| Summary: | Seasonally, in 1998 and 1999, I examined spatial and temporal variation in
fish assemblages of agricultural, forested, and acid mine drainage tributaries within
the Wayne National Forest (WNF) in southern Ohio. Land use and natural
disturbance explained patterns in stream fish assemblages. Creek chub and green
sunfish were present in all land use types. Generally, with the exception of creek
chub and green sunfish, species most abundant in one land use type occurred
infrequently in the other land use types sampled. For example, redbelly dace and
blacknose dace dominated forested assemblages but rarely occurred in mining or
agricultural assemblages.
Agricultural sites consisted of higher order streams, located at lower
elevations with reduced canopy cover. Forested sites included intermittent streams
associated with higher elevation, low stream order, and high canopy cover. Acidic
conditions characterized mining sites, which otherwise remained physically similar
to forested sites. Stream order, elevation, and canopy cover explained the majority
of the variance in assemblage structure within 1998, and pH was also important. In
1999, water quality, specifically dissolved oxygen, and seasonal variation became
important. Assemblages changed following drought in 1999. Forested assemblages
remained most similar following drought, while agricultural assemblages exhibited
less similarity (i.e., greater variability). These results suggest that large-scale reach
characteristics and chemical signals related to land use are important to fish
assemblage structure, but in times of environmental fluctuation, water chemistry of
other site-specific variables may be of even greater importance due to physiological
tolerances and limitations of fishes. === Graduation date: 2002
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