Assessing the urban environmental quality of mountainous cities: A case study in Chongqing,China

Despite the degradation of urban environment associated with the rapid urbanization, limited studies have examined the spatial patterns and driving factors of urban environmental quality (UEQ) in mountainous cities in China. Using a case study of Chongqing, UEQ in mountainous cities was measured in the dimensions of physical environment, built environment, and natural hazards, followed by an exploration of its spatial pattern. It was found that the UEQ has been significantly affected by the factors of pollution and dense built environment. Pollution factor was highly correlated with industrial land ratio and land surface temperature, and dense built environment factor bore close relationship with road density, impervious fraction, and floor–area ratio. Through a cluster analysis, Chongqing was classified into five UEQ clusters and their spatial distribution was found as a combined polycentric and mosaic pattern. While mountains and hill ridges, riverside banks, small hills, and streams showed high UEQ indices, valley floors exhibited low UEQ values. Polycentric urban development adapting to mountainous landscapes was believed to contributing to the extremely low UEQ in urban center and subcenters. However, polycentricity, leading to appropriate spatial match of jobs/housing, also resulted in high UEQ in the peripheries. The effects of redevelopment, relocation or suburbanization on UEQ were also discussed through four examples.     

Performance in three shell functions predicts the phenotypic distribution of hard‐shelled turtles

Adaptive landscapes have served as fruitful guides to evolutionary research for nearly a century. Current methods guided by landscape frameworks mostly utilize evolutionary modeling (e.g., fitting data to Ornstein–Uhlenbeck models) to make inferences about adaptive peaks. Recent alternative methods utilize known relationships between phenotypes and functional performance to derive information about adaptive landscapes; this information can then help explain the distribution of species in phenotypic space and help infer the relative importance of various functions for guiding diversification. Here, data on performance for three turtle shell functions–strength, hydrodynamic efficiency, and self‐righting ability–are used to develop a set of predicted performance optima in shell shape space. The distribution of performance optima shows significant similarity to the distribution of existing turtle species and helps explain the absence of shells in otherwise anomalously empty regions of morphospace. The method outperforms a modeling‐based approach in inferring the location of reasonable adaptive peaks and in explaining the shape of the phenotypic distributions of turtle shells. Performance surface‐based methods allow researchers to more directly connect functional performance with macroevolutionary diversification, and to explain the distribution of species (including presences and absences) across phenotypic space.     

A trait‐based approach to predict population genetic structure in bees

Understanding population genetic structure is key to developing predictions about species susceptibility to environmental change, such as habitat fragmentation and climate change. It has been theorized that life‐history traits may constrain some species in their dispersal and lead to greater signatures of population genetic structure. In this study, we use a quantitative comparative approach to assess if patterns of population genetic structure in bees are driven by three key species‐level life‐history traits: body size, sociality, and diet breadth. Specifically, we reviewed the current literature on bee population genetic structure, as measured by the differentiation indices Nei's G_ST, Hedrick's G′_ST, and Jost's D. We then used phylogenetic generalised linear models to estimate the correlation between the evolution of these traits and patterns of genetic differentiation. Our analyses revealed a negative and significant effect of body size on genetic structure, regardless of differentiation index utilized. For Hedrick's G′_ST and Jost's D, we also found a significant impact of sociality, where social species exhibited lower levels of differentiation than solitary species. We did not find an effect of diet specialization on population genetic structure. Overall, our results suggest that physical dispersal or other functions related to body size are among the most critical for mediating population structure for bees. We further highlight the importance of standardizing population genetic measures to more easily compare studies and to identify the most susceptible species to landscape and climatic changes.     

新疆北疆地区景观生态类型分类初探：以新疆沙湾县为例

1　前　　言新疆生态环境的现状喜忧参半,绿洲内部生态环境得到改善,但沙漠化过程不断加剧,成为新疆生态环境良性循环的极大隐患。景观生态学以综合整体的思想审视生态环境的现状和变化,为我们更成功地解决所面临的生态问题提供了新的理论和方法。本文试图在新疆沙湾县生态环境监测工作的基础上,提出适宜于新疆北疆地区的景观生态类型分类系统,以便更好地认识、利用和管理各类景观,达到人地共生和持续发展的目的。2　沙湾县环境概况沙湾县地处北疆天山中部的依连哈比尔尕山北麓与准噶尔盆地南缘之间,界于Ｅ84°57′～86°09′和Ｎ43°20′～…     

Landscape genomics reveals genetic evidence of local adaptation in a widespread tree,the Chinese wingnut (Pterocarya stenoptera)

Understanding the genetic basis underpinning local adaptation is one of the fundamental issues in ecological and evolutionary biology. In this study, we investigated the genomic basis underlying local adaptation of the Chinese wingnut (Pterocarya stenoptera C. DC). Our population genomic analyses revealed nine spatial genetic clusters across the current distribution range of this species. Based on the assessment of genetic–environment association, we found that adaptive divergence of the P. stenoptera populations were mainly shaped by solar radiation during fruit development, temperature seasonality, annual temperature, precipitation, and air humidity. In particular, our genome-wide scanning identified a total of 801 candidate single nucleotide polymorphisms (SNPs) that are highly correlated with diverse environmental factors. Further functional annotation of the SNPs identified some candidate genes that are involved into temperature, water, and light adaptation. Taken together, our results suggest that natural selection during local adaptation has contributed to the success of survival to diverse heterogenous environmental conditions. Our study provides important insights into the fundamental knowledge of the genetic basis underlying the local adaptation of non-model species.     

