农业生态系统中生物多样性的功能—兼论其保护途径与今后研究方向

重点论述了农业生态系统中生物多样性的功能，其功能主要表现在害虫控制、土壤侵蚀防治、退化环境恢复、消除污染和促进养分循环等方面。探讨了农业生态系统中生物多样性的保护途径及今后开展的研究重点。     

生物多样性与生态系统功能

该文阐述了生物多样性与生态系统功能的密切相关性。分析了生物多样性的丧失对生态系统功能将带来的影响。提出了未来应深入研究的五个方面：相对于物种和功能组其它水平生物多样性的改变带来的影响如何；目前已知的科学知识是否适用于所有的生态系统；各级水平食物网多样性对生态系统功能的重要性；其它全球变化过程与生物多样性——生态系统功能的变化模式如何相互作用；生物多样性变化引起生态系统功能变化会产生什么样的经济后果。     

植物功能多样性及其与生态系统功能关系研究进展

生物多样性影响生态系统的多种功能。生物多样性的急剧丧失使得对其影响评定尤为重要和紧迫,因此,生物多样性与生态系统功能关系成为生态学研究的热点问题之一,其中功能多样性与生态系统功能关系的研究成为近十年该领域研究的重点。文章首先概括了植物功能多样性的多种定义,并详细介绍了目前被广泛接受的定义"功能多样性是某一群落内物种间功能特征的变化范围或指特定生态系统中所有物种功能特征的数值和范围"。其次重点阐述了围绕植物功能多样性开展的5个重要研究论题:(1)分别从功能丰富度、功能均匀度、功能离散度3个方面介绍了功能多样性算法,并强调要注重多指数相结合以综合描述功能多样性;(2)植物功能性状间主要体现为权衡关系,植物功能性状受到了气候、土壤、海拔、地形地貌、放牧、土地利用方式等一系列因素的影响;(3)基于植物功能性状更有利于探讨环境过滤和相似性限制对群落构建的驱动作用;(4)功能多样性与物种多样性间呈现正相关、负相关和饱和曲线等一系列关系,之所以呈现不同关系与资源状况和外界干扰密切相关;(5)尽管很多研究都证明了功能多样性对生态系统功能具有正效应,但依然存在两个主要的争议,一方面是物种多样性、功能多样性在生态系统功能维持中的相对重要性,另一方面是选择效应与互补效应在功能多样性与生态系统功能关系中的适用性。最后,提出了该领域需要进一步深入开展的4个研究方向:开展多尺度研究、重视多营养级研究,加强野外观测与受控实验相结合的研究、深化生态系统多功能性的研究。     

森林生态系统土壤真菌群落及其影响因素研究进展

真菌是全球生物多样性的重要组成部分,在森林生态系统功能中发挥着重要作用,通过共生-寄生的相互作用影响着动植物的群落结构。高通量测序技术(Roche FLX 454,Illumina MiSeq)的兴起,使得研究人员能够仔细构建真菌群落的生物地理格局和生态效应,极大地促进了人们对真菌功能特征、多样性的理解。文章综述了森林生态系统真菌群落的最新研究进展,分析了真菌群落多样性地理尺度上的变化趋势与驱动因素,并重点关注植被类型与真菌多样性的关系。研究结果发现,地理距离引起的森林类型的变化是影响真菌群落的主要因素之一。在森林生态系统中,海拔梯度的真菌群落多样性存在上升、下降、"单峰"、无显著变化4种模式,且不同森林类型的驱动因素也存在差异。森林土壤真菌群落组成和多样性受到各种土壤特征(pH、C/N)的影响,植被类型对真菌群落的影响方式也存在不确定性。在今后的研究过程中,有必要对较小尺度上真菌群落的分类和功能结构进行更多分析,探讨海拔梯度下优势植被多样性与真菌群落的关系。在植被类型复杂多样的森林生态系统中,对特异性树种、混交林以及林区(从土壤到植物圈)真菌群落的分类和功能结构进行进一步研究。此外,了解驱动元素循环的生物(人类、植物和土壤生物)以及调节其活动的环境条件(气候、土壤理化特性和地形),从而提高我们对真菌群落与生态系统功能的认识,利用功能基因探索真菌群落组成并探索生态系统功能之间的联系。     

