Echolocation signals reflect niche differentiation in five sympatric congeneric bat species

Echolocating bats can be divided into guilds according to their preferred habitat and foraging behaviour, which coincide with distinct adaptations in wing morphology and structure of echolocation signals. Although coarse structuring of niche space between different guilds is generally accepted, it is not clear how niches differ within guilds, or whether there is fine-grained niche differentiation reflected in echolocation signal structure. Using a standardized performance test, here we show clutter-dependent differences in prey-capture success for bats from five species of European Myotis. These species are morphologically similar, sympatric, and all belong to the guild labelled "edge space aerial/trawling foragers". We further demonstrate a strong correlation between the prey-detection ability of the species and the respective search-call bandwidth. Our findings indicate that differences in echolocation signals contribute to within-guild niche differentiation. This is the first study relating sensory abilities of a set of potentially competing animal species to a direct measure of their respective foraging performance, suggesting an important role of sensory ecology in the structuring of animal communities.     

Niche lability in the evolution of a Caribbean lizard community

Niche conservatism--the tendency for closely related species to be ecologically similar--is widespread. However, most studies compare closely related taxa that occur in allopatry; in sympatry, the stabilizing forces that promote niche conservatism, and thus inhibit niche shifts, may be countered by natural selection favouring ecological divergence to minimize the intensity of interspecific interactions. Consequently, the relative importance of niche conservatism versus niche divergence in determining community structure has received little attention. Here, we examine a tropical lizard community in which species have a long evolutionary history of ecological interaction. We find that evolutionary divergence overcomes niche conservatism: closely related species are no more ecologically similar than expected by random divergence and some distantly related species are ecologically similar, leading to a community in which the relationship between ecological similarity and phylogenetic relatedness is very weak. Despite this lack of niche conservatism, the ecological structuring of the community has a phylogenetic component: niche complementarity only occurs among distantly related species, which suggests that the strength of ecological interactions among species may be related to phylogeny, but it is not necessarily the most closely related species that interact most strongly.     

浙江天童国家森林公园鸟类生态位格局

2010年10月至2011年9月对浙江天童国家森林公园样地进行调查,共记录鸟类32种,3 129只次.依据鸟类的栖息活动格局将11种优势种和常见种鸟类划分为地面灌木层活动集团、树干中层活动集团、树冠层活动集团.聚类分析表明,鸟类各集团栖息基层活动空间位置相对分离,使得三大集团对资源充分利用.分析发现5种优势种鸟类在植物群落垂直方向各有相对稳定的分布层.同种鸟类随季节变化在植物群落垂直方向的分布呈动态变化.优势种鸟类的生态位宽度大,且同科的鸟类生态位重叠值最大.     

三峡库区不同生境类型蝶类多样性调查及分析 (三峡地区资源环境生态研究)

1998—2003年对长江三峡库区阔叶林、灌丛、林缘灌丛、农田、草地等5种不同生境类型蝴蝶分布状况进行调查。获得蝴蝶7 853只,隶属12科157属380种。蛱蝶科蝴蝶的属、种和个体数均为最多,说明此类群最适应库区当前的环境条件;珍蝶、喙蝶、绢蝶等科蝶类是三峡库区的稀有类群,也是库区蝶类生物多样性保护的关键类群。阔叶林、灌丛、林缘灌丛是该区域物种多样性的重要生境,特别是灌丛类生境。各类型生境的多样性指数,灌丛(0.584 5)和农田(0.474 0)的年间波动较小,草地(0.329 8)的年间波动较大。在5种类型中,灌丛的蝶类多样性指数(0.584 5)相对较高,是库区内最适于蝴蝶生存的生境。研究表明蝴蝶分布特征与生境关系密切,植被类型越接近、空间复杂程度越相似的生境,其蝴蝶生态分布特征越相似。蝴蝶生境保护对于三峡库区蝶类多样性保护具有重要意义。     

