Trichomycete prevalence in Thomas Brook, Nova Scotia, exposed to different levels of human activity

Abstract

The Thomas Brook in the Annapolis Valley, Nova Scotia, was the focus of an Agriculture and Agri-Food Canada wastershed evaluation of beneficial management practices (WEBs) project from 2004–2008. The stream is impacted by human activities along its course, with residential influences and farming operations. The water quality in Thomas Brook was assessed in 2006, and the current study done in 2011–2012 used the same standard invertebrate metrics to measure water quality. This project also examined the prevalence of gut endosymbionts (trichomycetes) in aquatic invertebrates to determine whether water quality affects this community of obligate microorganisms in their hosts. The water quality was improved in Thomas Brook in 2011/2012 compared with that measured in the earlier study. There were 34 taxa of trichomycetes recorded in benthic insects in the stream, including two new species. The trichomycete community was rich in dipteran hosts (midges and black fly larvae), but the prevalence of gut fungi in ephemeropteran (mayfly) nymphs in the system was low, perhaps due to the impact of human activities on water quality.