Discerning spatial patterns of biodiversity and understanding their proximate and ultimate causes is central to biogeography and macroecology. There has been substantial research on species richness along latitudinal and altitudinal gradients. Both ecological and evolutionary factors may drive diversity along these gradients but their effect on the distribution of species as mediated by species-specific traits has received far less attention.
In my first chapter, I focused on species functional trait variation along a latitudinal gradient. I found the effect of environmental filtering at higher latitudes, suggesting that environmental does play an important role in the distribution of species. Studies involving species environment relationships are important in identification and conservation of biodiverse areas. They are also important in the context of rapid climate change and in answering questions as to whether species will move to track their habitat or adapt to new environmental conditions.
To further understand this, in my second chapter, I modeled the potential distribution of 153 endemic woody species of the Western Ghats. Species distribution models (SDMs) are invaluable tools in mapping and conservation of endemic species, and also to understand the relationship between a species and its abiotic and biotic environment and which in turn can help us to generate a predictive map of where populations could potentially occur. For modeling the distribution of these species, I used MaxEnt and Ensemble methods. Species distribution models (SDMs) are used to understand the relationship between species and their environment which is then used to generate a predictive map of where populations could potentially occur. I compared these two methods and to show that Ensemble methods are better than single models. The most important environmental factor varied greatly from one species to another. However, it was observed that Precipitation of the Coldest Quarter, Slope and Forest Canopy Height contributed the most for a number of species.
For my third chapter, I used the results of species distribution modeling (binary maps) from the previous chapter to carry out preliminary assessments of conservation status of 151 endemic woody plants of Western Ghats, based on the categories and criteria proposed by the IUCN. I applied IUCN Criterion B for risk assessments and found that more than 50% of the endemic woody plants are threatened (1.9% Critically endangered, 23.84% Endangered, 30.46% Vulnerable). Of 151 endemic species, only 56 species have been assigned a conservation status by IUCN.