生物多样性保护及其研究进展（综述）

由于人口的增长和人类经济活动的加剧，致使生物多样性受到了严重的威胁，引起国际社会的普遍关注．生物多样性是生物及其与环境形成的生态复合体以及与此相关的各种生态过程的总和，具有十分重要的价值，是人类生存的物质基础．各国政府和有关的国际组织积极投入到保护生物多样性的全球行动中．为了促进保护工作，国内外都开展了相关的研究工作．综观该领域的研究现状，可以看出以下７个方面已成为当前生物多样性研究的热点：①生物多样性的调查、编目及信息系统的建立；②人类活动对生物多样性的影响；③生物多样性的生态系统功能；④生物多样性的长期动态监测；⑤物种濒危机制及保护对策的研究；⑥栽培植物与家养动物及其野生近缘的遗传多样性研究；⑦生物多样性保护技术与对策．结合我国的具体情况，建议优先考虑以下４个方面的研究：①生物多样性的调查、编目与动态监测；②物种濒危机制及保护对策的研究；③生物多样性的生态系统功能与生态系统管理；④栽培植物与家养动物及其野生近缘的遗传多样性研究．     

生态系统生物多样性研究及其保护对策

本文综述了生态系统多样性在生物多样性保护中的意义及５个中心研究问题，即生物群落或生态系统关键种、生物多样性关键地区、生态系统多样性的持续性、受害生态系统的恢复生态学、生态系统多样性保护对策及保护途径。文章还分析和讨论当前国际上有关生态系统多样性保护的对策和实践。     

气候变化对生物多样性的影响:脆弱性和适应

气候变化对生物多样性影响及其适应直接关系着未来生物多样性的保护.气候变化对生物多样性影响、生物多样性在气候变化影响下的脆弱性、生物多样性适应气候变化方面进行了总结分析,对存在的问题进行了讨论,对今后研究提出了一些建议.过去的气候变化已使物种物候、分布和丰富度等改变,使一些物种灭绝、部分有害生物危害强度和频率增加,使一些生物入侵范围扩大、生态系统结构与功能改变等.未来的气候变化仍将使物种物候和行为、分布和丰富度等改变,使一些物种灭绝、使有害生物爆发频率和强度增加,并将可能使生态系统结构与功能发生改变等.生物多样性适应气候变化包括了自然适应和人为适应两个方面,自然适应体现在物种适应性进化、迁移、生态系统稳定性和弹性等,人为适应体现在种质基因保存、物种异地保护、自然保护区规划设计、生态系统适应性管理、生态恢复和气候灾害防御等.目前,生物多样性对气候变化影响的脆弱性、生物多样性自然适应和人为适应气候变化方面的研究都还不系统深入,需要加强生物多样性自然适应和人为适应气候变化方面的研究.     

植物多样性对土壤微生物的影响

生物多样性强烈地影响生态系统的过程.生态系统过程的变化可导致生物多样性衰减并因此导致生态系统功能衰退.植物种丰度和植物功能多样性对土壤细菌群落的代谢活性和代谢多样性有成正比的影响.土壤细菌的代谢活性和代谢多样性随植物种数量的对数和植物功能组的数量而直线上升.其原因可能是由植被流入土壤的物质和能量的多样性和数量的增加,也可能是由土壤动物区系起作用的土壤微生境的多样性的增加造成的.由于植物多样性的丧失所引起的植物生物量的减少对分解者群落有强烈的影响微生物生物量将可能减少,因为在大多数陆地生态系统中,有机碳源限制着土壤微生物的活性.     

