Melo, A. S., D. K. Niyogi, C. D. Matthaei e C. R. Townsend. 2003. Resistance, resilience and patchiness of invertebrate assemblages in native tussock and pasture streams in New Zealand after a hydrological disturbance. Canadian Journal of Fisheries and Aquatic Sciences 60: 731-739.

Abstract--Disturbance caused by a high discharge event is perhaps the most important driving-force affecting invertebrates in streams, causing reduction in abundance and redistribution of individuals among habitats and patches. We generated hydrological disturbances to investigate the role of disturbance in streams in two land uses: native tussock grasslands and exotic pasture catchments. We tested whether physical differences in streambed structure confer higher resistance and resilience in tussock rather than pasture sites. We also investigated changes in patchiness in riffles in the streams caused by the disturbance. Invertebrate abundance decreased immediately after the disturbance, but species density and species richness (rarefied) remained unchanged. Eight days after the disturbance event, abundance was similar to samples collected immediately before the disturbance. Resistance (measured as decrease in abundance) and resilience (measured as recovery within eight days) did not differ significantly between the land uses. Patchiness increased in both stream types immediately after the disturbance, but decreased to pre-disturbance levels after eight days. Disturbance caused a redistribution of individuals among patches, some receiving individuals, others losing individuals, and some remaining unchanged.

Última atualização: 27 de maio de 2003