Coverage of protected freshwater wetlands

Freshwater Wetland

For this indicator, freshwater wetland refers to areas of land dominated by plant species that grow in freshwater saturated soils or grow tall enough to emerge above areas of shallow freshwater. These include areas of bog, swamp and fen, but do not include open water, flowing water, or salty (saline or brackish) water.

We use classes from the Land Cover Database¹ to identify areas that are predominantly freshwater wetlands: Herbaceous Freshwater Vegetation, Flaxland and Deciduous Hardwoods (where the wetland context attribute is Yes).

Herbaceous Freshwater Vegetation includes areas dominated by herbaceous aquatic vegetation as a component of freshwater wetlands. Common plants include sedges, rushes, or grasses, herbs or moss species.

We include Deciduous Hardwoods that have a wetland context, because an estimated one third of the freshwater wetlands remaining in the Waikato region have been invaded by willow or alder species². Willow and alder stands often mask diverse understories with abundant native wetland species and are important habitat for many wetland fauna.

When reporting on the extent and condition of freshwater wetlands at the regional scale it is important therefore to consider and report on the extent of all wetland types, including areas dominated in the canopy by non-native deciduous hardwoods. Such sites are important repositories of indigenous biodiversity and can be priority areas for wetland restoration.

Terrestrial and saltwater (saline) habitat protection is covered by other indicators in the State of the Environment Indicator series. Some vegetation types in the Land Cover Database can establish in wetland or terrestrial habitats, such as Flaxland, Fernland, and Manuka and/or Kanuka scrub. For the purpose of this indicator, the Fernland, and Manuka and/or Kanuka scrub land cover classes have been allocated to the terrestrial State of the Environment Indicators.

Protected areas

Legally protected areas are defined as: places where natural or cultural resources and biodiversity are protected, maintained and managed by law.³

We have limited our definition of legal protection to areas protected in perpetuity or for a specified period under one of the following acts:

• Conservation Act 1987
• National Parks Act 1980
• Reserves Act 1977
• Wildlife Act 1953
• Queen Elizabeth the Second National Trust Act 1977
• Local Government Act

The Reserves Act 1977 and Conservation Act 1987 offer the most common methods for protecting public land in perpetuity, particularly with a focus on biodiversity protection. Either act can be used to register land as a conservation covenant or Nga Whenua Rahui (with the same text appearing in each act).

Land under legal protection for conservation purposes is managed in New Zealand by a number of agencies. The main tenure types are described below.

The Department of Conservation (DOC) is the central government organisation charged with conserving the natural and historic heritage of New Zealand. DOC is responsible for protecting and preserving the majority of legally protected public land in New Zealand. Most of the DOC reserves come under the Conservation Act, with some under the Reserves Act. They include areas of Stewardship land which are subject to potential disposal but until such time are to be managed for their natural and historic values.⁴

The Queen Elizabeth the Second National Trust (QEII Trust) works with private landowners who wish to have some or all of their land legally protected. A covenant is registered on the title to the land, providing legal protection that binds the current and all subsequent landowners. The Trust generally contributes to the establishment of the covenant and regularly monitors the land to ensure it is managed in accordance with the covenant conditions. The first covenant was registered in 1979.

Ngā Whenua Rāhui was established in 1991 to provide a vehicle for protection of Maori-owned land in multiple titles. Ngā Whenua Rāhui kawenata can be registered under the Reserves Act 1977 (s77a) or the Conservation Act 1987 (s27a). Kawenata are vested for 25 years and are renewable. Trend reporting will indicate the extent to which such protected areas remain protected after their renewal period ends. To date no kawenata have reached the end of their vesting period in the Waikato region. Kawenata Management Agreements are not treated as protected land for the purposes of this indicator.

Local authority reserves are a range of reserve types protected under the Reserves Act 1977, including Esplanade Reserves, Scenic Reserves and Recreation Reserves. Local purpose reserves may be set aside for specific purposes such as drainage, water supply or sewage management. Local purpose road reserves were treated as "Indeterminate" for the purpose of this indicator, as the assumption is that this land is set aside for future road widening purposes.

Regional parks were established under the Local Government Act 2002. In the Waikato region, as of 2016, this was limited to the section of the Hunua Ranges and other Regional Parks inherited as part of the local authority boundary adjustments in 2012.

