Indigenous biodiversity
Evaluating significance under section 6(c) of the Resource Management Act 1991
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.
return to evaluating significance – overview
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” (Bay of Plenty Regional Policy Statement (RPS), incorporating Change no. 1).
- “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” (Waikato RPS).
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
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” (Bay of Plenty Regional Policy Statement (RPS), incorporating Change no. 1).
- “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” (Bay of Plenty RPS, incorporating change no. 1).
- “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” (Waikato RPS).
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” (Bay of Plenty RPS, incorporating Change no. 1).
- “It is indigenous vegetation or habitat that is, and prior to human settlement was, nationally uncommon such as geothermal, Chenier plain, or kaarst ecosystems” (Waikato RPS).
- “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” (Ashburton District Plan).
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
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” (Bay of Plenty Council Regional Policy Statement, incorporating Change no.1).
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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” (Bay of Plenty Regional Policy Statement (RPS), incorporating Change no. 1).
- “Indigenous vegetation or habitat of indigenous fauna provides habitat for indigenous species at key stages of their life cycle” (Bay of Plenty RPS, incorporating change no. 1).
- “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” (Waikato RPS).
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
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” (Bay of Plenty Regional Policy Statement (RPS), incorporating Change no. 1).
- “It is an area of indigenous vegetation or habitat that forms part of an ecological sequence,8 that is either not common in the Waikato Region or an ecological district, or is an exceptional, representative example of its type” (Waikato RPS). (Note: footnote 8 in this quoted material directs the reader to the Waikato RPS Glossary for a definition of ‘ecological sequence’.)
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 Waikato Region of similar habitat types, and which contains all or almost all indigenous species typical of that habitat type4” (Waikato Regional Policy Statement (RPS). (Note: Waikato RPS footnote 4 text states: “This criterion is not intended to select the largest example only in the Waikato Region of any habitat type”.)
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
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 Resource Management Act 1991 (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. An example of this is the Bay of Plenty Regional Policy Statement (with Change No. 1) where only one or more of 17 criteria (written as ‘standards’) need to be met for an area to be ‘significant’. While there are three viability criteria, none of these three criteria need to be met for a site to be ‘significant’.
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.
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
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 Environment Waikato. The justification behind this is that these areas have already been evaluated for significance.
The relevant Environment Waikato (Regional Policy Statement) criteria are 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.
Environment Canterbury includes in its list of regionally significant features areas that have been previously assessed and identified by other agencies as Sites of Special Wildlife Interest (SSWI), Protected Natural Areas (PNA) Programme recommended areas for protection, or wetlands listed as Oceania sites, while acknowledging that in some cases the information will be outdated and needs site verification. However, the assumption is that such sites are considered significant unless recent evidence suggests otherwise.
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
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 the Waikato Regional Policy Statement where there is a criterion that makes natural wetlands of indigenous species ‘significant’. This is particularly important for the Waikato Region where so much of its formerly extensive wetland complexes have been drained and with only remnants surviving today.
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).”
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
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 from the Buller District Plan:
“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.
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
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 (PDF) 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.
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
Criteria addressing other non-ecological matters
The s6(c) criteria sets from several councils include criteria that address human values and uses. For example, the Bay of Plenty Regional Policy Statement criteria set for indigenous vegetation or habitat for indigenous fauna include criteria that address Māori, historical and local community values (PDF). Other potential criteria include proximity and accessibility.
return to evaluating significance under section 6(c) of the Resource Management Act 1991 – overview
Additional commentary on criteria for assessing ecological significance
Criteria set 3 in Appendix F of the Bay of Plenty Regional Policy Statement (PDF 1.54MB) contains a comprehensive set of criteria for assessing the significance of indigenous vegetation and habitats of indigenous fauna at the regional level. Another example is the criteria set in Appendix 3 of the Waikato Regional Policy Statement (PDF 756KB).
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.
