Setting priorities for biodiversity conservation in the Department of Conservation factsheet

The process for setting priorities

DOC plans its work around four Intermediate Outcomes (IOs). Each of these outcomes has several Objectives (IOOs) for goals that are to be achieved within 25 years. The first IO is 'The diversity of our natural heritage is maintained and restored'. At present, there are five IOOs within this IO.

DOC uses the spatial conservation planning software Zonation to identify priority sites that meet two of those IOOs – 'Ecosystem representation' and 'Threatened species persistence'.

There is potential to extend this to the others but at present, priorities for other natural heritage Objectives are set locally or within specific projects, eg allocation of pest fish funding, and pest control associated with the Battle for our Birds programme.

Zonation ranks potential management sites (Ecosystem Management Units/EMUs or Species Management Units/SMUs) in an order that allows the greatest coverage of the full range of New Zealand ecosystems. The sites have previously been identified for DOC by panels of in-house and external experts. The ranking maximises the range covered by selected sites at any level of implementation, ie top 10, top 100, top 500 etc., while also taking into account:

• current site condition (past management gain)
• future gains to be made
• cost to achieve these gains

Maximising the range of ecosystems covered means that top-ranked management units are not necessarily the individual 'best sites' in terms of species diversity or condition, but the group of sites that together best represent the range of ecosystems.

In 2017, the current ranking of EMUs (established in 2013) was replaced by an integrated ranking of Ecosystem-and-Species Management Units. During the 2017 ranking, sites supporting threatened species were weighted according the following factors for each species:

• degree of threat risk
• taxonomic uniqueness
• degree of endemism

Sites were also weighted to reflect the proportion of that ecosystem at the site relative to the ecosystem's remaining New Zealand-wide extent (meaning that sites with wetlands, sand dunes and lowland forests tend to be weighted higher than other sites).

Ecosystem weightings are only one piece of information that goes into the ranking. As was the case in 2013, current site condition and the likely effectiveness and cost of management will also contribute to it.

The cost of management at a place will reflect work needed to protect the ecosystems and species present. This may include intensive management, eg mouse control, not considered necessary to protect the wider ecosystem but essential for the well-being of threatened species present at the site.

EMUs make up about one third of public conservation land. DOC aims to work on the top 850. 

Map of EMUs across New Zealand (PDF, 5,022K).

How do we know that we have achieved desired outcomes?

For species, there are two measures of a successful outcome:

• The number of threatened or declining species receiving management.
• The security of the species, ie is the management in place sufficient to secure the species from extinction?

However, these measures may be broken down by taxonomic group, eg number of birds, number of mosses, or by degrees of threat risk, eg number of Critically Threatened species, number of At Risk species.

For ecosystems, there are several measures of a successful outcome.

• Integrity – Does the management carried out result in healthy and functioning ecosystems?
• Adequacy – Is the amount of each ecosystem type managed sufficiently large and/or in three or more locations?
• Completeness – Is the full range of New Zealand ecosystem types represented in the managed places?
• Coverage – In relation to all other ecosystems, is each ecosystem managed over an area proportionate to the area it would naturally occupy?

Key terms

EMU (Ecosystem Management Unit) – possible site for conservation management. It should be large enough to provide a functioning example of one or more ecosystems and of an appropriate size for management. An EMU may include land or water of any tenure.

Ecosystem type – The kind of ecosystem, eg kauri forest, spinifex duneland, alpine tarn.

Representation – Representativeness is central to the selection of sites for protection or the management of ecosystems (and species/ taxonomic units) that represent, or sample, the full variety of biodiversity (ideally at all levels of organisation). Closely related concepts clarify the meaning of representativeness—comprehensiveness (the ability of a set of sites to represent the full range of ecological communities and processes of a landscape) and complementarity (the manner in which sites (and species) are selected to ensure that together they sample the full range of variation). In practice, this means that when an additional site is selected, account is taken of new sites that are available, and what they can add to those sites that have already been selected.

SMU (Species Management Unit) – A place that is known to be important for the conservation of threatened species for which we have enough information to plan management. An SMU is able to support viable populations of one or more species over the long term, is important for the species' national security and may be on land or water of any tenure.

Other information

• Zonation