苏南丘陵区典型森林生态系统服务价值估算

针对苏南丘陵区杉木、马尾松、毛竹、栎林等4种典型森林生态系统,实测了其主要的生态系统服务功能,运用多种生态经济学方法估算了4种林分的生态服务价值。生态服务价值包括直接使用价值和间接使用价值,间接使用价值包括气体调节、涵养水源、保土固肥、防止水库淤积、营养物质循环、净化环境价值等。研究区杉木、马尾松、栎林、毛竹4种林分的生态系统服务价值中,间接经济价值分别是其直接经济服务价值的1.82、2.12、3.16、4.04倍,单位面积的森林生态系统服务价值分别为192397.30、113262.69、88350.51、103289.69元·hm-2·a-1。在区域研究中,根据地方实测的数据进行估算,能提高计量森林生态服务功能价值的精度。     

Species, functional groups, and thresholds in ecological resilience

The cross-scale resilience model states that ecological resilience is generated in part from the distribution of functions within and across scales in a system. Resilience is a measure of a system's ability to remain organized around a particular set of mutually reinforcing processes and structures, known as a regime. We define scale as the geographic extent over which a process operates and the frequency with which a process occurs. Species can be categorized into functional groups that are a link between ecosystem processes and structures and ecological resilience. We applied the cross-scale resilience model to avian species in a grassland ecosystem. A species' morphology is shaped in part by its interaction with ecological structure and pattern, so animal body mass reflects the spatial and temporal distribution of resources. We used the log-transformed rank-ordered body masses of breeding birds associated with grasslands to identify aggregations and discontinuities in the distribution of those body masses. We assessed cross-scale resilience on the basis of 3 metrics: overall number of functional groups, number of functional groups within an aggregation, and the redundancy of functional groups across aggregations. We assessed how the loss of threatened species would affect cross-scale resilience by removing threatened species from the data set and recalculating values of the 3 metrics. We also determined whether more function was retained than expected after the loss of threatened species by comparing observed loss with simulated random loss in a Monte Carlo process. The observed distribution of function compared with the random simulated loss of function indicated that more functionality in the observed data set was retained than expected. On the basis of our results, we believe an ecosystem with a full complement of species can sustain considerable species losses without affecting the distribution of functions within and across aggregations, although ecological resilience is reduced. We propose that the mechanisms responsible for shaping discontinuous distributions of body mass and the nonrandom distribution of functions may also shape species losses such that local extinctions will be nonrandom with respect to the retention and distribution of functions and that the distribution of function within and across aggregations will be conserved despite extinctions.     

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.     

The use of marked point processes in ecological and environmental forest studies

The paper presents new applications of marked point processes in forestry. The tools are pair correlation functions and mark connection functions. Studies of the structures of even-aged pine forests in Siberia show a tendency of development from clustering in young stands towards random distribution in elder stands for the trunk positions. The tree tops as the movable parts of trees are still more regular in old forests. Furthermore, in Siberian fir forests interesting tendencies of attraction between members of several tree classes are detected. Finally, studies of the distribution of damaged trees in some central European forests show that there the damaged trees appear as singletons; dominating trees are preferentially damaged.     

Experimental and environmental factors affect spurious detection of ecological thresholds

Threshold detection methods are increasingly popular for assessing nonlinear responses to environmental change, but their statistical performance remains poorly understood. We simulated linear change in stream benthic macroinvertebrate communities and evaluated the performance of commonly used threshold detection methods based on model fitting (piecewise quantile regression [PQR]), data partitioning (nonparametric change point analysis [NCPA]), and a hybrid approach (significant zero crossings [SiZer]). We demonstrated that false detection of ecological thresholds (type I errors) and inferences on threshold locations are influenced by sample size, rate of linear change, and frequency of observations across the environmental gradient (i.e., sample-environment distribution, SED). However, the relative importance of these factors varied among statistical methods and between inference types. False detection rates were influenced primarily by user-selected parameters for PQR (tau) and SiZer (bandwidth) and secondarily by sample size (for PQR) and SED (for SiZer). In contrast, the location of reported thresholds was influenced primarily by SED. Bootstrapped confidence intervals for NCPA threshold locations revealed strong correspondence to SED. We conclude that the choice of statistical methods for threshold detection should be matched to experimental and environmental constraints to minimize false detection rates and avoid spurious inferences regarding threshold location.     

