Wastelands or Preferred-lands? Indicators for redefining Desert conservation

Abstract

Desert ecosystems though crucial in shaping global climate, are often perceived to have limited function and are frequently designated as wastelands due to low biotic diversity and abundance. We explore the functional properties of desert through assessment of spatio-temporal variations of avian species richness and insect abundance of the relatively understudied Thar in Rajasthan. The study was conducted across four contrasting ecoregions (Western Thar (WT), Eastern Thar (ET), Transitional Zone (TZ), and Cultivated Zone (CZ) spanning 33 counties of Rajasthan. Monthly avian diversity were obtained from crowdsourced eBird data. Insect diversity and abundance accross the ecoregions were curated from the annual surveys of ZSI, India. The leads were corroborated with five years feeding behaviour observational data recorded from a representative site spanning 852 acres. There was a significant seasonal differences in bird species richness between the ecoregions with the most pronounced variations between summer and winter and CZ exhibiting the highest spatial variability followed by WT. WT also recorded the highest insect diversity and abundance, especially the orders Orthoptera, Hymenoptera, Coleoptera, Lepidotera and Diptera. The correlation matrix between bird and insect abundance and Kernel Density Estimation (KDE) plot indicated the relation between diverse dietary preferences and migratory patterns. These observations challenge the conventional notion that resource-limited environments harbour lesser biodiversity especially in arid environments. The dominance of insectivory among winter migrants aligns with the higher density of resident arthropods and emphasizes the pivotal role of insects as a food source during the migratory period. The adaptability of resident species to varied food sources, particularly arthropods, provides a means to strategically navigate during resource constraints. This study thus provides a unique framework to (a) redefine the functional importance of desert using migratory birds as prominent ecological indicators. (b) include an ecological criteria during policy formulation for biodiversity conservation. It also emphasizes reevaluation of deserts during designation of wastelands especially in the unique WT eco-regions when evolving developmental as well as ecological restoration strategies.

Avian Atlas: Unveiling the Diversity Divide in Desert Realms between Tropics

“…Such biogeographic distribution patterns in birds are known to be correlated to the trophic niche breadth (Fargallo et al, 2022). However, our further investigation on geographic distinctness of desert through mapping avian biodiversity with observational data, revealed that trophic niches not only play a crucial role in determining regional diversity but also the influx of migratory species (Mukherjee et al, 2024). These migratory birds due to their wide distribution (Pereira and Cooper, 2006), sensitivity to environmental changes (Smits and Fernie, 2013) and extensive existing data (Fraixedas et al, 2020), are often chosen as indicators for studying large-scale ecosystem functioning.…”