PARENT SESSION
Poster Session 3: Aquatic Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 210 D, Level 2, Palais des congrès de Montréal
Habitat influences on arthropod abundance and diversity in Connecticut salt marshes.
Schaumburg, Kristin1, Langellotto, Gail1, Giuliano , William, 1 Louis Calder Biological Field Station, Armonk, NY, USA
ABSTRACT- The plant community of Connecticut salt marshes has been severely altered in the last few decades due to the proliferation of the invasive species, Phragmites australis. Areas dominated by saltmeadow hay (Spartina patens) and salt grass (Distichlis spicata) are becoming diminished as Phragmites spreads throughout coastal habitats. Such large scale changes in the plant community no doubt influence the community structure of higher trophic levels. To assess the extent to which Phragmites invasion has impacted arthropod communities, we determined the abundance and diversity of arthropods on 20 salt marshes in Connecticut between April and August of 2003. Both grazing and detritivorous arthropods were collected using a vacuum suction-sampler and a soil corer. Specimens were sorted and counted in the lab, where they were identified at least to the level of family. Habitats were classified according to the percent cover of vegetation (Phragmites, S. patens, D. spicata, other) intercepted along two 50-meter transects located adjacent to arthropod sampling sites. We predicted that arthropod community composition between habitats dominated by native plants versus Phragmites would significantly differ at both the second and third trophic levels. Where Phragmites was prevalent, detritivorous flies and crustaceans were prominent members of the arthropod community and herbivorous insects such as planthoppers were rare. Where S. patens and D. spicata were prevalent, arthropod community composition was more diverse for both taxonomic family and ecological guild. These results suggest that the invasion of Connecticut marshes by Phragmites is having profound effects on the diversity and abundance of arthropod detritivores, herbivores, predators and parasitoids. Furthermore, these results suggest that a fundamental shift in food web structure is occurring on CT salt marshes as a result of Phragmites invasion.
Key words: phragmites australis, spartina patens, arthropods, diversity