Abstract
Lakes in urban areas face increasing salinization from the widespread application of road de‐icing salts. Chironomid (Diptera: Chironomidae) larvae are common bioindicators and important lower‐trophic‐level organisms, but their response to road salt in urban lakes is not well‐characterized. Here, we examine chironomid remains from the surface sediments of 34 urban lakes in Halifax, Nova Scotia, Canada, to characterize community response along a road‐salt impact gradient (6–250 mg Cl − L −1 ). We ask if chloride significantly affects chironomid assemblages, if so at what concentrations, and if we can identify indicator taxa. A forward‐stepped redundancy analysis using a suite of environmental data from municipal monitoring identified chloride, aluminum, and depth as significant drivers of chironomid assemblage structure ( p p = 0.005) and rarefied richness ( p = 0.03). Threshold Indicator Taxa Analysis suggested most community change occurred at 78.5 mg Cl − L −1 , and we constructed binomial models for the five taxa identified by this analysis as indicators of chloride (all p − L −1 ).