水生高等植物对湖泊生态系统的影响

从多种角度分析了水生高等植物在湖泊生态系统中的作用以及和其它生物的关系,并从覆盖率、群落结构、植物配比等角度讨论了湖泊水生高等植物的最佳保有生物量。表明水生高等植物在湖泊生态系统中具有重要的环境生态功能和初级生产功能,水生高等植物的消退与过量生长都会导致湖泊生态系统生物多样性下降、生态系统变得脆弱和不稳定;维持湖泊生态系统良性循环,水生植物的生物量至少要大于1000g/m2,水生植物的覆盖度要大于30%,除了控制水生植物在水体中的总体生物量,还应重视挺水植物、浮叶植物、沉水植物和漂浮植物之间生物量的合适比例,并需密切注意水生植被群落结构的变化情况。     

Partitioning selection and complementarity in biodiversity experiments.

The impact of biodiversity loss on the functioning of ecosystems and their ability to provide ecological services has become a central issue in ecology. Several experiments have provided evidence that reduced species diversity may impair ecosystem processes such as plant biomass production. The interpretation of these experiments, however, has been controversial because two types of mechanism may operate in combination. In the 'selection effect', dominance by species with particular traits affects ecosystem processes. In the 'complementarity effect', resource partitioning or positive interactions lead to increased total resource use. Here we present a new approach to separate the two effects on the basis of an additive partitioning analogous to the Price equation in evolutionary genetics. Applying this method to data from the pan-European BIODEPTH experiment reveals that the selection effect is zero on average and varies from negative to positive in different localities, depending on whether species with lower- or higher-than-average biomass dominate communities. In contrast, the complementarity effect is positive overall, supporting the hypothesis that plant diversity influences primary production in European grasslands through niche differentiation or facilitation.     

Diversity-dependent production can decrease the stability of ecosystem functioning

There is concern that species loss may adversely affect ecosystem functioning and stability. But although there is evidence that biodiversity loss can lead to reductions in biomass production, there is no direct evidence that biodiversity loss affects ecosystem resistance (ability to withstand perturbation) or resilience (recovery from perturbation). Yet theory, laboratory experiments and indirect experimental evidence strongly suggest that diversity and stability are related. Here we report results from a field experiment with factorially crossed perturbation and diversity manipulations. We simulated drought perturbation on constructed grassland ecosystems containing 1, 2, 4, 8 or 32 plant species. Under unperturbed conditions, the species-poor systems achieved lower biomass production than the species-rich systems. However, the species-poor systems were more resistant to perturbation than the species-rich systems. The species-poor systems also showed a larger initial resilience following perturbation, although the original relationship between diversity and productivity was fully restored after 1year. Our results confirm that biodiversity increases biomass production, but they also point to the fact that such diversity--production associations may lead to an inverse relationship between biodiversity and the stability of ecosystem functioning.     

巢湖十五里河河口湿地植物群落多样性分析

依据巢湖十五里河河口植物群落野外调查资料,运用PCORD软件中Euclidean距离和Ward’s meth-od聚类方法研究了河口湿地植物群落的特征及多样性变化;用收获法研究了植物群落的生物量变化。研究显示:十五里河河口湿地植物群落由21个种组成,它们隶属于18属,11科,其中假稻(Leersia japonica)、北水苦荬(Veronica anagallis aquatica)、长芒野稗(Echinochloa caudata)、芮草(Beckmannia syzigachne)、黄花蒿(Artemisia annua)和水花生(Alternanthera philoxeroides)为优势种;河口湿地植物群落可分为8个组合,其中分布在湖堤附近的黄花蒿 北水苦荬(Artemisia annua Veronica anagallis aquatica)组合多样性指数和均匀度指数最高,分别为2.06和0.94;组合中物种多样性指数与物种丰富度和均匀度指数线性相关性不明显,其相关系数分别为0.609和0.549;组合的分布、生物量和多样性均与水位变化有密切关系。     

Changes in plant community diversity and aboveground biomass along with altitude within an alpine meadow on the Three-River source region

The grassland is an important component of terrestrial ecosystems and plays a significant role in biodiversity and ecosystem functions.In the present study,the changes of plant species diversity and aboveground biomass productivity were examined along with the altitude in natural alpine grassland in the source region of three rivers on the Qinghai-Tibetan Plateau.Eleven experimental locations were selected with altitudes ranging from 3862 to 4450 m above sea level(a.s.l.).The results indicated that Kobresia pygmaea meadow,Kobresia humilis meadow and Salix cupularis shrub meadow had higher indices of diversity and aboveground biomass.The distribution of species diversity,richness and aboveground biomass showed similarly unimodal patterns across the altitude gradient with the highest indices appeared at mid-altitudes locations.The changing trend of species diversity,richness and evenness also showed significant unimodal patterns with total aboveground biomass,and the highest species diversity occurred at intermediate level of productivities.This research would provide a valuable reference for the protection of grassland biodiversity and maintaining of the grazing ecosystem function in the source region of the Three Rivers.     

