Community assembly processes in fragmented forests and its testing methods

Abstract

Nowadays, almost all forests in the world are fragmented, and thus, it is necessary to understand how forest fragmentation influence assembly of forest communities. This review summarized the main community assembly processes in the field of community ecology, namely ecological drift, dispersal, selection and speciation, and summarized the relative roles of these community assembly processes in fragmented forests. Due to differences in formation trajectory of different forests in fragmented region, the relative effects of the above four ecological processes are different for different types of forest communities: reassembled community (i.e., forest communities re-assembled through secondary succession in fragmented habitats) and disassembled community (i.e., continuous forest disassembled into fragmented forests). The effects of ecological processes can be effectively tested by analyzing short-term observed species distribution pattern within and among communities (e.g., species abundance distribution analyses, null model combined with beta diversity analyses, and convergence and divergence of functional trait distribution, etc.), controlled experiments, and long-term community monitoring (e.g., community dynamics analysis). Yet, it is insufficient to assess ecological processes undergoing habitat fragmentation by controlled experiments. In the future, studies should focus on developing and testing theoretical models, designing controlled experiments to investigate varied ecological processes undergoing habitat fragmentation, and combining ecological theory with practical biodiversity conservation.