桐庐生态公益林主要林分类型的土壤水文效应

以浙江省桐庐县生态公益林定位监测站为依托,研究了该区域不同林分类型土壤层的水文效应.结果表明:与无林地对比,各林分类型土壤的蓄水能力、渗透性能均优于无林地;不同林分类型土壤的蓄水能力、渗透性能也存在着一定的差异,其中落叶阔叶林土壤的蓄水能力、渗透性能最好;Horton入渗模型对各样地土壤入渗过程拟合效果较好,有着较好的适用性;土壤理化因子、土壤根系因子与土壤渗透性能的相关分析显示研究区土壤渗透性能受多个因素影响,其中土壤非毛管空隙度与土壤初渗、稳渗速率相关性最高,为首要影响因素;基于主成分分析,各样地土壤综合水文效应优劣依次为落叶阔叶林>常绿阔叶林>杉木林(Cunninghamia Lanceolata)>毛竹林(Phyllostachys heterocycla)>马尾松林(Pinusmassoniana Lamb)>经济林>无林地.     

森林生态系统生态资产核算的模式与方法

全球变化背景下.植被对CO2的减排作用得到了广泛关注.森林生态系统具有诸多功能,不同功能的货币化基准难以统一,是进行总体生态资产价值定量核算的制约要素.在资源、环境与生态经济原理指导下,分析相关方法评估生态系统生态资产的可行性,选择量化评估参数,并通过多种模式与方法进行估算乌鲁木齐城市2004年森林生态系统的生态资产.森林生态系统涵养水源类、生物多样性维持类、净化空气类、保护土壤类以及大气调节类生态资产分别为0.224 8×108元、10.608 8x108元、0.630 8×108元、0.2592×108元及12.9653×108元,乌鲁木齐市森林生态总资产为24.6889×108元.各类生态资产具有一定的时空差异性.城市森林生态系统生态资产估算模式及方法的研究具有重要的理论价值与现实意义.     

森林生态系统的水文调节功能及生态学机制研究进展

森林水文调节功能是森林所实现的重要服务功能之一,可是由于森林资源被无节制的开采利用,导致人们不断遭受森林破环所带来的洪旱灾害。因此关于森林生态水文功能研究已成为生态学和水文学的研究重点之一。近年来,国内外对森林水文调节过程及其生态学机制进行了广泛深入的研究,所以文章从森林的水文过程出发,对林冠截留、树干流、凋落物层截留、林地水分涵养和蒸发蒸腾及其影响因子的国内外研究现状进行了归纳分析,研究认为林地各冠层均能够截留降雨,降低雨水动能,从而减少地表径流的产生和对地表的冲击;凋落物层能蓄留水分、抑制蒸散、减缓地表径流;而树干流改变降雨水平空间格局,影响水分入渗以及土壤水源涵养。森林结构复杂,明显改变了降雨分配过程,而森林水文过程及调节功能又受到森林结构的制约,因此定量定性探讨森林生态系统的结构、过程与水文调节功能之间关系,是未来森林生态水文功能研究的重点。     

Indigenous ecological knowledge of Borana pastoralists in southern Ethiopia and current challenges

Indigenous ecological knowledge (IEK) of Borana pastoralists on strategies of sustainable resource utilization, forage species, ecological interactions, rangeland condition and trend was documented using discussions, a semi-structured questionnaire survey and analytical workshops. Traditional strategies of rangeland and water management were described and the most important forage species identified. Pastoralists' perceptions were compared across age, gender and site. There was a positive correlation between pastoralists' preference ranking of forage species and crude protein content of the species. IEK of men and women was complementary. The process of rangeland degradation was described as shortage of grass and decrease in density and frequency of highly palatable grass species, leading to low milk production and reduced conception rates in cows. The results confirmed that the IEK of these pastoralists could still provide the basis for sustainable resource utilization and rangeland rehabilitation. However, the young generation in the area had not only limited knowledge but also showed less interest to learn and apply the traditional resource management strategies. Therefore, there is high need to perpetuate, document and use this IEK for sustainable development. On the other hand, shortage of forage resources as a result of rangeland shrinkage (leading to rangeland degradation and woody plants encroachment), less application of IEK, the gap between traditional and formal systems, and trends of disobeying traditional rules and regulations were identified as current challenges for the Borana pastoralists.     

