Capturing the complex | EurekAlert! Science news

(Santa Barbara, California) – Although our planet is primarily made up of oceans and human marine activities are more intense than ever, we know remarkably little about the state of ocean biodiversity – the diversity and balance of species which are healthy and productive Support ecosystems. No wonder, because the biodiversity in the sea is complex, the effects on humans are uneven and the species react differently to various stress factors.

“It’s really hard to know how a species is doing just looking from the shore or diving underwater on SCUBA,” said Ben Halpern, 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 experiences, and only the few species that you happen to see that day.” While these snapshots are valuable, they are only part of a much broader picture of the cumulative effects of humans on endangered marine species. Even less obvious are changes in effects over time and vulnerability ratings for those effects, which vary by type.

However, the picture of marine biodiversity is becoming much clearer. In a unique 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 the cumulative effects on humans – Marine species at risk in a recent period. Their insights could go a long way in creating concrete conservation measures for the most vulnerable members of the marine community.

Multi-dimensional mapping

“This is the first of its kind to look at the effects of human activity on marine species and the first to look at changes over time,” said O’Hara, a graduate student at the Bren School. The researchers took data on 1,271 threatened and near-threatened marine species from the Red List of the International Union for Conservation of Nature and Natural Resources (IUCN) and mapped the endangered species from 2003 to 2013 along the range and anthropogenic stressors.

“We focused on those species that are known to be at higher risk of extinction, as it is particularly important from a conservation perspective to understand where and how our activities continue to endanger these species,” said O’Hara. “Not every species is equally affected by various human activities – some species are more sensitive to fishing pressures, while others are more susceptible to rising sea surface temperatures or ocean acidification.” Mapping over an 11-year period would also give researchers a sense of the cumulative human impact, a method they first used in an earlier study that focused on representative marine habitats.

It’s not a shock. The human impact on marine biodiversity is increasing, dominated by fisheries, direct human disturbance through acidification of land and oceans. But there were some unexpected discoveries for the writers. The extent to which endangered species are exposed to this pressure from human activity and the rate at which the pressure is expanding and intensifying is worrying. Corals are the most severely affected marine organism on earth.

“I was surprised at the extent to which corals were affected – coral species are exposed to essentially full-range impacts, and those impacts are becoming more intense, especially climate-related,” said O’Hara. “We hear stories about coral bleaching and the like, but our results really show the effect we are having.” The species of the Coral Triangle – the tropical waters that connect Indonesia, the Philippines, Papua New Guinea, and the Solomon Islands -, as well as the species in the North Atlantic, North Sea, and Baltic Sea, are hardest hit by human influences.

The information from this approach could provide decision-makers with a deeper understanding of where and how human activities affect marine biodiversity, which could lead to effective solutions. For example, treating areas with overlapping human impacts can maximize the conservation benefits for multiple species in the area. Effective conservation measures can help relieve the pressure of climate change phenomena such as ocean acidification or rising sea temperatures.

The team could have the opportunity to implement its findings later this year at the 15th United Nations Conference of Parties on Biodiversity, where 197 participating nations and territories will develop a framework for protecting and conserving global biodiversity.

“This framework will include goals for the protection of land and ocean areas worldwide, as ordered by President Biden to protect 30% of US territories and coastal waters by 2030,” said O’Hara. “We hope that our study will highlight those areas where such protection can most benefit the species and ecosystems at greatest risk.”


Disclaimer: AAAS and EurekAlert! are not responsible for the correctness of the press releases published on EurekAlert! by contributing institutions or for the use of information via the EurekAlert system.

Comments are closed.