Ranking and Evaluation Systems

A summary of some ranking and evaluation systems used on the West Coast. The following information is drawn from several references of relevance to the West Coast Marine Protection Forum process and the content of this report.

Introduction – Evaluation for Nature Conservation7

“The identification and comparison of the conservation values of natural areas and natural features are among the hardest tasks for the person working in nature conservation. It is not difficult to describe a natural area, its biota and physical features, and the ecosystem they comprise. To evaluate it for nature conservation, and to assess the degree to which it warrants protection is another question incorporating both social and scientific values.

The application of the text is restricted to terrestrial, freshwater and brackish ecosystems. The general goal and criteria of nature conservation apply equally to marine ecosystems, but their application there will require the work of marine specialists.

Seven criteria form the scientific basis of evaluation [of natural areas and in defining priorities for protection]:

Sand dune and beach vegetation8

RATING SYSTEM
Beach sites were ranked according to the following values (0 to 5 for each making a total out of 20).

Diversity – of communities and landforms. Systems that have extensive vegetation sequences and/ or diversity of dune landforms score highly.

Natives – number or proportion of native sand species, or good representation of characteristic or rare dune species.

Modification – degree of human or animal interference in the system.

Weeds – degree of invasion by weed species. Those without weeds score highly.

[The sites] having total ratings of 5 or more, are considered to be of national priority for conservation.

Low ratings for botanical values [with ratings less than about 0] for most sites along the Karamea to Greymouth section of coast reflect the general low diversity of landforms and the high degree of modification and weed presence. But these ratings do not negate the fact that pockets of intact vegetation are still to be found here, and that some of them are particularly important for conservation because they form part of vegetation sequences which extend inland to the coastal hill country.”

Wildlife9 10

(a) Morse (1981)
VALUATION OF HABITATS
Since one of the objectives of this survey was to assist planners in deciding the most appropriate use for an area of land, a wildlife value was assigned to each ‘habitat of note’.

In general terms, this value is a measure of the priority for preserving a given habitat. A variety of factors are used to assess this value. They include size, proximity to adjacent similar areas, extent of modification, species diversity, and presence of rare or endangered species, diversity of vegetation and other feature of the habitat, and the uniqueness or representativeness of the habitat type nationally or regionally.

The following criteria, modified from Imboden ( 978), were used as guidelines for the allocation of a conservation value.

OUTSTANDING

IHIGH

MODERATE - HIGH

MODERATE
All habitats supporting good numbers of species which are typical of that particular habitat within an ecological region and which have not been heavily modified by man’s influence.

POTENTIAL
All areas of some wildlife significance which are limited by size, heavy modification or other reasons, but are of potential wildlife value if left to regenerate or re managed or developed for wildlife. (May include habitat which functions as a corridor or is sub-optimal habitat which is necessary for maintaining genetic diversity.)

It should be noted that there is no ‘low’ category. There are several reasons for this. Firstly, only a selection of habitats is recorded in our surveys; habitats of no known significance remain unclassified. Secondly, as a result of the severe reduction of forests and wetlands through man’s activities, all remaining wetlands and forests, particularly lowland forests, are important for the conservation of communities adapted to these habitat types. Thirdly, the term ‘low’ is often equated with lack of value (see Imboden 1978).”

(b) Coker P M & Imboden C (1980)
This report uses rating criteria that are very similar to Morse ( 98 ).
VALUATION OF HABITATS
Since one of the objectives of making such an inventory is to enable planners to decide on the most appropriate use of a particular piece of land, a value was assigned to each habitat recorded. This value depends on a variety of factors such as the uniqueness or representativeness of the whole biotic community on a local, regional, national and international scale, its size and proximity to adjacent similar areas, extent of modification, species diversity, and list of individual species it supports (e.g. the presence of rare or endangered species).

The following criteria were used as guidelines for the allocation of a conservation value Imboden ( 978).

