生物多样性的生态系统功能

本文从以下几个方面综述了生物多样性对生态系统功能和作用的影响：第一,几个关于物种在生态系统中的不同地位和生物多样性如何影响生态系统功能的假说;第二,生物多样性与生态系统的稳定性;第三,生物多样性如何影响生态系统的生产力;第四,生物多样性对生态系统可持续性的影响。此外还提出了几个需要继续探讨和关注的问题。     

生物多样性和生态系统功能研究综述

生物多样性和生态系统功能之间关系 ,是生态学和环境科学的热门话题。围绕这一主题 ,文章系统回顾了近 2 0年来的研究历史及学术界的不同观点 ,全面展示了目前在理论和实验领域的主要工作结果和研究进展 ,并对今后的发展趋势和面临的挑战作了展望。理论和实验研究都表明 ,生物多样性趋于与生态系统功能 (稳定性 )呈正相关性 ,但是多样性并非是这种关系的直接驱动力。生态系统功能 (稳定性 )潜在地依赖于物种之间相互作用的强度 ,物种的功能反应特性以及生态系统的类型和尺度等。在生物多样性和生态系统功能的研究中 ,重要的不只是结论 ,还应包括其中所隐含的机制。     

生物多样性与生态系统功能关系研究进展

生物多样性和生态系统功能关系的研究,是生态学和环境学的一个中心论题。围绕这一主题,首先介绍了生物多样性及生态系统功能的含义;其次,一方面历史地回顾了生物多样性与生态系统功能关系的研究,另一方面结合近20年间的研究及实验,分别从多样性与生产力、多样性与稳定性、多样性与生态系统可持续性3个方面系统地阐述了二者关系研究的主要论点;最后,对其今后面临的挑战及发展趋势进行了展望。     

生物多样性与生态系统功能:进展与争论

生物多样性与生态系统功能的关系已成为当前人类社会面临的一个重大科学问题,生物多样性的空前丧失,促使人们开展了大量研究工作来描述物种多样性-生态系统功能关系,并试图揭示多样性与系统功能关系的内在机制,本文将多样性对生态系统功能作用机制的有关假说分为统计学与生物学两大类：前者是从统计学角度来解释观察到的多样性-系统功能模式,包括抽样效应,统计均衡效应等;而后者是基于多样性的生物学效应给出的,包括生态位互补,种间正相互作用,保险效应等,本文较为详细地介绍了该领域内有代表性的实验工作,包括“生态箱”实验,Cedar Creek草地多样性实验,微宇宙实验,欧洲草地实验,以及在这些实验结果解释上的激烈争论。     

陆地生态系统服务与生物多样性研究进展

在生物多样性迅速消失的压力下,人类面临生态系统服务质量严重下降的威胁。为了使生态系统的重要功能更直观的展现在人们面前,许多学者把生态系统服务对人类的惠益进行整理分类,最有影响力的是千年生态系统评估(MA,Millennium Ecosystem Assessment)把生态系统服务分为供给、调节、文化和支持服务四类,服务的核心是生态系统的产品、过程和格局。生态系统服务的识别与分类是生态系统功能的对象化过程,也是以人类需求来审视生态系统的过程。生态系统通过结构-过程-功能这一途径来实现生态系统服务,各种服务的直接动力来源于自然界生物地球化学循环,生物多样性通过生态系统属性和过程来影响生态系统服务形成和维持。生物多样性越高,生态系统功能性状的范围越广,生态系统服务质量就越高、越稳定。全球变化中的土地利用和土地覆盖变化是生物多样性快速下降的主要原因,也是目前影响生态系统服务最广泛、最剧烈的驱动力,而这正是人类活动造成的,人类需求和生态系统有限的服务能力之间在不同尺度表现出严重冲突。要提高生态系统服务质量,要在不同区域进行重点不同的布局,尽可能的扩大生态系统规模和提高生态系统功能,核心是提高生物多样性水平。     

生物多样性科学前沿

由国际生物科学联盟（ＩＵＢＳ）在１９９１年首先提出,至今已由其它５个重要国际组织或项目（ＳＣＯＰＥ、ＵＮＥＳＣＯ,ＩＣＳＵ,ＩＧＢＰ－ＧＣＴＥ及ＩＵＭＳ）共同主持的ＤＩＶＥＲＳＩＴＡＳ是迄今生物多样性科学研究唯一的国际性项目。１９９６年７月,科学指导委员会草拟了本阶段新的操作计划,并于同年８月在ＩＵＢＳ执行委员会上讨论。操作计划详述了１０个组成方面的内容,其中５个为核心组成部分,其它５个为特别目标     

