Terrestrial Environment

Shifting Ranges of Species

Undeniably, climate change is altering the conditions of terrestrial environments. As temperatures rise, ecological niches are shifting northward at a rate of approximately 100 km every 20 years. Animal and plant species gravitate toward cooler climates that are more favourable for their survival. However, these shifts have repercussions on the health of ecosystems that can result in adaptation difficulties, the spread of disease, increases in exotic invasive species and changes in trophic networks. A trophic network is defined as the movement of energy and resources within an ecosystem during feeding interactions between species.

Photo: Japanese knotweed, McGill University

Definition | Range

The distribution range of a given species is the geographic area corresponding to the presence of this species, be it an animal or a plant. The range must satisfy the conditions (temperature, resources, predators, etc.) that allow the species to adapt based on its attributes in order to survive and reproduce. 

Number of species whose range will shift as a result of climate change

Figure 1

Potential response of 765 species to climate change in the 20th century in southern Quebec, Source: Berteaux, 2014


Unfortunately, a number of tree and other plant species as well as certain animal species are unable to keep up with the rate at which their habitat is changing, notably near the northern edges of their respective ranges. In fact, by the end of the century, between 5 and 20% of forest ecosystems may no longer be suitable for a number of tree species. 

Certain vulnerable species (e.g. woodland caribou, wood turtle, western chorus frog, butternut) could even face extinction due to their inability to adapt to changing conditions. Range shifts may also translate into habitat contraction, which reduces the space available to support a sufficiently large and healthy population.


Shifting habitats may also lead to increased spread of disease. For example, the white-footed mouse, whose range was formerly limited to the United States, is now able to survive in southern Quebec thanks to milder temperatures. This rodent is a prime host for ticks that carry Lyme disease, which has become relatively frequent in regions of southern Quebec such as Montérégie and Estrie. 

This is also the case for the arctic fox and rabies, which is dangerous to humans. Global warming affects both the distribution and quality of the arctic fox’s habitat as well as the species’ migratory behaviour and interactions. In this regard, the future incidence dynamics of rabies are unknown.


More Exotic Invasive Species

Rising temperatures also encourage the presence and proliferation of invasive species, including non-native ones. Invasive species compete for resources and space at the expense of other species, which can result in a loss of biodiversity. Some of these species can even aggravate allergies in humans. Such is the case with ragweed, whose range may very well expand while its pollen production increases.

Japanese knotweed, Eurasian watermilfoil, giant cow parsnip and common reed (Phragmites) are all examples of invasive species in Quebec that are spreading due to climate change. Invasive plants compete with native species by monopolizing available space and resources (light, nutrients). In doing so, they prevent other species from reproducing and dispersing normally and can even drive them to extinction, which ultimately harms biodiversity. These plants can also degrade the soil and accelerate the spread of certain diseases.

More Exotic Invasive Species

As is the case in terrestrial environments, climate change is conducive to the proliferation of invasive species in the lakes and rivers of Quebec, including the St. Lawrence. For example, the growth and proliferation of Eurasian watermilfoil, an exotic invasive aquatic plant, are fuelled by rising water temperatures. 

Seasonal Changes and Ecological Imbalance

The life cycle of species is also upset by the later and later arrival of snow in winter and the increasingly early spring thaw. This notably has an impact on certain species that rely on camouflage tactics to protect themselves from their predators. For example, the fur of the short-tailed weasel turns white in winter as the days grow progressively shorter. A later-occurring first snow renders this camouflaging technique ineffective, making the weasel more easily visible to its predators. The small mammal must therefore migrate northward to adapt its life cycle to the changes in its local environment.

Variations in the availability of plant resources needed by species to survive also forces the animals that depend on them to move. This can cause ecological imbalances such as changes in species’ development stages and feeding relationships, and, ultimately, a loss of biodiversity.

Aquatic Environment

Shifting Ranges of Species

Climate change is altering the conditions of aquatic environments: rising water temperatures, lower concentrations of oxygen, higher concentrations of carbon dioxide, acidification, etc. As a result of these changes, the ranges of aquatic species may shift. In fact, these species must migrate or expand their range in order to find suitable conditions to survive. Those that are unable to adapt to these changes or move to new habitats become vulnerable and therefore prone to extinction.

Rising summer water temperatures in the shallow lakes of northern Quebec is believed to threaten the survival of several species of fish such as the arctic char, trout (including lake trout) and salmon.

Seasonal Changes and Ecological Imbalance

Water temperatures that rise earlier in spring disrupt the life cycle of the species inhabiting these aquatic environments. In fact, this temperature increase creates favourable conditions for plankton blooms. If temperatures rise early in the season and the plankton blooms too soon, certain species of crustaceans and fish will not be sufficiently developed to feed on this plankton, thereby causing mortality in these species. To survive, they must migrate north.

Changes in the conditions of aquatic environments also affect predator-prey relationships. For example, due to the warming of their habitat, trout may venture into deeper, cooler waters to forage. The fish can therefore become scarcer in shallower, warmer lakes, thereby disrupting the food chain. Trout are important predators and changes in their feeding behaviour and diet can have an impact on the availability of their prey.

Research project

Mapping the Impacts of Climate Change on Salmonid habitat in the Northern Lakes of Québec

The mapping tool and model developed will better equip MFFP fisheries managers to evaluate salmonid habitats quality in Québec’s northern lakes and thereby prioritize actions to adapt their resource management measures according to the response of the fish habitats to climate change, based notably on changes in temperature and dissolved oxygen in the lakes.

Coastal Environment

In coastal environments, climate change is leading to reduced ice cover and rising sea levels. Together, these two phenomena aggravate the issues of erosion and coastal flooding. These threats can degrade coastal ecosystems such as beaches, beach terraces, sandspits, tombolos, barrier beaches and maritime marshes by forcing them to migrate inland.

However, this migration can sometimes be hampered by obstacles that are too close to the coast such as a cliff or even a road. As it seeks to migrate, the ecosystem finds itself trapped between the sea and the obstacle, a phenomenon known as coastal squeeze. Ecosystems facing coastal squeeze could deteriorate or even gradually disappear in the coming decades if no planning measures are implemented to ensure their protection. 


On the other hand, climate change is causing declines in water oxygen concentrations and changes in water temperature in the Gulf of St. Lawrence and its Estuary. These phenomena could cause mortality in different species or modify their development, growth, reproduction, or migration patterns, in addition to altering the trophic relationships between species. Waterfowl as well as several species of molluscs and fish found in the Estuary and Gulf of St. Lawrence could be affected by these changes.

Furthermore, the harp seal is one of a number of species impacted by the reduced extent and duration of ice cover, as it reproduces exclusively on the pack ice. Seal pup mortality is also observed with increasing frequency due to the loss of sea ice.

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