OUTSTANDING
Presence of an endangered species

HIGH

MODERATE

POTENTIAL

It should be noted that there is no category ‘low’. There are several justifications for this (see detailed explanation in Imboden 979). Firstly, only a selection of habitats, those which have some value to wildlife, are recorded in our surveys; habitats of no known significance remain unclassified. Secondly, as a result of the severe reduction of forests and wetlands through man’s activities, all remaining wetlands and forests, particularly lowland forests, are important for the conservation of communities adapted to these habitat types. Thirdly, the term ‘low’ is too easily equated with valueless and no area can be of no value to wildlife. In all these kind of surveys, emphasis is laid on the positive information, i.e. the confirmation of a species’ presence rather than its absence.”

Archeaeology11

The report by Hooker ( 990) rates certain coastal areas of the West Coast as being either nationally or regionally significant, based on expert opinion. While the region’s archaeological values are described in the report, the actual criteria for the ratings are not specified.

Geopreservation Sites12

The report by Hayward & Kenny ( 999) and some associated ones are collectively referred to as ‘The Geopreservation Inventory’.

The inventory ‘aims to list the best examples of the wide diversity of natural physical features and processes that together characterise each part of New Zealand and document its long and complex geological history, the formation of its landforms and evolution of its unique biota.’ It also ‘aims to identify and list information about all the internationally, nationally and many of the regionally important earth science sites throughout New Zealand, irrespective of their current protected status.’

ASSESSMENT OF IMPORTNACE AND VULNERABILITY

IMPORTANCE
Sites are listed in this inventory under three levels (A-C) of significance. The importance assessment given to each site has been assessed by those informants familiar with the site.
A. International – site of international scientific importance
B. National – site of national scientific, educational or aesthetic importance
C. Regional – site of regional scientific, educational or aesthetic importance

VULNERABILITY
Each site has been given a vulnerability classification ( -5) depending on its perceived vulnerability to human activities.
1 . Highly vulnerable to complete destruction or major modification by humans
2. Moderately vulnerable to modification by humans
3. Unlikely to be damaged by humans
4. Could be improved by human activity
5. Site already destroyed (not necessarily by human activity).

Islands13

The West Coast Islands Inventory uses a significance rating system, but identifies those rock stacks and islands that support threatened and protected species, as well as describing the habitat and communities occurring there. Some of the islands are ranked in other reports (e.g. Coker & Imboden 980).

The overall rating given for each island or stack summarises its ecological value. The rating system is partly based on criteria adapted from Morse 98 and Johnson 992, and described in the table below. The overall rating for a site is judged by the column in which the site best falls in the table.

The ratings allocated should be considered with careful regard to the level of survey undertaken. For example, the many sites not yet surveyed in the field could contain threatened species that are not evident from a distant view or analysis of air photos. Ratings for unsurveyed sites are based mostly on their size and broad habitat structure. Because of this, the ratings are subject to review if further information is obtained.

Criterion Outstanding High Moderate Potential
Size and viability
(area of vegetated lland)		 More than one hectare 1000 to 10000m2. Several terrestrial and marine habitat types. 100 to 1000m2 Less than 100m2
Habitat Diversity
(marine and terrestrial) 		Highly diverse habitats Several terrestrial and marine habitat types Simple habitat structure Very simple habitat structure - little vegetation, little reef
Species: threatened, endemic or protected species; native wildlife (birds, seals); breeding or other importance sites; species diversity Self-sustaining population or breeding site of several threatened and endemic species Several such species present, or one highly threatened species At least one such species present None recorded but suitable habitat present
Biosecurity: introduced & pest species, modification Little or no identified biosecurity threat Low - moderate risk of pest invasion High risk of pest invasion Mostly dominated by pests

West Coast Coastal Resource Inventory (CRI)14

The Coastal Resource Inventory (CRI) was a programme “to provide information for the maintenance, enhancement and restoration of natural character and qualities of coasts and their sensitive use.” Information was collated for each Dept of Conservation conservancy, including the West Coast. A rating system was developed for the CRI document, but this was not used in the present Marine Protection Forum report. The present report has instead drawn information from the original source documents where relevant.

Threatened Species15

This DOC report classifies species according to their threat status. Of particular interest to the present report are the “threatened” classes: Nationally Critical, Nationally Endangered, Nationally Vulnerable, Serious Decline, Gradual Decline, Range Restricted, and Sparse. Other classes include those that are not evaluated, or not threatened: Introduced and Naturalised, Vagrant, Coloniser, Migrant, Data Deficient, Extinct, or Not Threatened. The basis for these ratings is described according to a variety of criteria.