天然黄山松群落主要树种营养生态位特征研究

【目的】了解戴云山天然黄山松群落主要乔木树种在不同土壤营养资源空间中的营养利用情况和空间占据能力,为更好地营造天然林提供理论依据。【方法】以福建省戴云山自然保护区天然黄山松群落为对象,通过生态位空间分割原理,应用生态位宽度、重叠度和相似性比例对黄山松群落主要树种生态位特征进行研究。【结果】①考虑资源利用率与对多维生态位宽度的测度存在显著性差异,在不同测度公式下生态位宽度较大的树种均是黄山松、罗浮栲、木荷、马尾松、鹿角杜鹃、野漆,宽度值均在0.700以上,但树种的重要值与生态位宽度值之间相关性不明显。②生态位宽度较大的黄山松、罗浮栲、木荷、马尾松、鹿角杜鹃、野漆生态位重叠平均值分别为0.424、0.321、0.328、0.290、0.303、0.294。③生态位宽度、生态位重叠度和生态位相似性关系表现为生态位宽度较大的树种对其他树种的生态位重叠概率较大,但生态位重叠度值不一定大。各主要树种生态位相似性和生态位重叠度的变化趋势基本吻合。【结论】在戴云山自然保护区,黄山松与其他树种重叠度偏大,占据相同资源的树种数量增加,但资源的减少造成树种竞争加强,黄山松的优势地位很可能被环境适应能力强的树种(木荷、鹿角杜鹃)所替代, 即这些物种很可能演替为优势种群。因此建议采用人工干扰措施并加强对研究区黄山松的管理和保护。     

Coral communities are regionally enriched along an oceanic biodiversity gradient

Ecological communities are influenced by processes operating at multiple scales. Thus, a better understanding of how broad- as well as local-scale processes affect species diversity and richness is increasingly becoming a central focus in modern community ecology. Here, in a study of unprecedented geographical scope, we show significant regional and local variation in the species richness of coral assemblages across an oceanic biodiversity gradient. The gradient that we sampled extends 10,000 km eastwards from the world's richest coral biodiversity hotspot in the central Indo-Pacific. Local richness and the size of regional species pools decline significantly across 15 islands spanning the gradient. In addition, richness declines across three adjacent habitats (reef slopes, crests and flats). In each habitat, a highly consistent linear relationship between local and regional species richness indicates strong regional enrichment. Thus, even on the most diverse coral reefs in the world, local coral assemblages are profoundly affected by regional-scale processes. Understanding these historical and biogeographical influences is essential for the effective management and preservation of these endangered communities.     

百里杜鹃国家森林公园优势种生态位研究

【目的】评估百里杜鹃国家森林公园杜鹃花科优势种的资源利用能力和空间占据能力,为经营管理提供依据。【方法】应用生态位宽度、生态位相似度及Pianka生态位重叠度计算方法,对百里杜鹃优势种群生态位特征进行研究。【结果】①群落中杜鹃花科植物(马樱杜鹃、露珠杜鹃、迷人杜鹃、映山红)生态位宽度较大,分别为1.709、1.576、1.411、1.062,是群落的优势种; ②该群落种群间的生态位相似性比例较小,生态位宽度与生态位相似性之间无显著关系; ③生态位宽度大的物种与其他物种发生重叠的概率更大,但生态位重叠值不一定大。【结论】杜鹃花科植物在群落中生态位宽度较大,而马缨杜鹃与露珠杜鹃的生态位重叠程度在降低,这主要与植物的生物-生态学特性有关,是种群对资源利用的长期适应性结果。     

Experimental niche evolution alters the strength of the diversity–productivity relationship

The relationship between biodiversity and ecosystem functioning (BEF) has become a cornerstone of community and ecosystem ecology and an essential criterion for making decisions in conservation biology and policy planning. It has recently been proposed that evolutionary history should influence the BEF relationship because it determines species traits and, thus, species’ ability to exploit resources. Here we test this hypothesis by combining experimental evolution with a BEF experiment. We isolated 20 bacterial strains from a marine environment and evolved each to be generalists or specialists. We then tested the effect of evolutionary history on the strength of the BEF relationship with assemblages of 1 to 20 species constructed from the specialists, generalists and ancestors. Assemblages of generalists were more productive on average because of their superior ability to exploit the environmental heterogeneity. The slope of the BEF relationship was, however, stronger for the specialist assemblages because of enhanced niche complementarity. These results show how the BEF relationship depends critically on the legacy of past evolutionary events.     

