Seasonal resource selection of an arboreal habitat specialist in a human-dominated landscape: a case study using red panda

Effects of sex and season (breeding and non-breeding) on microhabitat selection in Stejneger's bamboo pitviper (Viridovipera stejnegeri)

Habitat quality and availability are crucial for the survival and reproduction of animal species. Intraspecific and seasonal differences in habitat selection reflect adaptations to changing biological requirements and environmental factors. To investigate the effects of season (breeding and non-breeding) and sex on microhabitat selection in snakes, here we employed field surveys to analyze microhabitat selection data for Stejneger's bamboo pitviper (Viridovipera stejnegeri) across different sexes and seasons. Results indicated that although no significant difference was observed between groups, marked differences in certain microhabitat factors were noted. Specifically: (1) Non-breeding season females (NBF) displayed distinct differences in altitude, slope position, distance from roads compared to other groups. (2) Temperature exerted a lesser effect on non-breeding season individuals compared to breeding season individuals. Additionally, distance from roads only significantly impacted breeding season males, not females. (3) Regarding sexual differences, males and females differed in slope position and distance from residential sites, reflecting their distinct ecological requirements. Regarding seasons, differences in habitat selection between breeding and non-breeding seasons were primarily related to temperature, indicating behavioral changes linked to seasons. (4) Non-breeding season females exhibited the narrowest microhabitat niche width and the least microhabitat niche overlap with other groups, potentially due to their pronounced foraging requirements, which compel them to explore limited habitats with higher human disturbance but richer food sources. This study contributes novel insights into the habitat selection behaviors of snakes.

Comparison Study on the Trophic Niche of Red Pandas Using Stable Isotope Analysis

The red panda (Ailurus), a rare and endangered mammal native to the Himalayan-Hengduan Mountains, has a specialized bamboo diet. Combining morphological and genomic evidence, red pandas have been classified as Ailurus fulgens and Ailurus styani. However, previous studies focused on ecological aspects such as foraging behaviors, habitat use and threats within specific distributions; hence, there is still a gap in quantitative comparative studies on the trophic niches of these two species. In this study, we calculated and compared the isotopic trophic niche widths of A. styani and A. fulgens by measuring carbon and nitrogen stable isotopes in hair keratin of 102 red pandas, then conducting a fecal analysis to explore the diet of a population. The results showed that (1) there was no significant difference in δ13C values between A. styani (-24.73 ± 1.26‱, N = 86) and A. fulgens (-24.43 ± 1.20‱, N = 16); however, A. styani had 1.4‱ higher average δ1⁵N value than that of A. fulgens, and the isotopic niche widths converted by Bayesian ellipse model were A. styani SEAC = 4.40‱2, A. fulgens SEAC = 4.70‱2, which might be caused by their lower and narrower altitude distribution. (2) Niche widths of three genetic populations in A. styani were XXL-LS (5.16‱2), EH-GLG (3.40‱2), QL (2.31‱2), and the comparison of the fecal composition suggested their diet diversity, which might imply a degree of competitive pressure with sympatric animals. (3) Sichuan red pandas occupied a lower trophic position compared to other herbivores but higher than giant pandas in the same ecosystem, and the niche width of red pandas was two times larger than that of sympatric giant pandas, which was related to the foraging strategies and microhabitat selection of the giant and red panda. This research provides basic stable isotopic data for red pandas, offers scientific support for the differentiated and refined conservation and management of the red panda and its habitat, and develops the application of stable isotope analysis in the ecological studies of endangered species.

Alpine Musk Deer (Moschus chrysogaster) Adjusts to a Human-Dominated Semi-Arid Mountain Ecosystem

Comprehension of whether human and livestock presence affects wildlife activity is a prerequisite for the planning and management of humans and livestock in protected areas. Xinglong Mountain Nature Reserve (XMNNR) in northwest China, as a green island in a semi-arid mountain ecosystem, is one of the scattered and isolated areas for Alpine musk deer (AMD), an endangered species. AMD cohabits their latent habitat area with foraging livestock and humans. Hence, habitat management within and outside the distribution areas is crucial for the effective conservation of AMD. We applied camera traps to a dataset of 2 years (September 2018-August 2020) to explore seasonal activity patterns and habitat use and assess the impacts of AMD habits in XMNNR. We investigated AMD responses to livestock grazing and human activities and provided effective strategies for AMD conservation. We applied MaxENT modeling to predict the distribution size under current conditions. The activity patterns of the AMD vary among seasons. The optimum habitat average distance to cultivated land ranges of AMD (150~3300 m during grass period/100~3200 m during withered grass period), distances to the residential area ranges (500~5700 m during the grass period/1000~5300 m during the withered grass period), elevation ranges (2350~3400 m during the grass period/2360~3170 m during the withered grass period), aspect ranges (0~50° and 270~360°), normalized vegetation index ranges (0.64~0.72 during the grass period/0.14~0.60 during the withered grass period), and land cover types (forest, shrub, and grassland). Results present that the predicted distributions of AMD were not confined to the areas reported but also covered other potential areas. The results provide evidence of strong spatial-temporal avoidance of AMD in livestock, but gradually adjusting to human activities. These camera trap datasets may open new opportunities for species conservation in much wider tracts, such as human-dominated landscapes, and may offer guidance and mitigate impacts from livestock, as well as increase artificial forest planting and strengthen the investigation of the potential population resources of AMD.