Klemow, Kenneth M. 2004. PATTERNS OF NATIVE AND ALIEN PLANT SPECIES IN TWO WATERSHEDS IMPACTED BY ANTHRACITE MINING AND URBANIZATION. Contributed poster: Pennsylvania Academy of Science meeting. Abstract: Journal of the Pennsylvania Academy of Science 77:137.
Considerable interest has recently been focused on the role that human impact plays on promoting the establishment and spread of invasive alien species in ecosystems worldwide. To understand how mining and urbanization effect an increase in alien species, a detailed assessment of vegetation within 27 communities throughout two watersheds in northeastern Pennsylvania was conducted in 2001. Patterns of native and alien species were determined in each community to understand the degree to which alien species benefit from disturbance, and whether some strata are more impacted by aliens than others. Communities located on the mountain slopes fringing each watershed have not been subject to human disturbance since the early 1900s, and the plant communities there had low proportions (<5% cover) of alien species. In contrast, communities impacted by urbanization showed much higher (>60% total cover) dominance by aliens. Alien species were particularly well represented in herb and shrub layers, much less so among saplings and trees. Communities recovering from surface mining were dominated by stress-tolerant species that were largely native to Pennsylvania. The implications of these findings vis a vis efforts to promote regional biodiversity of native species in human-impacted ecoystems will be discussed.