珊瑚礁区的生物多样性及其生态功能

珊瑚礁区生物多样性程度可以与陆地热带雨林相提并论,目前关于珊瑚礁物种多样性及其空间分布特征方面研究进展迅速,是生物多样性研究的重要基地。作为一种生态资源,珊瑚礁还具有重要的生态功能,近年来由于全球气候逐渐变暖、人类活动影响不断加剧,导致其生物多样性缩减、生态功能严重退化。珊瑚礁生态系统多样性、遗传多样性已成为珊瑚礁研究热点,珊瑚礁生态环境效应和保护管理方面的研究也越来越受到重视。我国珊瑚礁主要分布在广阔的南海海域和海南岛、台湾岛、香港和广东广西沿岸,礁区生物种类繁多,多样性程度较高,以往研究主要涉及地质、地貌、生物、环境等方面,现今和今后一段时间里迫切需要加强生物多样性和生态功能研究,以确保更有效地保护和管理珊瑚礁。     

再论生物多样性与生态系统的稳定性

本文在简述生物多样性与生态系统稳定性研究动态的基础上,从生物多样性和稳定性的概念出发,指出忽视多样性和稳定性的生物组织层次可能是造成观点纷争的根源之一。特定生物组织层次的稳定性可能更多地与该层次的多样性特征相关,探讨多样性和稳定性的关系应从不同的生物组织层次上进行,抗动是生态系统多样性与稳定性关系悖论中的重要因子,如果根据扰动的性质,把生态系统（或其他组织层次）区分为受非正常外力干扰和受环境因子时间异质性波动干扰2类系统,稳定性的4个内涵可以理解为：对于受非正常外力干扰的系统而言,抵抗力和恢复力是稳定性适宜的测度指标;对于受环境因子时间异质性波动干扰和系统而言。利用持久性和变异性衡量系统的稳定性则更具实际意义。结合对群落和种群层次多样性与稳定性相关机制的初步讨论,本文认为;在特定的前提下,多样性可以导致稳定性。     

四川省生物多样性与生态系统多功能性分析

生态系统服务与人类福祉和可持续发展息息相关,近年来生物多样性丧失极大影响了生态系统服务。探究生物多样性与生态系统服务之间的关系成为当前生态学领域内的一个重大科学问题。以四川省各乡镇为单元,计算了景观尺度上的多样性指数,评估了四川省水土保持功能、水源涵养功能、固碳功能,并研究了两者之间关系。结果表明：在景观尺度上,Shannon''s多样性指数、修正Simpson''s多样性指数、景观丰度三种多样性指数可以较好表征四川省生物多样性空间分布格局。由景观丰度、欧式最近邻距离的标准差、景观丰度密度构成解释变量矩阵,RDA模型矫正解释率42.25%（P<0.001）,可更好解释由土壤保持功能、水源涵养功能、固碳功能构成的响应变量矩阵。四川省生物多样性及生态系统服务关系的模式有以下几种：（1）成都平原区区县空间距离较近,在生态系统服务和生物多样性梯度均差异较小;（2）盆周山地区、盆地丘陵区各区县在水土保持功能梯度上差异较大,与多样性关系较弱;（3）川西高原区区县在固碳、水源涵养梯度上差异较大,并有协同关系,多样性梯度差异较大;（4）川西高山峡谷区、西南山地区区县之间生态系统服务和多样性差异较大,生态系统服务可能存在强烈权衡关系,需进一步引入解释因子。     

生物多样性与生态系统稳定性研究进展

生物多样性和生态系统稳定性之间的关系是生态学的热门话题。围绕这一主题,文章回顾了其研究历史及学术界的不同观点,阐述了目前在理论和实验领域的主要工作结果、研究进展和存在问题。理论方面,由于生物多样性和生态系统稳定性的概念是复杂而多层面的,导致二者之间的关系仍然是复杂多样的。实验方面,已有实验仅仅强调了少数几种类型的多样性和稳定性,对多样性—稳定性关系的揭示有限。在生物多样性和生态系统功能的研究中,重要的不只是结论,还应包括其中所隐含的机制。未来的主要挑战是搞清生物多样性动态、生态系统过程和无机因子如何相互作用。     

Ecosystem structure, function, and restoration success: Are they related?

