In a new study published in Global Ecology and Biogeography, an international research group led by Dr. WANG Xugao of the Institute of Applied Ecology, Chinese Academy of Sciences, has made progress in understanding the ecological processes that determine local-scale patterns of spatial community dissimilarity in temperate forests.

Community dissimilarity (i.e., beta diversity) can be partitioned into species replacement (also called as species turnover) and species nestedness components. But little is known about the relative importance of various processes that influence patterns of species replacement and nestedness at local scales.

The new study, conducted by Dr. Wang and a group of scientists from China, the United States and Germany, examined the relative influence of dispersal limitation, habitat filtering and interspecific species interactions on local-scale patterns of the replacement and nestedness components in eight temperate forest mega-plots (20-35 ha) where the positions of all woody plants with DBH (Diameter at Breast Height) ≥ 1 cm were mapped.

The researchers simulated spatially explicit ‘null communities’ within each plot using a variety of spatial point process models representing different hypotheses on community-assembly mechanisms. They then compared the simulated patterns of community dissimilarity and its components with the observed counterparts.

In all eight forests, they found that the patterns of community dissimilarities primarily reflect species replacement phenomenon and the patterns can be best explained by dispersal limitation hypothesis.

They revealed that the nestedness component of community dissimilarity is “less prevalent” and are influenced by different processes. “Spatial nestedness for large and small trees was best explained by random placement and habitat filtering, respectively,” they said.

The researchers also found that interspecific interactions did not contribute to the local-scale patterns of species replacement and nestedness.

The study entitled “Ecological drivers of spatial community dissimilarity, species replacement and species nestedness across temperate forests” has been published in Global Ecology and Biogeography. Dr. WANG is the first and corresponding author of this paper.

This study is financially supported by the National Natural Science Foundation of China and the Strategic Priority Research Program of the Chinese Academy of Sciences.