Direct and indirect interactions among predators affect predator fitness, distribution, and overall community structure. Yet, outside of experimental settings, such interactions are difficult to observe and thus poorly understood. Patterns of niche overlap among predators reflect and shape community interactions and may therefore help elucidate the nature and intensity of intraguild interactions. To better understand the coexistence of two apex predators, snow leopards (Panthera uncia) and wolves (Canis lupus), we investigated their spatial, temporal, and dietary niche overlap in summer in the Pamir Mountains of Tajikistan. We estimated population-level space use via spatial capture–recapture models based on noninvasive genetics and camera traps, diel activity patterns based on camera trap detections, and diet composition from prey remains in carnivore scats, from which we estimated coefficients between 0 and 1 for overlap in space, time, and diet, respectively. Snow leopards and wolves displayed moderate spatial partitioning (0.26, 95% confidence interval [CI]: 0.17–37), but overlapping temporal (0.77, 95% CI: 0.64–0.90) and dietary (0.97, 95% CI: 0.80–0.99) niches. Both predators relied on seasonally abundant marmots (Marmota caudata) rather than wild ungulates, their typical primary prey, suggesting that despite patterns of overlap that were superficially conducive to exploitation competition and predator facilitation, prey were likely not a limiting factor. Therefore, prey-mediated interactions, if present, were unlikely to be a major structuring force in the ecosystem. By implication, carnivore conservation planning and monitoring in the mountains of Central Asia should more fully account for the seasonal importance of marmots in the ecosystem.
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Abstract Biologists have long pondered the extreme limits of life on Earth, including the maximum elevation at which species can live and reproduce. Here we review evidence of a self-sustaining population of mice at an elevation that exceeds that of all previously reported for mammals. Five expeditions over 10 years to Volcán Llullaillaco on the Argentina/Chile border observed and collected mice at elevations ranging from 5,070 m at the mountain’s base to the summit at 6,739 m (22,110 feet). Previously unreported evidence includes observations and photographs of live animals and mummified remains, environmental DNA, and a soil microbial community reflecting animal activity that are evaluated in combination with previously reported video recordings and capture of live mice. All of the evidence identifies the mouse as the leaf-eared mouse Phyllotis vaccarum, and it robustly places the population within a haplotype group containing individuals from the Chilean Atacama Desert and nearby regions of Argentina. A critical review of the literature affirms that this population is not only an elevational record for mammals but for all terrestrial vertebrates to date, and we further find that many extreme elevations previously reported for mammals are based on scant or dubious evidence.
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Abstract Aim The biodiversity crisis has highlighted the need to assess and map biodiversity in order to prioritize conservation efforts. Clearwing butterflies (tribe Ithomiini) have been proposed as biological indicators for habitat quality in Neotropical forests, which contain the world's richest biological communities. Here, we provide maps of different facets of Ithomiini diversity across the Neotropics to identify areas of evolutionary and ecological importance for conservation and evaluate their overlap with current anthropogenic threats.
Location Neotropics.
Methods We ran species distribution models on a data set based on 28,986 georeferenced occurrences representing 388 ithomiine species to generate maps of geographic rarity, taxonomic, phylogenetic and Müllerian mimetic wing pattern diversity. We quantified and mapped the overlap of diversity hotspots with areas threatened by or providing refuge from current anthropogenic pressures.
Results The eastern slopes of the Andes formed the primary hotspot of taxonomic, phylogenetic and mimetic diversity, with secondary hotspots in Central America and the Atlantic Forest. Most diversity indices were strongly spatially correlated. Nevertheless, species‐poor communities on the Pacific slopes of the Andes also sheltered some of the geographically rarest species. Overall, tropical montane forests that host high species and mimetic diversity as well as rare species and mimicry rings appeared particularly under threat.
Main conclusions Remote parts of the Upper Amazon may act as refuges against current anthropogenic pressures for a limited portion of Ithomiini diversity. Furthermore, it is likely that the current threat status may worsen with ongoing climate change and deforestation. In this context, the tropical Andes occupy a crucial position as the primary hotspot for multiple facets of biodiversity for ithomiine butterflies, as they do for angiosperms, tetrapods and other insect taxa. Our results support the role of ithomiine butterflies as a suitable flagship indicator group for Neotropical butterfly diversity and reinforce the position of the tropical Andes as a flagship region for biodiversity conservation in general, and insect and butterfly conservation in particular.
