Mangrove Enhancement as a Climate Change Adaptation Strategy in the Republic of the Marshall Islands (RMI).
Potential Ecosystem Service Shifts Following Colonization.
The ability of Small Island Developing States (SIDS) and Pacific Island communities to adapt to the increasing sea-levels, storm surge, saltwater intrusion, and other threats posed by global climate change is critical to the survival of many of these local communities as well as their cultures. One of the world’s most striking examples of a nation at great risk is the Republic of the Marshall Islands (RMI) in the central Pacific Ocean. Due to a combination of factors, including the country’s extremely low elevation above sea-level (an average of 2 meters) and lack of adequate structures to provide safety during extreme weather events, the RMI is expected to be severely impacted by the increased frequency and intensity of floods, droughts, coastal erosion, and elevated sea surface levels and temperatures predicted from global climate change models (IPCC, 2014).
The broad objectives of this project are to 1) collect and review some of the most up-to-date scientific knowledge regarding the potential effects of introducing mangrove trees in local communities and ecosystems from around the globe and 2) to assist the Republic of the Marshall Islands in developing climate change adaptation (and natural resource management) strategies for the 21 st century. The standard ecosystem services framework (provisioning, regulating, supporting, and cultural ecosystem services) from the Millennium Ecosystem Assessment (MEA, 2005) is applied to discuss the potential environmental changes brought about by mangrove introductions.
The first specific goal of this project is to provide an evaluation of potential impacts and benefits associated with mangrove introductions by examining their influences in regions where mangroves are historically present versus historically absent. The scientific literature indicates a clear distinction between these case studies. Introduction of mangroves into regions where other mangrove species already exist (Similar Species Introductions) tends enhance pre-existing mangrove related ecosystem services. Conversely, Exotic Species Introductions of mangroves into regions lacking shoreline vascular plants like mangroves tends to have more negative impacts on local communities and ecosystems. This apparent distinction is used as a foundation for much of the future scenario discussions in this paper.
The second major goal of this project is to examine how mangrove introductions in the Republic of the Marshall Islands, specifically, may affect local ecosystem services. Only the 5 historically occurring mangrove species present in the RMI are recommended to be used in mangrove introduction efforts into new habitats/islands within the RMI.
However, care must be taken when generalizing any location-specific impacts. Therefore the third goal of this project is to examine how several key ecological theories can help synthesize global lessons and guide future scientific research. Knowledge gaps in the fields of island biogeography, population genetics, invasive species ecology, etc. are highlighted as ways to advance basic science and provide baseline data for future comparative research.
The final goal of this project is to recommend specific actions to the Republic of the Marshall Islands regarding the introduction of mangroves as a strategy to combat the effects of climate change. This section of the report explores the likely changes to ecosystem services and the precautions to be heeded when introducing mangroves to outer atolls in the RMI.