Terrestrial Habitat & Species

Toronto and Region Conservation Authority (TRCA) monitors plants and animals in forests, wetlands and meadows across our regional watersheds by conducting biological inventories and assessments and surveying long-term fixed plots.


TRCA has set up long-term monitoring plots in forest, wetland and meadow habitats region-wide to measure how species and vegetation communities are changing over time in response to surrounding land use activities.  

With climate change and the ever-increasing demands on the land for further development, long-term terrestrial biodiversity data collection will help guide future decision-making with respect to restoration activities, environmental protection and the management of natural areas. 

What are the data telling us?

Impacts, both positive and negative, to species and vegetation communities over time are associated with influences from surrounding land use activities. Urban areas tend to exert more negative influences from the surrounding land use areas than rural zones. It is important, therefore, to not just minimize habitat loss but also the negative influences that activities from the surrounding landscape exert on remaining natural areas.

habitat quality infographic



TRCA terrestrial monitoring biological inventories

Since 2000, TRCA has collected inventory data on flora and fauna species as well as vegetation communities. These sites change from year to year based on funding, as well as land planning and management priorities.

Trained staff conduct an inventory by visiting a natural area and documenting what they see and hear. Inventories are done during the optimum time of year for seeing or hearing a particular species.

Vegetation Communities:

TRCA surveys for more than 400 vegetation community types when conducting biological inventories, including 201 Communities of Conservation Concern.   

Vegetation community boundaries are drawn on field maps, following the Ecological Land Classification for Southern Ontario (ELC). The dominant species are documented along with the level of disturbance that may be present (e.g., invasive species). 

Plant Species:

TRCA surveys for 936 native plant species when conducting biological inventories, including 564 Regional Species of Conservation Concern. 

Flora species of conservation concern are mapped, and a full species list is created for each site.  

Breeding Bird Species:

TRCA surveys for 158 native bird species during breeding season when conducting biological inventories, including 89 Regional Species of Conservation Concern. 

Surveys document territories for all breeding birds by listening for their distinct songs or calls, taking care to not include individuals that are still expected to be migrating through the area. A full list of potential breeding bird species is created for each site.  

Amphibian Species:

TRCA surveys for 10 native frog and toad species when conducting biological inventories, including 8 Regional Species of Conservation Concern. 

Surveys begin in early spring by listening for the distinct breeding calls of each frog species in wetland habitats. A full list of frog and toad species is created for each site. 

Note: During the site inventories, all incidental observations of mammals (including bats), reptiles (turtles and snakes) and amphibians (salamanders) are noted.  These observations are appended to the site fauna species list at the end of the field season. 

Scoring and Ranking: A Proactive Approach  

Based on NatureServe’s Natural Heritage Methodology, TRCA developed its own scoring and ranking system for all species and vegetation communities that are found throughout the Toronto regionThis system was developed in the late 1990s out of growing concern for common species disappearing as land use development expanded northward. This proactive approach is designed to alert conservation managers to potential local species declines and losses in the future. Currently 58% of species in the jurisdiction are Species of Regional Conservation Concern. 

tracking biodiversity infographic

What are the data telling us?

In the TRCA region there are 1150 native flora and fauna species, however, only 464 of these are still found in the urban core. Most Regional Species of Conservation Concern are found only in the more northern, rural portions of our watersheds with large amounts of natural cover. 


Urbanization causes or accelerates many threats to biodiversity including:  

  • climate change, 
  • disturbance from off-leash dogs and free-roaming cats, 
  • habitat loss (e.g., new developments), 
  • invasion of non-native species (e.g., through the dumping of yard waste and informal and formal trails) 
  • pollution (e.g., excessive use of de-icing salt on trails). 

It is apparent that the continual loss of natural cover and surrounding land-use in urbanizing areas will further exacerbate the loss of biodiversity occurring region-wide. 


Sue Hayes
Senior Program Manager, Terrestrial Inventories and Monitoring
Watershed Planning and Ecosystem Science