The definitions displayed below briefly outline the criteria for the “threatened” categories. For a full explanation of all categories you can view pages 7 to 2 of the publication.

1. Nationally critical
Very small population or a very high predicted decline.

2. Nationally endangered
Small population and moderate to high recent or predicted decline or Small to moderate population and high recent or predicted decline.

3. Nationally vulnerable
Small to moderate population and moderate recent or predicted decline.

4. Serious decline
Moderate to large population and moderate to large predicted decline, or Small to moderate population and small to moderate predicted decline.

5. Gradual decline
Moderate to large population and small to moderate decline.

6. Sparse
Taxa with very small, widely scattered populations.

7. Range restricted
These taxa either occur in a small geographic area, are restricted to a particular habitat, or require very specific substrates, and for colonial breeders, have fewer than 0 subpopulations.

The species that are considered to be threatened according to these criteria are listed by Hitchmough et al 2007.

Wetlands16 17 18

Cromarty & Scott ( 996) compiled a directory of selected wetlands in New Zealand considered to be internationally important.

“The criteria used in the selection process are those developed for the identification of wetlands of international importance for designation under Article 2 of the Ramsar Convention [a United Nations convention for the conservation and wise use of wetlands and their resources]. A wetland is suitable for inclusion in this directory if it meets any one of the criteria set out below: )

1. Criteria for representative or unique wetlands: A wetland should be considered internationally important if:

2. General criteria based on plants or animals. A wetland should be considered internationally important if:

3. Specific criteria based on waterfowl. A wetland should be considered internationally important if:

The following text summarises the system used by Partridge (2004) to allocate rankings for wetlands on the West Coast based on the available information.

Seven parameters were used as a tool to produce composite rankings for the wetlands. The parameters are on a 5-level scale from 0 to 4 (or in the case of ‘wetland size’, from 1 to 5), with a high score indicating low wetland modification and high natural values. The parameters are:

A mean score for each wetland was calculated using these seven parameters. Only those wetlands with four or more parameters were included, resulting in 234 wetlands being ranked. Correlation coefficients were calculated between each pair of parameters, and all were found to be highly significant (P<.00 ). This clearly indicates that if a wetland has high values for a parameter, then it tends to have high values for all. This however, does give the opportunity to examine situations in which parameters are higher or lower than would be expected from the mean. There are however risks and limitations to this technique that arise from a number of sources:

Davis (1 987) “identified those wetlands which are known to have significant fisheries values” and used the following ranking system.

“In order to identify wetlands of outstanding importance for fisheries, or for any other value, it is essential to develop selection criteria. The criteria used here (Table ) include features of the habitat, species composition, and use of the fisheries resource. These criteria are not mutually exclusive, and most wetlands qualified for inclusion on several counts.”

Table 1. Criteria for selecting nationally important wetlands for fisheries
1 . A habitat for a rare or endangered fish species.
2. A unique or diverse assemblage of fish species.
3. A habitat for a fish species with limited national distribution and/or declining numbers.
4. A biologically or scientifically important fishery or fish habitat.
5. An unmodified wetland habitat with significant endemic fisheries values.
6. A particularly good example of a specific type of fishery or fish habitat.
7. A remnant or regionally representative wetland with significant fisheries values.
8. A nationally important non-salmonid fishery, including commercial or traditional Maori fisheries.
9. A nationally important salmonid fishery.
10. A wetland which is particularly important as a water retention or riparian buffer zone for fisheries in the catchment.

“Once the list of nationally important wetlands was compiled… the wetlands identified for their fisheries values were ranked on a subjective scale:

A = outstanding, and must be included in the Schedule [a Schedule of Protected Waters announced by the NZ Government in 985] if at all possible;
B = significant, and should be included in the Schedule if non-fisheries values are also high
C = important, and inclusion in the Schedule would be desirable, but it may be necessary to resort to other measures of protection.”

7 O’Connor et al 1990
8 Johnson 1992
9 Morse 98
10 Coker & Imboden 1980
11 Hooker1 990
12 Hayward & Kenny1999
13 Neale 2006e
14 Neale1990
15 Molloy et al 2002
16 Cromarty & Scott 1996
17 Partridge 2004
18 Davis1 987

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