Habitat selection in stream-dwelling cyprinids:

Amanda M. Barmore and Christopher L. Higgins

Streams of the southwestern United States are subject to a wide array of environmental factors ranging from severe droughts to flash flooding.  In addition, many of these streams are faced with environmental perturbations due to anthropogenic modifications, such as the construction of reservoirs and current practices in the agriculture industry.  Stream fish are capable of responding to environmental perturbations by voluntarily selecting a different habitat within the stream where the conditions may be more suited for their survival and reproduction.  This process is believed to be ones of the most important ecological processes leading to the coexistence of similar species.  Most of the previous studies used exploratory statistics and field observations to identify the environmental variables or ecological factors that were most strongly correlated with habitat selection.  This approach is limiting because it does not allow a researcher to delineate the governing principles of habitat selection nor does it allow for the detection of habitat preferences.  Therefore, we are using a combination of laboratory experiments and field observations to identify habitat preferences and to delineate the factors involved in habitat selection.  More specifically, our study addresses the following questions: (1) What environmental factors do stream-dwelling cyprinids actively prefer when isolated in a laboratory setting? (2) Is habitat selection density dependent? (3) If so, at what density do biotic factors override abiotic preferences? (4) Can habitat selection observed in the field be predicted from data obtained in the laboratory?