Contrasting spatial distribution of pioneer versus non‐pioneer saplings in a Taiwanese forest: A multiple scale approach

Abstract

AbstractDispersal limitation and environmental filtering were recognized as the main dispersal‐based and niche‐based processes responsible for community assembly. These interactions usually leave more spatial signatures in sapling communities and create detectable spatial patterns in different functional types of species. We investigated saplings of pioneer and non‐pioneer species, which facilitated an understanding of species co‐existence and biodiversity recovery. Based upon mapped tree data in the subtropical evergreen broad‐leaved forest dynamics plot in Taiwan, we endeavored to: (1) determine the different spatial scales contributing to distribution patterns of pioneer and non‐pioneer saplings; (2) understand how dispersal limitation affects distribution of pioneer and non‐pioneer saplings; and (3) evaluate the degree to which the different environmental factors explain variation in species composition in pioneer and non‐pioneer saplings. We used the principal coordinates of neighbor matrices (PCNM) method, and variation partitioning to disentangle the contributions of these processes. Fine‐scale spatial patterns were more important for pioneer than for non‐pioneer saplings. Dispersal limitation was the main process influencing the spatial distribution of the non‐pioneer saplings. Environmental filtering was also an important process regulating the spatial distribution of saplings for both functional types, especially for pioneer saplings. Disturbance effects contributed to fine‐scale spatial variation in pioneer saplings, whereas topographic and soil effects contributed to broad and medium scale  spatial variation in non‐pioneer saplings. It was evident that different spatial patterns of saplings of different functional types served to facilitate tree regeneration and maintain species co‐existence in this subtropical broad‐leaved forest.