Larix principis-rupprechtii forest is an important vegetation formation and has a large distribution area in Luya Mountain Reserve,China.Spatial pattern analysis on individual trees in different age-classes of Larix p...Larix principis-rupprechtii forest is an important vegetation formation and has a large distribution area in Luya Mountain Reserve,China.Spatial pattern analysis on individual trees in different age-classes of Larix principis-rupprechtii was made in this paper.Here,we employed the technique of point pattern analysis,which could analyze pat-terns under all scales along a gradient.It was based on spatial mapped points of individual distribution.The results of this study showed that the densities of the five age-classes varied in the order:age-class 3>age-class 4>age-class 5>age-class 2>age-class 1.Although age-classes 1 and 2 have much fewer individuals than other three age-classes do,the popula-tion was stable at present.However,it would be necessary to take some measures for improving population regeneration for a long-time view.The individuals of all age-classes focused on clumping distribution in space;however,their distribution pattern varied with the change of scale.This mainly depended on biological features of Larix principis-rupprechtii and forest environments,but it also meant that the scale was an important factor in controlling spatial distribution pattern of tree individuals.The feature of clumping distribution became more significant with the increase of age.The relationships between individuals in different age-classes were almost all significantly correlated with each other.These associations became more significant within the older age-classes.This suggested that the individuals of different age-classes were interdistributed,by which the population could get benefits in resource utilization.The technique of point pattern analysis is effective and easy to be used in species pattern study.Its results are more closer to the reality,especially for community structure.展开更多
The spatial pattern analysis of population and community is important to understand community structure and has become one key topic in modern plant ecology.There are many techniques for analyzing one-dimensional patt...The spatial pattern analysis of population and community is important to understand community structure and has become one key topic in modern plant ecology.There are many techniques for analyzing one-dimensional pattern in ecological literature.Two-dimensional pattern analysis is better than one-dimensional analysis in the study on commu-nity spatial characteristics and structure.However,it is hard to analyze these two-dimensional patterns due to poor effective methodology.The two-dimensional sampling using two transects that meet at right angles was applied to get quadrat data in this work.And then the data from the two transects were analyzed separately by one-dimensional pattern analysis method,two-term local quadrat variance.The length,width,and area of patches at different scales of pattern for populations were obtained from the analysis.For community pattern,detrended correspondence analysis(DCA)was employed to summarize the species information firstly,and then the first DCA axis scores were analyzed to check its pattern.The application of this method to the pattern analysis on dominant populations and community for subalpine meadow(Comm.Polygonum viviparum+Carex rigescens+Kobresia bellardii)in the Luya mountains showed that it could release the characteristics of spatial pattern clearly and was a very effective technique.The method is easy to use and saves time with obvious advantages,compared with the two-dimensional pattern analysis methods presented in the litera-tures.In the study meadow,the patterns of the main dominant species,Polygonum viviparum,Carex rigescens,and Kobresia bellardii,were apparent and comparatively regular in shape with large areas of patches at the same scale compared with other species such as Festuca sp.and Thalictrum petaloideum.There were two or three scales of patterns for each plant population studied.This was related to population features,the interaction with environmental factors,and their dominant position in the community.The two scales of patterns for the meadow community were clear.The pattern of community was closely correlated with that of the main dominant species.The patches of dominant species were inter-distributed and overlapped,and formed the community pattern together.This is beneficial for utilization of resources,and keeping the community stable.展开更多
文摘Larix principis-rupprechtii forest is an important vegetation formation and has a large distribution area in Luya Mountain Reserve,China.Spatial pattern analysis on individual trees in different age-classes of Larix principis-rupprechtii was made in this paper.Here,we employed the technique of point pattern analysis,which could analyze pat-terns under all scales along a gradient.It was based on spatial mapped points of individual distribution.The results of this study showed that the densities of the five age-classes varied in the order:age-class 3>age-class 4>age-class 5>age-class 2>age-class 1.Although age-classes 1 and 2 have much fewer individuals than other three age-classes do,the popula-tion was stable at present.However,it would be necessary to take some measures for improving population regeneration for a long-time view.The individuals of all age-classes focused on clumping distribution in space;however,their distribution pattern varied with the change of scale.This mainly depended on biological features of Larix principis-rupprechtii and forest environments,but it also meant that the scale was an important factor in controlling spatial distribution pattern of tree individuals.The feature of clumping distribution became more significant with the increase of age.The relationships between individuals in different age-classes were almost all significantly correlated with each other.These associations became more significant within the older age-classes.This suggested that the individuals of different age-classes were interdistributed,by which the population could get benefits in resource utilization.The technique of point pattern analysis is effective and easy to be used in species pattern study.Its results are more closer to the reality,especially for community structure.
基金The study was supported by the National Natural Science Foundation of China(Grant No.30070140)the Teachers’Foundation of Education Ministry of China。
文摘The spatial pattern analysis of population and community is important to understand community structure and has become one key topic in modern plant ecology.There are many techniques for analyzing one-dimensional pattern in ecological literature.Two-dimensional pattern analysis is better than one-dimensional analysis in the study on commu-nity spatial characteristics and structure.However,it is hard to analyze these two-dimensional patterns due to poor effective methodology.The two-dimensional sampling using two transects that meet at right angles was applied to get quadrat data in this work.And then the data from the two transects were analyzed separately by one-dimensional pattern analysis method,two-term local quadrat variance.The length,width,and area of patches at different scales of pattern for populations were obtained from the analysis.For community pattern,detrended correspondence analysis(DCA)was employed to summarize the species information firstly,and then the first DCA axis scores were analyzed to check its pattern.The application of this method to the pattern analysis on dominant populations and community for subalpine meadow(Comm.Polygonum viviparum+Carex rigescens+Kobresia bellardii)in the Luya mountains showed that it could release the characteristics of spatial pattern clearly and was a very effective technique.The method is easy to use and saves time with obvious advantages,compared with the two-dimensional pattern analysis methods presented in the litera-tures.In the study meadow,the patterns of the main dominant species,Polygonum viviparum,Carex rigescens,and Kobresia bellardii,were apparent and comparatively regular in shape with large areas of patches at the same scale compared with other species such as Festuca sp.and Thalictrum petaloideum.There were two or three scales of patterns for each plant population studied.This was related to population features,the interaction with environmental factors,and their dominant position in the community.The two scales of patterns for the meadow community were clear.The pattern of community was closely correlated with that of the main dominant species.The patches of dominant species were inter-distributed and overlapped,and formed the community pattern together.This is beneficial for utilization of resources,and keeping the community stable.