ECOLOGY AND ENVIRONMENTAL SCIENCE
The seasonal use of microhabitats by invertebrate fauna associated with an ephemeral stream
in southeastern Kentucky. DANIEL DOUGLAS* and AMY BRACCIA, Department of Biological
Sciences, Eastern Kentucky University, Richmond, KY 40475.
Ephemeral streams are typically regarded as those streams that flow during and shortly after
precipitation events and carry water for a small portion of the year. Because of the unpredictable flow
rate, these streams can be variable in terms of biotic and abiotic parameters and they often present
many invertebrate taxa with a wide range of habitats. Although there have been studies of the aquatic
invertebrate fauna from these streams, few studies have focused on the invertebrate fauna during dry
periods. The primary objective of this study is to determine the seasonal use of microhabitats
(undersides of cobble, moss covered bedrock, and mixed substrates) by the invertebrate fauna in an
ephemeral channel of an old-growth forest in southeastern Kentucky. We hypothesized that during dry
periods, these channels serve as refugia for terrestrial and aquatic taxa. We established a 30 m
representative reach along the channel and sampled seasonally starting in August 2011 and ending in
June 2012. An Onset state logger was used to determine when the channel held water. Preliminary
results from mixed substrate samples show no significant differences among abundance and taxa
richness among seasons, however it appears that this habitat supports the greatest abundance and
highest richness of invertebrates compared to moss and cobble. Taxa present throughout the year were
found to be both aquatic and semi-aquatic, and the fauna was dominated by tubificid worms. Our
findings suggest that mixed substrates in this ephemeral channel provide habitat for a diverse fauna
even during dry periods.