Original paper

Crevice refuges as a source for algal colonists of disturbance-affected substrates

Bergey, Elizabeth A.


Algae protected in crevice refuges may be a source of colonists for denuded substrates following disturbance. This study explored the ability of algae that inhabit crevices in the sand-grain cases of the caddisfly Gumaga nigricula (Trichoptera: Sericostomatidae) to colonize denuded stream stones. In three laboratory experiments, caddisflies were introduced into sterilized flasks containing stream water and stream stones, and the flasks were incubated for three weeks. Algal colonization was assessed by measuring the chlorophyll-a concentration of the stones. Algal colonization of stream stones from caddisfly cases was successful, irrespective of time of association with the caddisflies (4 or 24 hrs) or whether the caddisfly cases were empty or occupied. This demonstration of algal colonization and establishment from crevice refuges to nearby substrates supports the concept that crevice-dwelling algae that are protected from disturbance can be a source of post-disturbance colonists that contribute to the high resilience of benthic algal assemblages.


caddisfly casescolonizationdisturbancestream algae