Geoscience Reference
In-Depth Information
ability of streams to sustain healthy and diverse fish populations. These effects can be
seen even in relatively rural landscapes such as the Lake Erie direct tributaries
watersheds (the Tribs), within the of the Maumee Area of Concern (AOC) in North-
west Ohio. A 1993-1996 statewide biological and habitat sampling project conducted
by Ohio Environmental Protection Agency (OEPA) revealed that all but 2 of the 27
sites sampled in the Tribs had poor to very poor biological integrity according to the
Index of Biotic Integrity (IBI) (OEPA
1988
). In addition, all of the sites fall below
targeted habitat quality as measured by the Qualitative Habitat Evaluation Index
(QHEI.) These scores are considerably lower than the targets set by the International
Joint Commission (IJC) and the OEPA (OEPA
2005
). In fact, biotic integrity and
habitat quality scores in the Lake Erie Tributaries are generally lower than the scores
for the more urbanized watersheds in the Maumee AOC (MRAP
2006
). In an area
without historically high levels of industrial use and urbanization, this brings to
question the factors driving the poor aquatic health of the Tribs.
Using secondary and public data, this study merged a variety of GIS, database and
statistical tools in an attempt to identify the watershed land cover types that influence
the biotic integrity of fish communities in the Lake Erie Tribs. IBI is a multi-metric
index that assesses a stream's ability to support healthy fish populations. The metric
weights fish species collected along various stream reaches according to their
pollution tolerance as well as their richness, trophic functions, reproductive
functions, abundance and deformities (OEPA
1988
). Fish communities can be
impacted at the local scale by habitat modification and at a larger scale by activities
within the drainage basin that input pollutants (chemicals, nutrients, sediments) and
alter temperature regimes. Watershed modifications can cause changes in the trophic
structure of a stream (Karr
1981
), reduce species diversity (Snyder et al.
2003
;
Robinson et al.
2002
; Roy et al.
2003
) and in extreme cases of toxicity may cause a
decrease in biomass (Karr
1981
). Due to their sensitivity to watershed activities, and
because they represent the top of the aquatic food web, fish communities are an ideal
subject when attempting to quantify the effects of land use on aquatic systems.
10.2 Study Area
The Lake Erie Tributaries are a collection of four individual creeks located east
of the Maumee watershed in northwest Ohio and drain directly into western Lake
Erie (Fig.
10.1
). Prior to the mid- 1800s, the area was part of the system of wetlands,
forests and grasslands known as the Great Black Swamp. Beginning in the mid-
nineteenth century the area was extensively channelized and deforested to allow
for settlement and crop cultivation. By the early 1900s most of the swampland had
been drained with only a handful of remnant forests and wetlands existing today
as evidence of the Tribs' rich natural history (Kaatz
1955
). The current landscape
is dominated by large plots of homogeneous cultivated land with patches of urban
and residential development and minimal amounts of forest.
The study area includes first through third order streams Wolf Creek, Cedar Creek,
Crane Creek and Turtle Creek and encompasses portions of Lucas, Wood and Ottawa