The following types of land designations are not included in this indicator:

• District Council Covenants issued as consent notices under the Resource Management Act 1991 (s108) or Conservation covenants on private land established under the Reserves Act 1977 (s77) or the Conservation Act 1987 (s27). The data sets for these areas are incomplete and many have not been digitised.
• Māori reserves and Māori reservations. The relevant Acts do not specifically require protection of biodiversity or natural values, although it is noted that many such sites are effectively managed for those values.
• Parcels in the Ngā Whenua Rāhui Kawenata (NWRK) database classified as “management agreements” - these are not registered on the title, or binding on future owners. 
• Private covenants entered as consent notices on land titles (e.g. Forest and Bird land). The data for private covenants other than those registered through the QEII National Trust is inconsistent and difficult to extract as many had not been digitised at the time of the indicator development.
• Areas of land classified in the CRS (Core Record System) as declared a reserve as such land is presumed to be pending registration in the Gazette, and therefore not formally reserved at the time the indicator was published. These will be incorporated in future updates of this indicator once they have been gazetted, assuming their CRS_Purpose field is updated.

The following were treated as having an "Indeterminate" level of protection fo the purpose of this indicator:

• Parcels that are classified as potential reserve types in the Core Record System attribute CRS Purpose (e.g. scenic reserve) but are not included in either the DOC, QEII or NWRK data layers, and are not listed as being owned or occupied by a local authority. Such areas are treated as “Indeterminate” in terms of legal protection.
• Parcels where CRS_purpose is not clear regarding reserve status, e.g. water supply, are treated as “Indeterminate”.

Threatened environments

In 2007, the Government released a statement of national priorities for protecting rare and threatened biodiversity on private land (Ministry for the Environment & Department of Conservation, 2007)⁵. The priorities are also relevant to public land.

Protecting biodiversity in Acutely and Chronically threatened land environments⁶ is a national priority (see Table 1). Here, 20 per cent is a critical threshold for measuring ecosystem vulnerability, because the rate of biodiversity loss increases dramatically when the amount of available habitat drops below 20 per cent of its original extent. Therefore, habitats in National Priority 1 Environments are the most in need of protection.

Table 1: Threatened Environment Classification description for National Priority 1 Environments

Monitoring area

This indicator covers the entire Waikato region, 2012 boundary using:

GIS_ALL.POL_2012_REGIONAL_AUTH_EW_L1 regional boundary (2012)

Data are reported within four spatial frameworks:

1. Region (2012) - GIS_ALL.POL_2012_REGIONAL_AUTH_EW_L1
2. District/city councils (2012) – GIS_ALL.POL_2012_TERR_AUTHORITY_EW_L1
3. Bioclimatic zones (1994) – GIS_ALL.BIOCLIMATIC_ZONES
4. Threatened environments (2007) – GIS_ALL.SNA_LENZ_TEC

Monitoring frequency

Updates will happen as new (region-wide) vegetation/cover spatial layers become available. It is estimated that this will be updated every five years.

Monitoring history

Information in this indicator is now separate to an indicator on Protected Coverage of Indigenous Land published on the Waikato Regional Council’s website in 2014 because:

• The 2014 Indicator used an older land protection layer which is no longer in use.

• The Landcover Databases v2 which was used in the previous indicator had some dataset errors and a corrected version was released in 2015

• the 2014 Indicator included terrestrial and freshwater wetland ecosystem types, which have now been separated into their own indicators.

Measurement technique

We use the LCDB 4.1 to find out the regional extent of freshwater wetlands. The LCDB (Land Cover Database) minimum mapping unit is 1 ha and the data are suitable for applications down to 1:25,000 scale.

We use the following databases to determine areas that are legally protected:

• Core Record System (CRS) layers, provided by CoreLogic to identify areas owned or occupied by local authorities where their purpose is stated as a form of reserve in PURPOSE column.
• DOC layer – GIS_ALL.DOC_CONSERVATION_AREA_WRC – Derived from data sourced from the Department of Conservation.
• QEII layer – GIS_ALL.QEII_TRUST_COVENANT – Provided by QEII Trust.
• NWRK layer – GIS_ALL.DOC_NGA_WHENUA_TRUST_COVENANT – Provided by the Department of Conservation.

The statistics are compiled using Feature Manipulation Engine (FME) software. Relevant land cover classes are selected from the Land Cover Database. See Waikato Regional Council document #2991195 for a description of the processes we use to calculate the statistics in FME.

