千岛湖雀形目鸟类群落嵌套结构分析

2006年4月至2007年11月, 采用截线法对千岛湖20个岛屿上的雀形目鸟类种类组成进行调查, 检验其群落是否符合嵌套式分布的格局。此外通过野外直接记录与辨认法对岛屿上的植物种类组成进行调查, 同时通过查阅文献资料和野外调查获得鸟类体长、分布宽度和生境专属性等生活史特征参数, 以及采用GIS分析测定岛屿面积和隔离度参数, 进而分析和探讨雀形目鸟类群落嵌套格局的影响因素。结果显示, 千岛湖岛屿雀形目鸟类群落呈现显著的嵌套结构, 岛屿面积、植物物种丰富度和生境专属性对其嵌套结构具显著性的影响。千岛湖岛屿雀形目鸟类存在着选择性灭绝过程; 植物物种丰富度和鸟类生境专属性则通过影响鸟类在不同生境下的分布对鸟类群落嵌套结构产生影响。上述结果表明千岛湖岛屿雀形目鸟类群落嵌套格局同时受到栖息地和物种两方面因素的影响, 为此我们认为应更多地关注那些面积较大和植物物种丰富度较高的岛屿, 以及生境专属性较高的种类等鸟类多样性及其栖息地的保护策略。     

千岛湖陆桥岛屿地表蚂蚁群落物种多样性空间格局及其影响因素

为了探讨千岛湖岛屿景观参数对地表蚂蚁群落物种α和β多样性空间格局的影响, 作者分别于2017和2018年的5-8月, 采用陷阱法、凋落物分拣法和手捡法调查了千岛湖33个岛屿上的地表蚂蚁群落, 并依据食性将其划分为捕食性蚂蚁和杂食性蚂蚁。利用回归模型分析了全部蚂蚁、捕食性蚂蚁和杂食性蚂蚁群落α和β多样性与岛屿景观参数的关系。结果表明, 岛屿面积对全部蚂蚁、捕食性蚂蚁和杂食性蚂蚁的物种丰富度均有显著的正向影响, 而隔离度则无显著作用。蚂蚁群落的β多样性由空间周转组分主导。岛屿面积差对全部蚂蚁、捕食性蚂蚁和杂食性蚂蚁群落β多样性的嵌套组分有正向影响, 隔离度差只对杂食性蚂蚁的总体β多样性有正向影响。因此, 岛屿面积是影响千岛湖地表蚂蚁群落物种丰富度的主要因素, 并且岛屿面积通过嵌套组分来影响蚂蚁群落的β多样性, 表现出选择性灭绝过程。此外, 不同食性蚂蚁可能因为扩散能力的差异对岛屿景观参数产生不同的响应。     

千岛湖陆桥岛屿鸟类集团对栖息地片段化的敏感性及其季节变化

为探究千岛湖陆桥岛屿不同鸟类集团对栖息地片段化敏感性的差异和季节变化,于2009年4月—2012年1月鸟类繁殖季(4、5、6月)和冬季(11、12、1月)对千岛湖41个陆桥岛屿鸟类集团进行了研究。结果表明,冬季杂食鸟对片段化敏感性高于食虫鸟,繁殖季时二者无显著差异,繁殖季和冬季时下层鸟对片段化敏感性均高于林冠鸟,冬季留鸟对片段化敏感性高于候鸟,繁殖季则无显著差异。杂食鸟和留鸟对片段化敏感性存在季节差异,而食虫鸟、林冠鸟、下层鸟和候鸟对片段化敏感性均无季节差异。不同鸟类集团对栖息地片段化敏感性的差异和季节变化规律,有助于人们在栖息地管理和保护区设计时采取更有针对性的鸟类保护措施。     

园林鸟类群落的岛屿性格局

岛屿群落由于受岛屿栖息地特征结构的影响而产生一系列特殊的格局。通过对杭州市园林鸟类群落的研究,分析了园林鸟类群落的物种数、组成和多度与园林岛屿性状的关系,从而确定了园林鸟类群落存在如下与园林的岛屿性状有关的格局:(1)在物种数方面,在相同的取样面积下,园林的物种数随园林面积的增大而减少;(2 )在群落组成上,园林鸟类群落呈现出不完全的嵌套格局,分布于物种数较少的园林中的物种多数也分布在物种数较多的园林中;(3)在物种多度方面,园林鸟类的总密度随面积的增大而减少,园林鸟类多度的均匀度随着面积的增大而提高。群落的岛屿性格局反映了栖息地的岛屿化对群落的影响,总称之为群落的岛屿效应。通过比较全年、繁殖季节、越冬季节和迁徙季节群落岛屿性格局的显著性,分析群落的稳定性与群落岛屿效应之间的关系,认为两者之间没有必然的联系,相对非稳定的群落也可导致显著岛屿效应     

