Diversity and Composition Plants Species Along Elevational Gradient: Research Trends

Abstract Studies on species richness pattern along elevation gradient is fascinatingly gaining consideration. We compiled data from 118 studies of elevational gradients between the years 2001- 2021 in a broad range of organisms throughout the world to estimate the designs of species richness and their determinants. The present study showed that more than half (57%) studies with unimodal hump-shaped richness pattern (maximum diversity at middle and lower at edges) followed by a monotonic decline (26%) in different taxa of plant. Nearly one-fifth studies (17.5%) followed either monotonic incline or reverse hump shaped or non-distinct patterns. Extensive studies in mountainous regions, more uniform model as a unimodal hump shape was present. In spite of latitudinal and elevation variation, both hemispheres showed similar patterns of species richness for all plant taxa. Some taxa showed bimodal and some others showed multi model patterns of elevation species richness patterns having peak diversity due to topographical and climatic factors. Upper and lower elevational ranges may provide extremities in temperature and rainfall for decreasing the species diversity. The mid domain effect may explain this species richness pattern. But this present study confirmed the presence of hump shaped species richness pattern due to extend of the midpoint elevation or elevation range considered for an individual species. Higher the midpoint value longer an elevation range that favours unimodal pattern.