Liana diversity and abundance as related to microenvironment in three forest types located in different elevational ranges of the Eastern Himalayas

Abstract

Background: Liana diversity and abundance in forests along an elevational range is poorly understood. Aims: To study the diversity and abundance of lianas in three forest types located in different elevational belts of the Eastern Himalayas, and to explore the role of microenvironmental factors in relation to liana abundance. Methods: Adult (≥ 0.2cm diameter at breast height) and juvenile lianas were enumerated in 0.1ha and 1m2 plots in lower montane, montane and upper montane forests between 1200 and 3000m above sea level. Ten microenvironmental variables were related to liana density within each forest type using stepwise forward multiple regression analysis, and across the forest types by using Canonical Correspondence Analysis (CCA). Results: Liana species richness followed the order: lower montane > montane > upper montane forest. Light and soil phosphorus (P) concentration were related to adult liana density. Soil pH, P, light and relative humidity were related to seedling density. The positioning of 43 liana species with respect to light, soil pH, nitrogen and P gradients in CCA plots indicated species-specific microenvironmental preferences. Conclusions : Liana diversity and abundance decreased with increasing elevation, and at each elevation were related to specific microenvironmental variables and differential species response.