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ABSTRACT Maintaining a healthy status is crucial for the successful captive breeding of critically endangered Rhinopithecus brelichi, it is conducive to ex situ conservation of this species and rejuvenation of its population. However, changes in the feeding environment and food can affect the composition and function of the gut microbiota in R. brelichi, ultimately impacting its health and adaptation. Herein, 16S rRNA gene sequencing was employed to determine the gut microbiota composition and functional variations between wild and captive R. brelichi populations. The results showed that the captive group had higher alpha diversity than the wild group, and significant differences were observed in their beta diversity. Captive and wild R. brelichi showed similar microbiota at the phylum level, which mainly comprised Firmicutes, Bacteroidota, and Spirochaetota, but captivity reduced the Firmicutes/Bacteroides ratio. Differential abundance analysis revealed that the relative abundance of microbiota related to cellulose degradation, such as Prevotellaceae_UCG_001, Christensenellaceae_R_7_group, Ruminococcus, and Fibrobacter, differed significantly between the two groups. Furthermore, the potential pathogens Acinetobacter and Treponema were significantly abundant in wild and captive groups, respectively. Functional predictions demonstrated that the most significant functional pathways at the second level between captive and wild monkeys were carbohydrate, amino acid, and lipid metabolisms. The captive monkeys exhibited higher digestive capacity and endocrine regulation as well as a higher risk of infectious diseases than wild monkeys. These findings can serve as a valuable theoretical basis for promoting the healthy breeding of R. brelichi and as a guide for future evaluation of the health of wild and captive monkeys.

Sympatric species inhabiting similar ecological niches can coexist by partitioning aspects of available ecological resources, such as temporal, spatial, and nutritional niches. Ungulates often coexist in the same habitat, resulting in temporal partitioning and divergence in foraging strategies and spatial utilization. To understand the temporal patterns of ecological differentiation and coexistence mechanisms among sympatric ungulates, we analyzed the monitoring data in Fanjingshan National Nature Reserve, Guizhou, China, from 2017 to 2022. Kernel density estimation was used to scrutinize disparities in diurnal activity patterns among four ungulates [tufted deer (Elaphodus cephalophus), Reeves' muntjac (Muntiacus reevesi), wild boar (Sus scrofa), and mainland serow (Capricornis milneedwardsii)] as well as the interspecies variances during different seasons, at diverse altitudes, and between breeding and non-breeding periods. Daily activity patterns differed significantly among four species, with those of tufted deer, Reeves' muntjac, and wild boar affected significantly by season and breeding cycle. In addition, the daily activity rhythms of four species were affected by altitude. Thus, the daily activity rhythms of these ungulates were resulted from a combination of environmental factors and interspecific competitive interactions, as well as the reproductive cycle of each species. Our results provided a scientific reference for the effective management of wildlife and forest ecosystems, and we suggest that knowledge of temporal dynamics should be integrated into conservation planning for these sympatric species.

Assessing the trophic niche and interspecific relationships between related species and determining how the species maintain differences in nutritional niches while coexisting in the same area are important topics in ecological research. Therefore, exploring the mechanism of food resource utilization, competition and coexistence among species distributed in the same region is important. In this study, we used fecal samples and metagenome sequencing technology to study the plant feeding habits and coexistence mechanisms of Tibetan macaques (Macaca thibetana) and grey snub-nosed monkeys (Rhinopithecus brelichi) within the same area. In the winter of 2020, we collected a total of 40 fecal samples from Tibetan macaques and grey snub-nosed monkeys; of those, 29 samples were considered valid and were analyzed using DNA metabarcoding. The results showed that in winter, Tibetan macaques consumed plants from 117 families and 184 genera, whereas grey snub-nosed monkeys consumed plants from 109 families and 165 genera. Diversity analysis revealed that there was a significant difference in the food composition of Tibetan macaques and grey snub-nosed monkeys. Tibetan macaques had a broader food niche width than grey snub-nosed monkeys at the family and genus levels. In winter, the food niches of Tibetan macaques and grey snub-nosed monkeys almost entirely overlapped (0.99). Our research provides detailed dietary data for Tibetan macaques and grey snub-nosed monkeys and valuable information that can aid in conservation efforts targeting these species.