Climate-Induced Adaptations in Gluta travancorica Bedd.: A Case Study from the Western Ghats Kerala, India After 25 Years

The Western Ghats of India are experiencing long periods of warming and drying, affecting threatened plant species endemic to this area. These species show adaptability to climate shifts through the timing of anthesis, flowering changes, fruit senescence, and incidence of new pollinators. This study focuses on Gluta travancorica Bedd. (Anacardiaceae), an endemic and threatened tree species occurs in the evergreen and shola forests of the southern Western Ghats, India. The drying of annual streams within the shola forests, combined with arid soil conditions resulting from insufficient summer showers, disrupts the synchronization of microclimates crucial for optimal flowering. This condition also affected the natural regeneration due to the recalcitrant behaviour of the seeds. Consequently, there was a noticeable shift towards delayed and extended flowering, with subsequent fruit aging aligning with the onset of the southwest monsoon, a strategy adapted to facilitate seed germination by the species. A notable adaptive response identified is the occurrence of vivipary, a rare phenomenon in non-viviparous G. travancorica, which is considered a genetic adaptive strategy reflecting environmental challenges in the degraded shola ecosystems as its allied species are habituated in peat swamps and tidal rivers of Malayan peninsula. The shift in anthesis timing from night to daytime, extended stigma receptivity period, and new insect incidence were recorded and treated as a biological adaptation to increase insect interactions and enhance the reproductive efficiency of the species. The study’s findings highlight the adaptations developed by G. travancorica as part of resilience to changing climate and microhabitat conditions in the shola forest ecosystems of Western Ghats, Kerala.