Sachin Bhardwaj Lock

My research aims to answer key questions about the factors shaping island crocodylian populations in the Anthropocene.

PhD project title:

Integrating Past Archives of Insular Crocodylians into Diversity Baselines and Future Projections

  

Sachin Lock

Project description:

As megafaunal apex predators, crocodylians have played crucial roles in maintaining the functionality of global freshwater ecosystems since their emergence over 100 million years ago. The significance of these ecosystems in a broader context is difficult to overstate; wetlands cover just 0.8% of the world’s land surface area but support 6% of all of its species. Despite their demonstrable resilience over a long evolutionary history, crocodylians have experienced substantial reductions in populations, distributions and functional diversity throughout the Quaternary as they have come under intensifying anthropogenic pressures. More than half of living crocodylian species are now threatened with extinction, with almost a third considered critically endangered. 

The decline of these species is most evident on islands, witnesses to the loss of several endemic crocodylians, alongside the decimation of the populations of others, from the Caribbean to Madagascar to Oceania, over the last 100,000 years. Islands make up only 3% of the planet’s terrestrial domain but are home to 20% of its species and account for a staggering 60% of extinctions over the past 500 years. Insular species are known to be both particularly susceptible to extinction and disproportionately responsible for the maintenance of local functional biodiversity, making their conservation of paramount importance.

The first step in facilitating conservation efforts is, however, to understand the extent of previous losses. This project will endeavour to disentangle complex and untold dimensions of extinction processes in island crocodylians, using the data of the past to inform the policies of the future. By conducting aDNA analyses, compiling past archives of species occurrences and including them in distribution models using a holistic approach, my research aims to answer key questions about the factors shaping island crocodylian populations in the Anthropocene.
 

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