Tropical rain forest fragmentation and its ecological and species diversity changes in Southern Yunnan

Background

Animal species richness is understood to decline with fragmentation of tropical forests. While the same is assumed of plant species richness, fewer studies have been undertaken on this subject. This study on sacred groves in southern Yunnan, southwestern China, evaluates the plant species richness of these tropical rainforest fragments.

Research goals & methods

Soil conditions, climactic conditions, and plant species were measured in plots in three fragmented rain forests and one primary forest in southern Yunnan. The results are compared to those of previous studies of the same area published in Mandarin and Cantonese. The total number of species per plot was reduced in the fragmented forests and the more seriously disturbed the fragment was, the more the species richness diminished. The abundance of some species and the dominant ranks of some families have changed with fragmentation. The heliophilous or pioneer tree species increased and the shade-tolerant species were reduced in the fragmented forests. In life form spectra, liana species increased, but epiphytic species decreased in the fragmented forests.

Conclusions & takeaways

The plant species diversity is generally lower in the fragmented forests than in the primary forest. Tree species with small populations could be lost first in the process of rain forest fragmentation. The microclimatic differences between inside and outside forest are less in the fragmented forests than in the primary forest, indicating that the forest climate mesification effect is reduced in smaller fragments.