生态系统中关键种类型及其管理对策

与其他物种相比,关键种（Ｋｅｙｓｔｏｎｅ ｓｐｅｃｉｅｓ）在其生态系统中具有更深刻的影响。根据野外考察和研究,笔者认为关键种应分为两类：一类对生态系统具有积极的、重要的作用,也就是一般所称的“关键种”,一旦它们受到严重干扰,很多依赖它们而生存的物种也将受到严重威胁或即将消失。另严则相反,具有潜在的消极作用,可称为“潜关键种”（Ｐｏｔｅｎｔｉａｌ ｋｅｙｓｔｏｎｅ ｓｐｅｃｉｅｓ）,一旦它们获得发展     

生态系统的环分析方法

生态系统的环分析方法郭中伟,李典谟（中国科学院动物研究所,北京１０００８０）ＬｏｏｐＡｎａｌｙｓｉｓｉｎＥｃｏｓｙｓｔｅｍＳｔｕｄｙ．￥ＧｕｏＺｈｏｎｇｗｅｉ;ＬｉＤｉａｎｍｏ（ＩｎｓｔｉｔｕｔｅｏｆＺｏｏｌｏｇｙ,,ＡｃａｄｅｍｉａＳｉｎｉｃａ,Ｂ...     

英国利用卫星勘查生态系统

英国利用卫星勘查生态系统王凯雄（浙江农业大学环境保护系杭州３１００２９）任何英国人都会告诉你英国的农村已不象过去那样了。以前的乡村风光─—空气中充满着鸟儿的歌声和禾草的香味,现在已只能偶尔一见了。田园景观已由于过度的耕作、汽车和城镇建设而逐渐遭到破坏...     

东莞市郊平原地农业生态系统模式

东莞市郊平原地农业生态系统模式陈荣均骆世明（华南农业大学生态研究所,广州５１０６４２）ＡｇｒｏｅｃｏｓｙｓｔｅｍＭｏｄｅｌｓｏｆＦｌａｔｌａｎｄｓｉｎｔｈｅＳｕｂｕｒｂａｎｏｆＤｏｎｇｇｕａｎ．ＣｈｅｎＲｏｎｇｊｕｎ,ＬｕｏＳｈｉｍｉｎｇ（Ｉｎｓｔｉ...     

生态系统的冗余与营养结构模型

生态系统的冗余与营养结构模型党承林黄瑞复（云南大学生态学与地植物学研究所,昆明６５００９１）ＲｅｄｕｎｄａｎｃｙｉｎＥｃｏｓｙｓｔｅｍｓａｎｄｔｈｅＭｏｄｅｌｆｏｒＴｒｏｐｈｉｃＳｔｒｕｃｔｕｒｅ．ＤａｎｇＣｈｅｎｇｌｉｎ,ＨｕａｎｇＲｕｉｆｕ（Ｉｎ...     

农业生态系统的人类生态学分析模式探讨

农业生态系统的人类生态学分析模式探讨李季（北京农业大学农业生态环境科学系,１０００９４）ＡｎＡｎａｌｙｔｉｃａｌＭｏｄｅｌｏｆＡｇｒｏｅｃｏｓｙｓｔｅｍｆｒｏｍＨｕｍａｎＥｃｏｌｏｇｙＰｅｒｓｐｅｃｔｉｖｅ￥．ＬｉＪｉ（ＤｅｐａｒｔｍｅｎｔｏｆＥｃｏｌｏｇｙａｎｄＥｎｖｉｒｏｎｍｅｎｔａｌＳｃｉｅｎｃｅｓ,ＢｅｉｊｉｎｇＡｇｒｉｃｕｌｔｕｒａｌＵｎｉｖｅｒｓｉｔｙ１０００９４）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（２）：２３－２４．Ｂａｓｅｄｏｎｔｈｅａｎａｌｙｓｉｓｏｆｏｕｒｃｕｒｒｅｎｔａｇｒｏ－ｅｃｏｌｏｇｉｃａｌｒｃｓｅａｒｃｈ,ａｎｅｗａｎａｌｙｔｉｃａｌｍｏｄｅｌｏｆａｇｒｏ－ｅｃｏｓｙｓｔｅｍｋｅｓｔａｂｌｉｓｈｅｄａｎｄｔｈｅｃｏｎｔｅｎｔｓｏｆｉｔｓｒｅｓｅａｒｃｈａｒｅｒｅｓｔｒｕｃｔｕｒｅｄ．Ｔｈｅａｉｍｏｆｔｈｅｓｅｉｓｔｏｐｒｏｖｉｄｅａｍｏｄｅｌｆｏｒｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｒｅｇｉｏｎａｌａｇｒｉｃｕｌｔｕｒｅ,ｗｈｉｃｈｃａｎｎｏｔｏｎｌｙｅｘｐａｎｄｔｈｅｃｕｒｒｅｎｔｒｅｌａｔｅｄｔｈｅｏｒｉｅｓａｎｄｍｅｔｈｏｄｏｌｏｇｉｅｓ,ｂｕｔ     