草地生态系统生物和功能多样性及其优化管理

草地生态系统作为陆地生态系统的主要类型之一,能够为人类提供丰富多样的生产和服务功能,在维持和保护生物多样性、提供生产力、土壤碳库、养分循环、防风固沙、保持水土、涵养水源、调节气候等方面发挥着重要功能。然而,随着城市化和工业化进程的加快,人类对自然界进行了高强度掠夺式开发利用,为谋求经济发展而不惜以牺牲环境与自然资源为代价,致使社会经济的发展同资源与环境保护之间的矛盾日益突出,如越来越多的生物面临灭绝、生态系统服务功能下降、全球气候变化等,而这些问题反过来又影响了社会经济的可持续发展。在人类活动附加于自然草地生态系统后,草地的利用与经营管理方式以依赖实践和经验为主导,而关于草地生态系统结构和功能的理论研究一直处于探索积累阶段而不能很好地指导实践,致使草地利用与发展经历了缺乏科学指导和合理调控的盲目发展模式。随着数学方法和信息技术等在生态学中的广泛应用,对生态系统结构、组分之间机理联系的深入认识,生态学家正试图利用信息科学、系统科学和网络分析技术,准确模拟生物多样性、多元生态功能网络,分析多功能之间的权衡关系,优化生态系统服务,实现对草地发展趋势的科学预警,加强草地良性发展的人为调控,以最终实现生物多样性保护、优化生态功能和可持续发展的科学管理系统。文章综述了生物多样性和草地生态系统功能与管理的重要研究进展,提出了促进草地生态系统可持续发展的建议与研究展望。     

养分管理与农田杂草生物多样性和遗传进化的关系研究进展

施肥被看作是一项潜在降低农田杂草对作物干扰的有效农作管理措施。不同施肥处理可形成具有不同养分状况的土壤条件,而土壤条件的差异是导致杂草生物多样性的重要因素。论证养分管理可显著改变农田杂草发生状况和杂草生物多样性,强调了深入开展不同养分管理模式对农田杂草生物多样性和遗传进化影响研究的重要性,提出了如何利用养分管理措施调节农田杂草,在控制杂草对农业危害的同时,保持一定农田可控杂草生物多样性的科学问题。长期N、P和K平衡配施,可维持杂草群落和杂草种子库的生物多样性与稳定性,兼顾杂草控制和杂草多样性保护,实现平衡施肥的经济效应与生态效应的统一。同时,农业生态系统中不同养分管理措施条件下的地表光辐射变化特征、不同光辐射变化对杂草种群种子萌发及植株建立的影响、优势杂草种群的确定及其生理生态和遗传进化规律是今后研究的重点和难点。     

稻田生物多样性构建的生态效应

农业集约化生产方式加速了农业生态系统单一化的进程,导致系统平衡破坏,病、虫、草害频发。在以农业生态环境改善和修复为手段的农业可持续生产和发展的模式中,以农作物多样性的合理布局来提高农业生物多样性水平和控制病、虫、草害的实践,显示出其强大的生命力,即将不同物种的作物或同一作物的不同品种按一定的组合方式和栽种模式进行合理的间栽和套作,将病、虫、草害的发生控制在可以承受的范围内。构建水生动物、水生植物与水稻共存的稻作系统,利用物种多样性、遗传多样性控制有害生物,是农业可持续发展的重要途径。本文综述了国内外稻田物种多样性、遗传多样性利用模式的研究进展,论述了稻田物种多样性、遗传多样性对稻作生态系统的改善,特别是水稻病、虫、草的控制效果及作用机理。     

Biotic habitat complexity controls species diversity and nutrient effects on net biomass production

