PARENT SESSION
Poster Session 20: Invasive Species
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Spatial patterns of female Alianthus altissima across an urban -to-rural land use gradient in the mid-Atlantic region, USA.
Landenberger, Rick*,1, McGraw, James1, Warner, Timothy2, 1 West Virginia University, Morgantown, WV, USA2 West Virginia University, Morgantown, WV, USA
ABSTRACT- Analysis of the spatial distribution and abundance of an invasive plant species can help in identifying the factors that influence important demographic rates including seed dispersal, germination, survival, and fecundity. Furthermore, by focusing on the location and abundance of reproductive members of the population, estimates of future population patterns become possible. When spatial patterns of individuals are described in combination with environmental features such as land use type, slope, aspect, and elevation, it is possible to generate hypotheses about specific biotic and abiotic factors that shape the spatial structure of these populations. Ailanthus altissima (tree of heaven) is a highly invasive tree that is increasingly common at the interface between urban and rural areas in the mid-Atlantic region, where it is poised to invade relatively natural, intact forest stands. To examine spatial patterns of abundance and to generate hypotheses concerning possible future patterns of invasion, we mapped all mature female trees in nine 85 ha plots across a typical urban-rural land use gradient using both high resolution aerial photography and complete ground searches. Rural plots were dominated by intact native forest and had the lowest density of mature females (0.01 females ha-1,), while urban plots had the highest density (0.38 females ha-1) (0.29 females ha-1 in suburban plots). Individuals in urban plots were more evenly distributed, were associated with a wider variety of land uses, and were less likely to occur along roads than those in suburban and rural plots. These patterns suggest that Ailanthus has a relatively mature presence in the urban environment, and has occupied much of its available habitat under current land use conditions. Because of its close proximity to road corridors in the suburban environment, Ailanthus appears to be poised to spread into the suburban-rural interface, areas that are currently experiencing significant changes in land use as human population pressures increase in this rapidly growing region.
Key words: invasive species, GIS, remote sensing