Describing and Evaluating Biodiversity Values

Ecological characterisation and assessment

Ecological characterisation and assessment are undertaken for a variety of purposes and at a variety of scales. A characterisation or description identifies the key species, communities and ecological processes present and should include pertinent attributes of the non-biotic environment.

Ecological assessments

An ecological assessment includes an evaluation of the relative ecological importance of the area and typically identifies threats and management requirements. The evaluation of relative importance typically occurs within the context of one of several spatial frameworks for terrestrial and aquatic environments.

There are a number of reasons that councils assess the ecological value of natural areas, which include:

  • providing information to assist a council to develop RMA plans and other methods and/or a strategy for promoting the maintenance of indigenous biodiversity (eg, developing schedules of significant areas of indigenous vegetation and/or significant habitat for indigenous fauna)
  • assessing environmental effects of regulated activities
  • prioritising proactive management (eg, pest control, funding for plants and fencing)
  • developing monitoring programmes
  • acquiring and managing reserves.

Ecological assessments tend to adopt similar methodologies, but there are variations in the detail of information gathered depending upon the purpose of the assessment and the resources available to undertake it.

Purposes and scales for ecological assessment range from broad scale rapid assessment for identifying priorities for protection (as in a Protected Natural Areas Programme ecological district survey) to a detailed ecological assessment of a single site as part of a resource consent application for a development (eg, a subdivision proposal).

Ecological assessment effort and methodology varies, and should be related to the type of ecosystem and the magnitude of the issue, whether that be the amount of expenditure being considered for purchase, restoration or enhancement or the level of potential impact of a proposed development. Extra effort should be expended in highly fragmented or depleted regions or ecosystem types. Even a highly degraded site may have value if it is a rare or depleted ecosystem or contains a population of a threatened species.

Assessment effort can be targeted. In some circumstances, local or expert knowledge about the environment can suggest that a particular value is likely to be present in a given site. For example, if a species such as kiwi is known to occupy similar habitat in the general area or has been sighted at the location in the past, then it is appropriate to request further information about the presence and abundance of kiwi.

Spatial frameworks for ecological assessment

The relative importance of an area is typically evaluated within the context of a spatial framework. In the terrestrial environment, the key spatial frameworks used in New Zealand are:

  • ecological regions and districts
  • Land Environments of New Zealand
  • land systems
  • ecodomains.

The River Environment Classification and Marine Environment Classification have been developed for rivers and the marine environment respectively.

‘Ecological regions and districts’ is the spatial framework for the Protected Natural Areas Programme. New Zealand is divided into 85 ecological regions and 268 ecological districts using information about geology, topography, climate and biota. Not all ecological districts have been surveyed.

Land Environments of New Zealand (LENZ) is a spatial framework developed by Landcare Research to provide a framework for the assessment of terrestrial biodiversity. Units are defined by computer analysis of available quantitative data on various climatic and geological/soil parameters that affect the growth of plants. ‘Land environments’ are areas with similar climatic and geological/soil characteristics. Unlike the ecological regions and districts spatial framework, a single land environment may be present in a number of non-contiguous locations. LENZ is scalable, with more environments being identified at finer levels of analysis.

Land systems are defined by expert opinion, using information on rock type, tectonics, climate and biota. The concept was developed by Landcare Research and Lucas Associates and land systems have been defined for several local authorities including Environment Bay of Plenty and Marlborough.

Eco-domains is a spatial framework developed for the Wellington Region. The boundaries are delineated manually using a variety of data sources addressing climate, soil type, rock type and vegetation. Sixty-four eco-domains have been developed for the Wellington Region.

The River Environment Classification divides river systems into units based on similarities and differences in a range of physical variables. The underlying assumption is that the physical variables chosen (‘controlling variables’) determine the physical habitat and therefore the biota most likely to be found there. Available physical databases are used to classify river reaches using ‘rules’ developed by an expert panel.

The Marine Environment Classification uses multi-variate clustering of several spatial data layers that describe the physical environment. The classification system has been developed at two scales:

  • a broad scale classification of the entire Exclusive Economic Zone (covering the area below the mean high water line (but not including estuaries) from approximately 25 to 58 degrees South and 158 degrees East to 172 degrees West)
  • at the regional scale for the Hauraki Gulf Region (encompasses waters below the mean high water line (but not including estuaries)).

