Recovery Patterns in Stream Communities Impacted by the Mt. St. Helens Eruption

摘要

Recovery patterns of benthic communities in seven small streams impacted to varying degrees by the eruption of Mt. St. Helens were examined in winter 1981-1982, particularly in relation to habitat constraints. Overall abundance and diversity of the communities were low, and instability of channel banks and bottom appears to severely limit re-establishment of biota. Communities appear to be undergoing cycles of establishment and denudation in concert with changes in landscape geomorphology. Disturbance events of varying frequencies were also simulated in experimental stream channels to more closely evaluate the response of benthic communities to periodic, non-catastrophic disturbances and to compare this with the response observed to catastrophic perturbation associated with volcanic eruption.