PARENT SESSION
Symposium 6: Anthropogenic Modification of North American Salt Marshes: Causes, Consequences and Recommendations
Organized by: B Silliman
Tuesday, August 5. 8:00 AM to 11:30 AM, SITCC Chatham Ballroom C.

A historical perspective on a cryptic invasion: Phragmites australis.

Saltonstall, Kristin^*,1, ¹ University of Maryland Center for Environmental Science, Cambridge, MD, USA

ABSTRACT- Over the past century, one of the most conspicuous changes to marshes along the Atlantic coast is the rapid spread of Phragmites australis. While native to these communities over much of this range, evidence suggests that the widespread invasions of this species are due to the introduction of a EurAsian lineage of Phragmites which has both outcompeted native populations of the species as well as moved into sites where it was not found historically. Native populations persist in some sites but little is known about their ecology and whether or not they will be able to compete with introduced populations. Clear determinations of human influences on this invasion are elusive, however it is apparent that substrate disturbance, alterations in hydrology, and nutrient inputs facilitate establishment and spread of the introduced lineage. Today introduced Phragmites is the dominant macrophyte in many intertidal environments and is considered poor habitat by many due to its high standing biomass and ability to rapidly accrete sediments thus altering marsh hydrology. Such characteristics may prove valuable however in the face of sea level rise and recurrent nutrient inputs due to coastal development.

Key words: invasive, Phragmites australis, wetlands