人类生产活动对土壤生态系统的影响

人类生产活动对土壤生态系统的影响武志杰（中国科学院沈阳应用生态研究所,１１００１５）ＩｎｆｌｕｅｎｃｅｏｆＨｕｍａｎＡｃｔｉｖｉｔｙｏｎＳｏｉｌＥｃｏｓｙｓｔｅｍ￥．ＷｕＺｈｉｊｉｅ（ＩｎｓｌｉｔｕｔｅｏｆＡｐｐｌｉｅｄＥｃｏｌｏｇｙ,ＡｃａｄｅｍｉａＳｉｎｉ－ｃａ,Ｓｈｅｎｙａｎｇ１１００１５）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（４）：４７－５１．Ｔｈｅｒｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｈｕｒｎａｎａｃｔｉｖｉｔｙａｎｄｓｏｉｌｅｃｏｓｙｔｅｍｉｓａｎａｌｙｓｅｄ．Ｓｏｉｌｅｃｏｌｏｇｉｃａｌｓｔｒｕｃｔｕｒｅａｎｄｉｔｓｆｕｎｃｔｉｏｎａｒｅｇｒｅａｔｌｙｉｎｆｌｕｅｎｃｅｄｂｙｈｕｍａｎａｃｔｉｖｉｔｉｅｓ,ｓｕｃｈａｓｆａｒｍｉｎｇ,ｆｅｒｔｉｌｉｚａｔｉｏｎ,ｉｒｒｉｇａｔｉｏｎａｎｄｐｏｌｌｕｔｉｏｎ．Ｓｏｉｌｅｃｏｓｙｓｔｅｍｕｒｇｅｎｔｌｙｎｅｅｄｓｔｏｂｅｐｒｏｔｅｃｔｅｄ．Ｋｅｙｗｏｒｄｓ：ｓｏｉｌｅｃｏｌｏｇｙ,ｈｕｍａｎａｃｔｉｖｉｔｙ,ｓｏｉｌｅｃｏｓｙｓｔｅｍ．１总论土壤生态系统是一种人工干预最多的生态系统。对于土壤生态系统,人类首要的企图是维持     

蒲洼农业生态系统能流的稳定性及其动态

在研究生态系统结构及功能的基础上,本文基于１９７５－１９９０年的数据,对蒲洼农业生态系统能流的稳定性及其动态进行了分析。通过建立能流模型,由李雅普诺夫稳定性原理,得出该生态系统能流的平衡态具有渐近稳定性。动态数学模拟表明,目前该系统的能量流动正从不稳定状态向稳定和平衡态过渡,这一过程大约需要７ａ时间。     

The Protozoan-Metazoan Trophic Link In Pelagic Ecosystems

ABSTRACT The evidence for a qualitatively and quantitatively important trophic link between planktonic Protozoa and higher order metazoan consumers is reviewed. the available data are obtained primarily, but not exclusively, from laboratory studies of calanoid copepod consumers and tintinnid ciliate prey from marine estuarine and nearshore environments. the data indicates that the protozoan-metazoan link is of similar magnitude and importance in the pelagic ecosystems of freshwaters. It is proposed that planktonic Protozoa constitute a high quality, nitrogen-rich food in the diets of their metazoan consumers. Implications of die trophic link to the consumers, prey, and ecosystem are discussed.     

Nematode Trophic Structure in Conventional and No-Tillage Agroecosystems

The effect of tillage intensity on nematode community trophic structure and the role of nematodes in the regulation of decomposition rates in agroecosystems were examined. Conventional (CT) and no-tillage (NT) agroecosystems were sampled monthly for 1 year. Tillage affected nematode trophic structure and total abundance. Monthly mean densities of bacterivorous, fungivorous, and total nematodes were greater in CT than in NT plots. In the summer, however, fungivorous and plant parasitic nematodes were more abundant in NT. No difference was detected for omnivore-predator nematodes.     

