Criteria for New Zealand threat rankings

Introduction

Find out about the criteria we use to assess the conservation status of our species.

Primary criteria

Nationally Critical

  • Less than 250 mature individuals (natural or unnatural); or
  • 250-1000 mature individuals and 50-70% decline over 10 years or 3 generations; 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.

Primary criteria table

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% increase Stable (±10%) 10 – 30% decline 30 – 50% decline 50 – 70% decline > 70% decline >100 000 20 000 – 100 000 5000 – 20 000 1000 – 5000 250 – 1000 < 250 Population 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

Notes:

  • 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 size level is considered natural, or results from human impacts.
  • 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 (number of subpopulations or area occupied) 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, 2008.

References

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.

Related

IUCN Red List of Threatened Species website

Threatened species management activity

Reports listing New Zealand native species that are classified in some way as threatened, and which had work targets – either active species management programmes or survey monitoring and research.

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