Geoscience Reference
In-Depth Information
Chapter 10
Utilizing Secondary and Public Data
to Examine Relationships Between Watershed
Land Cover and Biotic Integrity
in the Lake Erie Tributaries
Kari A. Gerwin and Patrick L. Lawrence
Abstract Since the late nineteenth century draining of the Great Black Swamp, the
watersheds of the Lake Erie Direct Tributaries (the Tribs) in Northwest Ohio have
undergone massive agricultural development and patchy residential and urban
growth. Landscapes of these watersheds are currently dominated by large plots of
homogeneous cultivated land with patches of urban and residential development
and minimal amounts of forest. The effects of intensive agricultural land use and
drainage modifications are reflected in the Tribs' degraded fish communities and
loss of riparian habitat. This study attempted to identify the relationships between
fish community quality, habitat quality, and land cover variables using secondary
data collected from 1993 to 1996 by the Ohio Environmental Protection Agency
(OEPA) and a maximum likelihood land cover classification of Landsat Thematic
Mapper (TM) imagery. Multiple regression analyses indicated that agriculture is a
significant predictor of fish community quality and habitat quality in the Tribs.
However, as this area continues to develop residential and urban land cover types
may play a larger role in stream quality.
Keywords Watershed • Fish communities • Habitat quality • Land cover
10.1
Introduction
Present landscapes in developed regions of the world are highly fragmented
and dominated by agricultural, urban and residential development. The effects of
land development are reflected in the water quality and biotic communities of rivers
and streams. Sedimentation, altered temperature regimes, toxicity and nutrient enrich-
ment have had deleterious impacts on overall stream ecosystem health and limit the