Biodiversity and ecosystem stability in a decade-long grassland experiment

Human-driven ecosystem simplification has highlighted questions about how the number of species in an ecosystem influences its functioning. Although biodiversity is now known to affect ecosystem productivity, its effects on stability are debated. Here we present a long-term experimental field test of the diversity-stability hypothesis. During a decade of data collection in an experiment that directly controlled the number of perennial prairie species, growing-season climate varied considerably, causing year-to-year variation in abundances of plant species and in ecosystem productivity. We found that greater numbers of plant species led to greater temporal stability of ecosystem annual aboveground plant production. In particular, the decadal temporal stability of the ecosystem, whether measured with intervals of two, five or ten years, was significantly greater at higher plant diversity and tended to increase as plots matured. Ecosystem stability was also positively dependent on root mass, which is a measure of perenniating biomass. Temporal stability of the ecosystem increased with diversity, despite a lower temporal stability of individual species, because of both portfolio (statistical averaging) and overyielding effects. However, we found no evidence of a covariance effect. Our results indicate that the reliable, efficient and sustainable supply of some foods (for example, livestock fodder), biofuels and ecosystem services can be enhanced by the use of biodiversity.     

岩溶地区森林自然恢复过程中植物和土壤微生物多样性的关联分析

本研究以岩溶地区森林自然恢复过程中的草丛(HL)、灌丛(SL)、灌乔林(SAF)、次顶极乔林(SCAF)和顶极乔林(CAF)为研究对象,对植物多样性与土壤微生物群落多样性进行关联分析,探究森林恢复能否促进整个生态系统的恢复,为岩溶森林生态保护修复和科学管理提供理论依据.结果表明:(1)随着森林的恢复,植物群落的物种丰富...     

Producer-decomposer co-dependency influences biodiversity effects

Producers, such as plants and algae, acquire nutrients from inorganic sources that are supplied primarily by decomposers whereas decomposers, mostly fungi and bacteria, acquire carbon from organic sources that are supplied primarily by producers. This producer-decomposer co-dependency is important in governing ecosystem processes, which implies that the impacts of declining biodiversity on ecosystem functioning should be strongly influenced by this process. Here we show, by simultaneously manipulating producer (green algal) and decomposer (heterotrophic bacterial) diversity in freshwater microcosms, that algal biomass production varies considerably among microcosms (0.0-0.67 mg ml(-1)), but that neither algal nor bacterial diversity by itself can explain this variation. Instead, production is a joint function of both algal and bacterial diversity. Furthermore, the range in algal production in microscosms in which bacterial diversity was manipulated was nearly double (1.82 times) that of microcosms in which bacterial diversity was not manipulated. Measures of organic carbon use by bacteria in these microcosms indicate that carbon usage is the mechanism responsible for these results. Because both producer and microbial diversity respond to disturbance and habitat modification, the main causes of biodiversity loss, these results suggest that ecosystem response to changing biodiversity is likely to be more complex than other studies have shown.     

巢湖十五里河河口湿地植被动态变化研究

河口湿地是水陆相互作用形成的独特生态系统,也是湖泊生态系统的重要组成部分。为探讨河口湿地植被在不同时期内种类和组成的变化,以及引起这些变化的主要环境因子,文章以巢湖十五里河河口湿地为对象,在巢湖处于枯水期和丰水期时,分别对其植物群落进行了野外调研,研究发现:枯水期河口湿地分布植物有21种,隶属于18属,11科;丰水期河口湿地分布植物11种,隶属于10属,7科;聚类分析结果显示枯水期时河口湿地植物组合类型有8种,丰水期时河口湿地植物组合类型为4种;枯水期时河口湿地植物物种多样性比丰水期时高,但其均匀度比丰水期时低;湖泊水位、河口水质和人类活动是河口湿地植物种类和组成变化的主要影响因子。     

