We propose to evaluate the community and ecosystem consequences of black locust invasion within six study areas in the Albany Pine Bush Preserve (Figure 1). Since a sub-set of these areas will undergo extensive treatment to restore Karner Blue butterfly habitat (e.g., black locust removal, replanting with native species, restoring appropriate nitrogen content), these areas have been selected within the range of Karner Blue recovery identified by the Albany Pine Bush Preserve Commission and the New York State Karner Blue butterfly Recovery Team. Each area was chosen to include a defined stand of black locust at least 0.03 ha in size, with an adjacent stand of a relatively high quality variant of the Inland Pitch Pine -- Scrub Oak Barrens community that has not been invaded by black locust. Historical records and field observations (presence of barrens species, size class distribution of black locust and scrub oaks, presence of an invading front) indicate that the black locust stands have developed from the invasion of a contiguous barrens habitat and will represent independent pairs of invaded and non-invaded control stands. Within each stand, the plant community composition and structure, and other ecosystem properties will be characterized.