若尔盖湿地生态安全监测方案研究

若尔盖湿地是黄河上游重要的水源涵养地,在涵养水源、调节径流和维持生物多样性等方面具有重要作用,是流域乃至国家生态安全的关键地区.近年来,由于全球气候变化和人类不合理的开发活动导致若尔盖湿地生态退化加剧,威胁区域和流域生态安全.在若尔盖湿地生态退化趋势与生态安全理论框架研究的基础上,对若尔盖湿地生态安全监测的主要内容进行...     

氮沉降对森林土壤碳收支机制的影响

森林土壤储存着全球陆地生态系统大约45%的碳,在维持全球碳平衡方面具有重要的作用。不断加剧的全球氮沉降对森林生态系统碳循环和碳吸存产生了深刻的影响,进而改变了森林生态系统的生产力和生物量积累。本文以欧洲和北美温带地区开展的有关氮沉降对森林生态系统影响的研究为基础,提炼出最可能决定加氮影响碳输入、输出效应方向和大小的因素：凋落物分解、细根周转、外生菌根真菌、土壤呼吸及可溶性有机碳淋失,并探讨了森林生态系统碳动态对氮沉降响应的不确定性。陆地生态系统碳氮循环密切相关,由于氮循环的复杂性,尽管以往碳循环研究都考虑了氮对碳循环的限制作用,但在碳氮循环耦合机理方面的研究还比较少见。在未来研究中,应通过探寻森林土壤碳氮相互作用特征,及土壤微生物、土壤酶等与土壤碳氮过程的互动机制,来增进氮沉降对森林碳储量和碳通量的理解。     

伊犁河谷北坡野果林群落结构及其与环境的关系

结合野外植被调查,在获取较为详细的生境数据基础上,探讨伊犁河谷北坡野果林群落与环境因子之间的定量关系.TWINSPAN和去趋势典范对应分析(DCCA)的结果表明:1)在伊犁河谷北坡野果林群落分布地段,地形因子、养分和水分条件是群落生境的基本因子;2)海拔因子指示出研究区野果林群落最基本的分化,说明海拔条件是制约研究区植物群落分布的最重要的因子;3)土壤表层水分状况与海拔关系较密切,反映了草本层群落所受到的水分条件影响;4)养分状况的差异,除了说明生境条件本身的差异外,也在一定程度上指示了群落现在生境的养分状况,受人为的影响较大.总之,在山地复杂的地形条件下,群落生境条件的差异非常显著,海拔、土壤含水率、全氮、坡向和pH值的组合,影响并控制着研究区各群落分布格局的形成.     

Establishing IUCN Red List Criteria for Threatened Ecosystems

Abstract: The potential for conservation of individual species has been greatly advanced by the International Union for Conservation of Nature's (IUCN) development of objective, repeatable, and transparent criteria for assessing extinction risk that explicitly separate risk assessment from priority setting. At the IV World Conservation Congress in 2008, the process began to develop and implement comparable global standards for ecosystems. A working group established by the IUCN has begun formulating a system of quantitative categories and criteria, analogous to those used for species, for assigning levels of threat to ecosystems at local, regional, and global levels. A final system will require definitions of ecosystems; quantification of ecosystem status; identification of the stages of degradation and loss of ecosystems; proxy measures of risk (criteria); classification thresholds for these criteria; and standardized methods for performing assessments. The system will need to reflect the degree and rate of change in an ecosystem's extent, composition, structure, and function, and have its conceptual roots in ecological theory and empirical research. On the basis of these requirements and the hypothesis that ecosystem risk is a function of the risk of its component species, we propose a set of four criteria: recent declines in distribution or ecological function, historical total loss in distribution or ecological function, small distribution combined with decline, or very small distribution. Most work has focused on terrestrial ecosystems, but comparable thresholds and criteria for freshwater and marine ecosystems are also needed. These are the first steps in an international consultation process that will lead to a unified proposal to be presented at the next World Conservation Congress in 2012.     