Ecological survey methodology at the district-wide scale

Broad scale rapid assessments tend to follow a similar process although there is usually greater emphasis on mapping for identifying priorities for protection (as in a Protected Natural Areas Programme ecological district survey).

The main components of broad scale assessments in terrestrial environments include:

  • studying aerial photographs, topographical, soil and geology maps
  • gathering existing ecological, botanical and zoological information, as well as information on the location of threatened species
  • using ecological district maps, Land Environments of New Zealand environment maps together with geology and soil maps to divide up ecological district into land systems
  • evaluating threatened environment maps
  • identifying original vegetation by using Landcare Research predicted-vegetation maps or, if there is more time, using old survey maps, topography, soils and so on
  • developing vegetation classification
  • mapping and classifying indigenous vegetation of ecological districts using field surveys, aerial photos and classification systems
  • undertaking a field survey of natural areas – using walk-through descriptions or survey sheets. This includes describing key vegetation patterns and vegetation types identifying flora and fauna present
  • ensuring wetlands, dune systems, riparian habitats, coastal forest, lowland ecosystems are a priority (eg, map all wetlands)
  • developing a database linking to vegetation polygons in a geographic information system (GIS)
  • developing an ecological unit classification (vegetation and landform)
  • identifying significant natural areas based on significance criteria
  • assessing representativeness based on original vegetation types as well as existing vegetation patterns
  • identifying significant fragments as well as larger areas
  • identifying areas that provide buffering, corridors and connections
  • evaluating the connections across the landscape and natural areas that are important as part of the wider landscape
  • identifying natural areas of value for fauna such as skinks and geckos as well as more visible species such as birds
  • describing the natural areas – this includes the key vegetation types and land units present, ecological significance within the district, special features and species present
  • summarising key findings
  • producing the report as well as GIS database and maps.

Ecological survey methodology at the site scale

Robust site-based scientific ecological assessment methods for terrestrial areas generally include the following components:

  • literature review and background information on the site’s history, age, composition, threatened or unusual species. Historical accounts will often give an insight into the original pattern of indigenous vegetation and habitats across the landscape. They can help to distinguish which parts of the landscape support remnant areas and which areas of vegetation have arisen as a result of disturbance since people arrived.
  • investigation of the underlying physical environment of the landscape. Indigenous vegetation patterns respond to the physical conditions and vary according to physical parameters such as soil, geology, slopes, drainage, altitude and climate. To that end, information about the physical aspects of the landscape, such as topographic maps, soil and geology maps and Land Environments of New Zealand information can be used to indicate the original ecosystems expected at a locality and the sort of regeneration that would be expected after disturbance
  • remote sensing, including reviewing topographic maps, recent and historic air photographs, 3D assessment of stereo pair air photos. These techniques give information about the vegetation and habitats that are present at a site and can also be helpful for context setting
  • seeking local knowledge of current conditions, values and changes over time from landowners, neighbours, local conservation or specialist groups – such as the Ornithological Society of New Zealand or Botanical Society, local authorities, Department of Conservation or staff from academic or research institutions and consultants with local knowledge
  • context setting – reviewing the wider landscape, taking into account relative loss of ecosystem extent in the ecological district or environmental domain, connections (via for instance waterways or forest fragment stepping stones), buffering by other vegetation types, or matrices (eg, if the site is part of an ecological sequence along an altitudinal or coastal to inland gradient, or part of a diverse matrix of habitat types)
  • field assessment to determine the site’s current size, shape, condition, structural intactness, species composition, evidence of functioning (eg, seedlings, nesting), existing weed or pest problems and other disturbances
  • report writing, including methodology and recommendations (may include peer review as appropriate).

A good site-based terrestrial ecological assessment should generally include:

  • ecosystem and hydrosystem type(s)/classification
  • size, shape, aspect, altitudinal range, location (map and geographic reference such as global positioning system or topographical map coordinates)
  • a species list (native and introduced, with the latter generally indicated by a * or separately listed)
  • tenure of the lands involved
  • a vegetation or habitat type map where appropriate, with scale, North arrow, date of representation (current or historic) and legend
  • a description of habitats and biological communities present (usually by reference to the dominant and/or most abundant species)
  • notes on any special features (threatened or locally endemic species, geomorphic features, species at their geographic or altitudinal limits, unusually high diversity)
  • notes on those species likely to be particularly susceptible to the impacts of climate change
  • the site condition, considering features such as impacts of grazing animals, pest animals, plant pests, constructed features (tracks and so on), water quality
  • methodology, including field survey effort (time spent, proportion of area covered, time of day/season visited), equipment used (eg, bat detectors, electric fishing gear, samples collected, analyses of data undertaken and so on)
  • limitations (eg, acknowledgement that the survey did not assess invertebrate fauna).

