浙江次生青冈林林木层的生物量模型及其分析

笔者用收获法对浙江建德山区的天然次生青冈常绿阔叶林群落的第一性生产力进行了研究,本文报告了林木层样木的生物量优化回归模型,并对模型进行了分析,检验和估算,结果表明,立木各器官变量之间存在着很好的相对生长关系,进行分层次,种类（组分）和自变量的模型选优是十分必要的,各种模型都有较高的精度,可以对该群落的生物量作出有效的估计;种间模型的有效组合适用于亚乔木层的种类和乔木层的伴生种类,种类（组分）间的模型差异与它们在群落中所处的地位或所起作用密切相关,净第一性生产力在各器官中的分配比例是植物群落结构与功能在种间关系,生态位分化和种群动态特征上的综合反映。     

水分梯度上放牧对内蒙古主要草原群落功能群多样性与生产力关系的影响

应用样线法对放牧对内蒙古草原沿水分梯度分布的主要植物群落:小针茅(Stipaklemenzii)群落、大针茅(Stipagrandis)群落、羊草(Leymuschinensis)群落和羊草杂类草群落多样性、生产力以及两者关系的影响进行了研究,结果表明,除羊草杂类草群落外,物种多样性、生活型多样性和水分生态类型多样性随放牧强度的加大而降低,但适度放牧增加了羊草杂类草群落的上述多样性指标。群落地上现存量一般随放牧强度的增大而下降,但小针茅群落反之,主要与1年生植物猪毛菜(Salsolacollina)的生物量迅速增加有关。除羊草群落外,其他群落0～10cm地下生物量随放牧强度的变化不显著;放牧显著降低羊草群落和羊草杂类草群落0～30cm地下生物量。多样性和生产力间的关系在群落水平上的趋势是不同的,但放牧影响下内蒙古草原4种群落多样性与生产力总体而言呈线性增加关系;同时两者之间的关系还和采用哪种多样性指标和生产力指标有关,用水分生态类型多样性比物种多样性更能反映与地上地下总生产力间的关系,得到放牧影响下内蒙古草原植物群落地上地下总生物量与水分生态类型多样性的回归方程。     

中国旱区样带尺度植物多样性和生产力与环境因子的关系

旱区植物多样性、生产力与环境因子的关系是旱区生态学研究的重要课题,对于揭示该地区植被的环境适应机制有重要的参考价值。基于中国旱区东西样带的系统采样和原位调查,定量分析了各影响因素对旱区植物多样性和生产力变化的解释作用,阐明了旱区群落生产力的调控机制。结果表明：(1)旱区群落性状加权值与地上生物量间的关系(R²=0.46)相较于Shannon-Wiener指数与地上生物量的关系(R²=0.21)更为紧密。(2)旱区群落Shannon-Wiener指数、群落性状加权值、地上生物量与年均降水量、土壤有机碳含量、土壤总氮含量线性正相关,与土壤总磷含量无显著相关性;Shannon-Wiener指数、群落性状加权值与年均气温线性负相关,地上生物量与年均气温无显著相关性。(3)年均降水量对旱区群落性状加权值的解释率为40.9%,两者为正相关关系;年均气温对Shannon-Wiener指数的解释率为28.3%,两者为负相关关系。(4)群落性状加权值对地上生物量的直接路径显著,年均降雨量、年均气温和土壤有机碳通过群落性状加权值间接影响地上生物量。     

科尔沁沙地恢复演替进程中群落物种多样性与地上生物量的关系

生物多样性与生产力的关系是当前生态学中研究的重点之一,以科尔沁沙地为研究对象,研究了沙地植被恢复演替进程中物种多样性与地上生物量的关系。结果表明:(1)科尔沁沙地植被恢复演替过程中,物种数量逐渐增加,从流动沙丘的6种到固定沙丘的30种,增加了4倍。一年生草本植物在各群落中占绝对优势,但随着演替的进行,生活型呈现多样化,多年生植物种类明显增加。藜科植物在流动沙丘阶段优势度明显,之后逐渐下降;禾本科植物的种数和优势度逐渐增加,在群落中的地位逐渐增强。多重比较表明,群落的地上生物量存在显著差异(F=18.926,n=360,P0.001),从流动沙丘到固定沙丘(3个恢复阶段的均值计算)地上生物量增加了580%。(2)随着演替的进行,群落Simpson指数、Shannon-winner指数和均匀度指数均呈现增加的趋势。(3)回归分析显示,群落物种多样性和生物量之间存在显著的负二次函数关系即单峰型函数关系,表明中等生产力水平物种多样性较高。     