千岛湖岛屿小型兽类群落分布格局及其影响因素

2007年秋季和2008年春季,采用夹夜法对千岛湖14个岛屿进行小型兽类群落组成调查,研究其群落空间分布格局及其影响因素。两季度共布置夹16 800只,捕获小型兽类1 037只,隶属2目2科7属11种。其中啮齿目（Rodenria）鼠科（Muridae）9种,食虫目（Insectivora）鼩鼱科（Soricdae）2种。结果显示：千岛湖小型兽类群落呈非随机分布格局;嵌套分析表明,千岛湖岛屿小型兽类群落呈现极显著嵌套格局,植物丰富度和生境专属性两项参数对其嵌套格局的形成具有显著影响,从而使适应力强的物种能够在多样的环境中生存,而适应力弱的物种则局限在特定的环境中。由于取样强度差异会过高地估计嵌套程度,故在研究中应尽量去除取样强度的干扰。     

生境片段化对千岛湖地表甲虫物种多样性的影响

在千岛湖片段化景观中选取20个陆桥岛屿和8个大陆样点,从2012年7月到2014年4月,按季度(春、夏、秋季)6次采用巴氏陷阱法收集地表甲虫,分析其物种多度、组成、多样性和季节动态,以及不同岛屿上的地表甲虫的物种多样性与岛屿面积和隔离度等岛屿空间特征的关系.结果表明: 共收集记录到地表甲虫26科101种3370头.大陆和大岛地表甲虫的物种丰富度有显著差异,且小岛地表甲虫密度显著高于大陆;大陆地表甲虫的物种组成变化较大,而岛屿上分布的地表甲虫的物种组成则变化较小.地表甲虫的物种丰富度与岛屿面积呈显著正相关,密度与隔离度呈显著正相关.夏季岛屿上地表甲虫物种丰富度高于春秋两季,岛屿与大陆样地的Shannon指数、Simpson指数和Pielou均匀度指数均在夏季最高、秋季最低.     

千岛湖岛屿特征与节肢动物多样性的关系

采用栅格采样法,于2006年4、5、8和10月对千岛湖库区50个不同大小岛屿中节肢动物的种类与数量进行了调查,分析了岛屿面积、海拔、形状和距离等因素对岛屿节肢动物物种丰富度的影响.结果表明:岛屿上节肢动物总物种丰富度、高扩散力物种丰富度和低扩散力物种丰富度均随岛屿面积的增大而增加,且岛屿面积与物种丰富度之间的关系符合经典岛屿生物地理学模型;节肢动物物种丰富度受岛屿面积、海拔和形状的综合影响,距离对岛屿上物种的丰富度没有显著影响;总的物种丰富度与岛屿形状指数和海拔呈显著正相关,岛屿面积和海拔与高扩散力物种的物种丰富度显著相关,而低扩散力物种与岛屿各地理因素之间的相关性均不显著.     

千岛湖岛屿小型兽类群落的多样性

2007 年秋季和2008 年春季,选取千岛湖地区14 个岛屿和2 个半岛作为样地,采用夹夜法进行小型兽类群落组成调查。两季度共布夹20 400 个,捕获小型兽类1 141 只,隶属2 目3 科9 属13 种,啮齿目(Rodentia)鼠科(Muridae)10 种和仓鼠科(Cricetidae)1 种,食虫目(Insectivora)鼩鼱科(Soricidae)2 种。利用以上结果分析其群落多样性,结果显示:14 个岛屿小型兽类群落春、秋两季的多样性指数、均匀度指数和优势度指数均呈现极显著差异且优势种发生变化;对可能影响岛屿小型兽类群落多样性的岛屿面积、距最近陆地距离、距最近大岛距离和植物丰富度等因素进行逐步回归分析,发现只有植物丰富度对小型兽类群落的物种丰富度有显著影响;对16 个样地按照物种组成比进行聚类,许源半岛样地与14 个岛屿聚为一类,姚家半岛样地单独归为一类,相似性指数比较结果亦显示姚家半岛样地与其它样地的相似性指数偏低。结论:景观破碎化导致千岛湖岛屿小型兽类群落的稳定性下降,物种多样性季节变化强烈;随岛屿面积的增加,小型兽类物种丰富度并非总是增加的,而是出现反复,呈现明显的小岛效应;14 个岛屿的物种与许源半岛样地物种构成比接近,推断在水库未形成前属同一生境。     

