation observed between certain species pairs, jaguars, pumas and ocelots exhibited positively associated capture rates. Abundance-mediated interaction modelling revealed weak to no evidence of interspecific interactions between the species driving spatial or temporal variation in abundance. Likewise, pairs of felids with similar body sizes had broadly overlapping daily activity patterns. However, temporal activity patterns reduced overlap between large- and medium-bodied felids, suggesting diel shifts may help mitigate interference competition and intraguild predation. Our findings highlight arboreal versus terrestrial prey selection as a key mechanism facilitating coexistence among size-based species pairs in neotropical forests. We demonstrate the benefits of incorporating high-resolution diet analysis, canopy camera trapping and arboreality assessments into future tropical carnivore ecology research to reveal how vertical niche dynamics facilitate species coexistence.