The clearance of tropical forests is a major cause of the decline of their biodiversity. However, the impact of the associated fragmentation on the remaining forest is less clear, despite decades of research efforts. Ferns and fern allies comprise the second richest vascular plant group after angiosperms. They have been recognized as indicators of environmental change, but are often understudied.
In a study published in Forests, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) investigated the factors influencing the abundance, species richness, and composition of ferns in the fragmented landscape of Xishuangbanna, China.
The researchers firstly produced a forest map to identify the forest fragments within the Xishuangbanna landscape and selected a total of 42 fragments, four of which were in protected areas, either entirely or partially. They then used a multi-model inference approach to assess whether fern abundance, richness, and composition were better explained by fragment size, topography (slope, aspect), forest structure (tree basal area, light availability), or soil properties.
Afterwards, they conducted a nestedness analysis to examine whether the composition of the fern communities in smaller fragments differed or represented a subset of the communities found in larger fragments.
They found that the forest fragments of all sizes are important when it comes to preserving the diverse, non-nested, tropical fern community of Xishuangbanna, China. The spatial distribution of fern species abundance and richness appears to be primarily driven by soil properties, and topography. However, fern species composition is mainly influenced by the forest structure.
“Our study shows that the different aspects of fern diversity result from the interaction with different environmental factors,” said Daniele Cicuzza of XTBG.
The study was financially supported by the Zero Extinction Project from the Center for Integrative Conservation of XTBG.
Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China