THE IMPACTS OF RECENT WILDFIRES ON STREAM WATER QUALITY AND MACROINVERTEBRATE ASSEMBLAGES IN SOUTHERN NORTHWEST TERRITORIES, CANADA
High-latitude regions are currently undergoing rapid ecosystem change due to increasing temperatures and modified precipitation regimes. Since 2012, the Northwest Territories (Canada) has been experiencing severe drought and wildfire seasons. In 2014 alone, fires within the Northwest Territories consumed over 3.4 million hectares of forested land; 1.4 times larger than the national yearly average for Canada. Wildfire is one of the most important agents influencing age structure and composition of forest stands, as such, it is a critical factor in ecosystem dynamics. The impacts of wildfire on terrestrial systems garner more attention compared to aquatic habitats. This is especially true when considering aquatic ecosystems, specifically sub-arctic streams, where the impact of fires on stream ecology and chemistry are relatively understudied. Freshwater ecosystems, such as lakes and streams, are relied upon by northern communities for their cultural significance and economic and environmental goods and services they produce, including country foods. This study examines the impact of recent wildfire on freshwater streams within the North Slave, South Slave, and Dehcho regions of the Northwest Territories (Canada) through analysis of their water chemistry and benthic macroinvertebrate assemblages. Benthic macroinvertebrates, the macroscopic organisms living within/on the substrate of streams, were sampled following methodologies outlined by the Canadian Aquatic Biomonitoring Network (CABIN). Biological indices (e.g. Species Richness, Shannon Diversity Index) were calculated and compared statistically to determine relationships regarding benthic diversity and abundance. Results of this study suggest that recent wildfires cause short-term perturbations in water quality, such as increases in dissolved aluminum, TSS and turbidity. In addition, results indicate slight structural changes in invertebrate communities of streams within burned catchments (impacted) compared to those in unburned catchments (control), including increased richness and abundance of primary consumers and their predators.