Ecological Heterogeneity In Reference Catchments Of The Baltimore Ecosystem Study: Progress Toward Patch Dynamics (presentation)
PICKETT, S.T.A.*, M.L. Cadenasso, L.E. Band, D. Tenenbaum, W.C. Zipperer.
The conceptual framework underlying the Baltimore Ecosystem Study relates spatial heterogeneity to human ecosystem processes. The first two of the three main questions driving the BES require the quantification of spatial heterogeneity in the four reference catchments of Oregon Ridge, McDonogh, Glyndon, and Rognel Heights. Our research will answer the two specific questions. 1) What structurally defined patches exist in each catchment? 2) What are the elements of heterogeneity in each catchment and how are those elements arranged? To delimit ecologically relevant patch types consisting of both built and natural covers, we will use 1 m resolution, false color infrared, leaf-on imagery from 1998. To quantify heterogeneity, we will use a program developed by Tenenbaum and Band to sample randomly arrayed, 100 m-long transects at a ratio of 1 transect/ha. This approach will provide a sample unbiased with respect to topography or infrastructural grids. Specific cover elements will be assessed for total amount, size of individual elements, adjacencies, and nature of edges. The patch delimitation and transect sampling will be repeated on imagery form different time periods. The quantification of heterogeneity is readily related through correlation, aggregation, or subdivision using relevant criteria to socio-cultural, hydrological, and soils components of the Baltimore ecosystem. The cover sample will be complemented by future ground based samples across the patch types delimited.