Wildlife Adaptation in Shifting Environments
Evidence of climate change is all around us: global average temperature is rising, wildfires are becoming more frequent and more common across Canada, snow and ice are melting faster, and flooding is becoming more severe. As we humans adapt to climate change, we are discovering new and innovative ways to reduce our carbon footprint, protect our natural environment, and respond when disaster strikes. But what do all these changes mean for our furry and not so furry friends?
As environments continue to shift, animals, too, are finding ways to adapt to these many changes. New Brunswick is a part-time home to many migrating species, from songbirds like orioles, thrushes, and warblers to large and endangered mammals like the North Atlantic right whale. As seasons continue to shift, animals are being forced to change their migration patterns to survive. If a species waits too long to migrate, it might be trapped in one environment and unable to make the journey. Species are finding new ways to adapt to these shifts in seasonality, overcoming climate change obstacles to complete their migrations.
Pink salmon of the Pacific Ocean are one of several species migrating earlier in response to climate change. Researchers at the University of Alaska at Fairbanks confirmed that the migration period of pink salmon is a genetic response rather than an environmental one1. This means that the salmon are triggered to migrate by their genes rather than environmental conditions, representing a true adaptation! Since pink salmon are a short-lived species, typically surviving two years, they are more likely to adapt to climate change quickly compared to longer living salmon species. With time, other migrating fishes, like Atlantic salmon, may come to possess genes that trigger an earlier migration.
For many species, their survival depends on the changing of their coat or plumage. As winter comes later and spring comes sooner in a changing climate, are species able to keep up? Animals are triggered to change their coat by the amount of daily sunlight, not the amount of snow2. So while our snow may melt earlier in the spring, the days do not grow longer at the same rate, leaving snowy owls snow white in a brown and grey forest. Research suggests that some species may be able to evolve to keep up with climate change. In a study of almost 200 wild hares, researchers at North Carolina State University found evidence of variation in when the hare’s coat changes color3. This could mean that the species is on the verge of adaptation to climate change! With time and a protected habitat, species may be able to adapt to seasonal changes and evolve to shed their fur and feathers earlier in the year.
For some species, a declining population occurs for many reasons: prey are not available, the species is over hunted or fished, habitat is lost to development, and new challenges emerge from climate change. For some species, the best available response to these pressures is to interbreed with other species, called species hybridization. There is evidence of species hybridization in many places around the world, including Canada! Researchers have found genetic evidence of interbreeding between southern and northern flying squirrels in Ontario following a series of warm winters that caused the southern flying squirrel to move northward4. Interbreeding between species typically produces offspring that are not as strong as the parent species, should the offspring survive at all. Often, if a hybrid offspring survives, they are not able to reproduce. While hybridization might be one adaptation pathway, there are a lot of hurdles for new hybrids species to overcome to survive and thrive in the face of climate change.
There is no question that many species are finding ways to adapt in ever-shifting environments; however, while many species are managing to survive, few are able to thrive. Should their environments shift at faster rates as climate change progresses, animals may not be able to adapt and evolve quickly enough. This is another reason why CPAWS-NB is advocating for a network of protected areas on land and at sea: to give our wildlife the best chance to adapt to climate change in protected habitats and healthy ecosystems. Protected areas will support native New Brunswick species as they slowly change their behaviours and their genes adapt to survive and thrive in shifting environments.
1 Kovach, R.P., Gharrett, A.J., & Tallmon, D.A. (2012). Genetic change for earlier migration timing in a pink salmon population. Proceedings of the Royal Society B, 279, 3870-3878.
2 Langley, L. (2018). How color-changing animals are rebelling against climate change. National Geographic News. Retrieved February 14, 2019: https://news.nationalgeographic.com/2018/02/animals-climate-change-winter-evolution/.
3 Marris, E. (2014). Can snowshoe hares evolve to cope with climate change? National Geographic News. Retrieved February 14, 2019: https://news.nationalgeographic.com/news/2014/07/140717-snowshoe-hares-climate-change-environment-animals-science/
4 Garroway, C.J., Bowman, J., Cascaden, T.J., Holloway, G.J., Mahan, C.G., Malcolm, J.R., . . . & Wilson, P.J. (2010). Climate change induced hybridization in flying squirrels. Global Change Biology, 16, 113-121.
Jess Baxter is the Program Support person at the Alzheimer Society of New Brunswick and a volunteer of CPAWS-NB. As an avid nature lover, Jess enjoys getting outdoors and spends her free time hiking, camping and exploring New Brunswick. Jess is passionate about environmental and animal welfare and is excited to be contributing to the CPAWS-NB blog!