五龙河自然保护区鸟类群落夏秋食性特征分析

2005年11月至2006年9月,对湖北五龙河自然保护区的鸟类群落进行了调查,并对夏秋两季的鸟类食性集团作了聚类分析。结果表明:该区记录鸟类82种;其中夏季50种,秋季51种。该区夏秋季的鸟类群落均以虫食性鸟类为主,且均为24种。夏季取食集团的第1类群是山地灌木林取食集团,由银喉长尾山雀、红头长尾山雀、暗绿绣眼鸟、棕颈钩嘴鹛组成;秋季取食集团的第1类群为河滩灌木丛取食集团,由灰鹡鸰、淡眉柳莺、褐柳莺、暗绿绣眼鸟、黄喉鹀、喜鹊组成。     

云南富源光皮桦种群与主要伴生树种生态位研究

运用Levins和Shannon-Wiener生态位宽度指数,对云南富源县光皮桦种群及其主要伴生树种的生态位进行了研究。结果表明:光皮桦生态位宽度最大,杉木、华山松次之,其他主要伴生树种的生态位宽度均较小,表明光皮桦对环境具有广泛的适应性,在群落中优势地位明显。光皮桦与杉木、华山松的生态位相似性比例较大,对资源有共享趋势;光皮桦与其他树种的生态位相似性比例较小。光皮桦群落中主要树种间的生态位重叠较低,表明主要树种间生态位分化程度较高,种间竞争关系较弱。     

人工灌丛生境草原沙蜥和丽斑麻蜥生态位分化的研究

在柠条灌丛生境,丽斑麻蜥(Eremiasargus)主要栖息于灌丛之中,而草原沙蜥(Phrynocephalusfrontalis)则主要栖息于灌丛之间的空地.二者空间生态位重叠指数较低,而营养生态位食物种类维重叠指数较高.以Nelson相似性系数衡量两种蜥蜴对资源的相互竞争能力,在空间生态位,草原沙蜥的竞争力大于丽斑麻蜥,而在营养生态位食物种类一维则相反.以各种因素衡量,丽斑麻蜥对灌从生境的适应能力强于草原沙蜥.     

Drought sensitivity shapes species distribution patterns in tropical forests

Although patterns of tree species distributions along environmental gradients have been amply documented in tropical forests, mechanisms causing these patterns are seldom known. Efforts to evaluate proposed mechanisms have been hampered by a lack of comparative data on species' reactions to relevant axes of environmental variation. Here we show that differential drought sensitivity shapes plant distributions in tropical forests at both regional and local scales. Our analyses are based on experimental field assessments of drought sensitivity of 48 species of trees and shrubs, and on their local and regional distributions within a network of 122 inventory sites spanning a rainfall gradient across the Isthmus of Panama. Our results suggest that niche differentiation with respect to soil water availability is a direct determinant of both local- and regional-scale distributions of tropical trees. Changes in soil moisture availability caused by global climate change and forest fragmentation are therefore likely to alter tropical species distributions, community composition and diversity.     

Simple rules yield complex food webs

Several of the most ambitious theories in ecology describe food webs that document the structure of strong and weak trophic links that is responsible for ecological dynamics among diverse assemblages of species. Early mechanism-based theory asserted that food webs have little omnivory and several properties that are independent of species richness. This theory was overturned by empirical studies that found food webs to be much more complex, but these studies did not provide mechanistic explanations for the complexity. Here we show that a remarkably simple model fills this scientific void by successfully predicting key structural properties of the most complex and comprehensive food webs in the primary literature. These properties include the fractions of species at top, intermediate and basal trophic levels, the means and variabilities of generality, vulnerability and food-chain length, and the degrees of cannibalism, omnivory, looping and trophic similarity. Using only two empirical parameters, species number and connectance, our 'niche model' extends the existing 'cascade model and improves its fit ten-fold by constraining species to consume a contiguous sequence of prey in a one-dimensional trophic niche.     

Complex evolutionary history of the vertebrate sweet/umami taste receptor genes

Adaptive evolution plays a role in the functional divergence and specialization of taste receptors and the sense of taste is thought to be closely related to feeding ecology.To examine whether feeding ecology has shaped the evolution of taste receptor genes in vertebrates,we here focus on Tas1r gene family that encodes umami(Tas1r1 and Tas1r3 heterodimer) and sweet(Tas1r2 and Tas1r3 heterodimer) taste receptors.By searching currently available genome sequences in 48 vertebrates that contain 38 mammals,1 reptile,3 birds,1 frog,and 5 fishes,we found all three members of Tas1rs are intact in most species,suggesting umami and sweet tastes are maintained in most vertebrates.Interestingly,the absence and pseudogenization of Tas1rs were also discovered in a number of species with diverse feeding preferences and distinct phylogenetic positions,indicating widespread losses of umami and/or sweet tastes in these animals,irrespective of their diet.Together with previous findings showing losses of tastes in other vertebrates,we failed to identify common dietary factors that could result in the taste losses.Our results report here suggest the evolution of Tas1rs is more complex than we previously appreciated and highlight the caveat of analyzing sequences predicted from draft genome sequences.Future work for a better understanding of taste receptor function would help uncover what ecological factors have driven the evolution history of Tas1rs in vertebrates.     