Effects of biodiversity on the functioning of trophic groups and ecosystems

Over the past decade, accelerating rates of species extinction have prompted an increasing number of studies to reduce species diversity experimentally and examine how this alters the efficiency by which communities capture resources and convert those into biomass. So far, the generality of patterns and processes observed in individual studies have been the subjects of considerable debate. Here we present a formal meta-analysis of studies that have experimentally manipulated species diversity to examine how it affects the functioning of numerous trophic groups in multiple types of ecosystem. We show that the average effect of decreasing species richness is to decrease the abundance or biomass of the focal trophic group, leading to less complete depletion of resources used by that group. At the same time, analyses reveal that the standing stock of, and resource depletion by, the most species-rich polyculture tends to be no different from that of the single most productive species used in an experiment. Of the known mechanisms that might explain these trends, results are most consistent with what is called the 'sampling effect', which occurs when diverse communities are more likely to contain and become dominated by the most productive species. Whether this mechanism is widespread in natural communities is currently controversial. Patterns we report are remarkably consistent for four different trophic groups (producers, herbivores, detritivores and predators) and two major ecosystem types (aquatic and terrestrial). Collectively, our analyses suggest that the average species loss does indeed affect the functioning of a wide variety of organisms and ecosystems, but the magnitude of these effects is ultimately determined by the identity of species that are going extinct.     

辽宁铁岭莲花湖湿地植物群落研究

铁岭莲花湖湿地中生长着大量的自然群落和人工种植群落,它们都对莲花湖湿地的生态环境有着重要的影响作用。通过对辽宁铁岭莲花湖湿地的36个样方进行了湿地植物资源和植物群落的调查研究,进行了群落分类,并在BioDiversityPro等软件的支持下,进行了物种多样性分析。结果表明：铁岭莲花湖湿地共有12种植物群落类型,其中陆生植物群落8种,水生植物群落4种。植物物种多样性在辽河大堤上自然群落中最大,在水中的人工群落中最小,自然群落在大堤上生长最为集中。对莲花湖湿地的生物多样性保护提出了对策建议,为今后莲花湖及类似湿地的研究提供了基础资料。     

多水塘湿地系统中水生植被恢复及其对面源污染的截留作用

多水塘湿地系统是我国特有的农业微景观结构,通过对巢湖六叉河小流域多水塘水生植被群落的组成和生物量及其对面源污染的截留作用进行研究,结果表明多水塘湿地系统内共有8种水生植被、5个优势群落,水生植被分布面积占多水塘系统总面积的12.6%;水生植被对氮磷面源污染负荷的截留率分别为12.0%和6.7%.     

Species diversity enhances ecosystem functioning through interspecific facilitation.

Facilitation between species is thought to be a key mechanism by which biodiversity affects the rates of resource use that govern the efficiency and productivity of ecosystems; however, there is no direct empirical evidence to support this hypothesis. Here we show that increasing the species diversity of a functional group of aquatic organisms induces facilitative interactions, leading to non-additive changes in resource consumption. We increased the richness and evenness of suspension-feeding caddisfly larvae (Insecta, Trichoptera) in stream mesocosms and found that the increased topographical complexity of the benthic habitat alters patterns of near-bed flow such that the feeding success of individuals is enhanced. Species diversity reduces 'current shading' (that is, the deceleration of flow from upstream to downstream neighbours), allowing diverse assemblages to capture a greater fraction of suspended resources than is caught by any species monoculture. The fundamental nature of this form of hydrodynamic facilitation suggests that it is broadly applicable to freshwater and marine habitats; in addition, it has several analogues in terrestrial ecosystems where fluxes of energy and matter can be influenced by biophysical complexity. Thus, changes in species diversity may alter the probability of positive species interactions, resulting in disproportionately large changes in the functioning of ecosystems.     

东安紫水国家湿地公园植物多样性评价

采用林分结构调查和线路踏查法,对湖南省东安紫水国家湿地公园植物多样性进行了调查,在层次分析法的基础上选取了物种丰富度、生态系统多样性、特有及稀有种和外来物种入侵4项指标,构建了植物多样性评价体系.同时调查统计了东安紫水湿地公园的植物组成、优势科属.结果表明:湖南省东安紫水国家湿地公园生态系统类型多样化且稳定性高,植物资源丰富;维管束植物有195科676属1100种,其中蕨类植物有31科56属92种,裸子植物有7科13属16种,被子植物有157科607属992种;被子植物是东安紫水湿地公园植物的重要组成部分,优势类群主要为禾亚科、菊科、蝶形花科、蔷薇科;植物多样性指数得分为76.92分.     