The influence of spatial and size scale on phylogenetic relatedness in tropical forest communities

The relative importance of biotic, abiotic, and stochastic processes in structuring ecological communities continues to be a central focus in community ecology. In order to assess the role of phylogenetic relatedness on the nature of biodiversity we first quantified the degree of phylogenetic niche conservatism of several plant traits linked to plant form and function. Next we quantified the degree of phylogenetic relatedness across two fundamental scaling dimensions: plant size and neighborhood size. The results show that phylogenetic niche conservatism is likely widespread, indicating that closely related species are more functionally similar than distantly related species. Utilizing this information we show that three of five tropical forest dynamics plots (FDPs) exhibit similar scale-dependent patterns of phylogenetic structuring using only a spatial scaling axis. When spatial- and size-scaling axes were analyzed in concert, phylogenetic overdispersion of co-occurring species was most important at small spatial scales and in four of five FDPs for the largest size class. These results suggest that phylogenetic relatedness is increasingly important: (1) at small spatial scales, where phylogenetic overdispersion is more common, and (2) in large size classes, where phylogenetic overdispersion becomes more common throughout ontogeny. Collectively, our results highlight the critical spatial and size scales at which the degree of phylogenetic relatedness between constituent species influences the structuring of tropical forest diversity.     

The value of patches of intertidal seagrass to prawns depends on their proximity to mangroves

Penaeid prawns were sampled with a small seine net to test whether catches of postlarvae and juveniles in seagrass were affected by the distance of the seagrass (mainly Zostera capricorni) from mangroves and the density of the seagrass in a subtropical marine embayment. Sampling was replicated on the western and eastern sides of Moreton Bay, Queensland, Australia. Information on catches was combined with broad-scale spatial information on the distribution of habitats to estimate the contribution of four different categories of habitat (proximal dense seagrass, distal dense seagrass, proximal sparse seagrass, distal sparse seagrass) to the overall population of small prawns in these regions of Moreton Bay. The abundance of Penaeus plebejus and Metapenaeus bennettae was significantly and consistently greater in dense seagrass proximal to mangroves than in other types of habitat. Additionally, sparse seagrass close to mangroves supported more of these species than dense seagrass farther away, indicating that the role of spatial arrangement of habitats was more important than the effects of structural complexity alone. In contrast, the abundance of P. esculentus tended to be greatest in sparse seagrass distal from mangroves compared with the other habitats. The scaling up of the results from different seagrass types suggests that proximal seagrass beds on both sides of Moreton Bay provide by far the greatest contribution of juvenile M. bennettae and P. plebejus to the overall populations in the Bay.Communicated by M.S. Johnson, Crawley     

桐庐生态公益林主要森林类型土壤抗水蚀功能综合评价

以浙江省桐庐县生态公益林定位监测站为依托,研究了该区域不同森林类型土壤的抗水蚀功能。对比无林地,各森林类型的土壤均有较好的抗水蚀功能。选取土壤初渗速率、稳渗速率、非毛管孔隙度、总孔隙度、水稳性指数、团聚度、分散率、〉0.25水稳性团聚体含量、有机质含量为评价指标,以优劣解距离法为基础,构建了土壤抗水蚀功能综合评价方法。结合实测数据,对研究区各样地土壤的抗水蚀功能进行评价。结果表明：土壤抗水蚀功能为青冈林（Cyclobalanopsis glauca）〉杉木林（Cunninghamia Lanceolata）〉香樟林（Cinnamomum camphora）〉毛竹林（Phyllostachys heterocycla）〉马尾松林（Pinus massoniana）〉板栗林（Castanea mollissima）〉无林地;其中青冈林土壤的抗水蚀功能属较强等级,香樟林、杉木林、马尾松林、毛竹林、板栗林属中等等级,无林地属较弱等级。     

Concentrating anthropogenic disturbance to balance ecological and economic values: applications to forest management

