Habitat suitability for Sociable Lapwing (Vanellus gregarius) increases across its global range, but populations continue to decline
Abstract
Migratory birds are among the most threatened animals globally. Environmental drivers of bird distributions outside the breeding grounds, particularly in the tropics, remain poorly known. We assessed the year-round habitat suitability for the Sociable Lapwing (Vanellus gregarius), a critically endangered, long-distance migratory bird that moves between Central, West, and South Asia. We combined annual bird occurrence data from a historical records database and satellite tracking, with environmental metrics from Landsat satellite imagery for the period 1990–2024. We trained a multi-temporal random forest model to predict species occurrence as an indicator of primary productivity, surface moisture, vegetation openness, and terrain ruggedness over 34 years. Across the range, the overall habitat suitability, i.e., the probability of occurrence predicted from species distribution model, increased through the annual cycle over the study period. On the breeding grounds, habitat suitability increased in the dry steppe and meadow steppe of Kazakhstan. At the stopover locations, irrigated cropland in the coastal areas, drylands, and deserts, as well as cultivated floodplains of larger rivers, were predicted to be of high suitability. Some of the largest gains in habitat occurred on the wintering grounds in western India and eastern Africa, where suitability increased in semi-arid mosaic landscapes comprising subsistence agriculture and savannas. Our results suggest that although the habitat suitability across the Sociable Lapwing range has increased over the past 3 decades, this has likely not contributed to an increase in Sociable Lapwing numbers, which continue to decline globally. Future research should, therefore, focus more on surveys outside breeding range including GPS tracking, and close monitoring of agricultural land-use change supported by satellite remote sensing.
Leon Nill
Ph.D. student
Matthias Baumann
Senior Researcher
