Avifaunal Richness and Abundance Along an Urban Rural Gradient with Emphasis on Vegetative and Anthropogenic Attributes in Tiruchirappalli, India

Abstract

Urban expansion and human migration from rural to urban locations have complex relationships with environmental change. Habitat fragmentation, loss of biodiversity and vegetation changes are some of the most common impacts of urbanisation. In many Indian cities, the urban core is characterised by historical human settlements with narrow lanes and packed commercial establishments, while urbanisation that occurred after 1970s preferred spacing between the dwellings with more greenery or urban forestry. As urbanisation progresses, the urban fringes have more scope for incorporating environmental concerns and conservation. In this study, we measured species richness and abundance of birds within varied urban habitats and landscapes along the urban–rural gradient in Tiruchirappalli, India. We also tried to determine the linkage between bird diversity and landscape attributes including anthropogenic factors. Our observations showed that within urban areas, certain landscapes favoured species richness while many habitats are unfriendly for species but encouraged homogenisation. As we move from urban core towards rural gradient, the species richness increased; however, it is not uniform in all peripheral directions. Interestingly, the urban fringes at certain pockets had richness equivalent to rural locations. Species richness positively correlated with vegetation cover while built cover, noise, vehicular movement and pedestrians had negative impacts. As the urban fringes are in various stages of development, they have more scope for integrating ecological and biodiversity considerations and in this aspect wetlands, riverine farmlands and urban forests may play a crucial role in retaining native birds and also supporting migratory bird species.