To maintain healthy ecosystems, natural-disturbance-based management aims to minimize differences between unmanaged and managed landscapes. Two related approaches may help accomplish this goal, either applied together or in isolation: (1) concentrating anthropogenic disturbance through zoning (with protected areas and intensive management); and (2) emulating natural disturbances. The purpose of this paper is to examine the effects of these two approaches, applied both in isolation and in combination, on the structure of the forest landscape. To do so, we use a spatially explicit landscape simulation model on a large fire-dominated landscape in eastern Canada. Specifically, we examine the effects of (1) increasing the maximum size of logged stands (cutblocks) to better emulate the full range of fire sizes in a fire-dominated landscape, (2) increasing protected areas, and (3) adding aggregated or dispersed intensive wood production areas to the landscape in addition to protected areas (triad management). We focus on maximizing the amount and minimizing the fragmentation of old-growth forest and on reducing road construction. Increasing maximum cutblock size and adding protected areas led to reduced road construction, while the latter also resulted in less fragmentation and more old growth. Although protected areas led to reduced harvest volume, the addition of an intensive production zone (triad management) counterbalanced this loss and resulted in more old growth than equivalent scenarios with protected areas but no intensive production zone. However, we found no differences between aggregated and dispersed intensive wood production. Our results imply that differences between unmanaged and managed landscapes can be reduced by concentrating logging efforts through a combination of protected areas and intensive wood production, and by creating some larger cutblocks. We conclude that the forest industry and regulators should therefore seek to increase protected areas through triad management and consider increasing maximum cutblock size. These results add to a growing body of literature indicating that intensive management on a small part of the landscape may be better than less intensive management spread out over a much larger part of the landscape, whether this is in the context of forestry, agriculture, or urban development.     

Mechanisms of nonlethal predator effect on cohort size variation: ecological and evolutionary implications

Understanding the factors responsible for generating size variation in cohorts of organisms is important for predicting their population and evolutionary dynamics. We group these factors into two broad classes: those due to scaling relationships between growth and size (size-dependent factors), and those due to individual trait differences other than size (size-independent factors; e.g., morphology, behavior, etc.). We develop a framework predicting that the nonlethal presence of predators can have a strong effect on size variation, the magnitude and sign of which depend on the relative influence of both factors. We present experimental results showing that size-independent factors can strongly contribute to size variation in anuran larvae, and that the presence of a larval dragonfly predator reduced expression of these size-independent factors. Further, a review of a number of experiments shows that the effect of this predator on relative size variation of a cohort ranged from negative at low growth rates to positive at high growth rates. At high growth rates, effects of size-dependent factors predominate, and predator presence causes an increase in the scaling of growth rate with size (larger individuals respond less strongly to predator presence than small individuals). Thus predator presence led to an increase in size variation. In contrast, at low growth rates, size-independent factors were relatively more important, and predator presence reduced expression of these size-independent factors. Consequently, predator presence led to a decrease in size variation. Our results therefore indicate a further mechanism whereby nonlethal predator effects can be manifest on prey species performance. These results have strong implications for both ecological and evolutionary processes. Theoretical studies indicate that changes in cohort size variation can have profound effects on population dynamics and stability, and therefore the mere presence of a predator could have important ecological consequences. Further, changes in cohort size variation can have important evolutionary implications through changes in trait heritability.     

Pastoralism,nature conservation and ecological sustainability in Western Australia's southern shrubland rangelands

Two major issues are discussed in this paper. The first is the commitment of Federal and State Governments to the maintenance of biodiversity and nature conservation through their endorsement of conservation strategies. Based on a rangeland biophysical resource inventory survey (Pringle et al., 1994) it is contended that existing nature conservation reserves are not representative of the biological diversity in the region. In 1990, less than 1% of the survey area was under nature reservation. Whilst 13 of 17 land types are present in reserves, most of the reserves consist of land types least suitable for pastoralism (but not necessarily lacking conservation value). The land types most subject to preferential grazing and most threatened from a nature conservation perspective are poorly (three types) or not (four types) represented, and certainly not replicated, in nature reserves of the survey area, which exceeds 100 000 km2. Of the 23 priority plant species for nature conservation occurring in the survey area, 21 are not known to occur in nature reserves. Nature conservation in the area needs to improve because of the unrepresentativeness of the existing nature reserves and the absence of numerous priority plant species for nature conservation from these areas. We should recognize that reservation is but one nature conservation strategy. Viewed as a land tenure issue, this paper presents a case for a more representative nature reserve system, and substantial changes in outlook towards off-reserve nature conservation. First, an integrated appraisal of findings from rangeland and biological surveys is required. Together they provide a strong foundation for nature conservation planning, from which a more representative nature reserve system can be planned. Given that off-reserve nature conservation values are still likely to be substantial, partly as a result of compromise with existing land uses, new approaches to land management, sensitive to these values, may be required.The second major issue concerns the success of maintaining regional biological diversity in the arid shrubland rangelands of Western Australia, which will be strongly influenced by the use of the semi-natural matrix of lands under pastoral management. In six suggested opportunities, this paper addresses how this use may be achieved. Central to the ideas is a regional approach in which all stakeholders can contribute to, and have ownership of, regional environmental management plans. This paper emphasizes the role that conservative pastoral management might be able to play and some approaches to encourage more widespread participation of pastoralists in nature conservation management.     

