Primary criteria for New Zealand threat rankings

In this section:

Primary criteria for assessing a species risk of extinction.

Total number of mature individuals. Nationally critical. Nationally endangered. Nationally endangered. Nationally vulnerable. Nationally vulnerable/Naturally uncommon. Nationally endangered/Naturally uncommon. Naturally uncommon/Recovering. Nationally vulnerable/Naturally uncommon. Naturally uncommon/recovering. Naturally uncommon/Relict. Not threatened/Naturally uncommon range restricted/Relict. Declining. > 10% increaseStable (±10%)10 – 30% decline30 – 50% decline50 – 70% decline> 70% decline>100 00020 000 – 100 0005000 – 20 0001000 – 5000250 – 1000< 250Population trend *

* Predicted and ongoing due to existing threats

Abbreviations: Dec = Declining, NC = Nationally Critical, NE = Nationally Endangered, NT = Not Threatened, NU = Naturally Uncommon, NV = Nationally Vulnerable, Rec = Recovering, Rel = Relict, RR = Range Restricted.

Population changes are calculated over 10 years or three generations, whichever is longer.

Where more than 1 option is available in a cell, the key distinction is whether the current population level is considered natural, or results from human impacts.

NURR (Naturally Uncommon, Range Restricted) is triggered when the breeding range is < 100,000 ha.

Secondary criteria

If population size is very difficult or impossible to estimate then secondary criteria can be used to help determine a species threat ranking.

Secondary criteria can be found on page 15 of New Zealand Threat Classification System manual. 

Text description of primary criteria table:

Nationally Critical

  • Less than 250 mature individuals (natural or unnatural); or
  • Any population size with a greater than 70% population decline over 10 years or 3 generations, whichever is longer.

Nationally Endangered

  • 250-1000 mature individuals (natural or unnatural) with a 10-50% population decline; or 
  • 250-1000 mature individuals (unnatural) with a stable population; or
  • 1000-5000 mature individuals with a 50-70% population decline.

Nationally Vulnerable: 

  • 250-1000 mature individuals (unnatural) with a population increase of more than 10%; or 
  • 1000-5000 mature individuals (unnatural) with a stable population; or
  • 1000-5000 mature individuals with a 10-50% population decline; or
  • 5000-20,000 mature individuals with a 30-70% population decline; or
  • 20,000-100,000 mature individuals with a 50-70% population decline.

Declining:

  • 5000-20,000 mature individuals with a 10-30% population decline; or
  • 20,000-100,000 mature individuals with a 10-50% population decline; or
  • >100,000 mature individuals with a 10-70% population decline.

Recovering: 

  • 1000-20,000 mature individuals with a population increase of more than 10%

Relict: 

  • 5000-20,000 mature individuals with a stable population; or
  • More than 20,000 mature individuals with a stable or increasing population; or
  • All Relict species occupy less than 10% of their original range.

Andrew J. Townsend, Peter J. de Lange, Clinton A.J. Duffy, Colin M. Miskelly, Janice Molloy and David A. Norton. 2008. New Zealand Threat Classification System manual, 2008.

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