Diversity and dispersal interactively affect predictability of ecosystem function

Theory and small-scale experiments predict that biodiversity losses can decrease the magnitude and stability of ecosystem services such as production and nutrient cycling. Most of this research, however, has been isolated from the immigration and emigration (dispersal) processes that create and maintain diversity in nature. As common anthropogenic drivers of biodiversity change--such as habitat fragmentation, species introductions and climate change--are mediated by these understudied processes, it is unclear how environmental degradation will affect ecosystem services. Here we tested the interactive effects of mobile grazer diversity and dispersal on the magnitude and stability of ecosystem properties in experimental seagrass communities that were either isolated or connected by dispersal corridors. We show that, contrary to theoretical predictions, increasing the number of mobile grazer species in these metacommunities increased the spatial and temporal variability of primary and secondary production. Moreover, allowing grazers to move among and select patches reduced diversity effects on production. Finally, effects of diversity on stability differed qualitatively between patch and metacommunity scales. Our results indicate that declining biodiversity and habitat fragmentation synergistically influence the predictability of ecosystem functioning.     

扎龙生态资源在生物教学与科研中的优势

扎龙属北温带大陆性季风气候,是同纬度地区景观最原始、物种最丰富的湿地自然综合体.独特的地理环境、多样性的动植物资源、特有的珍惜物种、突显的生态系统服务功能,模式化的生态特征变化等,为进行动植物野外实习和生态学研究提供了极佳场所,本文对扎龙生态资源在生物教学与科研中的优势进行了探讨.     

General patterns of taxonomic and biomass partitioning in extant and fossil plant communities

A central goal of evolutionary ecology is to identify the general features maintaining the diversity of species assemblages. Understanding the taxonomic and ecological characteristics of ecological communities provides a means to develop and test theories about the processes that regulate species coexistence and diversity. Here, using data from woody plant communities from different biogeographic regions, continents and geologic time periods, we show that the number of higher taxa is a general power-function of species richness that is significantly different from randomized assemblages. In general, we find that local communities are characterized by fewer higher taxa than would be expected by chance. The degree of taxonomic diversity is influenced by modes of dispersal and potential biotic interactions. Further, changes in local diversity are accompanied by regular changes in the partitioning of community biomass between taxa that are also described by a power function. Our results indicate that local and regional processes have consistently regulated community diversity and biomass partitioning for millions of years.     

Effects of anthropogenic disturbance on richness-dependent stability in Napahai plateau wetland

Unique plateau wetlands in China provide essential ecosystem functions and services and influence the health,environment and security of the downstream regions.In recent years,these plateau wetlands have experienced significant anthropogenic disturbance,but studies that evaluate the effects of such disturbance on ecological stability are rare.Our study tested how three typical types of human-related activities affect plant richness and ecological stability in Napahai plateau wetland,Shangri-La,China.The results showed that the anthropogenic disturbance had a direct effect on richness,and an indirect effect on stability mediated by richness.Anthropogenic disturbance did not alter the positive relationship between plant richness and community stability,and the stabilizing effect of richness could be explained by statistical averaging,overyielding effect,and component population stability.Our study complements previous studies that tested the richness-stability relationships in synthesized assemblages with richness specifically manipulated and studies that introduced mowing treatment to mimic real anthropogenic disturbance.The results further suggest that necessary steps,such as anthropogenic disturbance mitigation and plant richness conservation,are urgently required for maintaining healthy plateau wetlands and for sustaining their ecosystem functions and services.     

扎龙生态资源在生物教学与科研中的优势

扎龙属北温带大陆性季风气候,是同纬度地区景观最原始、物种最丰富的湿地自然综合体。独特的地理环境、多样性的动植物资源、特有的珍惜物种、突显的生态系统服务功能,模式化的生态特征变化等,为进行动植物野外实习和生态学研究提供了极佳场所,本文对扎龙生态资源在生物教学与科研中的优势进行了探讨。     

铁岭莲花湖湿地生物多样性研究进展

湿地生物多样性对于维持湿地生态功能和生态系统稳定有重要作用,湿地生物多样性研究的深入开展,对生物多样性保护和生态恢复具有重要意义,也为制定可持续利用规划提供可靠依据.简要介绍铁岭莲花湖湿地的自然概况,从植物种类的多样性、动物种类的多样性、植物群落的多样性和生物多样性评价几个方面,对现有研究成果进行评述,并对铁岭莲花湖湿地生物多样性的下一步研究进行展望.