Spatial heterogeneity is a very important issue in studying functions and processes of ecological systems at various scales. Semivariogram analysis is an effective technique to summarize spatial data,and quantificatio...Spatial heterogeneity is a very important issue in studying functions and processes of ecological systems at various scales. Semivariogram analysis is an effective technique to summarize spatial data,and quantification of spatial het-erogeneity. In this paper, we propose some prmciples to use semivariograms to characterize and compare spatial heterogene ity of ecological systems and use an example of old growth forests of Korean pine to demonstrate these prmciples and to dis-cuss its charactcristics of spatial heterogeneity.展开更多
Large areas assessments of forest bioinass distribution are a challenge in heterogeneous landscapes, where variations in tree growth and species composition occur over short distances. In this study, we use statistica...Large areas assessments of forest bioinass distribution are a challenge in heterogeneous landscapes, where variations in tree growth and species composition occur over short distances. In this study, we use statistical and geospatial modeling on densely sample.d forest biomass data to analyze the relative importance of ecological and physiographic variables as determinants of spatial variation of forest biomass in the environmentally heterogeneous region of the Big Sur, California. We estimated biomass in 280 forest Plots （one plot per 2.85 km2） and meas- ured an array of ecological （vegetation community type, distance to edge, amount of surrounding non-forest vegetation, soil properties, fire history） and physiographic drivers （elevation, potential soil moisture and solar radiation, proximity to the coast） of tree growth at each plot location. Our geostatistical analyses revealed that biomass distribution is spatially structured and autocorrelated up to 3.1 kin. Regression tree （RT） models showed that both physiographic and ecological factors influenced bio- mass distribution. Across randomly selected sample densities （sample size 112 to 280）, ecological effects of vegetation community type and distance to forest edge, and physiographic effects of elevation, potential soil moisture and solar radiation were the most consistent predictors of biomass. Topographic moisture index and potential solar radiation had apositive effect on biomass, indicating the importance of topographically- mediated energy and moisture on plant growth and biomass accumula- tion. RT model explained 35% of the variation in biomass and spatially autocorrelated variation were retained in regession residuals. Regression kriging model, developed from RT combined with kriging of regression residuals, was used to map biomass across the Big Sur. This study dem- onstrates how statistical and geospatial modeling can be used to dis- criminate the relative importance of physiographic and ecologic effects on forest biomass and develop spatial models to predict and map biomass distribution across a heterogeneous landscape.展开更多
Based on the concepts of landscape ecology and landscape heterogeneity, this paper concludes that the spatial and temporal heterogeneity in ecological systems is the kernel of landscape ecology. From views of structur...Based on the concepts of landscape ecology and landscape heterogeneity, this paper concludes that the spatial and temporal heterogeneity in ecological systems is the kernel of landscape ecology. From views of structure, function and dynamics, the concepts and ecological significance of the spatial and temporal heterogeneity of landscape as well as its roles and applications in landscape ecology are reviewed. Finally, the characteristics of hierarchy and scale, and the effects of human on the landscape heterogeneity are discussed.展开更多
Landscape ecology is an interdisciplinary field that has been rapidly developing in the past few decades. New ideas and perspectives that emphasize spatial heterogeneity, hierarchical linkages, and interactions betwee...Landscape ecology is an interdisciplinary field that has been rapidly developing in the past few decades. New ideas and perspectives that emphasize spatial heterogeneity, hierarchical linkages, and interactions between pattern, process, and scale have given the field an unique and significant identity. This paper is intended to review and synthesize the recent advances in landscape ecology, presenting a set of core concepts and theories, which include scale, pattern-process, spatial heterogeneity, edge effect, hierarchy theory, patch dynamics, patch-corridor-matrix model, island biogeographic theory, metapopulation theory, landscape connectivity, neutral models, and percolation theory.展开更多
文摘Spatial heterogeneity is a very important issue in studying functions and processes of ecological systems at various scales. Semivariogram analysis is an effective technique to summarize spatial data,and quantification of spatial het-erogeneity. In this paper, we propose some prmciples to use semivariograms to characterize and compare spatial heterogene ity of ecological systems and use an example of old growth forests of Korean pine to demonstrate these prmciples and to dis-cuss its charactcristics of spatial heterogeneity.
基金financially supported by the National Science Foundation (EF-0622770 and EF-0622677)the USDA Forest Service–Pacific Southwest Research Stationthe Gordon & Betty Moore Foundation
文摘Large areas assessments of forest bioinass distribution are a challenge in heterogeneous landscapes, where variations in tree growth and species composition occur over short distances. In this study, we use statistical and geospatial modeling on densely sample.d forest biomass data to analyze the relative importance of ecological and physiographic variables as determinants of spatial variation of forest biomass in the environmentally heterogeneous region of the Big Sur, California. We estimated biomass in 280 forest Plots （one plot per 2.85 km2） and meas- ured an array of ecological （vegetation community type, distance to edge, amount of surrounding non-forest vegetation, soil properties, fire history） and physiographic drivers （elevation, potential soil moisture and solar radiation, proximity to the coast） of tree growth at each plot location. Our geostatistical analyses revealed that biomass distribution is spatially structured and autocorrelated up to 3.1 kin. Regression tree （RT） models showed that both physiographic and ecological factors influenced bio- mass distribution. Across randomly selected sample densities （sample size 112 to 280）, ecological effects of vegetation community type and distance to forest edge, and physiographic effects of elevation, potential soil moisture and solar radiation were the most consistent predictors of biomass. Topographic moisture index and potential solar radiation had apositive effect on biomass, indicating the importance of topographically- mediated energy and moisture on plant growth and biomass accumula- tion. RT model explained 35% of the variation in biomass and spatially autocorrelated variation were retained in regession residuals. Regression kriging model, developed from RT combined with kriging of regression residuals, was used to map biomass across the Big Sur. This study dem- onstrates how statistical and geospatial modeling can be used to dis- criminate the relative importance of physiographic and ecologic effects on forest biomass and develop spatial models to predict and map biomass distribution across a heterogeneous landscape.
文摘Based on the concepts of landscape ecology and landscape heterogeneity, this paper concludes that the spatial and temporal heterogeneity in ecological systems is the kernel of landscape ecology. From views of structure, function and dynamics, the concepts and ecological significance of the spatial and temporal heterogeneity of landscape as well as its roles and applications in landscape ecology are reviewed. Finally, the characteristics of hierarchy and scale, and the effects of human on the landscape heterogeneity are discussed.
文摘Landscape ecology is an interdisciplinary field that has been rapidly developing in the past few decades. New ideas and perspectives that emphasize spatial heterogeneity, hierarchical linkages, and interactions between pattern, process, and scale have given the field an unique and significant identity. This paper is intended to review and synthesize the recent advances in landscape ecology, presenting a set of core concepts and theories, which include scale, pattern-process, spatial heterogeneity, edge effect, hierarchy theory, patch dynamics, patch-corridor-matrix model, island biogeographic theory, metapopulation theory, landscape connectivity, neutral models, and percolation theory.