片段化景观中壳斗科植物种子捕食和扩散模式

生境片段化伴随的面积效应和边缘效应, 可改变分散贮食动物的竞争强度、觅食行为以及隐蔽条件, 影响种子捕食和扩散模式。阐明生境片段化对多物种种子捕食和扩散的影响, 对理解片段化生境中的植物更新和生物多样性维持十分重要。该研究在浙江省千岛湖地区的岛屿和大陆上开展了针对6种壳斗科植物的种子捕食和扩散实验, 分析了物种、分散贮食动物相对多度、种子产量、岛屿大小和边缘效应如何共同影响种子命运和种子扩散距离。主要结果: (1)种子命运和扩散距离在物种间存在显著差异; (2)大陆比岛屿有更长的种子留存时间, 小岛种子留存时间最短, 岛屿内部比岛屿边缘有更长的种子留存时间; (3)物种和岛屿大小对种子原地取食率存在交互作用, 白栎(Quercus fabri)种子在大岛上有更高的原地取食率; (4)种子在小岛上有最高的扩散率, 分散贮食动物相对多度对种子扩散后贮藏率有负效应。表明在千岛湖地区, 生境片段化改变了种子捕食和扩散模式, 且面积效应对不同物种的种子捕食和扩散模式产生了不同作用, 从而影响森林群落更新和生物多样性维持。     

湖南浏阳大围山繁殖期鸟类物种多样性的动态分析

繁殖期是鸟类生活史的重要阶段,掌握繁殖期鸟类的物种多样性及其种群动态对鸟类保护具有重要意义。2016—2020年,采用样线法在湖南浏阳大围山于每年5月和7月分别开展1次系统的鸟类物种多样性调查。期间共记录到鸟类100种,隶属于10目38科。其中,留鸟73种、夏候鸟22种、冬候鸟2种、旅鸟3种;国家一级重点保护鸟类有1种,即白颈长尾雉(Syrmaticus ellioti),国家二级重点保护鸟类有白鹇(Lophura nycthemera)、黑冠鹃隼(Aviceda leuphotes)、红嘴相思鸟(Leiothrix lutea)等12种。2016—2020年依次记录到鸟类64种、68种、63种、56种和57种。鸟类群落的Shannon-Wiener指数在2018年最高(3.421),在2020年最低(3.062)。年际间鸟类物种组成周转率呈逐年上升趋势,依次为77.27%、81.68%、84.87%和94.69%。调查期内5月的鸟类群落各项多样性指数均值略高于7月。常绿-落叶阔叶混交林、针阔混交林、常绿阔叶林和灌丛是大围山繁殖鸟类最主要的生境,其中常绿-落叶阔叶混交林鸟类群落的Sha...     

Effects of Fragmentation and Sea-Level Changes upon Frog Communities of Land-Bridge Islands off the Southeastern Coast of Brazil

We investigate the composition of anuran communities of land-bridge islands off the southeastern coast of Brazil. These islands provide natural long-term experiments on the effects of fragmentation in the Brazilian Atlantic Forest (BAF). We hypothesize that Pleistocene sea-level changes, in combination with other abiotic variables such as area and habitat diversity, has affected anuran species richness and community composition on these islands. Data from the literature and collections databases were used to produce species lists for eight land-bridge islands and for the mainland adjacent to the islands. We assess the effects of area, number of breeding habitats and distance to the mainland upon anuran species richness on land-bridge islands. Additionally we use nestedness analysis to quantify the extent to which the species on smaller and less habitat-diverse islands correspond to subsets of those on larger and more diverse ones. We found that area has both direct and indirect effects on anuran species richness on land-bridge islands, irrespective of distance to the mainland. However, on islands with comparable sizes, differences in species richness can be attributed to the number and quality of breeding habitats. Anuran communities on these islands display a nested pattern, possibly caused by selective extinction related to habitat loss. Common lowland pond-breeders were conspicuous by their absence. In the BAF, the conservation of fragments with a high diversity of breeding habitats could compensate for the generally negative effect of small area upon species richness. We suggest that sea-level changes have an important role in shaping composition of anuran species on coastal communities.     

