2.3 Degradation of the Natural Heritage System

Natural areas such as forests, prairies, wetlands and aquatic habitat provide many services and benefits to the economy, society, and the environment. Natural areas provide shelter and food for wildlife, remove pollutants from air and water, produce oxygen through photosynthesis and provide valuable recreational and educational opportunities. They are the green infrastructure that helps buffer the impact of climate change and severe weather, which in turn reduces the impact on the municipal budget. Invasive plants can have a large negative impact on natural areas and threaten these important services that they provide.

Invasive plants reduce species diversity and species richness by competing heavily for resources such as light, moisture and soil nutrients that native plants require to establish and grow. These changes in species composition affect wildlife that are adapted to native plant communities.

Invasive species can change the entire composition of vegetation over time changing the overall nature and function of the community. Invasive plants can reduce forest regeneration through direct competition with native tree seedlings, resulting in reduced density and slowed growth rate. In turn, reduction in forest regeneration results in the loss of wildlife habitat, and decreases the diversity of a stand, making it more vulnerable to insects and disease as well as to the incursion of other invasive species. Ultimately, invasive plants affect the intricate linkages that make ecosystems strong and resilient.

Protecting the City’s Natural Heritage features from the threats of invasive plant species is imperative to maintaining the overall ecological integrity and ecosystem health of the Natural Heritage System.