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Forested Coastal Wetland Displacement in the 21st Century Driven by Saltwater Intrusion as Consequence of Rising Sea-level

Photo of Forested coastal wetland dominated by Pterocarpus officinalis, in the north coast of Puerto
Rico.


Forested coastal wetland dominated by Pterocarpus officinalis, in the north coast of Puerto Rico. Snapshot : Coastal wetlands are facing challenges to their persistence due to accelerated sea-level rise, limited and fragmented coastal lands for migration, and modified surface freshwater flows. Accelerated sea-level rise in the Caribbean is affecting coastal wetlands due to saltwater intrusion, which has a significant negative effect on recruitment of new trees.

Principal Investigators(s) :
Heartsill Scalley, Tamara 
Research Location : Puerto Rico
Research Station : International Institute of Tropical Forestry (IITF)
Year : 2019
Highlight ID : 1533

Summary

Coastal wetlands are shrinking rapidly due to land-use activities. Accelerated sea-level rise is also affecting coastal wetlands, particularly in islands with limited coastal plains. USDA Forest Service scientists analyzed coastal wetland changes in Puerto Rico by applying the Sea Level Affecting Marshes Model under two scenarios by 2100. They also analyzed mortality and recruitment in a freshwater swamp dominated by the tree Pterocarpus officinalis Jacq. in the context of landscape saltwater intrusion and drought. Their results indicate mangroves and estuarine water would replace the areas currently covered by other saltwater and freshwater wetlands, and found that saltmarsh would encounter the most relative loss among wetland types. A moderate sea-level rise of 1 meter (1.09 yard) by 2100 allows expansion of mangroves but would decrease saltmarsh and freshwater wetlands. A 2-meter (2.18 yards) sea level rise would decrease the distributions of all vegetated wetlands, mostly replaced by estuarine water. In freshwater swamp forests, saltwater intrusion and drought increased tree mortality during 2003–2015 compared to the previous study period of 1994–2003. Saltwater intrusion had a significant negative effect on tree recruitment, more than on tree mortality. Coastal wetlands are facing challenges to their persistence at current locations due to accelerated sea-level rise, which brings saltwater intrusion and is in turn compounded by fragmented coastal lands and modified surface freshwater flows.

Forest Service Partners

External Partners

 
  • University of Puerto Rico