Enhancing Coral Reef Resilience
Hawai‘i’s first statewide bleaching event in 2015 resulted in up to a 90% loss in live coral cover in some parts of West Hawai‘i. With more severe and frequent bleaching predicted in the years ahead, TNC has been surveying coral colonies at 40 West Hawai‘i sites to identify the reefs most likely to survive a warming ocean so that we can implement management actions to help them adapt to climate change.
In 2018, our third year of surveys confirmed that the most resilient reefs are in areas with limited shoreline access and exposure to human impacts. Guided by this information, TNC will be working with the State and community partners to develop management actions that preserve the most intact reefs and enhance resilience at more degraded sites. Our science also showed that deep water reefs are less likely to be refuges for species impacted in shallow areas, thus highlighting the importance of effectively managing shallow areas.
Globally, efforts to curb climate change are focused on reducing the use of fossil fuels. Carbon emissions also can be dramatically reduced through forest conservation and management. Trees have the greatest potential to reduce emissions because they absorb and sequester carbon dioxide as they grow, removing it from the atmosphere. Reforestation and better forest management on a global scale could remove seven billion tons of carbon emissions annually by 2030, equivalent to taking 1.5 billion gasoline-burning cars off the roads.
In Hawai‘i, TNC began working with national carbon experts to assess forest growth and sequestration rates at one of our Hawai‘i Island preserves. This analysis is an important step toward our next goal of establishing a pilot carbon sequestration project to serve as a model for other Hawai‘i landowners.
Saving Coral Atolls
With coastal erosion, sea-level rise and other impacts intensifying, low-lying coral islands like Palmyra are on the front line of global climate change. TNC’s Palmyra Atoll Rainforest and Reef Resilience Project aims to provide other Pacific atolls with a model for reducing such impacts.
Here's how it works: Palmyra’s rainforest and surrounding coral reefs are interdependent ecosystems. The rainforest is preferred nesting habitat for hundreds of thousands of seabirds, which deposit guano that enriches the soil. The guano is then flushed into the ocean by rain, delivering important nutrients that increase the resilience of the atoll’s coral reefs.
Palmyra’s rainforest once dominated the atoll, but copra farming, black rats and deforestation by the U.S. military during World War II reduced it to a few patches. In its stead are thick groves of introduced coconut palms ill-suited for seabirds. Rats were eradicated from Palmyra in 2011, igniting a resurgence of native bird and plant life. A major native rainforest restoration project is underway. When completed, it will flip forest dominance and restore ecological balance to the atoll, maximizing the seabird-driven nutrient cycle and increasing terrestrial and marine ecosystem resilience to climate change impacts.