基于系统发育和功能性状的森林群落构建机制

群落物种共存机制是生态学研究的重要论题。共存物种的生态和进化相似性是用于验证群落构建机制的关键信息之一,生态学家常用系统发育和基于功能性状的方法间接或直接估算相似性,从而揭示驱动群落构建的主要生态学过程。系统发育分析方法和基于功能性状的方法均能检验生境过滤和竞争排斥过程在群落构建中的作用,并为解决生态位理论和中性理论之争提供新的视角。根据现代物种共存理论,在不同的功能性状进化模式下,不同生态过程构建的群落功能结构和系统发育结构可能不同,聚集的群落系统发育结构可能在性状进化保守的情况下由生境过滤过程构建,也有可能在性状趋同进化的情况下由竞争排斥过程构建而成,因此检验功能性状系统发育信号对于推断群落构建机制显得十分必要,联合系统发育和功能性状的研究将能更加精确地推断驱动群落构建的主要生态过程。联合系统发育和功能性状研究干扰和次生林演替对群落系统发育结构物种共存机制的影响,将有助于认识群落物种多样性对干扰的响应及不同演替阶段群落的构建机制,为群落的管理和恢复提供依据。     

复合种群生态学研究现状与展望

随着生境的破坏和逐渐片断化，越来越多的物种处于濒危状态，因此保护破碎生境的物种多样性就迫在眉睫．复合种群理论是当今国际数学生态学、理论生态学和保护生物学的一个主要研究前沿，并提供了保护濒危物种及种群的新的理论依据，也为生境破坏对物种造成的伤害做出预测和度量．本文首先对复合种群的已有概念、理论和模型做了全面的分析和总结；其次对复合种群生态学研究中存在的问题进行分析；最后结合作者参与的研究课题，尝试对复合种群生态学的研究方法进行探讨．     

南亚热带4个苗木的生态位

在模糊超体积生态位理论的基础上,研究了南亚热带4个不同演替阶段树种苗木的生态位,探索森林群落演替的规律．以所测定的净光合作用强度值为指标,度量包括pH值、矿物质营养浓度、土壤含水量三个生态因子的三维生态位．结果表明：生态位宽度的大小次序为马尾松（0．4056）,荷木（0．3614）,藜蒴（0．3108）和黄果厚壳桂（0．3068）,正好对应演替不同阶段的优势种;生态位重叠最小值为0．6827,表示总体上物种对资源的竞争较激烈;种间竞争系数介于0．6359和0．7357之间,表示物种问有回避竞争的趋势,这往往有助于物种共存;利用Cody和May的原则会带来生态位重叠的偏差最大为0．1262,最小为0．0361,因此应该避免使用Cody和May的原则．     

张广才岭北部山地次生林树栖食虫鸟类资源分割的研究

各集团之间的取食行为比较表明，它们在取食行为上的分离导致在一定程度上分割了这一环境中资源空间。有些集团（如树干一侧干凿取一拾取集团）的取食行为表现为有较大的宽度，以更为广泛的方式利用环境资源，而有些集团表现为特化，这种类型集团所包含的物种一般比较少。研究表明，在构成东北山地次生林树栖食虫鸟类群落时，关键因素是物种之间的资源利用关系。     

Differentiation of Epinephelus moara from E. bruneus by improved nest-tetra-primer-specific PCR

Epinephelus moara and E. bruneus are closely related species in the genus Epinephelus (Perciformes, Serranidae). Their morphological similarity, changing color pattern at different stages and living conditions make them difficult to be differentiated. To identify these two species, an improved nest-tetra-primer-specific PCR assay was developed. Three specific molecular markers, the control region NC1 (394 bp), species-specific internal region ND2-M (268 bp) and ND2-B (122 bp), were identified in the mitochondrial ND2 gene from these two grouper species. Five markers were also discovered in the ITS1 regions of their nuclear ribosomal DNA, which were the control regions NC2 (588 bp) and NC3 (563 bp), and species-specific internal regions rDNA-M (426 bp), ITS1-M (488 bp) and ITS1-B (304 bp). This method provided a highly specific, precise, reliable and rapid molecular marker technique to discriminate between the two grouper species, as well as a new way of DNA identification to differentiate closely related species in fishes.