Abstract:

Forests are becoming increasingly fragmented worldwide. Compared to other woody plants (i.e., trees and shrubs), lianas are more concentrated near the edge than in the forest interior. Therefore, understanding how lianas respond to edge effects is important for predicting the impacts of lianas on forests dynamics. In this study, change of lianas on the edge-to-interior gradients was investigated in a subtropical mid-montane moist evergreen broad-leaved forest in the Ailao Mountains, SW China. Ten 20 m × 50 m transect sample plots were established in 13-, 35- and 53-year forest edges along the gradient situated perpendicular to the edges. Each plot was divided into five 20 m × 10 m quadrats, and those lianas with ≥ 2.0 m in length and ≥ 0.2 cm in diameter at breast height (DBH) were measured. We recorded a total of 2,426 individual lianas in the 3-ha sample plots, representing 31 species in 19 genera and 14 families. Our results are as follows: (1) Liana species richness and abundance decreased with increasing distance from the edge; the distance of edge effects for the 35-year forest edge was 30 m, and 20 m for 13- and 53-year forest edges. Liana breast height area in the 53-year forest edge was significantly higher within 20 m of the forest edge than in the forest interior, whereas there was no significant difference along the edge to interior gradient in the 13- and 35-year forest edges; (2) Liana species responded differently to edge effects, including species present exclusively at or near the edges (within 20 m of the edge), species density decreased with increasing distance from the edge, and species were insensitive to edge effects, which showed minor variation or random fluctuation throughout the gradient; and (3) Results from the canonical correspondence analysis (CCA) indicated that canopy openness, edge age and soil moisture were the most important factors that determined the distribution of lianas at the forest edges.

Key words: lianas, community, species, edge effects, subtropical forest