摘要: The distribution and diversity of the species are closely related to the global climate. As the most widely distributed species of Bufonidae in China, the study of the distribution pattern and habitat suitability of the Asiatic toad under climate change can help us understand the reply pattern of Bufonidae habitat to climate change. Here, combined with the Maxent model and GIS technology, the effects of climate change on the distribution pattern and habitat suitability of the Asiatic toad were comprehensively analyzed. The results show that the rainfall during the wettest season (Bio16) and the mean temperature of the driest season (Bio9) have a considerable impact on the distribution of the Asiatic toad. In the next 30 to 50 years, across the overall spacial scale of the Chinese mainland, the habitat of the Asiatic toad will be primarily in the eastern part of China and less in south part, while its distribution area will expand to the midwest and northwest parts of China. Overall, the area in which it can be distributed will be reduced and suitable habitat will shift to some regions of higher latitude and elevation. In a word, we systematically analyzed the changes of the distribution pattern and habitat suitability of the Asiatic toad with climate change, and we aim to provide data on how climatic variation may impact amphibians.

摘要: Small and isolated populations face several intrinsic risks, such as genetic drift, inbreeding depression, and reduced gene flow. Thus, patterns of genetic diversity and differentiation have become an important focus of conservation genetics research. The golden snub-nosed monkey Rhinopithecus roxellana, an endangered species endemic to China, has experienced rapid reduction in population size and severe population fragmentation over the past few decades. We measured the patterns of genetic diversity and population differentiation using both neutral microsatellites and adaptive major histocompatibility complex (MHC) genes in 2 R. roxellana populations (DPY and GNG) distributed on the northern and southern slopes of the Qinling Mountains, respectively. Eight MHC-linked haplotypes formed by 5 DQA1 alleles, 5 DQB1 alleles, 5 DRB1 alleles, and 4 DRB2 alleles were detected in the 2 populations. The larger GNG population showed higher genetic variation for both MHC and microsatellites than the smaller DPY population, suggesting an effect of genetic drift on genetic variation. Genetic differentiation index (FST) outlier analyses, principal coordinate analysis (PCoA), and inferred population genetic structure showed lower genetic differentiation in the MHC variations than microsatellites, suggesting that pathogen-mediated balancing selection, rather than local adaptation, homogenized the MHC genes of both populations. This study indicates that both balancing selection and genetic drift may shape genetic variation and differentiation in small and fragmented populations.

摘要: In areas highly affected by anthropogenic disturbances, artificial (human-made) freshwater ecosystems can provide habitat for maintaining and conserving regional freshwater biodiversity. We assessed how the physical habitat of artificial ponds affected the structure of benthic macroinvertebrate assemblages. To do so, we tested two hypotheses. (1) Physical habitat disturbances are not detrimental to the diversity of nearby artificial ponds, and (2) Physical habitat disturbances do not cause significant shifts in taxonomic composition. Our results rejected both null hypotheses, i.e., macroinvertebrate diversity metrics correlated significantly and positively with Physical Habitat Integrity index scores, and only sites with high habitat condition scores were significantly associated with sensitive indicator taxa. Our results highlight the importance of maintaining physical habitat conditions for sustaining the ecological health of artificial ponds.

摘要: Despite long-standing interest, the mechanisms driving aquatic macroinvertebrate drift in tropical streams remain poorly understood. Therefore, the objective of this study was to evaluate which environmental metrics drive macroinvertebrate drift in neotropical sky island streams. We evaluated whether altitude, the abundance of food resources, and variations in water quality influenced macroinvertebrate drift density, diversity, richness, and functional feeding groups. An hypothesis was developed to test whether increased altitude, lower food availability (particulate organic matter), and discharge would increase the density, taxonomic richness, and diversity of drifting invertebrates. Nine headwater stream sites were sampled in the rainy and dry seasons in the Espinhaco Meridional Mountain Range (EMMR) of southeast Brazil. Samples were collected using drift nets deployed from 5:00 p.m. to 8:00 p.m. The abundance of food resources was assessed through estimates of coarse (CPOM) and fine (FPOM) particulate organic matter, and primary producers. CPOM availability was an important explanatory variable for Gathering-Collectors and Scrapers, Altitude was important for Shredders and Predators, and FilteringCollectors were linked to water discharge, suggesting that functional group drift masses were linked to different ecosystem components. Water temperature, conductivity, dissolved oxygen, current velocity, FPOM biomass and microbasin elevation range exerted little influence on macroinvertebrate drift. Regarding taxa composition, this study also found that Baetidae and Leptohyphidae (Ephemeroptera) and Chironomidae and Simuliidae (Diptera) were the most abundant groups drifting.