Influence of habitat features of urban streetscapes on richness and abundance of avian species

Sarbasis Dutta,Subhendu Mazumdar,Goutam Kumar Saha

doi:10.2478/orhu-2021-0002

Abstract

Abstract In human-dominated landscapes, roads are known to negatively influence birds causing decline in species richness, as well as reduction in the number of avian species. However, linear stretches of green spaces formed by roadside plantations in urban streetscapes can support diverse avian communities. In spite of being an integral habitat feature of urban areas, there is a clear paucity of studies on avian diversity in urban streetscapes. The present study was carried out in Kolkata, where data on avian species richness and abundance was collected from 16 randomly placed belt transects (replicates), each of 500 m length and 20 m width, on different major roads throughout the study area keeping a minimum gap of 200 m between adjacent transects to avoid data overlapping. Each of these transects were traversed on foot twice in a month from January to March 2017 during days with calm weather conditions. We recorded 31 species of birds belonging to 8 orders and 19 families, of which maximum species belonged to the order Passeriformes (13 species). We found that both abundance and species richness of birds in transects with higher number of trees (78±4.1 individuals and 19.55±1.703 species of birds) were significantly higher than transects with fewer trees (53.74±2.5 individuals and 9.5±0.789 species of birds). Amongst various habitat features along these streetscapes, the total number of trees positively influenced both species richness (GLMM: F1, 90=14.485, P<0.05) and abundance of birds (GLMM: F1, 90=8.081, P<0.05). However, the other land use variables (i.e. number of bushes, waterbodies, markets and buildings) neither influenced the abundance of birds nor the species richness. Our findings can be useful for urban development to perceive the importance of various habitat features in urban streetscapes in sustaining avian diversity.

Highlights

Cities and towns across the globe are ever-expanding with explosion in human population (Fuller et al 2009)
As compared to the year 2000, a three-fold increase in urban areas have been predicted by 2030 (Seto et al 2012) leading to large scale loss, degradation and fragmentation of habitats coupled with environmental changes (McKinney 2006, BarMassada et al 2014), destruction of forests (Fischer et al 2007), reduction of wilderness areas (Olagunju 2015) and increase in impervious surfaces (Barnes et al 2001), which often threatens the survival of many species worldwide in these areas (Marzluff et al 2001, Sol et al 2017)
Among all avian species observed during the study, only the Indian Spotted Eagle Clanga hastata fall under the IUCN vulnerable (VU) category, while the remaining species are categorized as least concern (LC) species

Summary

Introduction

Cities and towns across the globe are ever-expanding with explosion in human population (Fuller et al 2009). Animals in urban areas face greater amount of anthropogenic pressures (such as increased vehicular traffic, air, noise and light pollution, loss of vegetation cover and increased impervious surfaces). In such scenario, various native greenspaces serve as important and remnant patches of habitats for wildlife thriving in human-dominated landscapes (Miller 1997, Milton 2002). Studies on the richness and diversity of birds have been carried out in urban greenspaces, like parks, forest remnants, cemeteries (Lussenhop 1977, Kocian et al 2003, Croci et al 2008, Nielsen et al 2014)

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