A direct relationship between ecosystem structure and function has been widely accepted by restoration ecologists. According to this paradigm, ecosystem degradation and aggradation represent parallel changes in structure and function, restoration following the same path as spontaneous succession. But the existence of single bidirectional trajectories and endpoints is not supported by empirical evidence. On the contrary, multiple meta-stable states, irreversible changes and hysteresis are common in nature. These situations are better described by state-and-transition models. Merging those models into the structure–function framework may help to develop new hypotheses on ecosystem dynamics, and may provide a suitable framework for planning restoration activities. We use the relationship between ecosystem function and the effort needed to restore a degraded ecosystem (i.e. restorability) as an example. A linear relationship between ecosystem structure and function suggests that ecosystem degradation and restorability are directly related. This may not be true when multiple states, not necessarily connected, are considered. We show two case studies that support this point, and discuss the implications of the incorporation of state-and-transition models into the structure–function framework on relevant topics of restoration ecology and conservation biology, such as the choice of reference ecosystems, the evaluation of restoration actions, and the identification of priority areas for conservation and restoration.     

Biodiversity loss and the taxonomic bottleneck: emerging biodiversity science

Human domination of the Earth has resulted in dramatic changes to global and local patterns of biodiversity. Biodiversity is critical to human sustainability because it drives the ecosystem services that provide the core of our life-support system. As we, the human species, are the primary factor leading to the decline in biodiversity, we need detailed information about the biodiversity and species composition of specific locations in order to understand how different species contribute to ecosystem services and how humans can sustainably conserve and manage biodiversity. Taxonomy and ecology, two fundamental sciences that generate the knowledge about biodiversity, are associated with a number of limitations that prevent them from providing the information needed to fully understand the relevance of biodiversity in its entirety for human sustainability: (1) biodiversity conservation strategies that tend to be overly focused on research and policy on a global scale with little impact on local biodiversity; (2) the small knowledge base of extant global biodiversity; (3) a lack of much-needed site-specific data on the species composition of communities in human-dominated landscapes, which hinders ecosystem management and biodiversity conservation; (4) biodiversity studies with a lack of taxonomic precision; (5) a lack of taxonomic expertise and trained taxonomists; (6) a taxonomic bottleneck in biodiversity inventory and assessment; and (7) neglect of taxonomic resources and a lack of taxonomic service infrastructure for biodiversity science. These limitations are directly related to contemporary trends in research, conservation strategies, environmental stewardship, environmental education, sustainable development, and local site-specific conservation. Today’s biological knowledge is built on the known global biodiversity, which represents barely 20% of what is currently extant (commonly accepted estimate of 10 million species) on planet Earth. Much remains unexplored and unknown, particularly in hotspots regions of Africa, South Eastern Asia, and South and Central America, including many developing or underdeveloped countries, where localized biodiversity is scarcely studied or described. "Backyard biodiversity", defined as local biodiversity near human habitation, refers to the natural resources and capital for ecosystem services at the grassroots level, which urgently needs to be explored, documented, and conserved as it is the backbone of sustainable economic development in these countries. Beginning with early identification and documentation of local flora and fauna, taxonomy has documented global biodiversity and natural history based on the collection of "backyard biodiversity" specimens worldwide. However, this branch of science suffered a continuous decline in the latter half of the twentieth century, and has now reached a point of potential demise. At present there are very few professional taxonomists and trained local parataxonomists worldwide, while the need for, and demands on, taxonomic services by conservation and resource management communities are rapidly increasing. Systematic collections, the material basis of biodiversity information, have been neglected and abandoned, particularly at institutions of higher learning. Considering the rapid increase in the human population and urbanization, human sustainability requires new conceptual and practical approaches to refocusing and energizing the study of the biodiversity that is the core of natural resources for sustainable development and biotic capital for sustaining our life-support system. In this paper we aim to document and extrapolate the essence of biodiversity, discuss the state and nature of taxonomic demise, the trends of recent biodiversity studies, and suggest reasonable approaches to a biodiversity science to facilitate the expansion of global biodiversity knowledge and to create useful data on backyard biodiversity worldwide towards human sustainability.     

