| Summary: | The community structure of stream communities are treated as bioassays of stream
ecosystems and changes to species patterns within those communities reflect response to
multiple stressors including natural fluctuations in environmental variables. Research has
focused on the structure of fish assemblages and there is increasing interest in
environmental factors structuring turtle communities. Both fishes and turtles can be
sampled using common methods, but are rarely studied together. Our objective was to
compare distribution of fish and turtle species based on measured environmental variables
in East Texas, USA. Species distributions were influenced by flow, substrate, and emergent
vegetation. Results from Monte Carlo permutation tests suggest that downed woody debris
and water temperature also had a strong influence on species distributions.
Co-correspondence analysis showed considerable overlap of species scores in the absence of
environmental variables. The five macrohabitats sampled exhibited varying degrees of
connectivity and thus species mixing, which is driven by annual fluctuations in
precipitation. Results from this study suggest that turtles and fishes can be considered
simultaneously and exhibit similar patterns of species distribution across the landscape,
at least at local scales.
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