Experts Predict Future Extinctions With the Fossil Record

It's no secret that countless species are threatened or in danger of extinction across our tiny blue world. What may be a surprise, however, is that a great deal of those extinctions may be natural. A new study has taken to the fossil record to determine just how many species would still be on their way out even if humans had not been around to sully their natural habitats.

"Our goal was to diagnose which species are vulnerable in the modern world, using the past as a guide," Seth Finnegan, an expert in integrative biology at the University of California, Berkeley, explained in a statement. "We believe the past can inform the way we plan our conservation efforts. However, there is a lot more work that needs to be done to understand the causes underlying these patterns and their policy implications."

The resulting study, which can be found in the May 1 issue of the journal Science, shows that when human intervention and influence is taken into account, the pattern of extinction seen in this day and age practically mirrors what has been seen over the past 23 million years.

Finnegan and his colleagues then used this pattern to help predict which ocean areas and marine organisms would be most at risk today without the added threat of human-caused habitat destruction, overfishing, pollution, and ocean acidification.

"It's very difficult to detect extinctions in the modern oceans, but fossils can help fill in the gaps," added co-author and conservation biologist Sean Anderson, for Simon Fraser University in Burnaby, British Columbia. "Our findings can help prioritize areas and species that might be at greater risk of extinction and that might require extra attention, conservation or management." (Scroll to read on...)

Predictably, their results showed some trends that evolutionary and biological experts have long suspected. According to the study, animals with the smallest geographic ranges face the greatest risk of extinction - as it is far easier for tiny and isolated habitats to be radically changed by natural disasters or extreme weather shifts overnight.

Additionally, complex sea mammals like whales, dolphins and seals appear far more prone to extinction than many sharks or invertebrate species. Simple bivalves - clams and mussels in particular - were found to be 10 times less likely to experience species-specific extinctions, despite the fact they are so incredibly biodiverse.

And while the study focused on revealing patterns and not the cause and effect behind them, this may have a lot to do with how readily these groups can adapt to a changing world. Bivalves, for instance, survived many mass extinctions in the past because of their hardy nature. Even today, species like the infamous zebra and golden mussels are becoming exceptionally successful invaders because of their ability to adapt with changing water temperatures.

Other invertebrates have even proven their adaptability in the fossil record by going through radical physical changes. The octopus, for instance, evolved from a heavy and stiff clam-like creature to the uniquely mobile creature we see today. (Scroll to read on...)

By comparing extinction patterns of the past with areas where human activities, such as fishing, impact the oceans, researchers also revealed regions that may boast particularly vulnerable species. These areas include high-biodiversity regions of the tropics such as the Indo-Pacific and the Caribbean, as well as regions such as Antarctica that harbor many unique species.

"The implications of these patterns for the future of coastal marine ecosystems will depend on how natural risk and current threats interact," added study co-author Paul Harnik, an assistant professor of geosciences at Franklin and Marshall College in Lancaster, Pennsylvania. "By understanding these patterns in the past, we hope to provide a framework for understanding global change."

That's an understanding the researchers hope can help them focus conservation efforts in the years to come.

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