Existing large-scale datasets that may be used in ecological assessments, including cautions

Protected Natural Areas Programme
In some parts of the country, Protected Natural Areas (PNA) Programme ecological region and/or district surveys and associated reports have been completed. These can be helpful, but should be used with an understanding of their original purposes and limitations and consideration of the age of the information.

It is tempting to regard areas that have been recommended for protection in a PNA Programme report as being a full list of areas that should be considered as significant under s6(c) of the RMA. However, the purpose of the PNA Programme was to recommend for protection only the best examples of natural areas that represent the ecological diversity of a district. In addition, the programme was not intended to be the final identification of all of the good examples. It should also be noted that the PNA Programme had a terrestrial focus that included palustrine wetlands and sometimes smaller lakes.

PNA Programme information can still be useful as a snapshot in time. Information about the vegetation classes and types and the land-systems and landforms can be a helpful reference.

Sites of Special Wildlife Interest
The local Sites of Special Wildlife Interest (SSWI) data set is available in hard copy form (maps and field sheets) in relevant Department of Conservation offices. In some cases, reports have been prepared, although the associated maps may not be sufficiently detailed for some site-based work. The sites identified in these databases should not be considered as being a full list of areas that can be considered as significant under the RMA. The purpose of the survey programme underlying this database was to identify good wildlife habitat. The emphasis was on those species that can be relatively rapidly located at a site. The SSWI database does not include areas of significant vegetation or habitats of threatened plant species unless wildlife of interest was also found.

This is now an old dataset with most of the survey work having been done in the 1980s and a number of the identified wildlife habitats have changed as have some of the species of fauna present.

Wetlands of Ecological and Representative Importance
Wetlands of Ecological and Representative Importance (WERI) is a computer database that contains records on approximately 3000 wetlands throughout New Zealand. Information includes: size; location; land ownership; classification (hydroclass, geomorphic origin, community class, dominant plant species); modifiers and threats; buffer, wildlife and vegetation values; other ecological values; cultural values; significance; and sources of

This is a relatively superficial database prepared in the 1980s with no accompanying map. It is useful for an overall picture but should be used with caution when making decisions about a particular site.

NIWA freshwater fish database
This is an electronic database managed by the National Institute of Water and Atmospheric Research (NIWA). Site information on fish records is added as it becomes available from a variety of organisations from throughout New Zealand. The database is not user friendly and does need to be accessed and interpreted by a suitable expert.

While the database is continually added to, there is no systematic survey programme. This means that an absence of records for a site should not be interpreted to mean that there is nothing of interest present. In addition, many of the records have been obtained from electric fishing, which is a method only suited to certain types of water bodies.

Other datasets
Other relevant datasets include the Department of Conservation’s Bioweb and herbaria at universities, Crown research institutes and Te Papa. Regional councils have a variety of datasets, especially for freshwater environments.

Evaluating significance under section 6(c) of the RMA

Section 6(c) of the RMA requires all those exercising functions and powers under the Act to recognise and provide for “the protection of areas of significant indigenous vegetation and significant habitats of indigenous fauna”, including on private land.

A variety of criteria sets have been developed for assessing significance under s6(c). The types of format have usually been one or more of:

  • open-ended criteria
  • standards to be met
  • factor headings
  • use of filter criteria (note filter criteria should be used with caution).

Criteria sets typically include various combinations of the following elements:

  • representativeness
  • rarity and distinctive features
  • naturalness
  • ecological context
  • diversity of ecological units and patterns
  • size and shape
  • ecological viability
  • sites previously assessed and identified as being of ecological value
  • particular threatened habitat types
  • migratory species passage
  • indigenous cover in land environments
  • non-ecological matters.

When criteria sets for evaluating ecological significance under s6(c) are being prepared the following should be addressed.

