On the Trail of Bush Frogs: Diversification and Endemism in a Tropical Biodiversity Hotspot
Abstract: Biodiversity hotspots are irreplaceable regions of endemism in the world that are threatened by extinction forces. However, in these regions, many species and higher taxa are unknown or not well defined. In addition, the historical processes underlying the high diversity and endemism in tropical biodiversity hotspots such as the Western Ghats (WG) of Peninsular India were poorly understood. He selected bush frogs, a group of arboreal frogs, as a model taxon to understand the diversity, diversification, and patterns of endemism in the WG. The talk will be along the following threads:
1) Addressing biodiversity shortfalls and its consequences;
2) Discovery of evolutionary radiation and its diversification; and
3) Testing for areas of endemism and its importance.
Extensive sampling across 15 mountains resulted in many new lineages. Phylogenetic reconstruction revealed the largest vertebrate radiation in the WG escarpment. The diversification analysis showed allopatric speciation, small in situ radiations, and the persistence of old lineages underlie the origin of the endemics. A substantial proportion (>70%) of endemics had ranges of less than 1° latitude (< 1000 km²). The analysis of endemism identified the high altitudes of the southern mountains as the main centres of paleo- and neo endemism. In summary, the results show extreme local endemism among bush frogs, and highlight the mountains in the Western Ghats as landscapes of endemic evolutionary histories.
Bio: Dr. Vijayakumar received his PhD in evolutionary biogeography from the Indian Institute of Science (IISc). Before embarking on his doctoral research, he led expeditions to various regions, including the Nicobar archipelago, to map the distribution of amphibian and reptilian diversity and understand their ecological biogeography. After the 2004 tsunami, he shifted his focus to the Western Ghats region, where he addressed, as part of his PhD research (with Dr. Kartik Shanker), questions on historical processes driving diversification and diversity in a bush frog clade. In his postdoctoral research at George Washington University, his team discovered an ancient frog family. He was part of discovery and descriptions of over 20 species of frogs, lizards, and snakes. He is presently an independent researcher and his interests are in conservation biogeography. Besides research on endemism, he enjoys teaching, photography, sound recording and making maps.