Thoughts on Recolonization of Endorheic Cold Desert Spring-Streams

Abstract

Possible routes for recolonization of cold desert spring-streams that experience severe winter spates are evaluated. Because the entire stream, including headwater areas, is affected, initial recolonization appears to be largely by survivors of the spates, including newly hatched larvae from surviving eggs. Drift, upstream migration, and oviposition are not important initially, but may play roles as the stream recovers or during periods of oviposition by immigrants later in the year. Taxonomic composition is unpredictable owing both to the disappearance of common species and the appearance of new species. The fauna is low in diversity. The spates appear to be largely stochastic events, and recolonization is related to both deterministic and stochastic processes.