The effect of floods on stream invertebrates has been the topic of a number of studies by stream ecologists. Rapid re- establishment of populations following extreme floods is common yet we do not understand the mechanisms responsible for this recovery. This pilot project will begin to test the hypothesis that debris dams lessen the detrimental effect of floods on stream meiofauna and that the effect of these mitigating patches (dam) will be greatest for those species with slowest reproductive rates. Start up funds will be used to begin work to determine if faunal reproduction is rapid enough to account for recovery of populations following floods. Additional development time will be invested in determining if the high abundances of fauna near debris dams are linked to flood events. This study will begin to provide data on the mechanisms determining which species of stream invertebrates persist at a given locale over time, and pave the way for longer project which will experimentally examine the interplay of dispersal, reproduction and patch dynamics.