Effects of grassland connectivity on plant diversity in Poyang Lake
With the acceleration of global landscape fragmentation,it is of great significance to reveal the impacts of landscape connectivity on biodiversity in order to restore ecological process and protect biodiversity.Taking the grassland of Poyang Lake as research object and from the integrated perspective of combined water level change and species dispersal,this study firstly analyzed the dynamics of grassland structural and functional connectivity respectively after identifying the distribution pattern of grassland at different water levels using landscape pattern indices and the graph-based connectivity indices.Then,the effects of grassland connectivity on plant diversity and the scale effects were discovered by means of the linear regression model.Moreover,the multiple stepwise linear regression model was applied to compare the relative explanatory power of structural and functional connectivity to plant diversity pattern.The results are shown as follows:(1)The grassland in Poyang Lake exhibits a landscape characteristic of"expanding when water falls while shrinking when water rises".It faces both inundation and segmentation effects of water with water level change,and its shrinkage always coexists with landscape fragmentation.(2)With the increase of water level,the area of grassland patch continues to shrink,the shape tends to be simple,the density reduces,and the fragmentation intensifies,resulting in a decrease of grassland structural connectivity.Meanwhile,the number of components increases,the probability of connectivity reduces,so that grassland functional connectivity decreases significantly.(3)The higher the connectivity of grassland,the higher the richness of plant species at the landscape scale,and the higher the similarity of plant communities at the patch scale.Functional connectivity is more effective in explaining plant diversity pattern than structural connectivity does.This study can provide some references for landscape pattern optimization and plant diversity conservation in lake areas from a new perspective of landscape connectivity.
万方数据
维普
