| With emphasis on sustainable ecosystem management, ecological mapping at landscape scale provides basic information about the nature and distribution of ecosystems for natural resources management, planning, monitoring and assessment. Landtype association (LTA) and ecological landtype (ELT) are two landscape scales of ecological units in a hierarchical ecological classification system developed by the USDA-Forest Service for use in ecosystem management. LTA is a complex of complementary landscape components (ecological landtypes) that combine through spatial adjacency to create ecological contrasts across regions. ELT is a subdivision of LTA unit based on similarities in landform, soils, geomorphic processes, and plant associations. The goal of this study is to develop, describe and verify a scientifically based system of map units for Pennsylvania that incorporates ecological principles and processes across landtype association and ecological landtype scales.;At the LTA level, the influences of topography and terrain topology on ecosystem distributions motivated an ecological mapping approach with the concern for ecological, hydrologic and environmental aspects of the area that separates LTA units into three major categories, as highland habitat (HH), transitional terrace (TT), and dual drainage (DD). Highland habitat is designated as being primarily headwater stream areas composed of mounding or arching to level upper land surfaces. Dual drainage is designated to be areas having both large streams and small tributary streams. Transitional terrace is intermediate level elevated terrain unit that is otherwise similar to highland habitat, but also receives some hydrologic influx from adjacent upland along partial margin. A GIS-assisted, top-down classification method was adopted in the mapping procedure, and produced 10,782 LTA units delineated across the state with size ranging from 100 to 5,000 acres. These units were classified into eighteen subtypes according to their topographic and hydrologic characteristics. (Abstract shortened by UMI.). |