基于生态过程模型和森林清查数据的森林生长量估算对比研究

利用遥感驱动的生态过程模型-Boreal Ecosystem Productivity Simulator （BEPS）、2001-2006年国家森林资源连续清查数据（一类清查-样地尺度）和2003-2009年森林资源规划设计调查数据（二类调查-区域尺度）,分别计算江西省吉安市的森林生态系统生长量,从不同空间尺度和森林类型对3种数据源估算的森林生长量进行了分析。结果表明,样点尺度上,BEPS模型模拟的森林生长量（4.18 Mg·hm^-2·a^-1）低于群落生长量（5.86 Mg·hm^-2·a^-1）,与乔木层生长量（4.29 Mg·hm^-2·a^-1）基本一致,模型模拟结果与两者的拟合R2分别为0.48和0.43。区域尺度上,BEPS模型模拟、二类调查数据计算的群落及乔木层生长量分别为4.65、4.36和3.34 Mg·hm^-2·a^-1,BEPS模型估算的吉安市各县森林总生长量与二类调查数据计算的群落、乔木层生长总量拟合R2分别达0.84和0.83。一类清查数据计算结果高于二类清查数据计算结果,BEPS模型模拟森林生长量分别与基于一类清查数据计算的乔木层生长量及二类调查数据群落生长量较为一致。从研究区两种主要森林类型来看,常绿阔叶林年平均生长量高于常绿针叶林,常绿针叶林与模型估算结果差异小于常绿阔叶林。最后利用模型估算了研究区2001-2010年平均生长量,为认识研究区的森林生长空间分布差异及更新森林生物量提供支持。     

Ecology of subtropical hermit crabs in S.W. Madagascar: cluster structure and function

The Madagascar coast (both) has a higher density and diversity of hermit crabs than is known from any other locality in the western Indian Ocean. Of the 20 species occurring at Anakao (S.W. Madagascar), 11 aggregated into clusters, including all but one of the species above the subtidal zone. The mean number of hermit crabs and species in clusters varied with several spatial parameters and time. Over 80% of the community clustered in certain habitats in particular tidal zones, whilst as low as 3% clustered in others. The highest intensity of clustering with shore zone was coincident with peak numbers of hermit crabs. The initiation and duration of clusters of hermit crabs above the eulittoral was driven by circadian rhythms, whilst those in the eulittoral were governed by tidal state. Clusters above and below the eulittoral were longer in duration, and those in the subtidal were more temporally variable than those above it. Certain pairs of species showed positive correlations of occurrence and (more rarely) of abundance, and all the correlations (of occurrence) of one, Clibanarius eurysternus, were negative. Positive correlations of occurrence were related to the degree of shell-use commonality between species pairs. Eulittoral species clustered with other individuals of approximately similar size and exchanged shells upon cluster disintegration. There was evidence of a dehydration-reduction function to shell clustering in addition to shell-exchange facilitation. The highly variable species-specific strategies of clustering may be important in alleviating both intra- and interspecific competition in assemblages of similar and highly abundant species.     

Severe storm disturbances and reversal of community structure in a southern California kelp forest

Regular observations made over a period of 5 yr in four permanent transects provided data on plant, sea urchin, and fish densities which indicate that two unusually severe winter storms in 1980 (Storm I) and 1983 (Storm II) had different effects on a southern California kelp-forest community. Storm I removed all canopies of the giant kelp Macrocystis pyrifera, but spared most understory kelps, mainly Pterygophora californica. Hence, the previously large accumulation of detached drift kelp, mostly M. pyrifera, disappeared. Denied their preferred diet of drift kelp, the sea urchins Strongylocentrotus franciscanus and S. purpuratus then emerged from shelters to find alternative food. Without effective predators, they consumed most living plants, including the surviving understory kelps. This weakened the important detritus-based food chain, as indicated indirectly by declining abundances of algal turf and fish (Embiotocidae) that eat small animals living in turf. In 1983, Storm II reversed the process by eliminating exposed urchins, while clearing rock surfaces for widespread kelp settlement and growth. By summer 1984, the kelp grew to maturity to form extensive canopies despite elevated water temperatures during summer and fall of 1983. Thus, severe storms may have vastly different effects on community structure, depending on the state of the community before the disturbance.