Modeling habitat suitability for the Rocky Mountain ridged mussel (Gonidea angulata), in Okanagan Lake, British Columbia, Canada

Abstract

A habitat suitability model was constructed to increase knowledge of the Rocky Mountain ridged mussel (RMRM, Gonidea angulata Lea), a rare and endemic species, using Geographic Information Systems (ArcGIS 10.1) and the classification package Random Forest. Identifying possible relocation sites, sites of high importance, and the overall potential distribution of RMRM were accomplished using existing Foreshore Inventory and Mapping (FIM) substrate data and G. angulata presence data (Ministry of Environment). In addition, diverse aspects of mussel habitat quality were documented, including: clay presence, dissolved oxygen concentration, shoreline morphometry, species of fish and other mussels present, geomorphometric description, and effective fetch. Important variables, potentially limiting the distribution of RMRM, as identified in these analyses, include effective fetch > 10 km, medium-high (%) embeddedness of substrates, high (%) sand, and low (%) boulder occurrence. Effective fetch (i.e., site exposure), used as a proxy for potential energy (from wind) can explain the distribution of RMRM in Okanagan Lake. This model was successful in predicting previously unknown locations of RMRM. This model was developed as a tool for Forests, Lands and Natural Resource Operations (Province of BC) to improve management of this species in the Okanagan Valley.