Context

New Zealand’s wetlands (especially swamps, fens and marshes) and active sand dunes are much altered in condition and reduced in extent as a result of human activity. Of the naturally uncommon ecosystems that have been mapped, four are both endangered and have less than a fifth of their current extent under protection. These are volcanic dunes, young tephra plains and hillslopes, coastal turfs and shell barrier beaches. The data presented highlights the specific ecosystem types most in need of further protection.

Key findings

• Wetlands and active sand dunes are much reduced in extent (only 10% of the original extent of wetlands is left) and altered in composition from their pre-human state. These ecosystems support unique communities of plants and animals, and provide ecosystem services.
• Of the different types of wetland; swamps, fens and marshes are a high priority for protection. All remaining freshwater wetlands face significant threats; in particular, from land-use change (drainage, vegetation clearance), invasive species and nutrient enrichment.
• To date, 71 different types of naturally uncommon ecosystems have been described for New Zealand. These ecosystems range from those that are small in size (100 m² to a few hundreds of hectares), but geographically widespread, to those that are larger (e.g. ten thousands of hectares) but geographically restricted. As each has distinct environmental conditions and support unique communities of plants and animals, including rare and threatened species, they make significant contributions to our national biodiversity.
• Based on the International Union for the Conservation of Nature (IUCN) Red list criteria or ecosystems, 45 of these naturally uncommon ecosystems are threatened. Of these, 18 are classified as critically endangered (the highest level of threat), 17 as endangered, and 10 as vulnerable.
• Of the 23 mapped critically endangered or endangered ecosystems, four (volcanic dunes, young tephra plains and hillslopes, coastal turfs, shell barrier beaches) have less than 20% of their total area under public conservation land or other formal protection.
• Of the 23 mapped critically endangered or endangered ecosystems that occur on public conservation land, one (old tephra plains or ‘frost flats’) has more than 90% of this classed as ‘Stewardship land’, the least secure level of protection. Based on the New Zealand Land Cover Database v4.1 (LCDB v4.1), there have been minimal land use changes between 2008 and 2012.

Figure 1: Change in wetland area by wetland type, pre-human and 2008

Figure 2: Extent of active sand dunes 1950s - 2008

Figure 3: Threat status of naturally uncommon ecosystems

Figure 4: Land tenure of Critically endangered, Endangered and Vulnerable naturally uncommon ecosystems

Figure 5: Stewardship proportion of Critically endangered, Endangered and Vulnerable naturally uncommon ecosystems

Why is this important?

Wetlands, sand dunes and other naturally uncommon ecosystems are still seriously under-protected in New Zealand. Their protection should remain a priority in national and regional conservation policy statements. All remaining New Zealand wetlands should rate as high priority for protection if New Zealand is to meet its international obligations under Target 11 of the Convention of Biological Diversity. Similarly, most remaining active dune systems are facing significant threats and these are likely to continue, particularly from invasive plant species, coastal development and projected sea-level rise.

The application of the IUCN’s Ecosystem Red-List criteria to naturally uncommon ecosystems provides a rational basis to identify which ecosystems are the most threatened and so inform conservation priority setting. Of the 45 threatened ecosystems, the four ecosystems that have so far been identified as having less than 20% of their total area under formal protection are of the top priority for future protection efforts. It is a high priority to define the conservation status of the lands supporting old tephra plains (frost flats) as more than 20% of their total extent on Public Conservation Land is classed as ‘Stewardship Land’ (the lowest level of protection).

Definitions and methodology

• This uses information from Measure 6.1.4: “Proportion of threatened naturally uncommon and significantly reduced habitats under protection”.
• The contemporary and estimated pre-human extents of wetlands were mapped at 1:50,000 to a minimum size of 0.5 ha. The historic extent was estimated from the national Fundamental Soil Layers (FSL) database based on soil drainage and other soil properties and refined using a 15m digital elevation model derived from 20 m digital contours.
• The contemporary extent was mapped using 26 Landsat Enhanced Thematic Mapper (ETM+) satellite imagery, and wetland point and polygon data. The data were collated from recent surveys, field work, or photo-interpretation held by local and central government. The list of naturally uncommon ecosystems developed by experts on the basis that they each covered less than 0.5% of the land area of mainland New Zealand.
• The total area of sand dunes has been assessed at regular intervals, and historical estimates of total extent were available for 1911, 1950, 1970s, 1980s, and the 1990s. A current (2008) map of active sand dune extent was developed by DOC using a mix of existing data and recent remote imagery.
  A list of 71 naturally uncommon ecosystems was created by experts on the basis that they each covered less than 0.5% of the land area of mainland New Zealand. DOC and Landcare Research have produced maps for 33 of them by using pre-existing maps, modelling and interpretation of aerial imagery. Of these, 22 are threatened. Land tenure and protection status were examined using GIS analysis. The wetland maps still need to be ground-truthed in parts of the country (e.g. North Island) and most of the naturally uncommon ecosystem maps have yet to be ground-truthed. As such, the statistics presented here must be interpreted with caution.

Data quality

This measures is classified as a national indicator.

Relevance

This measure relates to indicator 1.6.1 - Ecosystem representation and protection status.

Accuracy

This measure complies with the data quality guidelines used in New Zealand’s Environmental Reporting framework.

Outcomes Monitoring Framework

The Department of Conservation’s (DOC’s) Outcomes Monitoring Framework provides a platform on which DOC and others can assess outcomes in a clear, structured and transparent way (Lee et al., 2005). It has been developed as a logical hierarchy that is based on broad, overarching Outcomes, beneath which are nested Outcome Objectives, Indicators, Measures and Data Elements to provide ever increasing levels of detail. The framework is scalable, as the indicators and measures remain compatible and consistent whether applied locally, regionally or nationally.

The recently updated framework provides a roadmap for gathering information to meet the specific objectives of DOC and other agencies (McGlone and Dalley, 2015). The provision of a national framework with agreed outcomes, indicators and measures supports collaboration with land management and regulatory agencies, allowing for more integrated environmental policy and ‘State of the Environment’ reporting. DOC has partially implemented a national monitoring and reporting system, whereby priority indicators and measures are routinely used to report on progress against the objectives and outcomes. This factsheet reports on a measure for the 2018/2019 year.