功能多样性对典型阔叶红松林生产力的影响

为比较生物量比率假说与生态位互补假说在解释生产力变异的相对重要性, 探讨生物多样性和生产力之间的关系是否受到生物和非生物因素的影响, 该研究依托小兴安岭9 hm ²阔叶红松(Pinus koraiensis)林动态监测样地, 通过计算群落初始生物量、物种多样性、功能多样性、植物性状的群落加权平均值和测定环境因子, 运用线性回归模型、结构方程模型, 比较了物种多样性和功能多样性与生产力的相关性。结果表明: (1)物种多样性和功能多样性均对生产力有显著作用, 功能多样性比物种多样性与生产力的关系更为密切; (2)功能多样性指数比群落加权平均值能更好地解释生产力变异, 说明生态位互补假说更适用于解释阔叶红松林群落内生产力的变异; (3)生物多样性与生产力的关系受生物因素与非生物因素的共同作用, 相较于多样性和功能性状组成(植被质量), 初始林分生物量(植被数量)能更有效地解释生产力的变异。生物多样性与生产力关系的研究应从植被质量与植被数量同时出发, 评估生态系统过程的多种非生物和生物驱动因素, 同时维护森林功能多样性, 加强植物与土壤环境的保护, 对有效增加生产力和维持生物多样性具有重要意义。     

温带针阔混交林生物量稳定性影响机制

森林生态系统通过响应环境波动和干扰而产生时间变化, 对其稳定性机制的研究有利于生态系统服务。温带针阔混交林是全球森林生态系统的重要组成部分, 该研究致力于探索超产效应、林分结构、物种异步性及优势物种稳定性对温带天然针阔混交林群落稳定性的影响, 以明确主要影响机制。该研究分别设定物种丰富度、胸径变异系数、物种异步性和优势物种稳定性为解释变量, 群落生物量稳定性、生物量平均值和生物量标准差为响应变量, 构建3个结构方程模型, 比较各变量间直接与间接效应的相对大小。主要结果为: (1)结构方程模型提供了良好的拟合效果, 并占群落生物量稳定性变化的40.6%; (2)物种丰富度与生物量平均值、生物量标准差均呈显著负相关关系, 路径系数分别为-0.103和-0.061; (3)胸径变异系数与群落生物量稳定性及生物量平均值均呈显著负相关关系, 路径系数分别为-0.123和-0.097; (4)物种异步性与群落生物量稳定性、生物量平均值、生物量标准差均呈显著正相关关系, 路径系数分别为0.055、0.085和0.055; (5)优势物种稳定性与群落生物量稳定性和生物量平均值呈显著正相关关系, 路径系数分别为0.623和0.085, 与生物量标准差间显著负相关, 路径系数为-0.608。研究结果表明尽管林分结构和物种异步性对温带针阔混交林群落生物量稳定性均有显著影响, 但优势物种稳定性是最主要的直接影响因素。     

功能多样性对典型阔叶红松林生产力的影响

为比较生物量比率假说与生态位互补假说在解释生产力变异的相对重要性,探讨生物多样性和生产力之间的关系是否受到生物和非生物因素的影响,该研究依托小兴安岭9 hm~2阔叶红松(Pinus koraiensis)林动态监测样地,通过计算群落初始生物量、物种多样性、功能多样性、植物性状的群落加权平均值和测定环境因子,运用线性回归模型、结构方程模型,比较了物种多样性和功能多样性与生产力的相关性。结果表明:(1)物种多样性和功能多样性均对生产力有显著作用,功能多样性比物种多样性与生产力的关系更为密切;(2)功能多样性指数比群落加权平均值能更好地解释生产力变异,说明生态位互补假说更适用于解释阔叶红松林群落内生产力的变异;(3)生物多样性与生产力的关系受生物因素与非生物因素的共同作用,相较于多样性和功能性状组成(植被质量),初始林分生物量(植被数量)能更有效地解释生产力的变异。生物多样性与生产力关系的研究应从植被质量与植被数量同时出发,评估生态系统过程的多种非生物和生物驱动因素,同时维护森林功能多样性,加强植物与土壤环境的保护,对有效增加生产力和维持生物多样性具有重要意义。     

