A novel approach to assess the cumulative impacts of thawing permafrost on aquatic systems using both Indigenous knowledge and western scientific knowledge

Increased temperatures and precipitation are intensifying mass wasting caused by the thawing of ice-rich permafrost in the western Canadian Arctic. Specifically, disturbances known as retrogressive thaw slumps deliver large quantities of sediment and dissolved materials into adjacent waterbodies, thereby negatively affecting culturally and ecologically important fish habitat. Very little information exists regarding the impacts of thaw slump expansion on fish habitat in northern Canada. To understand the risk of these potential impacts, we combined spatial data on cumulative thaw slump impacts in the Teetł’it Gwinjik (Peel River) Watershed, Gwich'in Settlement Region, with detailed information about fish habitat derived from Gwich'in knowledge and western scientific knowledge using a mixed methods approach. Areas at high risk of experiencing the cumulative impacts of slumping were found along the mainstem of the Peel River and its major tributaries. Gwich'in knowledge holders were concerned about the impacts of slumping on future access to fish. These findings raise concerns about the impact of permafrost thaw on Indigenous fishing livelihoods in the region and highlights the need for additional research.