Disturbance frequency and functional identity mediate ecosystem processes in prairie streams

Direct and indirect effects of central stoneroller (Campostoma anomalum) on mesocosm recovery following a flood: can macroconsumers affect denitrification?

“…Our study is one of the first to separate the effects of grazing caused by N remineralization from other grazing mechanisms (but see Knoll et al 2009), and it adds to the growing body of evidence that macroconsumers shape prairie stream recovery (Bertrand et al 2009). In addition, ours is the first study to analyze the effect of a macroconsumer on denitrification in a lotic system.…”

“…The mesocosms were then drained and immediately refilled. Scouring removed most organic matter accumulated over the 1-wk colonization period, homogenized biomass of algal and macroinvertebrate communities across mesocosms, and had effects similar to scouring floods in nearby streams (Bertrand et al 2009). After scouring, plastic-mesh baskets (5.5 3 10 3 10 cm, 2 3 1.25-cm mesh) were filled with dry rocks and placed flush with the mesocosm bottom for later measures of ecosystem structure and function.…”

“…Grazers influence algal community composition and standing crop during succession in desert streams, but the degree of effect depends on the grazing species (Peterson and Grimm 1992). In Kings Creek, a highly studied prairie stream, return times of disturbance are short, and .M of the scouring floods occur within 12 d of each other (Bertrand et al 2009). Recovery of the algal community in these prairie streams also occurs rapidly.…”

“…Algal biomass returns to preflood levels within 3 wk of a scouring flood event (Dodds et al 1996a). Nutrients and primary production strongly affect recovery of these streams (Dodds et al 1996a), but recovery trajectories also are influenced by macroconsumers (Bertrand et al 2009). Short-term recovery of the algal community is especially influenced by macroconsumers, whereas the final state of an ecosystem is less dependent on the presence of macroconsumers .…”

Dynamic influences of nutrients and grazing fish on periphyton during recovery from flood

“…Aquatic insects emerging from Kings Creek also readily colonized mesocosms. After 30 d, mesocosms were scoured with a high-pressure hose and drained to simulate flooding as described by Bertrand et al (2009). Mesocosms were refilled with water and circulation was started within 24 h. The simulated flooding reset the benthic algal and macroinvertebrate community by removing most of their biomass.…”