Fossils of extinct marine species providing insights on today’s extinction hotspots

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Researchers are using fossils of extinct marine species over the course of last 23 million years to gain insights into the species at risk of extinction today and also gaining an understanding of where hotspots of extinction may be located.

Dr. Heike Lotze and Dr. Derek Tittensor of Dalhousie’s Faculty of Science at Dalhousie University, Canada are members of an international research team of ecologists and paleontologists that is studying fossil records from the past 23 million years. The reason behind choosing this period is that it most closely resembles Earth today. Combining the data with the present state of our oceans, researchers are gaining greater insights on possible extinction of current species.

The team established a baseline of extinction risk in oceans by analysing data in a world with and without humans said Lotze, a Canada Research Chair in Marine Renewable Resources and associate professor at Dalhousie University.

Tittensor, an adjunct biology professor with Dalhousie and researcher with the United Nations Environment Programme World Conservation Monitoring Centre says that fossil record examination helps identify the species that were particularly vulnerable to extinction.

“Patterns of extinction over the last 23 million years can then be used to help us understand the extinction risk we’re seeing in modern ocean ecosystems”, he adds.

According to the fossil record, sharks and corals tended to be more resilient species, while whales, dolphins and seals were more prone to extinction. Species with smaller geographic ranges were also more prone to extinction.

The ecologists in the group then used what they learned from the fossil record to determine which marine areas and species would be most at risk today, given the added threats from human activities and climate change. The rich biodiversity, high impact levels, and concentration of extinction-vulnerable species in areas like the Caribbean and Indo-Pacific, led to them being identified as extinction hotspots in the study.

“Historically, the species in these areas had higher natural extinction risks,” said Tittensor. “Today, they may be increasingly prone to accelerated extinction rates because of pressures like overfishing, pollution and climate change.”

“Areas that have naturally high extinction risk may need extra management and conservation efforts, especially if they also face high pressure from human activities in today’s ocean”, said Lotze.