基于土地利用的喀斯特地区生态系统服务功能价值评估——以贵州省为例

为探讨喀斯特地区生态系统服务功能价值特征,对贵州省生态系统服务功能价值进行评估,结果表明生态系统服务功能价值在2005、2010、2020年分别为1 610.43亿、2 357.86亿、4 328.89亿元.贵州省各类生态系统服务功能单价顺序为湿地>水体>森林>草地>农田>荒漠,其中湿地生态系统是荒漠生态系统服务功能价值的149.31倍.2005～2020年贵州省生态服务功能价值结构和土地利用结构以森林生态系统占绝对优势,各类型生态系统服务功能价值顺序为森林>农田>草地>水体>荒漠>湿地,各类型生态系统面积大小顺序为森林>农田>荒漠>草地>水体>湿地.2005、2010、2020年贵州省单位面积生态系统服务功能价值分别为9 142、13 385、24 573元/hm2.根据至2020年的土地利用规划,贵州省生态系统服务功能将持续增加.     

Spatially distributed modeling of the long-term carbon balance of a boreal landscape

Spatially and temporally distributed information on the sizes of biomass carbon (C) pools (BCPs) and soil C pools (SCPs) is vital for improving our understanding of biosphere-atmosphere C fluxes. Because the sizes of C pools result from the integrated effects of primary production, age-effects, changes in climate, atmospheric CO₂ concentration, N deposition, and disturbances, a modeling scheme that interactively considers these processes is important. We used the InTEC model, driven by various spatio-temporal datasets to simulate the long-term C-balance in a boreal landscape in eastern Canada. Our results suggested that in this boreal landscape, mature coniferous stands had stabilized their productivity and fluctuated as a weak C-sink or C-source depending on the interannual variations in hydrometeorological factors. Disturbed deciduous stands were larger C-sinks (NEP₂₀₀₄ = 150 gC m⁻² yr⁻¹) than undisturbed coniferous stands (e.g. NEP₂₀₀₄ = 8 gC m⁻² yr⁻¹). Wetlands had lower NPP but showed temporally consistent C accumulation patterns. The simulated spatio-temporal patterns of BCPs and SCPs were unique and reflected the integrated effects of climate, plant growth and atmospheric chemistry besides the inherent properties of the C pool themselves. The simulated BCPs and SCPs generally compared well with the biometric estimates (BCPs: r = 0.86, SCPs: r = 0.84). The largest BCP biases were found in recently disturbed stands and the largest SCP biases were seen in locations where moss necro-masses were abundant. Reconstructing C pools and C fluxes in the ecosystem in such a spatio-temporal manner could help reduce the uncertainties in our understanding of terrestrial C-cycle.     

Surface modelling of global terrestrial ecosystems under three climate change scenarios

A high accuracy and speed method (HASM) of surface modelling is developed to find a solution for error problem and to improve computation speed. A digital elevation model (DEM) is established on spatial resolution of 13.5 km × 13.5 km. Regression formulations among temperature, elevation and latitude are simulated in terms of data from 2766 weather observation stations scattered over the world by using the 13.5 km × 13.5 km DEM as auxiliary data. Three climate scenarios of HadCM3 are refined from spatial resolution of 405 km × 270 km to 13.5 km × 13.5 km in terms of the regression formulations. HASM is employed to simulate surfaces of mean annual bio-temperature, mean annual precipitation and potential evapotranspiration ratio during the periods from 1961 to 1990 (T₁), from 2010 to 2039 (T₂), from 2040 to 2069 (T₃), and from 2070 to 2099 (T₄) on spatial resolution of 13.5 km × 13.5 km. Three scenarios of terrestrial ecosystems on global level are finally developed on the basis of the simulated climate surfaces. The scenarios show that all polar/nival, subpolar/alpine and cold ecosystem types would continuously shrink and all tropical types, except tropical rain forest in scenario A1Fi, would expand because of the climate warming. Especially at least 80% of moist tundra and 22% of nival area might disappear in period T₄ comparing with the ones in the period T₁. Tropical thorn woodland might increase by more than 97%. Subpolar/alpine moist tundra would be the most sensitive ecosystem type because its area would have the rapidest decreasing rate and its mean center would shift the longest distance towards west. Subpolar/alpine moist tundra might be able to serve as an indicator of climatic change. In general, climate change would lead to a continuous reduction of ecological diversity.     

