Scientists have recently generated a map that shows the intensity of human impacts in the ocean (http://www.nceas.ucsb.edu/globalmarine). The colors on this map reflect the value of a human impacts “index” in each area of the ocean. Ocean conservationists and managers can use this map to determine where effort needs to be focused in the ocean to minimize the negative effects of humans on the marine environment. The human impacts map was generated using four main steps:
- They gathered or generate maps of all types of human activities that have an impact on ecosystems in the oceans. They used maps of 17 different activities in the categories described above in the Human Impacts section. They also gathered maps of the distribution of various marine habitat types, including coral reefs, mangroves, kelp forests, and seagrasses.
- The quantified the sensitivity of each type of marine habitat to the activities listed above. For example, coral reefs are more sensitive to nutrient run-off than kelp forests are.
- They then overlaid the human impacts maps generated in step 1 onto the marine habitat distribution map, and used the vulnerability score to translate the threat of these human activities into a measure of the impact on the marine environment.
- They then used studies that have documented the state of marine ecosystems throughout the globe to “ground-truth” their estimates of human impacts. In other words, they checked whether the predicted state of a marine ecosystem matched the actual state of the ecosystem documented in previous studies.