Assessing risk from current and future pressures on seagrass habitat – a nation-wide spatially explicit approach

Seagrass habitat provides many significant ecosystem services such as primary production and carbon storage. Yet, it is threatened due to human activities and globally is declining. Highlighting hotspots of risk for seagrass... [ view full abstract ]

Seagrass habitat provides many significant ecosystem services such as primary production and carbon storage. Yet, it is threatened due to human activities and globally is declining. Highlighting hotspots of risk for seagrass habitat is an important and useful tool for management, as it supports decision making on where and what threats to focus the management effort on. This project assessed risk to seagrass habitat at a nation-wide scale, using Australia as a case-study. Firstly, we generated an Australia wide potential seagrass habitat map (10 x 10 km grid size) by combining as many different sources of habitat data as possible. Then we identified 12 threats due to current human activities and 3 due to future climate change predictions. We attempted to collate spatially explicit layers for each threat, and were successful in generating 7/12 current and 3 future threats. Finding appropriate variables to reflect the threat at the national scale was challenging. In some cases, we combined a number of variables from different sources to generate the risk layers. For each threat, we categorized the risk into low, moderate and high, and in some cases were able to assign a spatially explicit level of certainty. We then weighted each risk and ran a cumulative risk-analysis for both current, and future threats. Under current conditions, there are hotspots of cumulative high risk in all coastal states and territories of Australia. When assessing future risk, southern Queensland and NSW, as well as the Gulf of Carpentaria in NT were the hotspots of high risk. With this information, we can prioritise management on a national scale to help make decisions on the most effective way to manage seagrass habitat. This approach and risk layers can also be translated to other habitats if the nation-wide habitat maps exist.