Understanding Patterns of Bird Species Distribution in the Western Ghats

Macroecology is the study of relationships between organisms and the environment at large spatial and temporal scales. This field of research examines patterns in species abundance, distribution and diversity. Understanding patterns in species distribution and richness can contribute significantly to our knowledge of community assembly and macroecological patterns, as well as to the effective conservation of threatened species and habitats. Although there have been a plethora of studies on birds in India over the years, there is a critical need to accurately delineate species distributions and understand patterns of richness. The focus of this study was to understand the factors (abiotic and biotic) that influence the distribution and composition of bird species in the Western Ghats, as well as to explore patterns in their geographic range sizes. The objectives of this study were addressed at the scale of the entire Western Ghats using a combination of field surveys, secondary data collection and species distribution modeling. The specific approaches to address these questions and the findings are outlined below. Chapter 2: Bird species in the Western Ghats – Patterns in composition and richness Fine-scale data on species presence and abundance are essential for exploring patterns in species distribution and richness. Despite the fact that birds have been extensively studied in the Western Ghats, systematic data collection and compilation of information over the entire mountain range has not been carried out, especially for the purpose of testing macroecological questions. This chapter describes patterns in bird species presence, abundance, composition and richness within the Western Ghats. The study area, site selection protocol and the sampling technique have also been described in detail. This dataset establishes a baseline of information about birds in the Western Ghats and subsets of this larger dataset will be used to address various questions in the following chapters. Chapter 3: Predicting bird species distribution in the Western Ghats Detailed knowledge of species’ ecological and geographical distributions is fundamental for conservation, as well as for understanding ecological and evolutionary determinants of spatial patterns of biodiversity. However, occurrence data for a vast majority of species are sparse, resulting in information about species distributions that is inadequate for many purposes. Species distribution models attempt to provide detailed predictions of distributions by relating presence or abundance of species to environmental predictors. In this chapter, we describe the usage of Maxent, a species distribution modelling technique based on presence-only data, to predict the distributions of bird species within the Western Ghats. For this purpose, we put together primary locations of bird species presence along with a published dataset. Using a number of important environmental layers, predicted species distribution maps were derived for 98 bird species, including 13 endemics,…