Potential Trade-offs Between Intra-specific and Inter-specific Trait Variations along an Environmental Gradient in Temperate Forests of Western Himalaya

Abstract:

Understanding and predicting how vegetation will respond to increasing climate change is of utmost importance for maintaining ecosystem functions and services in the Himalayan region. Species composition and diversity are highly dependent on topography and local climatic conditions in temperate regions. Although environmental filtering shapes the floristic composition and associated plant functional traits, it remains questionable how temperate species in the Himalayan region be able to adapt to gradual environmental changes. Here, we study ten broadly distributed woody species across an elevational gradient (1500-3000m) in temperate forests of Western Himalaya. We focused on twelve functional traits reflecting plant functional differentiation in growth and competitive strategies, stem transportation, leaf architectural pattern, and resource acquisition.

We found that plant traits were strongly related to elevation and soil nutrient concentration. However, there was a great variance in environmental gradients differences among plant functional traits. We found growth-related traits to be mostly related to local climatic conditions and edaphic factors, whereas leaf traits were highly correlated with slope aspect and soil nutrient concentration and woody traits were mostly related to increasing elevation and tree size. Overall, there was a greater interspecific variation than intraspecific variation in our study region. The results suggest that intraspecific trait variation has different spatial patterns as compared to interspecific trait variation with increasing elevation and decreasing temperature. The study throws light on plant functional trait variation between and among species with change in topography that allows them to acclimatize with change in climatic conditions. The study will also help in refining our understanding of how species are distributed across a vegetated landscape by quantifying the woody plant trait variation.