Shoreline marshes of Okanagan Lake: Are they habitats of high productivity, diversity, scarcity and vulnerability?

Abstract

AbstractAbundance and diversity (number of taxa) of planktonic and epibenthic invertebrates were examined between October and December 1994 in a small shoreline marsh of southwestern Okanagan Lake, British Columbia, and compared to adjacent shoreline that was (i) slightly modified by human activity, and (ii) heavily modified by riprap placement. Planktonic and epibenthic invertebrate abundance and diversity was several‐fold higher in the shoreline marsh habitat, intermediate in the slightly modified shoreline habitat, and lowest in the riprap shoreline. A mid‐1930 survey of Okanagan Lake reported that only 9% of its shoreline had rooted aquatic vegetation, so historically the lakeshore marshes were scarce. Currently, only small vestiges of such habitat remain in a 42 km stretch of its southwestern shoreline where 80% of this length has been altered by various development activities: 41% by lakeshore housing and cottages, 27% by lakeshore road riprap, and 12% by parks, swimming beaches and other recreational developments.