What are the physical and biotic processes that determine large scale spatial patterns of biodiversity? How do species and communities respond to climate change and other anthropogenic impacts and what are the ecological and evolutionary consequences of such responses? These and related questions form the focus of my research. We work primarily in marine systems using interdisciplinary approaches that combine ecological and genetic information from living species and populations with the temporal perspective afforded by the rich fossil record of marine invertebrates.
Origin and maintenance of latitudinal diversity gradients
The latitudinal gradient in diversity - the dramatic increase in the number of species and higher taxa from the poles to the tropics - is a global biodiversity pattern shared by both marine and terrestrial systems. Understanding the processes responsible for the origin and maintenance of such gradients is essential for informed management and conservation of biodiversity, especially in a world faced with rising temperatures, rampant overexploitation of natural resources and increasing urbanization. Yet despite over a century of work such processes remain poorly understood. We are working to better understand (i) the role of ecological processes in maintaining spatial gradients in diversity and (ii) the role of evolutionary and historical processes in generating such gradients. The former includes the role of temperature and other environmental variables in determining the number of species that can coexist in a given region as well as how species respond to changes in climate. As far as evolutionary dynamics are concerned, we are not only quantifying how origination and extinction rates change along latitude, a dynamic still poorly documented, but also how shifts in geographic distributions of taxa over time affect regional patterns of species richness. I am also involved in developing theoretical models to explore how in situ speciation and extinction rates interact with patterns of biotic interchange between regions to create large scale spatial gradients in biological diversity.
Anthropogenic impacts on coastal marine ecosystems
Intertidal and subtidal habitats harbor a diverse fauna of invertebrates, plants and fish yet these habitats are among those most impacted by human activities and least protected. While harvesting practices and other activities of an expanding coastal population all over the world are generally thought to be negatively affecting the species living in these habitats, little quantitative data still exist on the nature and extent of such impacts. In addition, how human impacts are affecting macroecological relationships or biogeographic patterns also remain poorly studied. We have initiated large-scale studies that will quantify the ecological consequences of harvesting (legal and illegal), urbanization and climate change along the California coast. We also plan to initiate similar studies along other coastlines in the near future.
A more detailed description of our research and a complete list of our publications can be found at http://www.biology.ucsd.edu/labs/roy/.
Kaustuv Roy received his Ph.D. from the University of Chicago, where he completed postdoctoral training.