Ministry of Environment


Sensitive Ecosystems Inventories

Sensitive Ecosystems Inventories (SEI)

About SEI

A Sensitive Ecosystems Inventory (SEI) systematically identifies and maps at risk and ecologically fragile ecosystems in a given area. The information is derived from aerial photography, supported by selective field checking of the data. SEI mapping methodology (PDF 728 KB) is based on original air photo interpretation for SEI polygons, or as an SEI theme based on Terrestrial Ecosystem Mapping (TEM) polygons.

The purpose of the Sensitive Ecosystems Inventory (SEI) project is to identify remnants of at risk and ecologically fragile terrestrial ecosystems and to encourage land-use decisions that will ensure the continued integrity of these ecosystems. It is intended for use in a variety of land-use planning processes. A Conservation Manual produced for the SEI for East Vancouver Island and Gulf Islands provides guidance on the protection of sensitive ecosystems. Similar guidelines and recommendations have been produced for other SEI projects.

The ecosystem types identified vary from region to region, according to the natural ecosystems found there, but usually include forested ecosystems, woodlands, wetlands, riparian areas and natural meadows and grasslands.


SEI Projects and Partners

These projects are carried out by two or more partners. The initial projects were a joint federal/provincial initiative of Environment Canada (Canadian Wildlife Service), the BC Ministries of Sustainable Resource Management and Water, Land and Air Protection, and the Habitat Conservation Trust Fund. SEI projects have also been initiated and/or received support and funding from ENGOs, regional districts and local governments (see individual project pages for details).



The SEI is a "flagging" tool that provides scientific information and support to local governments and others who are working to maintain biodiversity.

Maps are produced digitally using ArcInfo GIS and are also available in hard-copy at a scale of 1:20,000, using TRIM, the standard provincial government digital base map. Because the SEI is based on air photos and mapped at a 1:20,000 scale, we recommend field verification of SEI polygon boundaries and detailed ecological assessment by a professional biologist before land use decisions are made.



SEI maps and database information have been widely used in the preparation of Official Community Plans, parks and greenways plans, input to Forest Stewardship Plans and for many other site-specific planning and development purposes. As well, properties that include SEI sites could qualify as ecologically sensitive land for purposes of Canada’s Ecological Gifts Program.


Values of SEI

Ecosystems identified in a Sensitive Ecosystems Inventory are often the remnants of the natural ecosystems that once occupied a much larger area. As human activities change an increasing portion of the landscape, these remnant ecosystems become increasingly valuable as a piece of living history and the conservation of biodiversity.

They provide critical habitat for species at risk and include ecosystems at risk: Many rare species of plants and animals as well as rare ecosystems are only known to occur in specific SEI ecosystems eg. the east coast of Vancouver Island and the Okanagan.

They are biologically diverse: Sensitive ecosystems support a large variety of plant and animal species.

They provide wildlife corridors and linkages: Several of the ecosystems, particularly woodlands, riparian, older forest, mature, and older second growth forest provide important linkages between natural areas. Many wildlife species utilize a variety of different habitats and need to be able to move between them.

They bring nature into communities: Sensitive ecosystems provide patches of natural environments within developed landscapes in which plants, birds, animals and ecological processes can be observed. They provide greenways such as riparian corridors or gullies that form the backbone of many linear park systems. The scenic beauty of some ecosystems attracts visitors and is a source of pride and pleasure for local residents.

They provide recreational opportunities: Sensitive ecosystems may offer opportunities for low-impact recreation, including walking, bird-watching, photography, painting and sketching. Encountering wildlife in the backyard or on outings contribute to our quality of life.

They support learning environments: Many schools are now involved in projects with a focus on native plant community creation and wildlife habitat restoration. Children and their families are learning directly about the need and means by which to care for the environment through nature centres and hands-on workshops.

They create economic benefits: Property values increase on lands adjacent to greenway corridors, adding to local tax revenues. Events such as the Brant Festival in Qualicum Beach make significant contributions to the local economy. The increasing popularity of native plant gardening and backyard wildlife habitat creation is benefiting horticultural and landscape businesses as well as native species.

They are a legacy for future generations: Sensitive ecosystems form part of the network of greenspace for the region. By conserving important and sensitive ecosystems, ecosystem integrity and biodiversity are protected for future generations.


Species at Risk Act

The federal Species at Risk Act requires the development of recovery strategies and action plans for endangered, threatened and extirpated species, and management plans for species of special concern. Strategies include the identification of critical habitat for species needing protection. SEI is a valuable tool that can assist in the identification of likely habitat for rare and endangered species.

The Species at Risk Act also establishes the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as a legal entity, ensuring that species are assessed under a rigorous and independent scientific process that operates at arm's length from the government. The sensitive ecosystems identified for each SEI project are home to many COSEWIC-listed species, and the protection of SEI sites helps to ensure the protection of associated species at risk.