Rainfall and Elevation Influence the Local-Scale Distribution of Tree Community in the Southern Region of Western Ghats Biodiversity Hotspot (India)

Abstract

The present study characterises the tree communities with respect to topographic and climatic variables and identifies the most important environmental correlate of species richness in the southern region of Western Ghats Biodiversity Hotspot, India. Digitally derived environmental variables in combination with tree species richness information were analysed using Canonical Correspondence Analysis (CCA) to characterise the communities. Multiple regression technique based on stepwise backward elimination was used to identify the most important environment correlate of species richness. Canonical correspondence analysis results in six major tree communities along the first and second axes. Rainfall is the dominant environmental gradient influencing vegetation patterns on the first CCA axis while elevation showed the highest correlation with the second CCA axis. Backward elimination regression technique yielded rainfall as the most important environmental correlate of species richness. Results were in agreement with the observations in the Neotropics that rainier areas maintain high species diversity.

Functional trait and community phylogenetic analyses reveal environmental filtering as the major determinant of assembly of tropical forest tree communities in the Western Ghats biodiversity hotspot in India

“…2). These findings corroborate the quantitative analyses reported in earlier empirical studies that showed contrasting patterns of taxonomic turnover and phylogenetic structure of tropical tree species differing in leaf phenology (evergreen and deciduous), which was primarily influenced by precipitation, and water deficit (aridity index) associated with length of dry season and temperature (Ramesh et al 2010a(Ramesh et al , 2010bJoseph et al 2012;González-Caro et al 2014). Several processes may explain the observed pattern of taxonomic turnover and phylogenetic structure of tree communities in relation to environmental variables in the study region.…”

“…Although, a few studies have evaluated the role of historical and environmental factors underlying the composition, distribution and abundance pattern of tropical tree species with contrasting leaf phenology. They have not integrated the ecologically important traits and evolutionary relationship of co-occurring species in an integrated ecological analysis (Ramesh et al 2010a(Ramesh et al , 2010bJoseph et al 2012;Van Ommen Kloeke et al 2012;González-Caro et al 2014;Lohbeck et al 2015;Krishnadas et al 2016;Ge and Xie 2017). Our results show that taxonomic turnover and phylogenetic structure of tree communities in the study region is best predicted by precipitation gradient followed by temperature related variables and aridity index.…”

How Do Climatic Predictors Affect Tree Richness in Western Ghats, India?

“…3; Table 1). Interestingly, the present study has the same finding as a previous study [30], which argued that rainfall and elevation jointly determined the tree community diversity patterns in the southern part of the Western Ghats.…”

Surrounding vegetation matters for arthropods of small, natural patches of indigenous forest

“…Natural forests, which mostly occur in areas of high rainfall, are characterised by structurally complex vegetation (Eeley et al ., ; Robson et al ., ; Joseph et al ., ; Fang et al ., ). They also serve as a conservation priority for arthropod biodiversity (Lawes et al ., ).…”

“…Natural forests, which mostly occur in areas of high rainfall, are characterised by structurally complex vegetation (Eeley et al, 2001;Robson et al, 2009;Joseph et al, by grassland or, in recent years, surrounded by commercial plantation vegetation. The influence that the surrounding vegetation has on forest patch biodiversity is either positive or negative depending on the adjacent habitat (Kotze & Samways, 1999a;Driscoll et al, 2013).…”