BIODIVERSITY RESEARCH: Nestedness for different reasons: the distributions of birds,lizards and small mammals on islands of an inundated lake

Aim We examined whether the community compositions of birds, lizards and small mammals were nested in a fragmented landscape in the Thousand Island Lake, China. We also assessed whether the mechanisms influencing nestedness differed among these taxonomic groups. Location Thousand Island Lake, China. Methods Presence/absence matrices were compiled for birds (42 islands) and lizards (42 islands) using line‐transect methods, and for small mammals (14 islands) using live‐trapping methods from 2006 to 2009. Nestedness was analysed using BINMATNEST, and statistical significance was assessed using the conservative null model 3. We used Spearman rank correlations and partial Spearman rank correlations to examine associations of nestedness and habitat variables (area, isolation, habitat diversity and plant richness) as well as life‐history traits (body size, habitat specificity, geographical range size and area requirement) related to species extinction and immigration tendencies. Results The community compositions of birds, lizards and small mammals were all significantly nested, but the causal factors underlying nestedness differed among taxonomic groups. For birds, island area, habitat specificity and area requirement were significantly correlated with nestedness after controlling for other independent variables. For lizards, habitat heterogeneity was the single best correlate of nestedness. For small mammals, island area, habitat heterogeneity and habitat specificity were significantly correlated with nestedness. The nested patterns of birds, lizards and small mammals were not attributable to passive sampling or selective colonization. Main conclusions The processes influencing nested patterns differed among taxonomic groups. Nestedness of bird assemblages was driven by selective extinction, and lizard assemblage was caused by habitat nestedness, while nestedness of small mammals resulted from both selective extinction and habitat nestedness. Therefore, we should take taxonomic differences into account when analysing nestedness to develop conservation guidelines and refrain from using single taxa as surrogates for others.     

千岛湖岛屿维管植物β多样性及其影响因素

通过样地调查方法、Jaccard相异性指数、Spearman回归分析和非度量多维标度(NMDS)排序分析,研究了千岛湖154个岛屿上不同植物群落β多样性及其主要影响因素。结果表明不同的景观参数对不同植物生长型有不同程度的影响,其中(1)藤本、灌木的β多样性形成的主导因素是面积,即面积差越大的区域间的β多样性越高;(2)乔木的β多样性主要受到岛屿间距离的限制,岛屿间距离越远,β多样性越高;(3)草本植物的β多样性分布与岛屿面积差及岛屿间距离并未呈现出显著相关,即其分布不受这两种因素限制;(4)NMDS分析结果显示岛屿面积、形状、边缘面积比和岛屿到大陆最小距离等特征对千岛湖岛屿上植物β多样性起决定性的作用。千岛湖陆桥岛屿组成的片段化生境中植物β多样性受扩散限制和生态位假说的共同影响。     

Revealing Beta-Diversity Patterns of Breeding Bird and Lizard Communities on Inundated Land-Bridge Islands by Separating the Turnover and Nestedness Components

Beta diversity describes changes in species composition among sites in a region and has particular relevance for explaining ecological patterns in fragmented habitats. However, it is difficult to reveal the mechanisms if broad sense beta-diversity indices (i.e. yielding identical values under nestedness and species replacement) are used. Partitioning beta diversity into turnover (caused by species replacement from site to site) and nestedness-resultant components (caused by nested species losses) could provide a unique way to understand the variation of species composition in fragmented habitats. Here, we collected occupancy data of breeding birds and lizards on land-bridge islands in an inundated lake in eastern China. We decomposed beta diversity of breeding bird and lizard communities into spatial turnover and nestedness-resultant components to assess their relative contributions and respective relationships to differences in island area, isolation, and habitat richness. Our results showed that spatial turnover contributed more to beta diversity than the nestedness-resultant component. The degree of isolation had no significant effect on overall beta diversity or its components, neither for breeding birds nor for lizards. In turn, in both groups the nestedness-resultant component increased with larger differences in island area and habitat richness, respectively, while turnover component decreased with them. The major difference among birds and lizards was a higher relevance of nestedness-resultant dissimilarity in lizards, suggesting that they are more prone to local extinctions derived from habitat fragmentation. The dominance of the spatial turnover component of beta diversity suggests that all islands have potential conservation value for breeding bird and lizard communities.     