Legally protected areas in New Zealand for this indicator include:

• Department of Conservation Reserves (DOC_SOURCE)
• QEII Covenants (QEII_SOURCE)
• Ngā Whenua Rāhui Kawenata, excluding management agreements (NWRK_SOURCE)
• Other - typically protected under the Reserves Act by local authorities or other state owned entities identified from the Core Record System using the PURPOSE attribute from GIS_ALL.CRS_PARCEL, and Owner or Occupier attributes from GIS_ALL.CRS_PROPERTY_WHOLE_REGION. Note, that an occupier is defined as the legal ratepayer which in the majority of cases is also the owner.

We use Feature Manipulation Engine (FME) software and Excel to calculate the extent of freshwater wetland protected within the Waikato region, and by district council, bioclimatic zone and Threatened Environment.

Regional boundary

The total land area of the regional boundary has been estimated using data from both the Land Cover database as well as the GIS_ALL.POL_2012_REGIONAL_AUTH_EW_L1 layer.

For this indicator, the 2012 regional boundary was used a baseline for all time periods reported on. In future updates of this indicator, any change in the size or shape of the regional boundary will affect the total area of indigenous coverage, due to areas of indigenous cover being included or excluded from the new boundary. To account for this issue either all previous results need to be recalculated or the update should retain the 2012 boundary as a baseline rather than any new regional boundary layer.

The same holds true for the indicator results pertaining to territorial authorities in which the 2012 territorial boundaries (POL_2012_TERR_AUTHORITY_EW_L1) have been clipped to the 2012 regional land boundary. Retaining these boundary layers will enable consistent change analysis to be conducted. This indicator is a regional analysis and as such does not cover the Waitomo, Taupō and Rotorua territorial authorities in their entirety.

LCBD 4.1 classes

For the current extent of freshwater wetlands in the Waikato region, we use the LCDB 4.1 classes and wetland context attributes listed in Table 2.

Table 2: Target land cover groups and names from LCDB 4.1

This indicator is primarily created using Feature Manipulation Software (FME). However, a sample of queries were tested in GeoMedia to ensure that results from both are aligned.

For information on data quality (lineage, positional accuracy, attribute accuracy, logical consistency and completeness) see the updated metadata for the LCDB, available on the Terralink International Limited website.

1. Freshwater wetland extent and protection is based on LCDB Version 4.1 data¹. The LCDB gives a ‘snapshot’ of vegetation at the time when the data were collected and should not be considered as a definitive measure of present day vegetation cover.

2. Some vegetation types are incorrectly identified in LCDB 4.1 which may result in errors in extent of freshwater wetland that is legally protected.

3. The Lake and Pond land cover group is excluded from this analysis, however a significant component of this ecosystem type (which can support indigenous submerged macrophyte communities in addition to indigenous fauna communities) is in legal protection. Lake margins with emergent vegetation are included in the assessment where they are mapped by LCDB as one of the target classes.

4. Flax is a hardy species capable of thriving in wet or dry conditions. The LCDB class Flaxland is described in the Illustrated Guide to Target Classes for LCDB⁷ as predominantly a wetland class dominated by the swamp flax Phormium tenax. Therefore Flaxland is treated as a wetland class for the purpose of Waikato Regional Council SOE reports.

5. Fernland, Manuka and Grey Scrub vegetation classes can occur in wetland systems but are more frequently encountered in terrestrial systems. Wetland context attributes in LCDB are considered too unreliable for these classes to allow for a separation of terrestrial and wetland polygons. These LCDB classes were included as scrub classes in the terrestrial state of the environment indicators, and therefore are not included in the wetland SOE indicators.

6. Deciduous hardwoods are described in the Illustrated Guide to LCDB Classes⁷ as being “typically willow and poplar species growing adjacent to inland water and rivers, this class also includes stands of planted exotic deciduous hardwoods, such as oak (Quercus spp.), ash (Fraxinus excelsior) and elm (Ulmus spp.)”. An estimated one third of Waikato wetlands have a canopy of invasive deciduous hardwoods² (primarily grey willow, crack willow and, to a lesser extent, alder). Excluding this land cover will greatly underestimate the total area of freshwater wetland and proportion in legal protection. The Wetland Context attribute offers a method to separate out Deciduous Hardwood polygons that represent wetlands. A visual check using Google Earth of 120 Deciduous Hardwood polygons from the LCDB found a high degree of accuracy where wetland context = Yes (over 90 per cent agreement) but a lower degree of accuracy where wetland context = No (62 per cent agreement). This indicates that the extent of deciduous hardwoods with a wetland context is under-estimated in the LCDB. This may be partly offset by loose polygon boundaries that often include areas of terrestrial vegetation, particularly in narrow gullies.

