Determining NZ’s Top 10 Endangered Species

Species under consideration for the ranking of NZ’s most endangered species include some well-known and lesser-known species:

·         Maui’s dolphin

·         South Island long-tailed bat

·         Canterbury mudfish

·         New Zealand sea lion

·         Black-billed gull

·         Hamilton’s frog

·         land snails (including Powelliphanta spp.)

·         moths

·         herbs (including myosotis, linum, lepidiums, hypericums and pimeleas)

·         shrubs (hebe, kaka beak, native broom, olearia)

·         albatrosses

·         shags

·         marine invertebrates

·         freshwater invertebrates

·         fungi

·         beetles

·         gall mite

Lepidium kirkii – ‘Top 10’ contender

Lepidium kirkii habitat   Photo: Mike Thorsen

This tiny relative of the cabbage only inhabits very dry salty clays of Central Otago. What remains of its habitat are tiny scattered sites. In total, Lepidium kirkii occupies an area that would fit in most people's lounge, despite once being common on Central Otago's valley floors.

These tiny remnants are being swamped by weeds, being harvested for their clay, or being over-watered be irrigation systems. Also of concern is the invasive Albugo fungus that has been found in all remaining populations.

Is our decision-making system robust?

Our Advisory Group has developed what we believe is a robust decision-making system for determining NZ’s most endangered species. Email Liz (lsherwood@ihug.co.nz) if you would like a copy of our decision-making system, for interest or to comment on. Let us know if you think we are missing or over-emphasising any factors.

Scientists (mainly from the Department of Conservation) are now providing the Advisory Group with population details and threat information for species that are contenders for NZ’s ten most endangered species.

Contenders were identified using species data from the NZ Threat Classification System. We prioritised species categorised as Nationally Critical (the category closest to extinction), and removed species that are secure outside of NZ. Species are retained that qualified under NZ Threat Classification System Criteria B “Small population (natural or unnatural) with a high ongoing or predicted decline” or Criteria C “Population (irrespective of size or number of sub-populations) with a very high ongoing or predicted decline (> 70%)”, or if there has been a negative change in their category assessment since their previous assessment.

Experts viewing the prioritised list of Nationally Critical species have identified additional Nationally Critical marine invertebrates, freshwater invertebrates and fungi that were missing from the data.

To date, there are 60 species (including sub-species) under consideration for the top ten places. We will soon have enough specific population and threat data for our Advisory Group to apply the final analysis (Step 5 of the Decision System) to a complete and accurate list of most-endangered species.