草甸和沼泽植物群落功能多样性与生产力的关系

功能多样性-生产力关系研究结果支持质量比假说和多样性假说, 但对于这两种假说的适用条件尚有争议。通过对吉林省西部草甸和沼泽植物群落的地上生物量、2个物种多样性指标(物种丰富度和Shannon-Weaver指数)、7种植物性状的两类功能多样性指标(群落权重均值和Rao二次熵), 以及土壤环境因子进行调查测量, 研究了群落功能多样性与生产力的关系。结果表明: 1)功能多样性与生产力的关系比物种多样性与生产力的关系更为密切; 2)功能群落权重均值解释生产力变异的能力好于Rao二次熵, 即优势物种对群落生产力的影响作用更大; 3)水淹条件影响着功能多样性与生产力的关系, 以群落权重均值为基础的质量比假说适于解释草甸群落功能多样性与生产力的关系, 而以Rao二次熵为基础的多样性假说适于解释有强烈环境筛(水淹)的沼泽群落功能多样性与生产力的关系。     

锡林河流域一个羊草群落中土壤呼吸与生物量之间的相关性分析(英)

采用根系生物量梯度上土壤呼吸变化趋势线外推法对锡林河流域一个羊草 (Leymuschinensis (Trin .)Tzvel.)群落中根系呼吸占土壤总呼吸的比例进行了估计 ,对生物量各组分 (地上、地下部分 )之间以及它们与土壤呼吸间的相关性进行了分析。结果表明 :在测定年度 (1998年 )整个生长季的不同月份 ,该群落中根系呼吸量占土壤呼吸总量的比例在 14 %～ 39%之间 ,平均为 2 7% ;地上总生物量及根系生物量与土壤呼吸间的相关性较差 ,但地上活生物量与土壤呼吸间存在着显著的乘幂关系。上述结果与国外同类研究结果相比 ,具有很好的一致性。     

锡林河流域一个羊草群落中土壤呼吸与生物量之间的相关性分析

采用根系生物量梯度上土壤呼吸变化趋势线外推法对锡林河流域一个羊草(Leymus chinensis (Trin.) Tzvel.)群落中根系呼吸占土壤总呼吸的比例进行了估计,对生物量各组分(地上、地下部分)之间以及它们与土壤呼吸间的相关性进行了分析.结果表明:在测定年度(1998年)整个生长季的不同月份,该群落中根系呼吸量占土壤呼吸总量的比例在14%～39%之间,平均为27%;地上总生物量及根系生物量与土壤呼吸间的相关性较差,但地上活生物量与土壤呼吸间存在着显著的乘幂关系.上述结果与国外同类研究结果相比,具有很好的一致性.     

杉木拟赤杨混交林林分生产力及生态效应研究

 本文从林分结构、生物量、群落特征、生产力、培肥土壤、涵养水源及林内小气候等方面对不同混交模式的杉木拟赤杨混交林及其纯林进行的研究结果表明：杉木拟赤杨是具有较高生产力和协调种间关系能力的针阔混交树种。7年生3:1带状混交林蓄积量和生物量分别比杉木纯林提高7.24％和18.22％,同时混交林还表现出比杉木纯林更好的培肥土壤、涵养水源、改善林内小气候等生态功能。应用AHP法进行不同混交模式的综合选择结果表明：3:1杉木拟赤杨带状混交模式是值得南方林区大力推广的杉阔混交模式。     

Relationship between functional diversity and productivity in meadow and marsh plant communities

功能多样性-生产力关系研究结果支持质量比假说和多样性假说, 但对于这两种假说的适用条件尚有争议。通过对吉林省西部草甸和沼泽植物群落的地上生物量、2个物种多样性指标(物种丰富度和Shannon-Weaver指数)、7种植物性状的两类功能多样性指标(群落权重均值和Rao二次熵), 以及土壤环境因子进行调查测量, 研究了群落功能多样性与生产力的关系。结果表明: 1)功能多样性与生产力的关系比物种多样性与生产力的关系更为密切; 2)功能群落权重均值解释生产力变异的能力好于Rao二次熵, 即优势物种对群落生产力的影响作用更大; 3)水淹条件影响着功能多样性与生产力的关系, 以群落权重均值为基础的质量比假说适于解释草甸群落功能多样性与生产力的关系, 而以Rao二次熵为基础的多样性假说适于解释有强烈环境筛(水淹)的沼泽群落功能多样性与生产力的关系。     

