Context: Habitat connectivity is essential for the long-term persistence of species, but is commonly disregarded in climate change impact studies. The Tibetan Plateau contains a biome rich in endemic ungulates, which are highly sensitive to climatic variations and deserve particular attention in conservation planning against climate change. Objectives: We evaluated the response and vulnerability of habitat connectivity to climate change for four ungulate species endemic to the Tibetan Plateau, and examined the robustness of protected areas (PAs) for the conservation of these species under climate change. Methods: For each focal species, we developed ecological niche models to predict the spatial variations in habitat under climate change and conducted a network-theoretical analysis to estimate the consequent changes in habitat connectivity. Moreover, we used the circuit theory to characterize dispersal patterns of these species and conducted gap analyses to estimate the contribution of existing PAs to the conservation of these species. Results: The four focal species will experience a remarkable connectivity loss that outpaced their habitat loss in response to climate change. Currently, 53.39 and 46.64% of the areas that could contribute to the habitat suitability and connectivity, respectively, of these species are unprotected. These values could further increase under future climate conditions. Conclusions: Climate-driven habitat variations may lead to the loss of key connectivity areas between the habitats of ungulates, causing disproportionate decrease in habitat connectivity. The existing PAs on the Tibetan Plateau are not robust for the conservation of the four ungulates. Adjustment of certain key PAs may help to address the conservation gaps.

Cancer remains the primary cause of death worldwide. To develop less toxic anti-cancer drugs to relieve the suffering and improve the survival of cancer patients is the major focus in the anti-cancer field. To this end, marine creatures are being extensively studied for their anti-cancer effects, since extracts from at least 10% of the marine organisms have been shown to possess anti-tumor activities. As a classic Chinese traditional medicine, sea cucumbers and compounds extracted from the sea cucumbers, such as polysaccharides and saponins, have recently been shown to exhibit anti-cancer, anti-inflammatory, and anti-oxidant effects. Holothuria leucospilota (H. leucospilota) is a tropical edible sea cucumber species that has been successfully cultivated and farmed in large scales, providing a readily available source of raw materials to support the development of novel marine anti-cancer drugs. However, very few studies have so far been performed on the biological activities of H. leucospilota. In this study, we first investigated the anti-cancer effect of H. leucospilota protein on three cancer cell lines (i.e., HepG2, A549, Panc02) and three normal cell lines (NIH-3T3, HaCaT, 16HBE). Our data showed that H. leucospilota protein decreased the cell viabilities of HepG2, A549, HaCaT, 16HBE in a concentration-dependent manner, while Panc02 and NIH-3T3 in a time- and concentration-dependent manner. We also found that the inhibitory effect of H. leucospilota protein (≥10 μg/mL) on cell viability is near or even superior to EPI, a clinical chemotherapeutic agent. In addition, our data also demonstrated that H. leucospilota protein significantly affected the cell cycle and induced apoptosis in the three cancer cell lines investigated; in comparison, it showed no effects on the normal cell lines (i.e., NIH-3T3, HaCaT and 16HBE). Finally, our results also showed that H. leucospilota protein exhibited the excellent performance in inhibiting cell immigrations. In conclusion, H. leucospilota protein targeted the cancer cell cycles and induced cancer cell apoptosis; its superiority to inhibit cancer cell migration compared with EPI, shows the potential as a promising anti-cancer drug.

Geographical backgrounds and dispersal ability might have strong imprint on assemblage dissimilarity; however, these aspects have generally been overlooked in large-scale beta diversity studies. Here, we examined whether patterns and drivers of taxonomic beta diversity (TBD) and phylogenetic beta diversity (PBD) of breeding birds in China vary across 1) regions on both sides of the Hu Line, a line that demarcates China’s topographical, climatic, economic, and social patterns, and 2) species with different dispersal ability. TBD and PBD were calculated and partitioned into turnover and nestedness components using a moving window approach. Variables representing climate, habitat heterogeneity, and habitat quality were used to evaluate the effects of environmental filtering, whereas spatial distance was used to assess the influences of dispersal limitation. Variance partitioning analysis was used to assess the relative role of these variables. In general, TBD and PBD values were high in mountainous areas and environmental filtering largely determined TBD and PBD. However, different dominating environmental filters on both sides of the Hu Line led to divergent beta diversity patterns. Specifically, climate-driven species turnover and habitat heterogeneity-related species nestedness dominated the regions at east and west of the Hu Line, respectively. Additionally, bird species with stronger dispersal ability were more susceptible to environmental filtering resulting in more homogeneous assemblages. Our results indicated that regions with distinctive geographical backgrounds might present different ecological factors that lead to divergent assemblage dissimilarity patterns, and dispersal ability determines the response of assemblages to these ecological factors. Identifying a single universal explanation for the observed pattern without considering these aspects might lead to simplistic or incomplete conclusions. Therefore, it is essential to consider the combined effect of geographical background and dispersal ability for comprehensively understanding large-scale patterns of beta diversity and for planning conservation strategies.

Understanding how and why assemblage dissimilarity changes along spatial gradient is a great challenge in ecology, because answers to these questions depend on the analytical types, dimensions, and components of beta diversity we concerned. To obtain a comprehensive understanding of assemblage dissimilarity and its implications for biodiversity conservation in the Himalayas, we explored the elevational patterns and determinants of beta diversity and its turnover and nestedness components of pairwise and multiple types and taxonomic and phylogenetic dimensions simultaneously. Patterns of beta diversity and their components of different types and dimensions were calculated based on 96 sampling quadrats along an 1800−5400 m elevational gradient. We examined whether and how these patterns differed from random expectations using null models. Furthermore, we used random forest methods to quantify the role of environmental variables representing climate, topography, and human disturbance in determining these patterns. We found that beta diversity and its turnover component, regardless of its types and dimensions, shown a hump-shaped elevational patterns. Both pairwise and multiple phylogenetic beta diversity were remarkably lower than their taxonomic counterpart. These patterns were significantly less than random expectation and were mostly associated with climate variables. In summary, our results suggested that assemblage dissimilarity of seed plants was mostly originate from the replacement of closely related species determined by climate-driven environmental filtering. Accordingly, conservation efforts should better cover elevations with different climate types to maximalize biodiversity conservation, rather than only focus on elevations with highest species richness. Our study demonstrated that comparisons of beta diversity of different types, dimensions, and components could be conductive to consensus on the origin and mechanism of assemblage dissimilarity.