Canopy-forming plants and algae commonly contribute to spatial variation in habitat complexity for associated organisms and thereby create a biotic patchiness of communities. In this study, we tested for interaction effects between biotic habitat complexity and resource availability on net biomass production and species diversity of understory macroalgae by factorial field manipulations of light, nutrients, and algal canopy cover in a subtidal rocky-shore community. Presence of algal canopy cover and/or artificial shadings limited net biomass production and facilitated species diversity. Artificial shadings reduced light to levels similar to those under canopy cover, and net biomass production was significantly and positively correlated to light availability. Considering the comparable and dependent experimental effects from shadings and canopy cover, the results strongly suggest that canopy cover controlled net biomass production and species diversity by limiting light and thereby limiting resource availability for community production. Canopy cover also controlled experimental nutrient effects by preventing a significant increase in net biomass production from nutrient enrichment recorded in ambient light (no shading). Changes in species diversity were mediated by changes in species dominance patterns and species evenness, where canopy cover and shadings facilitated slow-growing crust-forming species and suppressed spatial dominance by Fucus vesiculosus, which was the main contributor to net production of algal biomass. The demonstrated impacts of biotic habitat complexity on biomass production and local diversity contribute significantly to understanding the importance of functionally important species and biodiversity for ecosystem processes. In particular, this study demonstrates how loss of a dominant species and decreased habitat complexity change the response of the remaining assembly to resource loading. This is of potential significance for marine conservation since resource loading often promotes low habitat complexity and canopy species are among the first groups lost in degraded aquatic systems.     

Cumulative ecological and socioeconomic effects of forest policies in coastal Oregon.

Forest biodiversity policies in multi-ownership landscapes are typically developed in an uncoordinated fashion with little consideration of their interactions or possible unintended cumulative effects. We conducted an assessment of some of the ecological and socioeconomic effects of recently enacted forest management policies in the 2.3-million-ha Coast Range Physiographic Province of Oregon. This mountainous area of conifer and hardwood forests includes a mosaic of landowners with a wide range of goals, from wilderness protection to high-yield timber production. We projected forest changes over 100 years in response to logging and development using models that integrate land use change and forest stand and landscape processes. We then assessed responses to those management activities using GIS models of stand structure and composition, landscape structure, habitat models for focal terrestrial and aquatic species, timber production, employment, and willingness to pay for biodiversity protection. Many of the potential outcomes of recently enacted policies are consistent with intended goals. For example, we project the area of structurally diverse older conifer forest and habitat for late successional wildlife species to strongly increase. 'Other outcomes might not be consistent with current policies: for example, hardwoods and vegetation diversity strongly decline within and across owners. Some elements of biodiversity, including streams with high potential habitat for coho salmon (Oncorhynchus kisutch) and sites of potential oak woodland, occur predominately outside federal lands and thus were not affected by the strongest biodiversity policies. Except for federal lands, biodiversity policies were not generally characterized in sufficient detail to provide clear benchmarks against which to measure the progress or success. We conclude that land management institutions and policies are not well configured to deal effectively with ecological issues that span broad spatial and temporal scales and that alternative policies could be constructed that more effectively provide for a mix of forest values from this region.     

Integrating functional connectivity and fire management for better conservation outcomes

Globally, the mean abundance of terrestrial animals has fallen by 50% since 1970, and populations face ongoing threats associated with habitat loss, fragmentation, climate change, and disturbance. Climate change can influence the quality of remaining habitat directly and indirectly by precipitating increases in the extent, frequency, and severity of natural disturbances, such as fire. Species face the combined threats of habitat clearance, changing climates, and altered disturbance regimes, each of which may interact and have cascading impacts on animal populations. Typically, conservation agencies are limited in their capacity to mitigate rates of habitat clearance, habitat fragmentation, or climate change, yet fire management is increasingly used worldwide to reduce wildfire risk and achieve conservation outcomes. A popular approach to ecological fire management involves the creation of fire mosaics to promote animal diversity. However, this strategy has 2 fundamental limitations: the effect of fire on animal movement within or among habitat patches is not considered and the implications of the current fire regime for long-term population persistence are overlooked. Spatial and temporal patterns in fire history can influence animal movement, which is essential to the survival of individual animals, maintenance of genetic diversity, and persistence of populations, species, and ecosystems. We argue that there is rich potential for fire managers to manipulate animal movement patterns; enhance functional connectivity, gene flow, and genetic diversity; and increase the capacity of populations to persist under shifting environmental conditions. Recent methodological advances, such as spatiotemporal connectivity modeling, spatially explicit individual-based simulation, and fire-regime modeling can be integrated to achieve better outcomes for biodiversity in human-modified, fire-prone landscapes. Article impact statement: Land managers may conserve populations by using fire to sustain or enhance functional connectivity.     