RESPONSES OF THE PHYTOPLANKTON COMMUNITY GROWTH RATE TO NUTRIENT PULSES IN VARIABLE ESTUARINE ENVIRONMENTS

In estuaries, phytoplankton are exposed to rapidly changing conditions that may have profound effects on community structure and function. In these experiments, we evaluated the growth, productivity, and compositional responses of natural phytoplankton communities exposed to limiting nutrient additions and incubation conditions typical of estuarine habitats. Mesocosm bioassays were used to measure the short-term (2-day) growth rate, primary productivity, and group-specific biomass responses of the phytoplankton community in the Neuse River Estuary, North Carolina. A three-factor (mixing, sediment addition, and nutrient addition) experimental design was applied using 55-L mesocosm tanks. Growth rates were determined using the ¹⁴C photopigment radiolabeling method, and the abundance of algal groups was based on quantification of chemosystematic photopigments by HPLC. For Neuse River Estuary phytoplankton communities, stratified (nonmixed), turbid, and low-nitrate conditions favored increases in cryptomonad biomass. Mixed, turbid, high-nitrate conditions were favorable for increased primary productivity and chlorophytes, diatoms, and cyanobacteria. The highest community growth rates occurred under calm, high-nitrate conditions. This approach provided an assessment of the community-level phytoplankton responses and insights into the mechanisms driving blooms and bloom species in estuarine waters. The ability to rapidly alter growth rates to capitalize on conditions conducive for growth may play an important role in the timing, extent, and species involved with blooms in estuarine waters. Adaptive growth rate responses of individual species, as well as the community as a whole, further illustrate the sensitivity of estuarine ecosystems to excessive N inputs.     

地下鼠生物学特征及其在生态系统中的作用

地下鼠生活型、行为、种群结构的特殊性,决定了此类动物对植被、土壤及生态系统作用的多样性。地下挖能改变土壤的物理环境,导致土壤类型、发育速率、营养可利用性、微地形等的变化。地下啃食直接影响植物的形态、丰富度、种间竞争、植被类型和物种多样性、生物是及群落组成构成等,植物对植食性动物的防御策略具有更明显的化学防卫特性。地下鼠与其他植食性动物种间竞争、空间利用等关系密切,是食肉动物重要的食物资源。地下鼠对生态系统生产力、空间异质性、营养结构和循环、碳素储存以及微量气体释放等生物地球化学过程均能产生影响,显示出有别于地面植食性动物的重要性和不可替代性。     

Seasonal changes in the relationship between plant species richness and community biomass in early succession

We analysed the relationship between plant species richness and productivity on first-year-old fields at two similar sites in central Europe. At both sites, a wide range of productivity levels was available resulting from different long-term fertilisation. In order to identify underlying mechanisms of the species richness–productivity relationship we included the seasonal dynamics and the number of individuals of each species in our analysis. We sampled 10 and 21 plots, respectively, at the two sites in May, June and July by harvesting all aboveground parts of vascular plants in 0.25 m² subplots. Species richness, number of individuals of each species and community biomass as a surrogate of productivity were recorded in each sample.At one site, the relationship between species richness and biomass was significantly positive in the May and June harvest. This relationship disappeared in the July harvest due to a reduction in species richness at high productivity levels. The relations between species richness and number of individuals and between number of individuals and biomass paralleled the species richness–productivity relation but the individual number–biomass relationship remained positive until the last harvest. Between-species differences in individual number–community biomass relationships and their seasonal dynamics revealed “interspecific competitive exclusion” even though the species richness–biomass relationships were not negative or hump-shaped. At the second site, species richness was not related to productivity or to number of individuals. Our study demonstrated the importance of temporal dynamics and regional processes in understanding species richness–productivity patterns.     

Species richness peaks for intermediate levels of biomass in a fractal succession with quasi-neutral interactions

The mechanisms that promote species richness, including net community interactions, are considered central to the investigation of the consequences of biodiversity loss for ecosystem functioning. Recently, some empirical studies at large spatiotemporal scales suggest that increasing species richness within natural communities results in a finer division of biomass among species rather than an increase in total biomass. In parallel, the most common pattern observed in nature is the peaked relationship between diversity and productivity estimated as total biomass. Thus, the aim of our study is to provide model predictions for the diversity–biomass relationship with various levels of net species interactions within communities: negative, neutral, quasi-neutral and positive. Using a scaling relationship between the number of species and total community biomass, we propose a new self-similar process of biomass partitioning during a community assembly process. At each step of the succession, K more species appear that are A times less abundant on average giving K=A^d; the parameter d being a fractal dimension related to the nature of interactions among coexisting species. Our results, compared to those from meta-analyses about empirical diversity–productivity relationships, illustrate that quasi-neutral interactions among coexisting species lead to the most commonly observed pattern: an 'envelope' where diversity peaks at intermediate values of total biomass, i.e. that the area below the hump-backed line (considered as the upper boundary) is filled with data points.     

