Tropentag, September 16 - 18, 2026, Göttingen "Towards multi-functional agro-ecosystems promoting climate-resilient futures"

Peri-urban cropland sustains avian biodiversity in tropical cities: evidence from urban India

¹International Maize and Wheat Improvement Center, Sustainable Agri-food Systems, India
²International Maize and Wheat Improvement Center (CIMMYT), India

Abstract

Rapid urban expansion in India, projected to add over 350 million urban residents by 2050, occurs through converting peri-urban croplands, plantations and fallows into built-up land. While these croplands sustain food production, their impact on urban biodiversity remains poorly understood, despite relevance to multifunctional land-use design in the Global South. Most urban ecology evidence comes from temperate cities with diverse agricultural systems. This study examines whether peri-urban croplands support bird communities comparably to built-up and other vegetated covers across three tropical Indian cities representing distinct biogeographies.
Bird data came from 360 fixed-radius point counts (120 per city) during December-February of 2020-2021 (Bhopal, Patna) and 2023-2024 (Coimbatore), yielding 14,576 individuals across 155 species. Observations were paired with land-cover data (Bhuvan Level-II) within 100m of each site, and a multi-scale framework combined community-level richness with species-level occurrence and abundance models to disentangle impervious cover from vegetated and agricultural matrix. City-wide change was quantified in Google Earth Engine using GHSL built-up (2000-2020) and ESA WorldCover cropland (2021).
Within sampling buffers, cropland accounted for 67% of vegetated cover, indicating birds encountered an agricultural rather than remnant natural matrix. City-wide built-up expanded 23-49% (2000-2020; Bhopal 49%, Coimbatore 37%, Patna 23%), while cropland still occupied 7-32% of municipal area in 2021. Negative binomial mixed-effects and species-level probit and negative binomial regressions spanned 55,800 species-by-site observations. Site-level richness declined with built-up cover, but disappeared once vegetation and water cover were included (ΔAIC = 24.2), with vegetation remaining a positive predictor. The cost of impervious surface, therefore, operates through loss of the vegetation it replaces. Replacing 1% built-up with 1% cropland raised occurrence probability by 0.020 and abundance by 0.16 individuals per species per site (both p < 0.001); cropland was statistically equivalent to fallow and plantation, with only scrubland supporting significantly higher abundance. Built-up cover also restructured composition through turnover rather than nested loss (partial Mantel r=0.098, p=0.001), with declining multivariate dispersion, a signature of biotic homogenisation that cropland retention helps offset. For tropical cities, where most of this century's urban growth will consume peri-urban agriculture, these findings reframe cropland as multifunctional land delivering biodiversity alongside food.

Keywords: Cropland, Global South, Land-use Planning, Peri-urban Agriculture, tropical Cities, Urban Birds

Contact Address: Ashiq Parambil-Peedika, International Maize and Wheat Improvement Center, Sustainable Agri-food Systems, Building No. 303, ICRISAT Campus, Patancheru, 502324 Hyderabad, India, e-mail: ashiqleo7gmail.com