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Find the IUCN Red List threat category interactively

Source: R/rl_threat_category.R
rl_threat_category.Rd

An interactive decision tree that walks you through the five IUCN Red List criteria (A to E) like a form filled in at the console, and tells you which threatened category (Critically Endangered, Endangered or Vulnerable) your values meet. You can go back to any earlier question to change an answer, and you review all your answers before the result is shown.

Usage

rl_threat_category()

Value

Invisibly, an object of class rl_threat_category: a list with

category

"CR", "EN", "VU", or NA when no threatened category is met;

criteria

the criteria met at that category, for example "A2; B1ab", or NA;

details

a tibble with one row per criterion assessed and the columns criterion, category, code and reason;

answers

a list of the values you entered.

Printing the object shows the report again. If you quit, NULL is returned invisibly.

Details

Start by choosing the criteria you have data for; only the questions for those criteria are asked. At every prompt you can type:

b

go back to the previous question;

q

quit without a result;

?

show help for the current question;

Enter

keep your current answer when you come back to a question, or leave an optional value unknown;

na

set an optional value back to unknown.

The thresholds are those of the summary of the five criteria in the IUCN Red List Categories and Criteria:

CriterionCRENVU
A1 reduction>= 90%>= 70%>= 50%
A2, A3, A4 reduction>= 80%>= 50%>= 30%
B1 extent of occurrence< 100 km2< 5,000 km2< 20,000 km2
B2 area of occupancy< 10 km2< 500 km2< 2,000 km2
B(a) number of locations1<= 5<= 10
C mature individuals< 250< 2,500< 10,000
C2a(i) largest subpopulation<= 50<= 250<= 1,000
C2a(ii) share in one subpopulation90-100%95-100%100%
D mature individuals< 50< 250< 1,000 (D1)
E probability of extinction>= 50% in 10 years or 3 generations>= 20% in 20 years or 5 generations>= 10% in 100 years

Criterion B also needs at least two of the conditions (a) severe fragmentation or a limited number of locations, (b) continuing decline and (c) extreme fluctuations. Criterion C also needs a continuing decline (C1) or a continuing decline with a small or concentrated subpopulation structure or extreme fluctuations (C2). D2 (a very restricted range facing a plausible, fast-acting threat) applies to Vulnerable only. When both are given and the extent of occurrence is smaller than the area of occupancy, the extent of occurrence is raised to equal it, as the guidelines require.

A taxon is listed in the most threatened category that any criterion qualifies it for. When no criterion is met, the taxon does not qualify for a threatened category on the information given; it may be Near Threatened, Least Concern or Data Deficient, which this function does not decide.

This is a screening aid, not a formal assessment. Read the definitions of the terms used (location, severe fragmentation, continuing decline, extreme fluctuations) in the IUCN guidelines before listing a taxon.

References

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. Gland, Switzerland and Cambridge, UK: IUCN.

IUCN Standards and Petitions Committee. 2024. Guidelines for Using the IUCN Red List Categories and Criteria. Version 16. https://cmsdocs.s3.amazonaws.com/RedListGuidelines.pdf

See also

rl_reduction() to estimate a population reduction for criterion A, rl_eoo() and rl_aoo() for the criterion B range metrics, and rl_generation_length().

Examples

if (FALSE) { # \dontrun{
res <- rl_threat_category()
res$category
res$details
} # }