高寒草甸不同草地类型功能群多样性及组成对植物群落生产力的影响

对不同类型草地功能群多样性和组成与植物群落生产力之间的关系进行了探讨。结果表明：(1)在矮嵩草(Kobresia humlis)草甸和金露梅(Potentilla froticosa)灌丛中,豆科植物的作用比较明显,而其他功能群植物的作用较弱。(2)在藏嵩草(Kobresia tibetica)沼泽化草甸和小嵩草(K．pygmaca)草甸中,虽然杂类草、C3植物和莎草科植物功能群的生产力占群落初级生产力的比例较大,但二者在统计上没有显著性差异,这表明群落生产力除受物种多样性的影响外,也受物种本身特征和环境资源的影响,更主要的是受到功能群内物种密度和均匀度的影响,即功能群组成比功能群多样性更能说明对生态系统过程的影响。(3)不同类型草地群落植物功能群盖度与群落初级生产力呈显著的线性相关。(4)不同类型草地群落生产力与功能群内物种数的变化均表现为单峰曲线关系,即功能群内物种数处于中间水平时,群落生产力最高。     

北美CHIHUAHUAN荒漠啮齿动物群落动态Ⅱ．季节性和周期性

本文利用时间序列分析方法和季节性指标,讨论了北美Ｃｈｉｈｕａｈｕａｎ荒漠由４科１０属１７种啮齿动物组成的群落的物种数、单位面积个体数与生物量、物种多样性的Ｓｈａｎｎｏｎ与Ｓｉｍｐｓｏｎ指数和均匀性等６个变量的季节变动、季节性和周期性。结果表明：（１）每个季节都有变量达到最大值,但除个体数和均匀性外,其余４个变量均在冬季达到最小值;（２）物种数与生物量及两个物种多样性指数之间,以及两个物种多样性指数相互之间有类似的季节变动规律;（３）除个体数外,群落数量动态的其他变量与８个物种种群的密度存在着显著的负相关关系;（４）物种数有最明显的季节性,季节性指标ＳＩ＝０．６２８;（５）物种数、个体数和生物量在９２个月的研究期中未显示出任何周期性。最后总结了该啮齿动物群落动态的时间模式,提出组成物种种群的扩散和休眠行为是形成这些模式的主要原因。     

Biodiversity–productivity relationship in ponds: Community and metacommunity patterns along time and environmental gradients

Primary production correlates with diversity in various ways. These patterns may result from the interaction of various mechanisms related to the environmental context and the spatial and temporal scale of analysis. However, empirical evidence on diversity‐productivity patterns typically considers single temporal and spatial scales, and does not include the effect of environmental variables. In a metacommunity of macrophytes in ephemeral ponds, we analysed the diversity‐productivity relationship patterns in the field, the importance of the environmental variables of pond size and heterogeneity on such relationship, and the variation of these patterns at local (community level) and landscape scales (metacommunity level) across 52 ponds on twelve occasions, over five years (2005–2009). Combining all sampling dates, there were 377 ponds and 1954 sample‐unit observations. Vegetation biomass was used as a proxy for productivity, and biodiversity was represented by species richness, evenness, and their interaction. Environmental variables comprised pond area, depth and internal heterogeneity. Productivity and species richness were not directly related at the metacommunity level, and were positively related at the community level. Taking environmental variables into account revealed positive species richness‐productivity relationships at the metacommunity level and positive quadratic relationships at the community level. Productivity showed both positive and negative linear and nonlinear relationships with the size and heterogeneity of ponds. We found a weak relationship between productivity and evenness. The identity of variables associated with productivity changed between spatial scales and through time. The pattern of relationships between productivity and diversity depends on spatial scale and environmental context, and changes idiosyncratically through time within the same ecosystem. Thus, the diversity‐productivity relationship is not only a property of the study system, but also a consequence of environmental variations and the temporal and spatial scale of analysis.