陷阱法和Winkler法调查土壤节肢动物多样性比较:以千岛湖岛屿封闭生境研究为例

陷阱法和Winkler法是调查土壤动物的两种常规方法,然而这两种方法的调查效率各有优劣。本研究于2010年秋季,在千岛湖中心湖区选取了15个面积不同的岛屿,同时采用Winkler法和陷阱法采集岛屿上的土壤节肢动物,在岛屿这一封闭生境中比较两种方法收集土壤节肢动物的效率。结果表明,两种方法捕获土壤动物类群丰富度差异不显著,但多样性指数差异极显著。Winkler法对常规土壤节肢动物类群的采集效率优于陷阱法,尤其对运动较缓慢、活动范围较小的土壤节肢动物类群的采集具有优势;陷阱法则更优于采集运动能力较强、活动范围较大的类群。基于样方的稀疏曲线结果说明,Winkler法能用少量样方快速获取研究区域的土壤节肢动物群落基本组成,推荐在面积较小的岛屿上使用;而在面积较大的岛屿上使用陷阱法能够获取更多的类群。ChaoJaccard相似性系数比较则显示两种方法所取的土壤节肢动物相似性在大型岛屿上差异较大,说明大样本数据的采集需要两种方法同时使用能够提高数据的完整性和可靠性。本研究的结果为土壤节肢动物研究的方法选择提供了数据支持,具有一定的实际应用性。     

千岛湖库区岛屿面积对植物分布的影响及植物物种多样性保护研究

修建大坝形成水库蓄水是造成景观破碎化的原因和形式之一.本研究选取了浙江千岛湖库区景观破碎化的典型区域小金山林场,调查了74个大小不一的岛屿,研究了面积对植物物种分布的影响,并比较了使物种多样性最大化的几种植物物种保护方案:小岛组合、中岛组合、大岛组合、大中小组合岛.调查共记录到乔木物种56种,灌木物种79种.将岛屿按照面积由大到小排序,将相对应分布的乔木、灌木绘制成植物物种分布表.结果显示:乔木中分布不受面积影响的物种有15种,受面积影响的有11种,介于两者之间的有30种;灌木物种中不受面积影响的有24种,受面积影响的有16种,介于两者之间的有39种.将乔木、灌木和总物种数分别累加,同时将相对应的岛屿面积按不同组合累加,绘制累加物种和面积关系图,发现在特定的相同累加面积下,组合岛的累加乔木、灌木、总物种数最多,小岛组合次之,大岛组合最少.因此,建立相同面积的保护区时,组合岛有利于保护更多的物种.     

Life-history traits associated with fragmentation vulnerability of lizards in the Thousand Island Lake, China

Following habitat fragmentation, the remnant faunal community will undergo a period of species loss or 'relaxation.' Theory predicts that species with particular life-history traits, such as a small population size, small geographical range, low fecundity and large body size, should be more vulnerable to fragmentation. In this study, we investigated the relationships between the above life-history traits and the fragmentation vulnerability index (the number of islands occupied) of five lizard species inhabiting recently isolated land-bridge islands in the Thousand Island Lake, China. Data on life-history traits were collected from field surveys (population density) and from the literature (body size, clutch size and geographical range size). The species–area relationships for lizards sampled from the mainland versus on the islands differed significantly (i.e. the number of species inhabiting islands was decreased relative to similar-sized areas on the mainland), indicating that species extinction has occurred on all of the study islands following isolation. For the fragmentation vulnerability index, model selection based on Akaike's information criterion identified natural density at mainland sites as the best correlate of vulnerability to fragmentation, supporting the hypothesis that rare species are most vulnerable to local extinction and will be lost first from fragmented landscapes. In contrast, there was little evidence for an effect of lizards' snout–vent length, clutch size or geographical range size on fragmentation vulnerability. Identification of species traits that render some species more vulnerable to fragmentation than others has important implications for conservation and can be used to aid direct management efforts.