Bridging Traditional and scientific knowledge through a novel predictive approach to understand the role of pathogens in the decline of a key Arctic species

The main objective of this project is to understand and quantify the potential role of parasites and pathogens in population dynamics and declines of barren-ground caribou (Rangifer tarandus groenlandicus) through ecological modeling and Indigenous observation and monitoring. We hypothesized that the costs of diseases will have a negative impact on caribou physiology and, as a direct consequence, a negative impact on caribou population dynamics. This is likely to be a combination of cumulative effects through subtle energetic mechanisms such as decreasing body condition and pregnancy rates, as well as direct mortality, fetal abortion, or infertility. We built a bio-energetic integral projection model to evaluate the impact of parasites and biting insects on caribou body condition, and as a result, caribou population dynamics. Results from this model demonstrate the significant impact that sub-lethal infection and behavioural modifications caused by parasites and insect pests can have on caribou. We then parameterized the model with environmental data from the Bathurst herd’s range between 1980 and 2020, when population declines occurred. This parameterization resulted in a greater than 50% population decline. While this did not perfectly capture observed declines of the Bathurst herd, it demonstrates the contribution that parasites and insect pests may have played. These results are feeding back into monitoring by directing efforts of Ekwǫ̀ Nàxoèhdee K’è to focus on caribou health, and the modeling framework can be used to forecast possible demographic trends under anticipated environmental conditions. This database includes data objects with results from baseline analyses