Livestock can have negative impacts on water quality – their urine and feces can increase water nutrient levels, and grazing can destroy riparian vegetation. In Ontario, Canada, regional bodies known as Conservation Authorities are partially responsible for water quality restoration. The Grand River Conservation Authority in southern Ontario developed a rural water quality program, which involved building fences along streams to restrict livestock access. It was hypothesized that the fencing would allow for passive restoration once the waste inputs were curtailed. Benthic macroinvertebrates were sampled in the fenced streams to assess how effective these fences have been at facilitating passive restoration to improve water quality. Variables such as fence length, and the time since fencing were considered. In 2014, 10 creeks with different fence lengths (200m – 1500m) and year they were initially fenced (2002 – 2010) were sampled once each month from May to August. Samples were collected downstream, midstream, and upstream of each fenced location. Insects were identified to family, and all other invertebrates were identified to the lowest possible taxa. ANCOVAs and Kruskal-Wallis tests were used to compare taxa richness, the Shannon-Weiner Index, Simpson’s Index, abundances of Ephemeroptera-Plecoptera-Trichoptera, Oligochaeta, and Chironomidae, and Hilsenhoff’s Family Biotic Index between sampling sites.
Results/Conclusions
According to Hilsenhoff’s Family Biotic Index, all sampling sites were likely to have substantial organic pollution present. There were also no statistically significant differences between the biological indices calculated downstream, midstream, and upstream of each site. Furthermore, when comparing invertebrate communities between fences of different ages and different lengths, the few significant differences that did exist out of the many tests that were conducted were not consistent month-to-month. Long-term records indicate that the fences have restricted livestock access to the creeks; however, the impacted state of the streams via organic pollution, and lack of significant differences within the streams suggest that passive restoration was not effective at improving water quality. It is likely that there may be other factors and inputs, particularly ones upstream, that are impairing the water quality. A variety of restoration techniques may need to be implemented at a larger scale for any water quality improvements to occur in these novel ecosystems.