生态系统营养动态的网络透视法

生态系统营养动态的网络透视法张晓爱（中国科学院西北高原生物研究所西宁８１０００１）ＮｅｔｗｏｒｋＰｅｒｓｐｅｃｔｉｖｅＭｅｔｈｏｄｓｆｏｒＳｔｕｄｙｉｎｇＴｒｏｐｈｉｃＤｙｎａｍｉｃｓｉｎＥｃｏｓｙｓｔｅｍ￥,ＺｈａｎｇＸｉａｏａｉ（Ｎｏｒｔｈｗｅｓ...     

Trophic control of grassland production and biomass by pathogens

Current theories of trophic regulation of ecosystem net primary production and plant biomass incorporate herbivores, but not plant pathogens. Obstacles to the incorporation of pathogens include a lack of data on pathogen effects on primary production, especially outside agricultural and forest ecosystems, and an apparent inability to quantify pathogen biomass. Here, I report the results of an experiment factorially excluding foliar fungal pathogens and insect herbivores from an intact grassland ecosystem. At peak in control plots, 8.9% of community leaf area was infected by pathogens. Disease reduction treatment dramatically increased root production and biomass by increasing leaf longevity and photosynthetic capacity. In contrast, herbivory reduction had no detectable effects at the ecosystem or leaf scale. Additionally, biomass of foliar fungal pathogens in the ecosystem was comparable with that of insect herbivores. These results identify pathogens as potential regulators of ecosystem processes and promote the incorporation of pathogens into trophic theory.     

Representing Density Dependent Consequences of Life History Strategies in Aquatic Ecosystems: EcoSim II

EcoSim II uses results from the Ecopath procedure for trophic mass-balance analysis to define biomass dynamics models for predicting temporal change in exploited ecosystems. Key populations can be represented in further detail by using delay-difference models to account for both biomass and numbers dynamics. A major problem revealed by linking the population and biomass dynamics models is in representation of population responses to changes in food supply; simple proportional growth and reproductive responses lead to unrealistic predictions of changes in mean body size with changes in fishing mortality. EcoSim II allows users to specify life history mechanisms to avoid such unrealistic predictions: animals may translate changes in feeding rate into changes in reproductive rather than growth rates, or they may translate changes in food availability into changes in foraging time that in turn affects predation risk. These options, along with model relationships for limits on prey availability caused by predation avoidance tactics, tend to cause strong compensatory responses in modeled populations. It is likely that such compensatory responses are responsible for our inability to find obvious correlations between interacting trophic components in fisheries time-series data. But Ecosim II does not just predict strong compensatory responses: it also suggests that large piscivores may be vulnerable to delayed recruitment collapses caused by increases in prey species that are in turn competitors/predators of juvenile piscivores. Received 24 February 1999; accepted 3 August 1999.     

Interannual Dynamics of the Trophic Structure of Zooplankton of the Southern Kuril Region

Based on the data on feeding ecology of common species of zooplankton, the main trophic groups of plankton of the southern Kuril region are identified. These are phytophages, zoophages, and omnivores. The interannual dynamics of trophic characteristics of the plankton community are examined. Predatory plankton significantly dominated in 1992–1994; however, in 1995–1996 its biomass decreased markedly. The biomass dynamics of predatory and nonpredatory zooplankton, as well as changes in the structure of nonpredatory zoolankton, suggest structural changes in the planktonic community.     

Invasion of a Top Predator into an Epipelagic Ecosystem can bring a Paradoxical Top-Down Trophic Control

We apply mathematical modeling to explore different scenarios of invasion of a top predator (carnivorous zooplankton or planktivorous fish) into an epipelagic plankton ecosystem. We use a ‘minimal’ model of three nonlinear ordinary differential equations (nutrient–phytoplankton–herbivores) with the top predator density as a time-dependent parameter. The ecosystem shows different types of response, which can be described in terms of top-down trophic control. Our investigation indicates that under certain conditions the plankton ecosystem model demonstrates a surprising kind of response: in a wide range of realistic ecosystem parameters the invasion of the top predator leads to a prominent increase in the average density of zooplankton and to a resulting decrease of phytoplankton density. This phenomenon is opposite to the ‘typical’ top–down control when the carnivore pressure decreases zooplankton density which, in turn, increases phytoplankton biomass. We call the revealed type of top-down control ‘paradoxical’. Examples of such a response in natural aquatic ecosystems were reported earlier but no clear explanation has been provided hitherto. In this paper, we analyze possible mechanisms of ‘paradoxical top–down control’ and show that it can occur in eutrophic epipelagic ecosystems subject to high rate of cross-pycnocline exchange.     

