PARENT SESSION
Poster Session #4: Invasions.
Monday, August 6, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall
116
A comparison of soil chemistry in recovering serpentine grassland and Virginia pine forest .
Derrickson, Elissa1, MacLellan, Megan1, Norden, Kim1, O'Sullivan, Anthony 1, Desjardins, Philip 1, 1
ABSTRACT- Maryland serpentine grassland is a habitat with rare endemic species that are threatened by the invasion of Pinus virginiana. It has been hypothesized that P. virginiana can alter the chemistry of the soil and facilitate succession of serpentine grassland to pine forest. We began to address this hypothesis by measuring soil chemistry and P. virginiana density along a transect passing from forest into serpentine grassland which had been recently cleared of P. virginiana. We counted P. virginiana seedlings in four 1m by lm quadrats at four sites along four 30m transects. The density of seedlings was higher within the forest compared to the grassland. Soil samples were taken from two of the quadrats at each site and were analyzed for soil particle size and for levels of ammonia, nitrate, nitrite, potassium, phosphorous, magnesium, calcium, iron, and pH. Recently cleared sites differed significantly from forest sites in pH, soil particle size, magnesium, iron, and soil nitrogen. Soil in areas of the recovering grassland which contained 6-11 P. virginiana seedlings/quadrat was significantly more acidic than soil within adjacent grassland quadrats which contained no seedlings. Additional work will allow us to compare these results to those obtained from grassland sites that have not experienced invasion by P. virginiana.
KEY WORDS: Pinus virginiana, serpentine