Changes in wildlife species disappearance risks indicator: data sources and methods, chapter 4


4. Methods

4.1 Committee on the Status of Endangered Wildlife in Canada status assessments

The Committee on the Status of Endangered Wildlife in Canada (the Committee) uses science and Indigenous and community knowledge to assess wildlife species at risk. All native mammals, birds, reptiles, amphibians, fish, arthropods, molluscs, vascular plants, mosses and lichens are included in the Committee's current mandate.

The Committee develops the prioritized Candidate Wildlife Species List of wildlife species needing assessment, manages the production of wildlife species status reports, and holds meetings at which wildlife species are assessed and assigned to risk categories. In all of its actions, the Committee uses the best available information to assess a wildlife species' risk of extinction or extirpation, which it may obtain from any credible source of knowledge of the wildlife species and its habitat.

The Committee annually commissions status reports for high-priority candidate wildlife species on the Candidate Wildlife Species List or for wildlife species that require reassessment (update status reports).

All status reports (including updated status reports and unsolicited reports) must meet the Committee's standards for quality and completeness. The reports are subject to thorough reviews by the appropriate Species Specialist Subcommittee and the Aboriginal Traditional Knowledge Subcommittee, as well as by jurisdictions that have a responsibility for the wildlife species (including governments of the provinces and territories where the wildlife species occurs, federal departments responsible for the wildlife species, and wildlife management boards). Additional outside experts may also be asked to review status reports. When the reviews are complete and any required revisions have been incorporated, the report is distributed to all Committee members.

The Committee members use status reports as a basis for discussion and for status assignment at semi-annual Wildlife Species Assessment Meetings. For each wildlife species considered at a Wildlife Species Assessment Meeting, the Committee sequentially considers each of five items to determine a Canadian status designation:

  1. Is there sufficient information presented in the report to determine wildlife species eligibility?
  2. Given sufficient information, is the wildlife species eligible for assessment?
  3. Is the status report adequate and acceptable for assessment purposes?
  4. What status is suggested by application of the Committee's approved quantitative assessment criteria and guidelines?
  5. Does the suggested status conform to the Committee definition for the proposed status category?

Following the completion of the assessment process, wildlife species are assigned one of seven status categories by the Committee: Extinct, Extirpated, Endangered, Threatened, Special concern, Not at risk or Data deficient. As of May 2016, 970 wildlife species had status categories assigned (Table 1).

4.2 Committee on the Status of Endangered Wildlife in Canada change status

The Committee also notes a change status in its assessments. The seven possible change statuses are: New, No change, In a higher risk category, No longer at risk, In a lower risk category, Changed and Reassigned. Species that have been assessed only once are given a change status of New. For all other species, the change status is based on the two most recent assessments. Species that are Data deficient on one date are given a status of Changed. The Reassigned status is used in cases where the unit being assessed has changed based on new information; examples might include a species that is split into subspecies or geographical units.

Table 1: Committee on the Status of Endangered Wildlife in Canada, number of species by status category and change status
Status category of wildlife species New No change In a higher risk category No longer at risk In a lower risk category Changed Reassigned
Extinct 1 11 1 0 0 0 2
Extirpated 2 18 0 0 0 1 2
Endangered 119 124 43 0 1 1 32
Threatened 63 47 32 0 16 0 14
Special concern 81 72 7 0 28 2 19
Not at risk 130 11 0 24 0 2 10
Data deficient 33 4 0 0 0 13 4
Total 429 287 83 24 45 19 83

Download data file (Excel/CSV; 664 B)

4.3 Derivation of indicator data

The Committee change status provides the base information for the Changes in Wildlife Species Disappearance Risks indicator. The indicator does not include species with a change status of New as they have only been assessed once. Species with a status of Changed are also excluded as they are Data deficient on one of the most recent assessments (Table 2). Species that are Data deficient in both recent assessments are assigned a change status of No change by the Committee, but are removed from the Changes in Wildlife Species Disappearance Risk indicator.

Table 2: Relationship between the Committee change status and Changes in Wildlife Species Disappearance Risk indicator
Committee on the Status of Endangered Wildlife in Canada change status Definition Changes in Wildlife Species Disappearance Risk indicator
New Wildlife species examined for the first time are assigned a category of New Excluded from the indicator
Changed Wildlife species moved to the Data deficient category from a risk category or to a risk category from the Data deficient category Excluded from the indicator
No change Wildlife species stays in the same category after reassessment No change[A]
In a higher risk category Wildlife species placed in a higher risk category after the most recent reassessment Higher risk
In a lower risk category Wildlife species placed in a lower risk category after reassessment Lower risk
No longer at risk Wildlife species moved to the Not at Risk category from a risk category Lower risk
Reassigned Wildlife species that has been assigned to a different designatable unit than previously Case-by-case assignment

Note: [A] Wildlife species that are Data deficient on both dates when an assessment was made are excluded from the indicator.

Wildlife species with a change status of Reassigned are individually examined, and grouped into units that can be considered as a whole. For example, a wildlife species that was split into two subspecies on reassessment would be treated as one unit in the indicator. As of May 2016, 83 wildlife species with a status change of Reassigned were grouped into 41 units whose status could be examined. If the direction of change could be determined unambiguously, the units were given a change category for the indicator. If the direction of change could not be determined, the unit was given a category Unknown and was not included in the indicator.

Of the 41 units, 12 were included in the indicator: 6 were assigned to the No change category, 3 to Lower risk and 3 to Higher risk. The remaining 29 could not be determined. For detailed information on the allocation of wildlife species with a change status of Reassigned from the Committee, consult Annex 1.

Overall, the Changes in Wildlife Species Disappearance Risk indicator provide information on 447 wildlife species.

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