Over the past decade, ticks have been moving northward across Canada. I was born and raised in Northern Saskatchewan, in a small community called Denare Beach which is just outside of Flin Flon Manitoba. In my lifetime, ticks were not an insect that was ever found in the north but over the past couple of years, they have begun invading farther north. In Saskatoon (6 hours south) where I live now, ticks were uncommon around 7+ years ago, however they are extremely abundant now and becoming worse year after year. As the climate is warming, habitats are shifting, and ticks are beginning to shift farther north. Ticks are unable to survive in extremely cold environments and the one year that there were very few ticks in Saskatchewan was when it was below -30 for 24 days in February. However cold snaps like this are increasingly rare and this is allowing the ticks to infiltrate new environments. Residents have found ticks in their community recently, where they were not noticed years ago. The community is concerned about the change to their local biosphere and are beginning to need to educate residents on the symptoms of lyme disease and ways to remove ticks from humans and pets.
Kari Lentowicz who has lived in the area her whole life and has traditional ecological knowledge (TEK) of the surrounding community was chosen as a indigenous community expert with tribal knowledge. She is an avid outdoorsperson with a scientific background. She noted that ticks were not traditionally in the Denare Beach community, but recent changes to the climate have made it more suitable to them. She explained that there has also been an increase in transport in and out of the region for goods and services as the community has continued to develop. She described how longer summers and have encouraged the ticks to move farther north and surprisingly, the ticks have been thriving in the northern climate even though they only arrived in the area about 5 years ago but began to be noticed 2 years ago. Two other local community members provided feedback, Faryn Bergman and Debra Knutson who have also lived in the area for the duration of their life. They both concluded that they have found recent evidence of ticks in the community and that they were not present past a few years ago.
Kari’s TEK describing warming climates and longer summers has been corroborated by researchers, but they also note the importance of migratory birds on the annual influx of ticks into northern latitutes. Ogden et. al (2008) notes how areas that are too cold to sustain ticks through the winter have them introduced through migratory birds during the spring. They note how the increasing spread of ticks across Canada is geographically isolated, therefore it is likely not influenced by terrestrial animals and would therefore be spread through migratory birds residing in locations as they migrate north. Ticks are then able to molt and reproduce throughout the spring and summer season in places that otherwise are not suitable habitats for ticks due to increasing temperatures and warm, longer summers increase the duration and intensity of the tick season (Bouchard et al., 2019). However, low temperatures reduce the amount of ticks that make it through their life cycle and warming temperatures associated with climate change are expected to increase the northward migration of ticks and expand their habitats to northern latitudes (Gabriele-Rivet et al., 2015). It is expected that the tick’s habitat will continue to expand northward as the climate continues to warm, which means that communities must be prepared to mitigate tick bourne diseases to reduce the risk to their residents.
References
Bouchard, C., Dibernardo, A., Koffi, J., Wood, H., Leighton, P. A., & Lindsay, L. R. (2019). Increased risk of tick-borne diseases with climate and environmental changes. Canada Communicable Disease report. 45(4), 83–89. https://doi.org/10.14745/ccdr.v45i04a02
Gabriele-Rivet, V., Arsenault, J., Badcock, J., Cheng, A., Edsall, J., Goltz, J., . . Y., & Ogden, N. H. (2015). Different ecological niches for ticks of public health significance in Canada. PloS one, 10(7). https://doi.org/10.1371/journal.pone.0131282
Ogden, N., Lindsay, R., Hanincova, K., Barker, I., Bigras-Poulin, M., Charron, D., . . . . Thompson, A. (2008). Role of migratory birds in introduction and range expansion of ixodes scapularis ticks and of borrelia burgdorferi and anaplasma phagocytophilum in Canada. Applied and Environmental Microbiology. 74(6), 1780-1790. doi: 10.1128/AEM.01982-07