Multispecies genetic objectives in spatial conservation planning

Growing threats to biodiversity and global alteration of habitats and species distributions make it increasingly necessary to consider evolutionary patterns in conservation decision making. Yet, there is no clear‐cut guidance on how genetic features can be incorporated into conservation‐planning processes, despite multiple molecular markers and several genetic metrics for each marker type to choose from. Genetic patterns differ between species, but the potential tradeoffs among genetic objectives for multiple species in conservation planning are currently understudied. We compared spatial conservation prioritizations derived from 2 metrics of genetic diversity (nucleotide and haplotype diversity) and 2 metrics of genetic isolation (private haplotypes and local genetic differentiation) in mitochondrial DNA of 5 marine species. We compared outcomes of conservation plans based only on habitat representation with plans based on genetic data and habitat representation. Fewer priority areas were selected for conservation plans based solely on habitat representation than on plans that included habitat and genetic data. All 4 genetic metrics selected approximately similar conservation‐priority areas, which is likely a result of prioritizing genetic patterns across a genetically diverse array of species. Largely, our results suggest that multispecies genetic conservation objectives are vital to creating protected‐area networks that appropriately preserve community‐level evolutionary patterns.     

Diversity and cover of a sessile animal assemblage does not predict its associated mobile fauna

Habitat-forming organisms often determine the structural properties and food resources available to a wide diversity of associated mobile species. Sessile invertebrate assemblages on marine hard substrates support an abundant fauna of mobile invertebrates whose associations with traits of their host assemblages are poorly known. To assess how changes to habitat-forming species are likely to affect their associated mobile fauna, the relationships between abundance, diversity and composition of mobile invertebrates and the diversity, cover and composition of the sessile assemblages they use as habitat were quantified in Sydney Harbour, Australia (33°50′S, 151°16′E). Similar compositions of sessile species were more likely to share a similar composition of mobile species, but univariate measures of the habitat (percent cover, species and functional diversity, prevalence of non-indigenous species) did not predict variation in associated mobile assemblages. These results demonstrate that in this habitat it is difficult to predict the diversity of marine assemblages based on common surrogate measures of biodiversity.     

Conservation of Insect Diversity: a Habitat Approach

Abstract: Neither time nor resources exist to design conservation plans for every species, particularly for little-studied, noncharismatic, but ecologically important taxa that make up most of biodiversity. To explore the feasibility of basing conservation action on community-level biogeography, we sampled a montane insect community. We addressed three issues: (1) the appropriate scale for sampling insect communities; (2) the association of habitat specialization—perhaps a measure of extinction vulnerability—with other ecological or physical traits; and (3) the correlation of diversity across major insect groups. Using malaise traps in Gunnison County, Colorado, we captured 8847 Diptera (identified to family and morphospecies), 1822 Hymenoptera (identified to morphospecies), and 2107 other insects (identified to order). We sampled in three habitat types—meadow, aspen, and conifer—defined on the basis of the dominant vegetation at the scale of hundreds of meters. Dipteran communities were clearly differentiated by habitat type rather than geographic proximity. This result also holds true for hymenopteran communities. Body size and feeding habits were associated with habitat specialization at the family level. In particular, habitat generalists at the family level—taxa perhaps more likely to survive anthropogenic habitat alteration—tended to be trophic generalists. Dipteran species richness was marginally correlated with hymenopteran species richness and was significantly correlated with the total number of insect orders sampled by site. Because these correlations result from differences in richness among habitat types, insect taxa may be reasonable surrogates for one another when sampling is done across habitat types. In sum, community-wide studies appear to offer a practical way to gather information about the diversity and distribution of little-known taxa.     