鼎湖山20公顷森林样地单个物种对群落的构建

大型固定监测森林样地已成为研究森林群落组织机制的一个重要平台。群落里个体之间的相互作用对群落的构建有相当重要的作用。以往的研究主要针对于物种之间的相互作用,而用群落里单个物种与其它所有个体之间相互关系来解释群落构建的研究还很少。采用单个物种-面积关系（ISAR）这一指标对鼎湖山20 hm2样地和BCI 50 hm2样地数据分析,来研究不同样地单个物种是如何对森林群落进行构建的。结果显示,与BCI样地和Sinharaja样地不同,鼎湖山样地大树对周围其它个体的作用几乎是中性的;而对于小树（胸径小于10 cm）来说,鼎湖山样地和BCI样地一样,随着尺度的增加＂吸引型＂物种减少,而＂中性＂物种增加。说明了不同的群落在不同的发育阶段,单个物种对群落结构的构建有重要的作用不同,将来的研究应该结合群落其它方面的因素来分析群落内个体之间相互作用,例如从时间尺度的谱系和空间因素去分析。     

人为干扰对小兴安岭森林湿地土壤碳组分和酶活性的影响

以小兴安岭落叶林沼泽湿地为研究对象,对比研究皆伐地、火烧地和落叶松湿地土壤碳组分和酶活性.结果表明:(1)3种湿地类型土壤SOC含量表现为对照地显著高于皆伐地和火烧地(p0.05),在0~10 cm土层中皆伐地与对照地相比降低了58.38%,火烧地与对照地相比降低了61.96%.皆伐地与火烧地在不同土层的土壤中SOC含量差异不显著(p0.05);DOC含量对照地显著高于皆伐地和火烧地(p0.05).在0~10cm土层中火烧地DOC含量是皆伐地的1.99倍,两者差异不显著(p0.05);不同干扰方式对土壤MBC含量影响的差异主要表现在0~10 cm的土层土壤,对照地分别比皆伐地和火烧地高23.13%和95.79%(p0.05).在不同的土层中皆伐地MBC含量均大于火烧地,与SOC含量的变化趋势一致.(2)与对照地相比,皆伐地与火烧地0~10 cm土层的土壤蔗糖酶活性分别降低了45.59%和36.76%,脲酶活性显著降低了18.22%和55.69%(p0.05),蛋白酶活性降低了19.65%和17.34%,淀粉酶活性降低了6.29%和10.69%.土壤碳组分和酶活性在垂直方向上均表现为随着土层深度增加而减小.皆伐和火烧造成森林湿地土壤碳组分和酶活性降低.     

江汉湖群典型湖泊生态系统健康评价——以梁子湖、洪湖、长湖、斧头湖、武湖为例

湖泊生态系统健康评价对湖泊生态健康状况评定、环境问题诊断和湖泊生态系统管理具有重要意义.根据江汉湖群实际情况和生态特点,选取江汉湖群五大湖泊—梁子湖、长湖、洪湖、斧头湖和武湖为研究对象,采用野外调查、资料收集并结合GIS技术的研究方法,从生物、水质、生境特征及生态压力4个方面选择15个代表性评价指标,构建江汉湖群典型湖泊生态系统健康评价指标体系,并利用基于模糊综合评价模型的评价方法,对江汉湖群五大湖泊生态系统健康进行评价.结果表明,江汉湖群五大湖泊生态健康综合评价得分值为5.47~7.46,梁子湖得分最高,其余依次为斧头湖、洪湖、长湖和武湖.从湖泊生态系统健康等级看,五大湖泊中梁子湖和斧头湖处于比较健康状态,而洪湖、长湖和武湖处于亚健康状态.通过实例分析表明,本研究建立的湖泊生态系统健康评价方法能够较客观系统地评价江汉湖群生态系统健康状况,具有较高的可行性和可靠性,可作为江汉湖群健康诊断的评价方法.本文研究结果可为江汉湖群的分类管理提供较为重要的参考依据.