Five-part Series Highlighting the Top Stories of the Watershed Plan
The first phase of the Watershed Plan characterizes the health of the Credit River Watershed and how it has changed from the 1950s to today.
This newsletter dives into our fifth and final story: biodiversity at risk. Our data show that plant and animal species throughout the watershed are at risk of declining or disappearing. But the good news is, there are actions we can take to reduce further biodiversity loss.
A Watershed Rich in Biodiversity
Over 1,200 native plant, mammal, bird, fish, amphibian and reptile species are found in the Credit River Watershed. These species provide valuable ecosystem services and help shape the watershed by creating natural communities and habitats like forests, wetlands and meadows.
Native Species in the Watershed
- 27 Amphibians and reptiles
- 274 Birds
- 62 Fishes
- 46 Mammals
- 147 Trees and shrubs
- 651 Other plants
Thousands of species in less well-studied groups also make their home here, including insects, fungi and non-vascular plants.
Most plant and animal species are native to the watershed, but some are not. People have introduced non-native species from other parts of the world to the watershed. Currently, there are at least 370 known species considered to be non-native, most of which are plants.
Our Biodiversity at Risk
Our results indicate that biodiversity is at risk in forest, wetland and stream ecosystems throughout the watershed. Threats to biodiversity include:
- Habitat loss: Species are losing their habitat due to land use change and degradation. This has been the largest factor driving the decline of biodiversity in the watershed.
- Climate change: We are seeing warmer and wetter conditions due to climate change. These conditions can create unsuitable habitat for some species.
- Invasive species: While most introduced species do not cause significant impacts to biodiversity, some are invasive. Invasive species can pose significant threats to native species by competing for space and nutrients or by killing trees and changing the structure of our forest and wetland communities.
- Road mortality: Roads can cause habitat fragmentation, leading to poor terrestrial connectivity and road mortality of various species. For example, snapping turtles, a species at risk, are frequently hit by cars when moving to nesting sites along gravel roads.
- Pollution: Pollution can cause unsuitable habitat conditions for wildlife and is a factor in population declines for some species, especially aquatic species.
As a result of these threats to biodiversity, at least 54 species that used to live in the Credit River Watershed are no longer found here. Of the native species that remain, there are over 48 species at risk of extinction and 83 species of conservation concern.
As the climate continues to change, it’s likely that the watershed will lose additional species in the next 30 years. Climate change is likely to replace habitat loss as the most pressing issue facing biodiversity in the watershed.
Changes in Species Population and Diversity
Declining Populations of Sensitive and Common Species
These species can represent some primary examples of the biodiversity loss we have seen.
- The ovenbird, a ground nesting bird species, has declined by 62 per cent
- Wood thrush, a species-at-risk, has declined by 36 per cent
- Populations of common bird species, American goldfinch and Northern flicker, have declined by 38 per cent
- The biomass of the coldwater-dependent species, brook trout, has declined by 53 per cent
Invasive Species in the Watershed
Approximately 370 non-native species are found in the watershed and 184 of them are invasive. Invasive species found in natural habitats, agricultural areas and cities include garlic mustard, European buckthorn, spongy moth, goldfish and red-eared slider turtle.
Invasive species can have serious health and economic impacts on people. For example:
- Direct contact with the sap of the invasive plant giant hogweed can cause blisters and burns on the skin
- Trees infested by the invasive insect emerald ash borer can be a hazard to safety and property
- The management of zebra mussels, that clog water intakes at water treatment facilities, are estimated to cost Ontario municipalities nearly $4.5 million every year
Take Action to Reduce Further Biodiversity Loss
- Plant native species and don’t dump garden waste.
- Protect your property from invasive species.
- Participate in habitat restoration: Restoring wetland, grassland and stream habitat improves ecosystem health and builds resiliency in the watershed.
- Implement low impact development (LID): Encourage and support the implementation of LID where possible. LID infrastructure mimics the natural water cycle to infiltrate, filter and store stormwater runoff. These processes help to improve water quality.
- Follow best practices for winter maintenance. Reduce winter salt use to reduce pollution in streams and groundwater.
To learn more about the Watershed Plan, visit cvc.ca/WatershedPlan.
By Shanice Badior, Coordinator, Watershed Plans and Analytics