The study results show that hotspots of cumulative impact are in coastal areas near urban centers and heavily polluted watersheds.
The research involved a four-step process.
First, the scientists gathered information to quantify and compare how different human activities affect each marine ecosystem. For example, fertilizer runoff was shown to have a large effect on salt marshes, but a much smaller one on rocky reefs.
Then the researchers gathered and processed data on marine ecosystems and human influences.
Next they combined data from the first and second steps to determine "human impact scores" for each location along the West Coast.
Finally, they compared regional results to global results for the same areas from the previous analysis.
"Comparing the global version of the map to regional-scale versions allows us to determine where it performs best," said biologist and paper co-author Kim Selkoe, also of NCEAS. "The high correlation is good news for marine managers in areas of the world that may be in need of maps of human impacts, but don't have the resources to undertake their own tailored analysis."
The study provides critical information for evaluating where certain activities can continue with little effect on the oceans, and where other activities might need to be stopped or moved to less sensitive areas, said Taylor.
As management and conservation of the oceans turns toward marine protected areas (MPAs), ecosystem-based management (EBM), and ocean zoning to manage human influence, such information will prove invaluable to managers and policymakers, said Halpern.
"The results are a wake-up call," he said. "We are significantly affecting the oceans."
|Contact: Gail Gallessich|
University of California - Santa Barbara