Plant Conservation in the Caribbean Island Biodiversity Hotspot

While the Caribbean is a recognized “biodiversity hotspot”, plant conservation has not received adequate attention; particularly, given the high levels of endemism in many plant groups. Besides establishing protected areas, there needs to be a sustained effort to study the taxonomy, systematics and ecology of the flora. Recent phylogenetic studies have shown high levels of endemism and conservation studies indicate a large propotion of the flora is threatened with extinction. Eight recommendations are given for plant conservation in the region.     

Impacts of tree species diversity on litter decomposition in northern temperate forests of Wisconsin, USA: a multi-site experiment along a latitudinal gradient

Over the past decade an increasing amount of research has sought to understand how the diversity of species in an ecosystem can influence fluxes of biologically important materials, such as the decomposition of organic matter and recycling of nutrients. Generalities among studies have remained elusive, perhaps because experimental manipulations have been performed at relatively small spatial scales where site-specific variation generates patterns that appear idiosyncratic. One approach for seeking generality is to perform parallel experiments at different sites using an identical species pool. Here we report results from a study where we manipulated the diversity of leaf litter from the same six dominant tree species in the litter layer of three forested ecosystems. These ecosystems spanned a 300 km latitudinal transect in Wisconsin, USA, and were characterized by a large gradient in temperature and moisture, and thus, rates of decomposition. After allowing combinations of one, two, four, and six species of leaf litter to decompose for 1 year, we found that increasing leaf litter richness led to slower rates of decomposition and higher fractions of nitrogen lost from litter. Across all sites, climate and initial litter chemistry explained more of the variation in decomposition rates than did litter richness. Effects of leaf litter diversity were non-additive, meaning they were greater than expected from the impacts of individual species, and appeared to be strongly influenced by the presence/absence of just 1–2 species (Tilia americana and Acer saccharum). The rate of decomposition of these two species was highly site-specific, which led to strong negative effects of litter richness only being observed at the southernmost sites where T. americana and A. saccharum decomposed more quickly. In contrast, litter diversity increased nitrogen loss at the northernmost sites where decomposition of T. americana was notably slowed. Our study shows that species diversity affected at least one of the two litter processes at each site along this 300-km gradient, but the exact nature of these effects were spatially variable because the performance of individual species changed across the heterogeneous landscape.     

生物多样性的熵值结构

多样性一般定义为生物进化过程中物种表现型的丰富程度。从广义上讲,生物进化与环境归类作用的结构复杂性对生物为多样性的解释是很有益处的。我们认为区域水平与样地水平上的气候归类型与植被归类型是最基本的划分因子,本文以中国东北部黑龙江省的山地植被为例,采用多等级熵值分配的方法来证明所使用的方法。我们得出气候归类型与植被归类型所占有的熵值成分要弱于物种表现型丰富度所占有的熵值成份。值得注意的是其相对的熵值贡献率对每一个因子的最大熵值的变化规律。分析结果表明气候归类型占有较低的熵值而植被归类型占有较高的熵值。因此仅仅以在区域气候型为主要指标所划分的物种生态位是不够的,而以小区域内的植被型为指标所产生的物种生态位具有较高利用价值。     

植物化感作用与生物多样性

本文简要地阐释了化感作用的含义、基本特征以及作用机制,并结合生物多样性理论,综述了化感作用研究中化感物种的多样性、化感物质的多样性及其释放途径的多样性,具体讨论了化感作用对物种多样性、遗传多样性及生态系统多样性中的种群生态、协同进化、土壤生境、生态系统功能和生物入侵等方面的可能影响。文中提出了化感作用的利用、管理应与生物多样性保护相统一的看法,并指出对化感作用与生物多样性的关系以及相互影响机制进行本质的探索,特别是对植物化感作用的生态服务功能与价值评估与探讨,可为保护生物学和系统生态学提供理论基础,这也是今后工作开展的一个重要方向。     

Biodiversity and wetlands

The implications of the Biodiversity Convention of the UNCED Conference in Rio are discussed in terms of the obligations of participating states. The importance of biodiversity is outlined with special reference to wetland ecosystems. The values of wetlands and wetland biodiversity are discussed and a possible classification strategy for their conservation and wise use is suggested.Corresponding Editor: R.E. Turner