CLIMATE-HABITAT RELATIONSHIP OF THE INDIAN SPINY-TAILED LIZARD IN ARID ECOSYSTEM OF BIKANER DISTRICT

zoology

The Thar Desert, spanning approximately 200,000 km² across the northwestern Indian subcontinent — primarily Rajasthan, India, and parts of Pakistan — represents one of the most thermally extreme and arid landscapes in Asia. Characterized by intense solar radiation, extreme diurnal and seasonal temperature fluctuations (ranging from below 5°C in winter to above 48°C in summer), low and erratic annual rainfall (100–500 mm), persistent hot winds (loo), and sandy to rocky substrate formations, the Thar presents a suite of harsh abiotic stressors that profoundly shape its faunal assemblages. The reptilian fauna is widely distributed in the Thar Desert. Out of 156 species of reptiles from India, as many as 65 species have been reported from the Thar. Crocodilian species, ghariyal, a rare reptilian species is also found in the basin of Chambal river in the Thar. While three species of lizard and tortoise (Trionyxgangeticus, Lissemypunctatapunctata, Geochelone elegans) are commonly found in desert districts of Rajasthan. Among the most ecologically specialized inhabitants of this desert ecosystem is the Indian Spiny-tailed Lizard (Saara hardwickii), a large, predominantly herbivorous agamid reptile whose life history, physiology, and behavioral ecology are intricately intertwined with the climatic extremes of this region. The species exhibits sophisticated ectothermic thermoregulation, exploiting the intense solar energy of the Thar to maintain optimal body temperatures (30–42°C) while retreating to deep burrow systems to avoid lethal thermal maxima. The arid climate's influence on vegetation structure — dominated by drought-resistant shrubs such as Calligonum polygonoides, Ziziphus nummularia, and annual ephemerals — directly governs food availability, reproductive timing, and juvenile survivorship in this species. contemporary climate change pose significant threats to S. hardwickii populations. Disruption of the thermal environment and loss of sparse but critical vegetative cover may compress the species' activity window, reduce reproductive success, and degrade burrow site availability. This review synthesizes existing ecological and climatological literature to highlight the vulnerability of S.hardwickii to climate-driven habitat change and underscores the necessity of integrating microclimate data into conservation planning for reptile fauna of the Thar Desert. KEY WORDS:- Thar Desert, reptilian species, thermoregulation, S. hardwickii, climate change.

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