Ecological Factors Influencing Movement of Creek Chub in An Intermittent Headwater Stream of the Ozark Mountains, Arkansas

Headwater streams are numerous, highly stochastic, and important for maintaining ecological processes in river networks.  Projected effects of climate change include more intermittent and less predictable hydrologic regimes in headwater streams.  We describe movement patterns of creek chub, Semotilus atromaculatus, adapted to intermittent stream conditions and evaluate the factors influencing movement using mark-recapture methods.  There was a significant difference in standard length between resident and mobile creek chub in March (two-sample t-test; d.f. = 55, t = 2.581, P = 0.013) and May (d.f. = 68, t = 4.622, P < 0.001; Table 2), with larger individuals being more mobile.  Standard length of mobile creek chub was not associated with distance moved for any mark-recapture sample.  Directional movement was significant only in the May mark-recapture sample with more individuals moving upstream than downstream (t = 3.02, P = 0.004).  The probability of movement from a pool was negatively correlated with increased habitat complexity and pool area (β = -0.44, P < 0.001 and β = -0.23, P = 0.002, respectively).  Understanding the biological processes and associated factors that govern population dynamics will enhance our knowledge of how species may respond and adapt to increased intermittency in headwater streams.