  • A council needs to decide between ‘standards’ based criteria and those that form a general list of matters to consider.
  • Criteria should be able to be assessed objectively, as this provides a transparent and repeatable assessment process.
  • A council needs to identify how many criteria need to be ‘met’ for a natural area to be considered ecologically significant.
  • A sustainability or viability filter should not be part of a significance assessment, but may be considered in setting conditions on consents or prioritising areas for management.
  • The criteria should encompass a wide range of important ecological attributes.

A criteria set should be developed in association with an ecologist and preferably also with local communities.

Criteria format types

A variety of criteria sets have been developed for assessing significance under s6(c). The types of format normally used include:

  • open ended criteria: usually criteria are assessed collectively and an assessment of ‘significance’ is a matter of expert judgement (an example of such a criterion could be the degree of naturalness relative to what remains in the ecological district)
  • standards to be met: usually one or more criteria are to be met before a site is considered to be ‘significant’ (eg, indigenous vegetation or habitat of indigenous fauna that supports one or more indigenous species that are threatened or rare nationally or regionally). Well-written standards are more transparent and can be easily applied and used in the field
  • factor headings: in this approach, criteria are written as a set of factors that are usually considered collectively. Two examples include representativeness and rarity. An assessment of such ‘criteria’ is a matter of expert judgement. There may be inconsistencies in the application of such ‘criteria’ as their wording provides little guidance
  • use of a filter criterion: in this approach, a site must meet a specific criterion to be considered ‘significant’. This is the case regardless of how well the site may meet other criteria. The filter criterion used is typically one addressing viability or sustainability. Given the wide variety of sites and situations, the use of a single filter criterion in assessing ‘significance’ is inappropriate.

The use of a filter criterion that all sites must meet (regardless of their other values) can lead to perverse outcomes. For example, if a site has to meet a viability criterion, this may (perversely) encourage some landowners to undertake damaging permitted activities (grazing a freshwater wetland) to ensure that the site is assessed as being ‘non-viable’ and, therefore, is not ‘significant’. Another example is where vegetation has to exceed a minimum height before it can be considered significant and, therefore, subject to restrictions on clearance. Such a filter criterion may (perversely) encourage landowners to clear indigenous vegetation before it reaches this height.

Equally, it is important to recognise that triggering one of the criteria only may cause a site to be listed as significant, which may not in fact be the case. Hence, filter criteria should be used carefully, recognising the above limitations.

Criteria addressing representativeness

Representativeness is a core criterion in ecological significance assessments. It is the degree to which a site could contribute to a network of protected sites that represent the full diversity of species, ecological communities and ecosystems in an ecological district or other spatial framework unit. It is determined from:

  • the extent of the original ecosystems and biological communities
  • the extent and quality of the remaining natural areas.

The assessment of representativeness should address both the original vegetation types as well as current ecosystem types (eg, regenerating forests, induced habitats).

Using the ‘standards’ approach to criteria writing, regional examples of such a criterion are as follows.

  • “Indigenous vegetation or habitat of indigenous fauna contains associations of indigenous species representative, typical or characteristic of the natural diversity of the region or any relevant ecological districts”
  • “It is vegetation or habitat that is currently under-represented (10% or less of its known or likely original extent remaining) in an ecological district or ecological region or nationally”

Criteria addressing rarity and distinctive features

Rarity and distinctive features are typically part of the core set of criteria for assessing ecological significance. Usually these matters are addressed in different criteria but where the criteria list is abbreviated, rarity and distinctive features are combined in one criterion. Rarity addresses the presence and abundance of rare and/or threatened species, associations, assemblages and communities at multiple scales. Distinctive ecological features include: unusual species distributions, national distribution limit boundaries, endemic species and assemblages and unusual species associations.

Examples of the rarity criteria are as follows.

  • “Indigenous vegetation or habitat of indigenous fauna supports an indigenous species or associations of indigenous species threatened or rare nationally, regionally or within the relevant ecological district”.
  • “Indigenous vegetation or habitat of indigenous fauna can contribute to the maintenance or recovery of a species threatened or rare nationally, regionally or within the relevant ecological district”.
  • “It is vegetation or habitat that is currently habitat for indigenous species or associations of indigenous species that are: threatened with extinction; or endemic to the Waikato region”

Examples of the distinctiveness criteria areas follows.

