Protecting Eelgrass and Blue Carbon ecosystems

Eelgrass ecosystems may rival rainforests in terms of their carbon sequestration abilities, despite their much smaller relative size. However, they are in widespread decline due to a myriad of anthropogenically driven changes. Loss of “blue carbon” ecosystems represent a reduction in the carbon sink and a source of carbon emissions to the atmosphere that are not currently accounted for. It also represents a loss of critical habitats for a number of marine and coastal species, reduced natural coastal defences and the many other significant services that these ecosystems provide. Anthropogenically driven changes do not act in isolation but are cumulative and synergistic. Furthermore eelgrass is an ecosystem engineer, so drivers of change and ecosystem responses form complex feedback loops creating bistability in ecosystems and unpredictable non-linear responses to threats. The complexity of these interactions is a challenge for quantification of threats and ecosystem responses. This has so far hamstrung efforts to calculate the impact on the global carbon budget, and ultimately to protect and restore these ecosystems. While largely qualitative in nature, systems analyses can help us to identify the most pervasive anthropogenic impacts (those which affect eelgrass in the greatest number of ways), and potentially synergistic and ameliorative relationships between drivers and consequences. This can help us to better assess levels of risk and priorities for conservation. Such analyses suggest that threats to eelgrass ecosystems cannot be considered in isolation and must be addressed simultaneously, and offer practical recommendations including that equal efforts must be made to restore adjacent saltmarsh and riparian ecosystems. To adequately protect eelgrass full, spatial protection of healthy eelgrass ecosystems and the adjacent foreshore is recommended