5.14 De Lange & Norton Classification of Uncommon Plants

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System Title	5.14 De Lange & Norton Classification of Uncommon Plants
Keywords	Threatened taxa, taxa status, classification, endangered, vulnerable, declining, naturally uncommon, range restricted.
Description	This system modifies the IUCN system for classifying threatened taxa. It focuses on addressing two problem areas with the IUCN system: the need to distinguish between those species that are naturally uncommon and those that are uncommon because of human activities; the need to identify species that are declining but are not yet threatened with extinction, without raising the problems associated with the old IUCN category "rare". The system has been developed to address the classification of threatened plants. The authors consider that it could easily be extended to other taxonomic groups. Key features of the system are that it: retains the IUCN threatened categories introduces new categories for naturally uncommon and recovering taxa recognises declining taxa that are not yet seriously threatened removes the lower risk classification entirely retains a category for taxa that are insufficiently known retains the existing IUCN category of "presumed extent".
Status	The system was published in a 1998 publication by the Royal Society of New Zealand.
Organisation	Department of Conservation
Jurisdiction	New Zealand
Contact person/position	Peter de Lange Scientist
Address	Science, Technology and Information Services Department of Conservation Private Bag Newton Auckland Phone +64 9 307 9279 Fax +64 9 377 2919 Email pdelange@doc.govt.nz Or David Norton University of Canterbury Private Bag 68908 Christchurch Phone +64 3 366 7001 Fax +64 3 364 2999
Available format	Published papers
Access	Freely available
Geographical coverage	New Zealand

Operational Specifications
Original Purpose.	To develop a classification system for threatened plants in New Zealand that better addresses the naturally uncommon species problem.
Scale of Operation	It operates at the national level.
GIS Compatibility	N/A
Relationship between levels in the classification system	N/A
Contributing databases/ classification systems	N/A
Contributing database GIS compatibility	N/A
Relationship with other classification systems and spatial frameworks.	It modifies the IUCN system for classifying threatened taxa to better address New Zealand requirements. The approach of De Lange and Norton has been further developed to produce the New Zealand Threat Classification.
Relationship with other databases	N/A

Current and emerging use for:
Assisting with determining historic state/ baseline	The historic status of the species needs to be known at a general level to allow the classification system to work properly.
Assisting with determining current state/ baseline	The classification system identifies the current state of particular taxa.
Asssisting with scenario building and modelling of possible futures	Trends over time in the status of particular taxa may be able to be used to model possible future scenarios.
Risk Assesment	The classification system identifies species at risk and attempts to identify the degree of risk
Monitoring site selection and sample design	N/A
Aggregating and reporting data locally, regionally and/or nationally	Data is collected at the national level.

Current use (who,level,why)

This classification system has been further developed to produce the New Zealand Threat Classification. This later system is being used by the Department of Conservation to classify the threat status of New Zealand plant and animal species.

User friendliness/public and decision maker understanding

A number of the IUCN categories are retained. The names for the categories in the revised de Lange & Norton system are reasonably self explanatory.

System strengths

It is simple and logical.
It recognises that not all uncommon species are threatened species
It provides for taxa that are still nationally widespread but in serious decline

Current limitations of the system

The system has been developed for plants in terrestrial environments. It may not work as well with other taxonomic groups in other environments.
Not all categories are directly internationally comparable.

References

De Lange, P.J.; Norton,D.A. 1998. Revisiting rarity: a potential perspective on the meanings of rarity and the classification of New Zealand's uncommon plants. Pp145-160 In: Ecosystems, Entomology and Plants. Royal Society of New Zealand Miscellaneous Series, No 48.

System Title