Terrestrial Habitat & Species

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



TRCA terrestrial habitat and species monitoring

TRCA has implemented long-term monitoring in forest, wetland and meadow habitats region-wide to measure how species and vegetation communities are responding over time to impacts from 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 surrounding areas exert on remaining natural areas.



Sue Hayes
Project Manager, Terrestrial Monitoring & Inventories
Environmental Monitoring & Data Management


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 390 vegetation community types when conducting biological inventories, including 184 Communities of Conservation Concern.
  • Plant Species: TRCA surveys for 1,857 plant species when conducting biological inventories, including 559 Regional Species of Conservation Concern.
  • Breeding Bird Species: TRCA surveys for 176 bird species during breeding season when conducting biological inventories, including 91 Regional Species of Conservation Concern.
  • Frog and Toad Species: TRCA surveys for 10 frog and toad species when conducting biological inventories, including 8 Regional Species of Conservation Concern.

For more than a decade, TRCA has been using a unique strategy in the protection of natural heritage systems within regional watersheds. All flora and vertebrate fauna species, as well as vegetation communities, found in the region have been assigned a rank based on scores that measure their local abundance as well as their sensitivity to development impacts. The goal of this ranking system is to proactively identify species at risk of becoming rare, threatened or locally extinct. Based on this usage of a local scoring and ranking approach, 693 species in TRCA’s jurisdiction are currently designated as Regional Species of Conservation Concern.

What Are The Data Telling Us?

In the TRCA region there are 1111 native flora and fauna species. However, only 418 of these are still found in the urban core. The large majority of Regional Species of Conservation Concern are found only in the more northern, rural portions of our watersheds with large amounts of natural cover.

TRCA terrestrial monitoring species and natural cover distribution map

Urbanization causes or accelerates many of the threats to biodiversity including: habitat loss, non-native invasive species, pollution, and climate change. It is apparent that the continual loss of natural cover and changes to surrounding land-use in urbanizing areas will only further exacerbate the loss of biodiversity occurring region-wide.


Sue Hayes
Project Manager, Terrestrial Monitoring & Inventories
Environmental Monitoring & Data Management


TRCA volunteer terrestrial monitoring

TRCA’s Terrestrial Volunteer Monitoring Program trains volunteers to monitor the forest, wetland, and meadow habitat in the Toronto region. By engaging volunteers, TRCA can provide an opportunity for citizens to contribute to environmental protection in a meaningful way, and to learn more about local native species and their habitat needs.

What Do We Monitor And Why?

Biodiversity is assessed through surveys that collect data on a set of mammal, bird, amphibian, plant and lichen species at fixed sites across the region. The severity of invasion by eight high priority invasive plants is also monitored.

The results inform many aspects of conservation work, including planning and habitat restoration. Tracking the sites over time allows us to measure our success at protecting and enhancing regional biodiversity. In 2015, a total of 663 surveys visits were completed across 51 sites by 128 volunteers.

Associated Documents

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Terrestrial biodiversity in the Toronto region: A decade of monitoring under the Terrestrial Volunteer Monitoring Program, 2003-2012

Since 2002, TRCA's Terrestrial Volunteer Monitoring Program has collected native indicator species presence data at a set of 56 fixed monitoring sites located in natural areas throughout the Toronto region. This 10-year report is the third in a series of technical documents that summarize and discuss findings and relate the results to complementary TRCA projects such as the Species of Conservation Concern scoring and ranking system, the Landscape Analysis Model output and the Terrestrial Natural Heritage System Strategy implementation. It interprets results to provide information for internal and external requirements, including those of conservation land and watershed management, partner municipalities, other agencies and organizations, TVMP volunteers, landowners and others.

What Are The Data Telling Us?

Data from 2002-2012 showed that biodiversity decreased dramatically with increasing urban land use. Monitoring sites that had increased road density had lower biodiversity, with species exposed to road salt toxins and mortality from cars. A decline in biodiversity was also apparent in the group of sites with public access versus those without. These results emphasize the importance of minimizing not just habitat loss, but also the negative influences that urban areas exert on remaining natural areas.

Conversely sites with the greatest area of natural cover within 500 metres had greater biodiversity and supported more Regional Species of Conservation Concern. Similarly, higher biodiversity scores were found at sites with an increased area of wetland within 2 kilometres.

This map illustrates the species richness scores for the Regional Species of Conservation Concern, with higher species diversity in rural areas of the jurisdiction, particularly the northwest, and significantly lower diversity in the urban zone.

TRCA Environmental Monitoring species richness map


Theresa McKenzie, B. Sc. Hons.
Coordinator, Terrestrial Volunteer Monitoring Program
Environmental Monitoring and Data Management