Terrestrial Natural Heritage
When natural communities are healthy, resilient, and connected, they form a robust natural heritage system that provides the functions and services upon which we depend. These systems are vital for creating habitat, enabling the movement of species for survival, and maintaining natural diversity. These ecological functions provide valuable ecosystem services that contribute to human well-being such as shade, clean air and recreational activities.
Wetlands, which cover 18% of the watershed, are particularly vulnerable to changes in water quantity and quality. Changes in streamflow and groundwater discharge, along with changes in temperature and atmospheric carbon dioxide, will likely alter the distribution and abundance of vegetation found within wetlands and increase their vulnerability to drying.
In the Lake Simcoe watershed, 90% of the swamps, 84% of the marshes, 50% of the fens and 100% of the bogs are vulnerable to drying up by 2100. Vernal ponds and ephemeral pools (seasonal pools of water that provide habitat for distinctive plants and animals) are likely to be early victims of climate change due to their sensitive nature and can therefore be used as early climate change indicators (a type of “canary in the coal mine” if you will). Wetlands within the watershed provide flood protection services valued at $169 million, which is very likely to be reduced as wetlands become degraded or lost as a result of climate change.
Woodlands, which cover 35% of the watershed, provide vital habitat to a range of species. Many of the tree species within the watershed will be impacted by changing temperature and rain/snow patterns. Communities with a poor ability to adapt (e.g. boreal forests) are likely to experience impaired growth and reproduction, increasing their susceptibility to pests and disease. More frequent extreme weather events such as drought, sustained high winds, and ice storms, associated with climate change have the potential to damage trees and cause hazards from falling limbs. Increased freeze thaw cycles and drought events can stress trees and decrease the average age of trees within a forest.
Timing of Life Cycle Events
For many species, seasonal and cyclic changes in temperature trigger transitions in life cycle events. For example, the timing of bud and leaf emergence, as well as wildlife breeding, migration and stages of development occur, at least partly, in response to temperature. As the climate continues to change, there will be mismatches in the timing of these important life cycle events such as migratory birds arriving before their food sources emerge.
Species Range Shifts
As air temperatures warm, populations of species at the northern limit of their range may become more abundant or colonize new habitat, whereas those species at the southern limit of their range may be threatened. As current habitats become unsuitable for some species, it is important to maintain habitat connectivity to facilitate movement between climate refuges to allow them to colonize new areas. Protecting and enhancing ecological connectivity will become increasingly important as the climate continues to change.
As both terrestrial and aquatic habitats shift under a new climate, the potential spreading of new or existing invasive species will increase. These invaders, such as the round goby or dog-strangling vine, often lack predators and out-compete local native species, allowing them to quickly grow and alter community dynamics.