Top-down effects of foraging decisions on local,landscape and regional biodiversity of resources (DivGUD)

Foraging by consumers acts as a biotic filtering mechanism for biodiversity at the trophic level of resources. Variation in foraging behaviour has cascading effects on abundance, diversity, and functional trait composition of the community of resource species. Here we propose diversity at giving-up density (DivGUD), i.e. when foragers quit exploiting a patch, as a novel concept and simple measure quantifying cascading effects at multiple spatial scales. In experimental landscapes with an assemblage of plant seeds, patch residency of wild rodents decreased local α-DivGUD (via elevated mortality of species with large seeds) and regional γ-DivGUD, while dissimilarity among patches in a landscape (ß-DivGUD) increased. By linking theories of adaptive foraging behaviour with community ecology, DivGUD allows to investigate cascading indirect predation effects, e.g. the ecology-of-fear framework, feedbacks between functional trait composition of resource species and consumer communities, and effects of inter-individual differences among foragers on the biodiversity of resource communities.     

克里雅河中游土地利用/覆被与景观格局变化研究

干旱内陆河流在维系绿洲形成与发展,连接干旱区绿洲各类生态子系统中具有举足轻重的作用。以克里雅河中游为研究区,基于遥感影像分析了1995年、2005年和2015年3个时期的土地利用/覆被与景观格局变化特征,采用缓冲区分析法,揭示了土地利用/覆被与景观格局的时空变化特征,用土地覆被转移指数模型计算了土地利用转移方向。研究结果表明:1)1995—2015年,克里雅河中游耕地持续增加,草地和水体呈减少趋势,耕地增加和水体减少主要发生在河道附近,草地退化在绿洲边缘较严重。在河道附近,耕地主要由水体和草地转入,水体主要转出到耕地,而在绿洲边缘草地主要转出为其他用地;2)从景观水平看,研究区整体景观具有破碎化趋势,景观多样性降低,分离度变大,整个景观向均匀化发展,此变化在河道附近和绿洲边缘较明显。从类型水平看,耕地斑块数量持续增加,有向连片生成的趋势。草地斑块分离度越来越大,逐渐失去了在绿洲中的优势。水体有破碎化趋势;3)从土地转移指数看,研究区土地覆被总体变差;河道附近土地覆被经历了退化-改善的变化过程,而其他缓冲带则是持续退化,尤其绿洲边缘退化程度最为严重。     

基于“源-汇”理论的生态型市域景观生态安全格局构建

生态型市域是随着我国生态文明建设不断深入而产生的一批以生态输出为己任,支撑区域乃至全国生态安全的重要生态型区域,该类区域景观生态安全格局的构建是协调域内社会经济与生态环境保护的基础。选取典型生态型市域张家口市,基于"源-汇"理论构建景观生态安全格局,划定不同保护重点的五大生态功能区,识别重点生态保护区、重点生态修复区和廊道系统,以此作为保障城市生态安全的基础,逐步形成"点-线-面"三位一体的立体保护体系,同时提出了生态安全格局构建的优先次序,为张家口市生态安全格局分步骤建设提供依据。研究结果表明,张家口市景观生态安全格局重点保护区缺失严重,缺失区域总面积达1555.77 km~2,占生态保护核心区面积的75.60%,重点生态修复区域比例较大,占全区面积的24.27%,生态廊道存在3个主要缺失区域,针对张家口市生态安全格局建设任务艰巨的现状,提出了分步骤建设的构建思路,即优先进行重点生态修复、重点生态保护缺失区域和生态廊道缺失区域建设,针对重点生态修复区域面积比例较大提出了分步修复的优先次序,即水域修复区林草水修复区林草修复区林水修复区水草修复区林地修复区草地修复区,并提出了优先建设冬奥会场及沿途生态廊道的思路,此外,为实现张家口区域生态系统的支撑作用,需在完成重点区域建设的基础上不断扩大生态保护范围。研究为欠发达生态型市域景观生态安全格局构建及生态环境保护体系建设提供了范例。     

人为干扰对神农架川金丝猴连通性及遗传多样性的影响

川金丝猴湖北种群是川金丝猴分布的最东缘,现主要分布于神农架国家公园和巴东自然保护区,其作为单独的管理单元,相对较低的遗传多样性、孤立的遗传状态和较小的种群数量,使得该种群面对环境变化脆弱性高。以神农架为研究区域,首先基于物种分布模型获得川金丝猴移动的阻力图层,利用电路理论分析适宜生境连接度;其次,设置道路和旅游两个人为干扰情景,运用最小费用距离模型与电路理论模型,分析道路和旅游活动对川金丝猴移动路径以及对不同亚群内和亚群间连通性的影响;最后,利用CDPOP软件模拟道路对川金丝猴遗传多样性的影响。结果表明:(1)神农架川金丝猴适宜生境分布较集中,生境斑块间存在多个潜在扩散区域;(2)道路改变了川金丝猴往来于南北生境间的最优路径,旅游干扰对川金丝猴移动路径无明显影响,其干扰主要在于川金丝猴对其具有回避性,回避距离为100 m;(3)道路显著降低金猴岭亚群内的连通性,并显著增加了所有亚群间的移动阻力,旅游活动对亚群内和亚群间的连通性无显著影响;(4)川金丝猴种群在150年内的遗传多样性呈下降趋势,道路的影响将加剧遗传多样性下降的程度。基于以上结果本文提出了针对性的保护建议,对于该物种的保护和其他濒危物种的类似研究具有较强的参考价值和借鉴意义。