Huebner, Cynthia .
Estimated Spread Rates and Population Growth of Microstegium vimineum (Trin.) A. Camus (Japanese Stiltgrass) from Roadside Populations into West Virginia Forests over Three Years.
Roadside populations of Microstegium vimineum (MV) adjacent to closed canopy forests in West Virginia were monitored for three years to estimate spread rates and population growth. MV is a shade tolerant, invasive, exotic grass. Five populations were monitored in the Ridge and Valley Province (RV), five in the Allegheny Plateau Province in Tucker County (Tucker) and six in Preston County (Preston) of the same province. Both Tucker and Preston are more mesic than RV. Patches (1 m2 or less in size) of MV were counted within a 30-m X 50-m area (1500 potentially colonized patches). The invasive front for each year was determined using two transects and measuring the distance at which MV patches were no longer contiguous along these transects. Patch colonization and extinction rates were not constant over time, and extinction rates did not differ significantly among the three areas. Tucker populations had significantly higher colonization rates than RV populations in 2006. The front line was significantly further from the roadside in the RV populations than the Tucker populations in all three years and the Preston populations in 2007. However, the RV populations had the lowest net reproductive rate (R0), with some populations showing a negative rate. Tucker populations had a significantly faster R0 than both Preston and RV populations from 2005 to 2006. Using R0(2005-2006) to estimate the intrinsic rate of growth, complete colonization would be expected in 12.0 and 11.1 years for the Preston and Tucker populations, respectively, and saturation of the patches would never occur for the RV populations. These results suggest that MV populations in drier regions may spread primarily along its front but grow at a slow rate with few disconnected patches. In contrast, the populations in the mesic sites tend to grow at a more rapid rate via more abundant, disconnected patches.
Log in to add this item to your schedule
1 - Northern Research Station, USDA Forest Service, 180 Canfield St., Morgantown, WV, 26505, USA
plant population biology.
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM