World - Global assessment of cumulative human impacts to at-risk marine species over time
Despite the fact that our planet is mostly ocean and human maritime activity is more intense than it has ever been, we know remarkably little about the state of the ocean's biodiversity -- the variety and balance of species that support healthy and productive ecosystems.
And it's no surprise -- marine biodiversity is complex, human impacts are uneven, and species respond differently to different stressors.
"It is really hard to know how a species is doing by just looking out from your local coast, or dipping underwater on SCUBA," said Ben Halpern, a marine ecologist at the Bren School of Environmental Science & Management at UC Santa Barbara and Director of the National Center for Ecological Analysis and Synthesis. "You only see a small patch of where a species lives and what it is experiencing, and only the few species you happen to see on that day." Though valuable, these snapshots are only part of a much larger picture of cumulative human impacts on at-risk marine species. Even less obvious are changes in impact over time and assessments of vulnerability to these impacts, which differs across species.
However, the picture of marine biodiversity is about to get a lot clearer. In a first-of-its kind study published in the journal Science, Halpern, lead author Casey O'Hara and co-author Melanie Frazier broaden and deepen our understanding of the state of marine biodiversity with a global assessment of cumulative human impacts to at-risk marine species over a recent time period. Their findings could go a long way toward concrete conservation measures for the most vulnerable members of the marine community.
"This is the first study of its kind looking at the effects of human activity on marine species, and the first looking at changes over time," said O'Hara, a doctoral student in the Bren School. Taking data on 1,271 threatened and near-threatened marine species from the International Union for Conservation of Nature and Natural Resources' (IUCN) Red List, the researchers mapped the at-risk species along range and anthropogenic stressors from 2003-2013.