  • “Indigenous vegetation or habitat of indigenous fauna is distinctive, of restricted occurrence, or at the limits of its natural distribution range, or has developed as a result of factors such as natural geothermal activity, historic cultural practices, altitude, water table, or soil type”.
  • “It is indigenous vegetation or habitat that is, and prior to human settlement was, nationally uncommon such as geothermal, Chenier plain, or kaarst ecosystems”.
  • “Distinctiveness/Special Ecological Characteristics – The type and range of unusual features of the area itself and the role of the area in relationship to other areas locally, regionally or nationally, including: – presence of species at their distribution limit; − levels of endemism; − supporting protected indigenous fauna for some part of their life-cycle (e.g. breeding, feeding, moulting, roosting), whether on a regular or infrequent basis; − playing an important role in the life-cycle of protected migratory indigenous fauna; − containing an intact sequence, or a substantial part of an intact sequence, of unusual ecological features or gradients”.

Criteria addressing naturalness

Naturalness is part of many sets of criteria that assess ecological significance. Naturalness is a simple, but ultimately complex concept. Typically the extent of ecological naturalness of an area is interpreted to mean how close the structure, composition and functioning of an area is compared with an ideal ‘original’ condition.

An example of a ‘naturalness’ criterion is:

  • “Indigenous vegetation or habitat of indigenous fauna is in a natural state or healthy condition, or is in an original condition”.

Criteria addressing ecological context

Most sets of criteria address ecological context. Ecological context includes:

  • the degree to which the site is important for connecting habitats and/or other sites of significance
  • the extent to which the condition of the site safeguards attributes of other important sites (eg, upstream riparian habitats enhancing adjoining and downstream riverine habitats; downstream fish passage protection maintaining fisheries values upstream).

Another aspect of ecological context is the value that small remnants can have in a landscape that has lost almost all of its indigenous vegetation. These remnants can provide seed sources for more mature tree species and provide seasonal food sources for birds that otherwise reside in more intact upland areas. Small but sustainable natural features can provide ‘stepping stones’ of habitat for indigenous wildlife across a developed landscape.

Examples of ecological context criteria are as follows.

  • “Indigenous vegetation or habitat of indigenous fauna contributes to the ecological viability of adjoining natural areas and biological communities, by providing or contributing to an important ecological linkage or network, or providing a buffer from adjacent land uses”.
  • “Indigenous vegetation or habitat of indigenous fauna provides habitat for indigenous species at key stages of their life cycle”.
  • “It is an area of indigenous vegetation or habitat for indigenous species (which habitat is either naturally occurring or has been established as a mitigation measure) that forms, either on its own or in combination with other similar areas, an ecological buffer, linkage or corridor and which is necessary to protect any site identified as significant under criteria 1–10 from external adverse effects”.

Criteria addressing diversity of ecological units and patterns

A criterion that addresses diversity of ecological units and patterns is part of many sets of criteria of assessing ecological significance. An example of a diversity and pattern criterion is as follows.

  • “Indigenous vegetation or habitat of indigenous fauna contains a high diversity of indigenous ecosystem or habitat types, or changes in species composition, reflecting the existence of diverse natural features (for example landforms, soil types or hydrology), or communities along an ecological gradient”.
  • “It is an area of indigenous vegetation or habitat that forms part of an ecological sequence, that is either not common in the Region or an ecological district, or is an exceptional, representative example of its type”

Criteria addressing size and shape

Some criteria sets address size and shape either on their own or as part of criteria addressing ecological viability. Size and shape criteria are derived from terrestrial reserve design principles where larger size and the shortest length of boundary relative to the size are preferred. This is because this minimises the edge effect. The importance of such criteria varies between habitat types.

Large extensive areas of vegetation have special values. These include habitats for species that require large ranges (eg, New Zealand falcon), and protecting intact ecological sequences covering broad altitudinal ranges or other environmental gradients. Options for protecting such areas are often limited so those large areas and ecological sequences can be particularly valuable.

An example of a size and shape criterion is as follows.

  • “It is an area of indigenous vegetation or naturally occurring habitat that is large relative to other examples in the Region of similar habitat types, and which contains all or almost all indigenous species typical of that habitat type”

Criteria addressing ecological viability/sustainability

Ecological viability criteria are commonly used when assessing priorities for establishing reserves and other protected areas. This is important because reserve acquisition is expensive and funds for acquisition and management are limited.

