College of Science

SNS Assistant Professor Publishes Article in Global Ecology and Biogeography

May 2, 2019

Distribution of sampling

Dr. Eric Crandall, SNS Assistant Professor, recently published a scientific paper in Global Ecology and Biogeography titled "The molecular biogeography of the Indo‐Pacific: Testing hypotheses with multispecies genetic patterns".

Stretching across two-thirds of the Earth’s circumference, from East Africa to Easter Island, the Indo-Pacific is the largest biogeographic region in the world. Like a bulls-eye in the middle of the Indo-Pacific, right in the Indo-Malay-Philippines Archipelago, sits the Coral Triangle. This site hosts the highest marine biodiversity in the world. As you move away from the Coral Triangle, biodiversity declines in all directions, creating a spectacular gradient of species diversity that characterizes the entire Indo-Pacific.

A scientist may ask, how do new species evolve in the Indo-Pacific? Most marine species have a tiny larval stage that may drift on ocean currents for vast expanses. Due to this, it is unclear where there might be barriers to these larvae that would cause populations on either side to become different species. To address the large size of the Indo-Pacific, biogeographers have subdivided this region into smaller sub-regions based on a variety of criteria.

For this paper, Dr. Eric Crandall led an international team of twenty one researchers, who assembled roughly two decades worth of genetic data from 56 coral reef species sampled across the Indo-Pacific. Collectively, they empirically tested how well data from each species fit into specific hypotheses.

The research team discovered that the data supported hypotheses which subdivide the Indo-Pacific into relatively few regions. Overall, these results reveal that there are only around 3 substantial barriers to larval dispersal in the entire Indo-Pacific: one on the western side of Sumatra, one between the continental islands of the West Pacific and the hot spot archipelagos of the Central Pacific, and one between Hawaii and the rest of the Indo-Pacific. How did so many species get created across so few barriers? The mystery of the Coral Triangle continues!

The paper arises from a collaborative network called the Diversity of the Indo-Pacific Network (DIPnet), which is co-founded and led by Dr. Crandall. The goal of the network is to foster international collaboration for research on ecology and evolution in the Indo-Pacific.

Congratulations to Dr. Crandall and his team of researchers on this insightful discovery!