7. District Council reserves data is derived from data provided by CoreLogic as well as District Councils and is based on the PURPOSE field in GIS_ALL.CRS_PARCEL layer. That field is not comprehensive or consistent and may not include all local purpose reserves.

8. Some local purpose reserves may have a lesser requirement for protection of biodiversity where it is inconsistent with the purpose of the reserve type (e.g. road reserve, water supply) and have been treated as indeterminate protection status in the analysis of the extent of legally protected freshwater wetland cover.

9. There are some areas of overlapping protection status. Where this occurred the parcel was allocated to a single entity using the best information available. Two DOC reserves in the region are also QEII covenants, these parcels were treated as DOC land, being the most recent legal status. Some minor areas of overlap are the result of digitising discrepancies between GIS layers sourced from different agencies.

10. The 2012 district council boundaries clipped to the regional land boundary were used for this indicator. Some district councils extend beyond the regional boundary, and statistics compiled at the district scale for the Waikato region may not reflect the pattern for those districts as a whole.

11. Trend analysis has been conducted on the basis of change in reserve status over time, rather than change in the underlying vegetation cover. Data layers accessible to the Waikato Regional Council do not have date registered for Department of Conservation or local authority reserves. Gazette notice dates reference only the most recent gazette notice and so may not reflect the date of original registration. Therefore trend data is presented only for QEII covenants and Ngā Whenua Rāhui Kawenata for which reliable registration dates are available.

12. In April 2010, the Ministry for the Environment published a State of the Environment indicator for the extent of “Areas of native land cover under legal protection”. The data for the Waikato region is based on the region’s boundary prior to boundary adjustments in 2011. For this reason the MfE data are unable to be used to present temporal trends in coverage of protected freshwater wetlands for the Waikato region.

Waikato Regional Council is in the process of creating a region-wide indigenous vegetation spatial layer (Bioveg). When Bioveg is completed it is expected to be a high quality layer which could be used as an alternative to the Landcover database. However, the scope of the Landcover database is broader than the Bioveg layer as the LCDB includes land cover classes that possibly may contain indigenous vegetation such as coastal sand and rock. 

Changes to the Land Cover database classification scheme are likely to influence the indicator results. In addition, it is expected that the accuracy of the Land Cover database will increase with new technology and this will influence the extent to which any change in indigenous cover can be accurately interpreted.

1. The Land Cover Database (LCDB) uses satellite imagery to map land cover in New Zealand. This indicator draws upon version 4.1 (LCDB4.1), which was released in July 2015 and includes corrections to all LCDB version time steps 1996/97, 2001/02, 2008/09 and 2012/13.
2. Leathwick, J. Clarkson, B. and Whaley, P. 1995. Vegetation of the Waikato Region: Current and Historic Perspectives. Landcare Research Contract Report LC9596/022. Landcare Research, Hamilton. 
3. Les Molloy. Protected areas - Specially protected areas, in Te Ara - the Encyclopaedia of New Zealand. 
4. Conservation Act and a Report on stewardship land
5. Ministry for the Environment & Department of Conservation 2007. Protecting our Places: Information about the statement of national priorities for protecting rare and threatened biodiversity on private land. Wellington, Ministry for the Environment & Department of Conservation. 
6. Threatened Environments
7. Thompson S, I Grüner, N Gapare.2003. New Zealand Land Cover Database Version 2. Illustrated Guide to Target Classes. Ministry for the Environment. Wellington

Figure 1 shows the location of freshwater wetlands in the Waikato region that are legally protected.

Figure 1: Protected freshwater wetlands in the Waikato region

See the above map as a larger PDF [PDF, 1.7 MB].

Today just over 1 per cent of the region's land area remains in freshwater wetlands, totalling 27,484 hectares. This comprises 19,086 hectares of Herbaceous Freshwater Vegetation, 7,900 hectares of Deciduous Hardwoods, and 498 hectares of Flaxland. (Figure 2). 

Reserves and private covenants currently protect 68 per cent of the region’s remaining Herbaceous Freshwater Vegetation, 40 per cent of the remaining Flaxland, and 48 per cent of the total extent of Deciduous Hardwood forests.

