Shilong Liu

Designing protected-area networks that remain effective under climate change is a challenge for environmental managers. The challenge is acute in dry-hot valleys, where biodiversity concentrates along narrow riparian zones and existing reserves were delineated under static-climate assumptions. Here, we present a transferable decision-support workflow that integrates species distribution modeling, multi-scenario climate projection, and quantitative gap analysis into a single management-oriented diagnostic. We apply it to four sympatric bee-eater species in the Yuanjiang dry-hot valley, Southwest China. Maximum entropy models projected habitat suitability under three future climate scenarios spanning low to high emissions for the 2030s. The projected habitats were then overlaid on existing reserves to identify gaps. Maximum temperature of the warmest month and distance to water jointly governed habitat suitability for all four species. Climate vulnerability, however, diverged sharply among species. Suitable habitat is projected to expand for the Blue-tailed (Merops philippinus), Blue-throated (M. viridis), and Chestnut-headed Bee-eaters (M. leschenaulti), but to contract for the range-edge Green Bee-eater (M. orientalis). Existing reserves capture less than 1% of suitable habitat, leaving roughly 24,000 km² unprotected. This exposes a structural mismatch between linear riparian habitat and polygonal reserve geometry. We propose a three-tier, climate-adaptive management response combining climate-refugia reinforcement, anticipatory corridor extension, and off-reserve conservation instruments. The workflow is transferable to other dry-hot-valley systems and gives environmental managers a favorable approach for diagnosing and remedying climate-induced gaps in regional protected-area networks.

Birds serve as ecological bioindicators of metal/metalloid contamination due to their continuous environmental exposure. In northeast China, where metal/metalloid pollution is a serious environmental issue driven by anthropogenic activities, its effects on birds remain understudied. This study analyzed tail feathers from ten terrestrial raptor species across four families to assess ecological risks from cadmium (Cd), lead (Pb), arsenic (As), zinc (Zn), copper (Cu), and manganese (Mn). Results showed that Tiger Shrike (Lanius tigrinus) had the highest As (54.35 ± 69.76 mg kg⁻¹) and Cd (5.45 ± 3.94 mg kg⁻¹) residues, followed by Brown Shrike (Lanius cristatus), which also exhibited elevated Pb concentrations (33.61 ± 93.20 mg kg⁻¹). This suggests Shrikes (Laniidae) are more susceptible to metal/metalloid contamination. Significant differences in pollutant levels were found between Little Owl (Athene noctua) and Long-Eared Owl (Asio otus), despite similar feeding behaviors, indicating species-specific sensitivity. Stable carbon isotopic (δ¹³C) values suggested that predatory birds feeding in habitats with lower δ¹³C values may have greater exposure to metal/metalloid pollutants. All studied predatory bird species, except Long-Eared Owl, showed at least one metal/metalloid concentration above toxicity thresholds, highlighting potential ecological risks. These findings emphasize the need for stringent control of anthropogenic metal emissions to mitigate adverse effects on wildlife and human health.

Habitat fragmentation and shifts related to climate change threaten global biodiversity, with impacts likely to be most pronounced at tropical regions. With global warming, migratory birds that breed at these regions are likely to be even more vulnerable to climate change than those in temperate regions. Here we inspected our idea using four sympatric bee-eater species: M. philippinus, M. viridis, M. orientalis, and M. leschenaultia. Based on field surveys and citizen science data, we modelled the current distributions of the four species with species distribution models (SDM), tested those models for robustness and then used them to predict climatically suitable breeding ranges in 2060 according to bioclimatic variables and different climate change scenarios. Results revealed that annual mean temperature (24°C), maximum temperature of the warmest month (33°C), low elevation (300–400 m), and distance to rivers were the important drives. Under future climates, suitable habitats for bee-eaters are predicted to consolidate along the main stem, with low-suitability areas declining sharply. While medium- to high-suitability zones expand, fragmentation risks intensify. The nonlinear responses to thermal, hydrological, and anthropogenic factors underscore their potential as ecological indicators. Their distribution dynamics and population trends provide early warnings of habitat degradation (e.g., cliff habitat loss) and quantify the efficacy of conservation interventions. This study advances biodiversity conservation strategies for dry-hot valleys, emphasizing the prioritization of critical habitats (e.g., riparian buffers and cliffs) and ecological corridor development. It further highlights bee-eaters as robust bioindicators for monitoring ecosystem health in thermally stressed riverine landscapes.

Understanding the mechanisms of community assembly is a key question in ecology. Metal pollution may result in significant changes in bird community structure and diversity, with implications for ecosystem processes and function. However, the relative importance of these processes in shaping the bird community at the polluted area is still not clear. Here, we explored bird species richness, functional, and phylogenetic diversity, and the assembly processes of community at the mine region of southwest China. Our results showed that the 3 dimensions of diversity at the mine area were lower than that at the reference sites. In the community assembly, the result was 0 < NRI/ NFRI < 1.96, which indicated deterministic processes (environmental filtering) might drive community clustering. The results of the neutral community model, and normalized stochasticity ratio, showed the dominant role of stochastic processes in shaping the bird community assembly. We further quantified the community-level habitat niche breadth (Bcom), and we found that there was no difference in Bcom-value between the mine area and reference sites. This indicates that the bird communities at the mine area and 3 reference sites were not subjected to extreme environmental selection (same or different resource allocation) to form a highly specialized niche. These findings provide insights into the distribution patterns and dominant ecological processes of bird communities under metal exposure, and extend the knowledge in community assembly mechanisms of bird communities living in the mine area.

Apportioning the sources of metals/metalloids is a critical step toward soil quality protection and ecological restoration. The objective of this study was to identify the potential sources of contamination of As, Cd, Cr, Cu, Hg, Mn, Pb, and Zn, and determine the contribution rates of each source, to rice and sugarcane agroecosystems of southwestern Guangxi, southern China. We collected a total of 300 soil samples at a former lead–zinc mine and at two reference sites, 6 and 60 km away from the mine, sampling both agroecosystems at each site. Overall, the positive matrix factorization (PMF) receptor model revealed that in rice paddies at the mine site, mining activities had the highest contribution (60.7% of all examined metals/metalloids), followed by irrigation (25.8%), and agrochemical application (13.5%). At the close reference site, agrochemical application contributed 42.8%, followed by irrigation (22.7%), natural sources (17.4%), and mining activities (17.2%). At the far reference site, agrochemical application was predominant (40.6%), followed by irrigation (32.5%), and natural sources (26.9%). In comparison, at the mine site and the close reference site in sugarcane ecosystems, agrochemical application was predominant (50.1% and 57.4%, respectively), followed by mining activities (49.9% and 42.6%). At the far reference site, agrochemical application contributed 51.2%, followed by natural sources (48.8%). Therefore, the PMF model indicated that the optimal solution was four or three sources per site for rice paddies, but only two sources per site for sugarcane, suggesting that sources of metal/metalloid contamination were more complicated in rice paddy than in sugarcane agroecosystems.