The desert fox, also known as the white-footed fox, is one of three sub-species of red foxes found in India. Although red foxes are among the most well-studied carnivores globally, there has been a lack of understanding about the ecology of this Indian sub-species (Vulpes vulpes pusilla). Desert foxes are distributed across the north-western states of Rajasthan and Gujarat. Although frequently seen in the sandy, arid regions of Rajasthan’s Thar desert, sightings of this fox are surprisingly low in the Banni grassland of Kutch, Gujarat.
The Banni landscape is a vast expansion of low-lying silt deposition between salt plains of the Greater Rann of Kutch and the elevated rocky habitats of mainland Kutch. It is a unique saline landscape dominated by salt-tolerant grasses and vast brushland of Suaeda nudiflora. The landscape was once considered one of the finest tropical grasslands of Asia but the rapid encroachment of a woody invasive Prosopis juliflora in the past few decades has altered large parts of this open landscape into dense woodland. P. juliflora is locally known as Ganda Bawal or “mad-tree”.
The desert fox is so well adapted to the harsh conditions of desert climates that ‘greening’ of desert habitats in the name of 'habitat improvement' have an adverse effect on its ecology. My research goal was to understand the impact of this habitat alteration on an open habitat specialist, the desert fox. Based on occupancy surveys and den-habitat selection, my study found that the expansion of woody invasive shrub has a negative influence on desert fox presence. Expanding woodland is shrinking the native Suaeda brushland and saline plains, the habitat which desert fox is more likely to occupy.
Due to seasonal waterlogging and high salinity, these habitats have avoided colonization of the woody invasive shrub and provide suitable open and visible grasslands to the desert fox. Denning is crucial for most desert-dwelling animals to avoid the extreme climatic variability in deserts. Desert foxes generally den in close proximity to seasonal wetlands under rich cover of native grasses and forbs. Dietary analyses reveal that the Indian desert fox is highly dependent on insect and plant-based diets. Its food habits are completely adapted to the desert climatic condition, as insects and plants are rich sources of water and nutrient in resource-poor desert landscapes.
The problem of woody encroachment is not just restricted to the desert fox in the Banni landscape but widely affecting a range of threatened fauna in grasslands across the globe. The different ways in which invasive species alter or affect the ecology and behaviour of grassland-dwelling animals needs further exploration, and can be useful for conservation of native fauna.