USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research TopicsTropical Ecosystems

Watersheds, Wetlands, and Water in the Asia-Pacific

Mangrove forest in Micronesia
Mangrove forest in Micronesia.

We conduct research on the basic ecological, hydrological, and biogeochemical function in streams, mangroves, and freshwater swamps in Hawaiʻi, the U.S. Affiliated Pacific Islands, and other SE Asian countries along the Pacific Rim.

Focus areas include:

  1. Identifying conditions that support aquatic biodiversity and ecosystems services.
  2. Developing innovative approaches to reduce impacts of exotic species.
  3. Quantifying and predicting ecosystem responses and adaptation to environmental stressors.
  4. Developing models and tools, and evaluating management options for restoring, sustaining and enhancing ecosystem function and productivity.

Major Areas of Research

Working with key partners in each country, permanent mangrove plots have been established across the Asia-Pacific region and are being used to monitor effectiveness of conservation and restoration in climate change adaptation and mitigation, the vulnerability of mangroves to sea level rise, and the effectiveness of community-based management.

Forest Structure
Research field crew collecting soil cores in mangroves in Micronesia

Forest structure and biomass, carbon stocks, and sedimentation rates are measured from each plot and compared among different land use types. Mangrove forests have been shown to store 5-10x more carbon than upland forests, primarily in their water-logged sediments. While conservation is the best strategy for protecting mangrove forests and their carbon stocks, restoration of degraded mangroves appears to be effective after 25-30 years, when carbon stocks and biomass approach levels of intact mangrove forests.

Sea-level Rise
Research field crew collecting rod surface elevation tables (rSET) in the mangroves in Micronesia

Within each mangrove plot, tools such as rod surface elevation tables, 210Pb radionuclides, or ground based LiDAR are being used to track changes in the elevation of the mangrove forest floor, what factors influence mangrove forest floor elevation, and determine whether or not mangroves are keeping up with sea level rise (SLR). Healthy sediment loads, belowground root growth, and location (e.g., mangrove interior vs. mangrove fringe) have been determined to be important factors at maintaining the elevation of mangrove forests relative to SLR.

Long-term Monitoring
An endemic native Hawaiian shrimp, locally known as ‘Ōpae kala‘ole (Atyoida bisulcata), in a stream of Hawai’i Island.

Long-term monitoring sites have also been established in streams across a naturally occurring rainfall gradient on Hawaiʻi Island. Hydrological, ecological, and biogeochemical data are collected to examine how changes in rainfall will impact Pacific Island streams. Decreasing rainfall results in decreased stream flow, shifts in aquatic invertebrate community structure as well as food resources for native aquatic species, and decreased fitness of the native shrimp, Atyoida bisulcata.