Mechanisms of benthic algal recovery following spates: comparison of simulated and natural events
1994
Peterson, C.G. (Arizona State Univ., Tempe (USA). Dept. of Zoology) | Weibel, A.C. | Grimm, N.B. | Fisher, S.G.
A manipulative field experiment was conducted to examine individual and interactive effects of scour and short-term nutrient enrichment (4 h exposure) on post-spate recovery of benthic algae in a desert stream. Recovery from these simulated-spate conditions compared to algal recovery patterns following a natural spate that increased water-column nutrient levels for 2 weeks. That event differentially scoured communities on artificial substrata in place for a long-term experiment, significantly reducing biomass in 49-day-old communities but causing no significant reduction of biomass in older, 133-day-old communities. Both natural and simulated spates reduced actual and relative abundances of diatoms within communities. In the manipulative experiment, scoured communities accrued biomass more rapidly than those not subjected to scour, but short-term enrichment had no effect. Accrual of diatoms and green algae was stimulated by the scour manipulation, while cyanobacteria maintained equal rates of growth in all treatments
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