Niche partitioning affects spatial distribution patterns of three Helicia species of the Lienhuachih evergreen broadleaf forest, central Taiwan

Sympatric congeneric coexistence of species is a remarkable feature which causes high alpha diversity in tropical forests. Understanding how niche partitioning and dispersal limitations affect sympatric congeneric coexistence of species would help us explain the high species diversity of forests. In this study, environmental factors, leaf functional traits, and spatial distributions of 3 congeneric subcanopy tree species, Helicia formosanaH. rengetiensis, and H. cochinchinensis, were surveyed in order to understand the coexistence of these 3 species in the subtropical Lienhuachih forest dynamics plot in Taiwan. A bivariate point pattern analysis was used to test the relationship among the 3 Helicia species. Principal coordinates of neighbor matrices (PCNMs) and variation partitioning were used to study niche partitioning and dispersal limitations that affect the distributions of the 3 species. In addition, we also calculated community-weighted means of leaf functional traits to test trait-environment relationships. Results of the bivariate point pattern analysis showed repulsion between each 2 pairs of the 3 species. The PCNM and variation partitioning results explained 60.6% of the variations in niche partitioning. Our results also supported habitat divergence affecting the distributions of these 3 Helicia species and which was also reflected in the divergence of leaf functional traits. Overall, our results concluded that niche partitioning is the main process affecting the distributions of the 3 Helicia species. Meanwhile, it also affects the leaf functional traits of the 3 Helicia species and maintains the coexistence and species diversity of congeneric coexistence of species in the Lienhuachih forest.

Abstract in English; article in Chinese.

Chang Li-Wan, Chiu Shau-Ting, Kuo Yau-Lun, Hsieh Chang-Fu, & Lee Pei-Hsuan
Taiwan Journal of Forest Science