NOAA Seeks Remedy for Invasive Tree Species Threat to California Salt Water Marsh

NOAA SEEKS REMEDY FOR INVASIVE TREE SPECIES THREAT
TO CALIFORNIA SALT WATER MARSH

Researchers from the National Oceanic and Atmospheric Administration’s National Estuarine Research Reserves are investigating an invasive newly discovered tree in southern California salt marshes. The NERR is also looking into ways to fight its spread and eliminate its presence to protect the native habitat. NOAA is an agency of the U.S. Department of Commerce.

Although research has been devoted to the tree’s invasion of fresh water and riparian areas, its adaptation to salt water and consequent invasion into the salt marsh is beginning to attract attention of the management and science communities.

“This project is an excellent example of how NOAA research is of direct relevance to coastal management,” states Richard Spinrad, assistant administrator of NOAA’s National Ocean Service, which implements NERR. “Here we have NOAA collaborating with academic and community partners to work through an invasive species issue that has the potential of changing an ecosystem. It is actually a wonderful illustration of adaptive management.”

This new project funded by NOAA Sea Grant studies the tree’s ability to adapt to the salt-water environment and examines the different methods being used in an existing eradication plan carried out by local officials. Research and monitoring will identify the most effective restoration strategies and feed that information back into the management community to improve the success of removal efforts.

“The lessons learned from this work can be applied to existing and future invasion threats in our NERR sites, and the insights gained into mechanisms of effect and efficacy of eradication will inform stewardship strategies in many habitats,” said Drew Talley, Ph.D., research coordinator for the NOAA’s San Francisco Bay NERR and primary investigator for this project.

Learning more about this invasive tree is important because of its potential to change the physical structure and food web of southern California’s salt marsh habitats. These wetland areas, characterized by 1.5-foot pickleweed marsh, are transforming into forests of tamarisk trees over 9 feet high. These invaders could interfere with the amount of sunlight that reaches the sediment, and leaves falling from the trees have the potential to change the chemistry of the soil. It might also be impacting bird interactions, including threatened and endangered species. For example, the trees may provide perches for hawks, which prey on the endangered Clapper rail.

Researchers hope to clarify how the tamarisk invaded the salt marsh. According to Talley, it may have been through seeds dispersed by the wind or downstream through the river valley system. The researchers are looking at tree ring slices to find any association with flood events.

Talley and research partner Jeff Crooks, Ph.D., research coordinator at NOAA’s Tijuana River NERR, are using old aerial photography and satellite imagery and doing innovative work with geographic information systems to learn more about how and when this tree invaded the reserve. The research is taking place within the Tijuana River NERR and is funded for the next two years.

NOAA’s National Ocean Service balances environmental protection with economic prosperity in fulfilling its mission of promoting safe navigation, supporting coastal communities, sustaining coastal habitats and mitigating coastal hazards.

NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of our nation’s coastal and marine resources.