Figure 2: Amount of the region’s freshwater wetlands and protection status

Almost 62 per cent of the Waikato region’s remaining areas of freshwater wetland are in some form of legal protection (Figure 3).

Most of the protected freshwater wetland cover is in Department of Conservation reserves (over 98 per cent) which protect 12,865 hectares of Herbaceous Freshwater Vegetation, 3,703 hectares of Deciduous Hardwoods, and 191 hectares of Flaxland.

On private land, QEII covenants protect 121 hectares of freshwater wetland, and Ngā Whenua kawenata a further 9 hectares. Most of the protected wetland on private land is Herbaceous Freshwater Vegetation (79 hectares) and Deciduous Hardwoods (45 hectares). Every year since 1996, an average of 6.5 hectares of privately owned freshwater wetland in the region has been protected under QEII covenants or Nga Whenua Rahui kawenta (Figure 4). This compares with an average of 1,200 ha of terrestrial indigenous vegetation protected per year in covenants or kawenata since 1996. In total, covenants and kawenata protect 0.5 per cent of the remaining areas of freshwater wetland in the region, compared with over 4 per cent of the remaining areas of terrestrial indigenous land cover.

District council reserves protect 115 hectares of freshwater wetland, mostly Deciduous Hardwoods (75 ha).

Figure 3: Freshwater wetland protection status in the Waikato region

Figure 4: Change in amount of freshwater wetland protected by QEII covenants or Ngā Whenua Rāhui kawenata

National Priority 1 Environments

Over 86 per cent of all of the remaining areas of freshwater wetland in the Waikato region occur within National Priority 1 Environments 

Wetlands are over-represented in these threatened environments because they tend to occur in lowland areas where much of the original native cover has been cleared. Often wetlands are the only natural features that remain in areas of intensively farmed lowlands.

As of 30 December 2016, the total area of freshwater wetland legally protected in Acutely and Chronically threatened environments was 16,361 hectares (16,339 ha in Acutely Threatened environments and 22 ha in Chronically Threatened environments). That represents nearly 70 per cent of all the freshwater wetland area that remains in those threatened environments.

Figure 5 shows that high proportions of the remaining wetlands in priority environments are already protected in Hauraki and Matamata-Piako districts. These districts are where one of New Zealand’s six Ramsar sites, the 10,000 hectare Kopuatai Peat Dome wetland, is located. However, across the region almost 7,320 hectares of freshwater wetland still remains unprotected in our most threatened environments. Most of that is in the Waikato District.

Figure 5: Amount of remaining freshwater wetland in National Priority 1 Environments by local authority

Figure 6 shows the proportion of freshwater wetlands protected in each bioclimatic zone.

In the Waikato region, freshwater wetlands are mainly confined to the lowland bioclimatic zone (below 300 m elevation), where 24,444 ha (89 per cent of the current extent) of freshwater wetlands occur. No freshwater wetlands are mapped in the subalpine to alpine zones (> 1,300 m elevation) in the LCDB¹.

In the montane bioclimatic zone (800 to 1,300 m elevation), all of the Herbaceous Freshwater Vegetation is in legal protection, however only 2 ha of freshwater wetland is mapped in that zone.

Submontane areas (300 to 800 m elevation) and coastal areas have the lowest proportions of their remaining areas of freshwater wetland in legal protection for all vegetation types.

In the lowland zone nearly 80 per cent of the remaining Flaxland and Herbaceous Freshwater Wetland is legally protected.

Figure 6: Proportion of remaining freshwater wetland protected in each bioclimatic zone

Within the district council areas, Matamata-Piako, and Hauraki districts have the highest proportion of their remaining wetland areas protected (Figure 7). These two districts share the 10,000 hectare Kopuatai Peat Dome, one of the Waikato Region’s three Ramsar Wetlands, protected by the Department of Conservation (DOC). Another Ramsar site, the 7,000 hectare Whangamarino Wetland reserve contributes to the large area of protected freshwater wetland in the Waikato District.

In the Waipā District, many of the peat lakes and the Moanatuatua Bog are protected by DOC or council reserves. Figure 7 shows that significant gains in wetland protection could be made by encouraging protection of wetlands on private land in the Taupō and Waikato districts. In these two districts over 8,253 hectares, one third of the region’s total area of freshwater wetlands, remain outside the reserve network.

Figure 7: Area of remaining freshwater wetland and amount protected in each local authority

Footnotes

1. LCDB = Landcover Database, the source data used to identify areas of freshwater wetland in the Waikato region.