Trophic Dependence of Ecosystem Resistance and Species Compensation in Experimentally Acidified Lake 302S (Canada)

Ecosystem resistance to the impacts of diverse human insults depends on the replacement of sensitive species by ones more tolerant of the stressor. Here we present evidence from a whole-lake acidification experiment (Lake 302S, Experimental Lakes Area, Canada) that resistance and species compensation decline with increasing trophic level. Diverse and fast-growing algal and rotifer assemblages with high dispersal potentials showed significant compensatory species dynamics, resulting in the maintenance of total biomass despite 30%–80% declines in species richness. Canonical correspondence analysis showed that significant compensatory algal and rotifer dynamics were best explained by differential species tolerances of acidified chemical conditions coupled with release from resource limitation and predation. However, less diverse cladoceran, copepod, and fish assemblages showed significant declines in total biomass and weak species compensation with loss of species during acidification. In comparison, algal and zooplankton species dynamics remained relatively synchronized in a nearby unperturbed reference lake (Lake 239) during the experiment. As a result, Lake 302S showed limited ecosystem resistance to anthropogenic acidification. Therefore, we hypothesize that lost species will increase the susceptibility of acidified lakes to the adverse impacts of other environmental stressors (for example, climate warming, stratospheric ozone depletion, invasive species). Consequently, the ecosystem stability of boreal lakes is expected to decline as global change proceeds. Received 2 January 2001; accepted 12 July 2002.     

Accelerating Trophic-level Dysfunction in Kelp Forest Ecosystems of the Western North Atlantic

We use archaeological, historical, ecological, and fisheries data to identify three distinct and sequential phases in the trophic structure of kelp forests in the western North Atlantics Gulf of Maine. Phase 1 is characterized by vertebrate apex predators such as Atlantic cod, haddock, and wolffish and persisted for more than 4,000 years. Phase 2 is characterized by herbivorous sea urchins and lasted from the 1970s to the 1990s. Phase 3 is dominated by invertebrate predators such as large crabs and has developed since 1995. Each phase change resulted directly or indirectly from fisheries-induced trophic-level dysfunction, in which populations of functionally important species at higher trophic levels fell below the densities necessary to limit prey populations at lower trophic levels. By using fractional trophic-level analysis, we found that phase changes occurred rapidly (over a few years to a few decades) as well as relatively recently (over the past half-century). Interphase durations have declined as fishing effects have accelerated in recent years. The naturally low species diversity of the kelp forest ecosystem we studied may facilitate rapid changes because the redundancy within each trophic level is low. If the biodiversity within controlling trophic levels is a buffer against trophic-level dysfunction, then our observations from Maine may be predictive of the fate of other, more diverse systems. If fishing successively targets most, or all, strong interactors at higher trophic levels, then as those population densities decline, the potential for trophic-level dysfunction and associated instabilities will increase.     

Development of an Index of Trophic Completeness for benthic macroinvertebrate communities in flowing waters

The analysis of the trophic structure of benthic macroinvertebrate communities can be used in biological assessments of the condition of river ecosystems. Using the trophic, or functional approach, the Index of Trophic Completeness (ITC) was developed. The goal was to overcome the problems and drawbacks of using conventional diversity or biotic indices in biological assessments of rivers, such as limitation to distinct geographical regions or focus on species richness without regard for ecosystem functioning. Following an extensive review of the literature on the trophic characteristics of benthic macroinvertebrates, a large number of species (±300) were characterized according to a number of trophic criteria: plant:animal ratio in the diet, feeding mechanism, food size, food acquisition behaviour, and energy and substance transfers. On the basis of their trophic characteristics, the species could be divided into 12 trophic groups. After examination of data from geographically diverse rivers, it was concluded that any undisturbed riverine benthic macroinvertebrate community should be represented by members of each of these 12 trophic groups, with each group fulfilling a function in the benthic community. Being a community which plays a central role in the functioning of the aquatic ecosystem, the benthic invertebrates are expected to respond to disturbances to the hydrobiocoenose. The outcome of an ITC assessment is clearly presentable in the form of a pie graph with 12 wedges, each representing one of the 12 defined trophic groups. Functionally complete communities are represented by 12 wedges; a blank wedge indicates that a trophic group is not represented. This paper describes the preliminary developments in the ITC method, its potential as a biological assessment method in rivers in different geographical zones, and presents examples of trial mappings of Russian and European rivers. The application of the ITC to these rivers demonstrated the absence of ITC trophic groups at sites under the influence of anthropogenic activity.