Ecological viability has been included as part of a set of criteria for assessing ecological significance in a number of council RMA documents. It can be appropriate to use ecological viability and sustainability criteria as long as a site does not have to meet ecological viability criteria to be considered ‘significant’ under s6(c) of the RMA.

A viability or sustainability criterion should not be used as a filter for determining significance. The use of filter criteria can be problematic and should be handled carefully. Improper use of these criteria can result in identification of ecological areas as being significant, whereas otherwise this may not be the case.

Criteria for addressing sites previously assessed and identified as being of ecological value

Some sets of criteria for assessing significance under s6(c) include areas set aside by statute or covenant for preservation purposes. An example is as follows.

  • “It is indigenous vegetation or habitat for indigenous fauna that has been specially set aside by statute or covenant for protection and preservation unless the site can be shown to meet none of criteria 3–11.”
  • “It is indigenous vegetation or habitat recommended for protection by the Nature Heritage Fund, or Nga Whenua Rahui Committees, or the Queen Elizabeth II National Trust Board of Directors, unless the site can be shown to meet none of criteria 3–11.”

It should be noted that some areas are covenanted as being significant for reasons other than their ecological values.

Criteria that address particular threatened habitat types

Some sets of criteria for assessing significance under s6(c) include provisions for specific threatened habitat types. An example is a criterion that makes natural wetlands of indigenous species ‘significant’.

The relevant criterion is as follows.

  • “It is wetland habitat for indigenous plant communities and/or indigenous fauna communities that has not been created and subsequently maintained for or in connection with: waste treatment; or wastewater renovation; or hydro electric power lakes; or water storage for irrigation; or water supply storage; unless in those instances they meet the criteria in Whaley et al (1995).”

Criteria addressing migratory species passages

Migratory species have special habitat requirements that include not only sites where they spend time, but the routes between those sites.

Most indigenous New Zealand freshwater fish species migrate between the sea and upstream fresh waters. This may involve distances of thousands of kilometres and include aquatic corridors of otherwise low ecological value. Many freshwater fish species travel through long distances of highly modified lowland rivers, which in themselves may not have high ecological values, but their continued existence as a unimpeded passage for native fish is essential both for the survival of those fish species and for maintaining the often high ecological values of less modified upland reaches. Another matter to consider is the protection of migratory bird passage from the adverse effects of tall moving structures such as wind farm turbines.

Sometimes migratory passages are addressed, at least in part in the ecological context and/or distinctiveness/special features criteria. Rather than deeming most lowland rivers ‘significant’ because they provide passage to native fish it may be appropriate to include a criterion that recognises that particular corridor attribute as ecologically significant.

An example of a criterion addressing migratory species habitat is:
“Migratory Habitat: The area is important as habitat for significant migratory species or for feeding, breeding or other vulnerable stages of indigenous species, including indigenous freshwater fish.”

It would be helpful to expand such a criterion to clarify that the passage between the habitats is also important, but primarily as an unobstructed corridor.

Note that climate change is likely to affect the availability and extent of migratory routes, particularly in habitats already at the margins of viability.

Criteria addressing indigenous cover in land environments

Priority 1 of the Statement of National Priorities for Protecting Rare and Threatened Indigenous Biodiversity on Private Land (April 2007) (PDF 1.39MB) is to protect indigenous vegetation associated with land environments (defined by Land Environments of New Zealand at Level IV) that have 20 per cent or less remaining in indigenous cover.

This is based on the premise that whatever is vulnerable is of value, which is not always true as there can be some very important unprotected areas of indigenous vegetation in land environments that still have large areas of indigenous vegetation remaining. Some but not all of these areas may be covered by National Priority 4 to protect the habitats of acutely and chronically threatened species, which include highly mobile species requiring large habitat ranges, such as eastern falcon, kereru and kukupa.

This concept needs to be used with caution to avoid perverse outcomes in land environments where there is valuable unprotected indigenous vegetation in land environments with more than 20 per cent indigenous cover.

Criteria addressing other non-ecological matters

The s6(c) criteria sets from several councils include criteria that address human values and uses. For example criteria that address Māori, historical and local community values. Other potential criteria include proximity and accessibility.

