Predator-prey interactions in a benthic stream community: a field test of flow-mediated refuges.

摘要: Ecological theory suggests that the impact of predation can be strongly modified by existence regions environment in which prey are less accessible to predators, underscores need for empirical studies examining factors influencing availability and importance such refuges. Our study tested whether benthic microhabitats with high flows provide suspension-feeding larval black flies (Simulium␣vittatum) a spatial refuge negative predatory flatworms (Dugesia dorotocephala) is reduced. We conducted short-term field experiment Chester Creek (southeastern Pennsylvania, United States) examine how number fly larvae inhabiting tile substrates responded manipulated variations flatworm abundance current speed. The declined increasing speed, thereby creating potential sites from these predators. Multiple regression analysis revealed final exhibited significant relationship positive After adjusting elapsed time initial abundance, flow predators explained 38% variation rate change abundance. correlation between had two components: positive, direct effect on larvae, arises because food-limited consumers prefer reside within faster where they feed at higher rates; combine yield indirect larvae. This demonstrates flow-mediated refuges (i.e., reduced due flows), although accounts small proportion total A consideration biomechanical relationships likely create wide range freshwater marine environments. In particular, will often experience greater dislodgement forces than their larger size project farther above bed speeds faster. Moreover, ability resist given force may many prey, especially those sessile or semi- sessile.