A link between ecological diversity indices and measures of biodiversity

The practice of environmental planning and protection frequently necessitates the quantification of ecological diversity. Traditional ‘ecological diversity indices’ are based on the abundances of species present. However, such indices are insensitive to taxonomic or similar differences. With equal species abundances they measure the species richness (species number) only. Conversely, so-called ‘biodiversity indices’ are based on species differences, but are insensitive to the abundance conditions. The quadratic entropy index is the only ecological diversity index, the value of which reflects both the differences ‘and’ abundances of the species. When a species list is given without abundance data, then, using the quadratic entropy index and postulating equal abundances, one gets the only biodiversity index derived from a traditional ecological index of diversity. Its extensive form is identical with the sum of differences or distances between the species present. This index trivially satisfies set monotonicity, an important property for biodiversity indices.     

Conservation Planning in Forest Landscapes of Fennoscandia and an Approach to the Challenge of Countdown 2010

Abstract:  Effective management of biodiversity in production landscapes requires a conservation approach that acknowledges the complexity of ecological and cultural systems in time and space. Fennoscandia has experienced major loss of forest biodiversity caused by intensive forestry. Therefore, the Countdown 2010 initiative to halt the loss of biodiversity in Europe is highly relevant to forest management in this part of the continent. As a contribution to meeting the challenge posed by Countdown 2010, we developed a spatially explicit conservation-planning exercise that used regional knowledge on forest biodiversity to provide support for managers attempting to halt further loss of biological diversity in the region. We used current data on the distribution of 169 species (including 68 red-listed species) representing different forest habitats and ecologies along with forest data within the frame of modern conservation software to devise a map of priority areas for conservation. The top 10% of priority areas contained over 75% of red-listed species locations and 41% of existing protected forest areas, but only 58% of these top priorities overlapped with core areas identified previously in a regional strategy that used more qualitative methods. We argue for aggregating present and future habitat value of single management units to landscape and regional scales to identify potential bottlenecks in habitat availability linked to landscape dynamics. To address the challenge of Countdown 2010, a general framework for forest conservation planning in Fennoscandia needs to cover different conservation issues, tools, and data needs.     

Habitat biodiversity as a determinant of fish community structure on coral reefs

Increased habitat diversity is often predicted to promote the diversity of animal communities because a greater variety of habitats increases the opportunities for species to specialize on different resources and coexist. Although positive correlations between the diversities of habitat and associated animals are often observed, the underlying mechanisms are only now starting to emerge, and none have been tested specifically in the marine environment. Scleractinian corals constitute the primary habitat-forming organisms on coral reefs and, as such, play an important role in structuring associated reef fish communities. Using the same field experimental design in two geographic localities differing in regional fish species composition, we tested the effects of coral species richness and composition on the diversity, abundance, and structure of the local fish community. Richness of coral species overall had a positive effect on fish species richness but had no effect on total fish abundance or evenness. At both localities, certain individual coral species supported similar levels of fish diversity and abundance as the high coral richness treatments, suggesting that particular coral species are disproportionately important in promoting high local fish diversity. Furthermore, in both localities, different microhabitats (coral species) supported very different fish communities, indicating that most reef fish species distinguish habitat at the level of coral species. Fish communities colonizing treatments of higher coral species richness represented a combination of those inhabiting the constituent coral species. These findings suggest that mechanisms underlying habitat-animal interaction in the terrestrial environment also apply to marine systems and highlight the importance of coral diversity to local fish diversity. The loss of particular key coral species is likely to have a disproportionate impact on the biodiversity of associated fish communities.