Additional commentary on criteria for assessing ecological significance

When developing criteria sets for evaluating significance under s6(c), planners should be aware of the following.

  • The term ‘significant’ is not prefixed with the qualifier ‘ecological’. Areas of vegetation and wildlife habitat could be significant for cultural, historical, educational, spiritual, recreational, scientific or aesthetic reasons.
  • An evaluation of ‘significance’ is scale dependent. A remnant that is of local significance is probably not of international significance. Regional
    policy statements typically consider significance at regional level and above. District plans consider significance at district level and above.
  • An evaluation of ‘significance’ is context dependent and often uses a spatial framework such as ecological regions and districts or Land Environments of New Zealand.
  • Indigenous vegetation is not restricted to forest or vegetation over a certain height. There are less prominent vegetation types such as herbfields, saltmarshes and grasslands. There are also smaller scale communities such as orchid communities in grasslands, shrublands or pine plantations.
  • Some areas of significance for indigenous fauna may be highly modified (eg, high tide roost sites in municipal parks and paddocks, gorse inhabited by Mahoenui giant weta, plantation forests utilised by kiwi, grazed alluvial flats used by brown teal for foraging).
  • Section 6(c) is not limited to terrestrial or freshwater wetland ecosystems, and equally applies to marine, river or lake ecosystems.
  • Viability/sustainability criterion relates to the ability or likelihood that a land environment is likely to survive on its own and is important because reserve acquisition is expensive and funds for acquisition and management are limited. However, a viability/sustainability criterion should not be used as a filter for determining significance. This is because in highly modified land environments remaining indigenous biodiversity is also likely to be modified and its long-term survival is uncertain without appropriate management, for example, removal of stock, weed control, return of a more natural hydrological regime. These sites may have important wildlife values and/or provide conditions necessary for rare, threatened or unusual species and assemblages. That these sites require management to ensure their long-term viability does not diminish their ecological significance.
  • Local government boundaries often cut through habitats so it is important to consider adjoining areas as part of the context when deciding what is significant within a particular council’s boundaries.

A criteria set should be developed in association with an ecologist and preferably also with local communities. Using local expertise and involving local communities helps to ensure that the criteria as a group are appropriate, workable and are upheld and recognised by local people. It is suggested that criteria be written as standards where one or more need to be met.

Actual assessments of ecological significance using criteria should be undertaken by an appropriately qualified expert. Different types of experts may be appropriate for different types of environments.

Scientific advice should be used throughout the criteria preparation process, to ensure that the final criteria are workable. For instance, criteria that refer to a site having ‘indigenous and endemic species’, without specifying the geographic unit to which endemic refers, lose the impact of the importance of locally endemic species.

The role of the Statement of Priorities for Protecting Rare and Threatened Indigenous Biodiversity on Private Land

The Statement of National Priorities for Protecting Rare and Threatened Indigenous Biodiversity on Private Land (April 2007) (PDF 1.39MB) issued by the Minister for the Environment and the Minister of Conservation is intended to inform councils in exercising their biodiversity responsibilities under the RMA. The statement identifies four priorities.

  • Protect indigenous vegetation associated with land environments (defined at Level IV) with less than 20 per cent remaining in indigenous cover.
  • Protect indigenous vegetation associated with sand dunes and wetlands.
  • Protect indigenous vegetation associated with ‘originally rare’ terrestrial ecosystems.
  • Protect habitats of acutely and chronically threatened indigenous species.

The statement sets out that the priorities do not collectively identify all indigenous biodiversity that is significant under s6(c) of the RMA.

The following list identifies some of the issues and cautions to be aware of in the use of this statement of priorities.

  • It lists priorities for protecting rare and threatened biodiversity – it does not address representativeness.
  • Land environments defined to Level IV are a relatively coarse filter in some areas of New Zealand where, for example, poor data about soil variability limits the identification of distinctively different areas at Level IV (eg, much of Northland).
  • There can be highly valuable unprotected areas on private land in land environments where there is more than 20 per cent indigenous cover. Vegetation and ecosystems within a land environment may vary considerably and what remains may be dominated by one vegetation type with few examples of other now uncommon/rare vegetation types.
  • The statement addresses terrestrial biodiversity only.