Southern Hills Environmental
Management Study
UPPER HUTT
Ecological Values and Constraints
Prepared for
Upper Hutt City Council
by
Boffa Miskell Limited
July 2008
APPENDIX 2
1.0
INTRODUCTION...............................................................................................................................2
2.0
SITE CONTEXT & LOCATION.......................................................................................................2
3.0
METHODOLOGY..............................................................................................................................2
4.0
RESOURCE DESCRIPTION.............................................................................................................2
4.1
Ecological Context...............................................................................................................2
4.2 Geology & Topography......................................................................................................2
4.3 Waterbodies..........................................................................................................................3
4.4 Historical Vegetation and Land Use..............................................................................3
4.5 Current Vegetation and Land Use. ................................................................................3
4.6 Historical Site Inventories................................................................................................4
5.0
ASSESSMENT AND EVALUATION OF THE EXISTING ENVIRONMENTAL VALUES.......4
6.0
SIGNIFICANT NATURAL AREAS. .................................................................................................5
7.0
ECOLOGICAL CONSTRAINTS and opportunities. .................................................................6
7.1 Management and Protection of Natural Values......................................................7
7.2 Ecological Corridors and Networks...............................................................................8
7.3 Future Ecological Potentials. ...........................................................................................8
7.4 Pine Management...............................................................................................................8
8.0
RECOMMENDED DEVELOPMENT CONTROLS........................................................................9
9.0
SUMMARY AND CONCLUSION. .................................................................................................9
10.0 REFERENCES. ..................................................................................................................................10
11.0 FIGURES...........................................................................................................................................11
Figure 1
Location and Site Context. ...............................................................................11
Figure 2
Historical Vegetation Map of the Southern Hills (1960).......................12
Figure 3
Vegetation Communities..................................................................................13
Figure 4
Ecological Constraints........................................................................................14
Figure 5
Site Photographs. ................................................................................................15
Southern Hills Environmental Management Study
Ecological Values And Constraints
Prepared for Upper Hutt City Council
July 2008
page 1
Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
1.0 INTRODUCTION
associations were identified and described through field observation and the use of aerial
photographs provided by Upper Hutt City Council.
Upper Hutt City Council commissioned Boffa Miskell Limited (BML) to provide advice in relation
to the Southern Hutt Hills as part of a strategy to guide future use and development of this
considerable area of land in Upper Hutt.
A number of biological databases were interrogated. These are listed in detail at the conclusion
of this report. All known published botanical information about the study area was reviewed and
base maps prepared prior to the site inspection.
The objectives of this study were to:
•
Assess and evaluate of the existing land use activities and environmental values of the
Site Inspections
‘Southern Hutt Hills’.
The site was visited on two occasions in May 2008. Given the size of the site and that it was
predominantly privately-owned, we used a rapid ecological survey methodology for this exercise
focusing on viewing the vegetation from key vantage points. In some areas, particularly around
the gated community of Mt. Marua, vegetation boundaries are a combination of what could be
seen from outside and aerial photographs and Google Earth.
•
Evaluate the opportunities and constraints in this area.
•
Assess the existing District Plan provisions and to identify what, if any, changes to the
District Plan could be made to ensure it suitably provides for the protection of the
identified values of the southern hills.
We used a generic approach to this survey based on the age and structure of the vegetation
communities present. In some areas, boundary delineation between vegetation types was
difficult and may need to be further refined, particularly those areas with scattered remnant
beech forest trees interspersed with wildling or old growth pines. A vegetation map was then
prepared based on this work.
As part of this process, we have undertaken the following:
•
Ecological field assessment to identify, describe and map the ecological features of the
study area.
•
Prepare a set of ecological constraints maps for the study area to be used to guide future
development.
•
Note that the ecological investigations did not extend to investigating the forests. The area was
divided into broad vegetation communities for the purpose of constraints mapping only. No
transects or other ecological survey methodology was used as part of this assessment.
Highlight ecological-related issues for consideration and discussion with Upper Hutt City
Council.
The site was visited on three occasions to map and describe the vegetation, and this combined
with aerial photography and topographical data allowed the mapping of ecological values, and
development of a map showing ecological constraints.
4.0 RESOURCE DESCRIPTION
4.1
2.0 SITE CONTEXT & LOCATION
The study area lies across the Sounds-Wellington Ecological Region (39) and the Tararua
Ecological Region. It contains within it parts of the Wellington Ecological District (39.01) and the
Cook Strait Ecological District (39.02).
The Southern Hills site is situated on the eastern Hutt hills slightly north east of residential
Pinehaven. The site boundary has been defined in consultation with the client, Upper Hutt City
Council, to approximately follow the base of the Southern Hills landform, adjacent to the flatter
valley floor. The study area includes the low lying hills from Silverstream Spur to Te Marua,
excluding the Blue Mountains ridge which runs parallel with the main ridge. It is approximately
1,536 ha in area.
The majority of the site lies within the Wellington Ecological District, which is characterised by
steep, strongly faulted hills and ranges. The district is very windy with frequent NW gales, warm
summers, and mild winters. It includes a range of soils derived from greywacke and loess and
areas of alluvial, peaty and stony soils in the valley. The Wellington Ecological District was
originally mostly forested. Today it is modified by farming and urbanisation, with pasture, gorse,
and regenerating shrublands throughout.
Very few indigenous remnants remain in the
extremely modified Wellington Ecological District and those that exist have a particular
significance. The Tararua zone is well represented by relatively unmodified forests in the Tararua
Ranges, Akatarawa-Whakatikei Block and Rimutaka Ranges.
Figure 1 shows the site in its wider landscape context. For the purposes of this report, only
vegetation within the boundary of the site in Figure 1 has been included.
3.0 METHODOLOGY
Background Research
4.2
Information on landforms, soils, and erosion was derived from the New Zealand Land Use
Resource Inventory (Page, 1990) and from Heine (1975) and Cowie et al (1967). Vegetation
W08017_MCP_Ecological Values for the Southern Hutt Hills_080718.doc
Ecological Context
Geology & Topography
The Southern Hills form a long band of low-lying hills which run from Silverstream in the south
the Te Marua in the north. There are two smaller ridge systems which run parallel with the main
3
W08017_MCP_Ecological Values for the Southern Hutt Hills_080718.doc
Southern Hills Environmental Management4 Study
Ecological Values And Constraints
Prepared for Upper Hutt City Council
July 2008
page 2
Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
ridge. The main area of these hills extends from the Blue Mountains to Te Marua and separates
the main Hutt valley from Mangaroa River.
Hard beech in these sites would have tended to form a mosaic with stands of hard beech on dry
spurs, ridges and poor soils, and other species including kamahi and tawa occurring on the
slopes and in gullies. Rimu would have been a likely emergent (Wardle 1984). In other areas
Halls totara, miro, and kamahi dominated forests at higher altitudes (600 m – 1200 m) while
rimu, rata, hinau, kamahi, and tawa dominated forests at middle altitudes (300 - 600 m).
The Southern Hills consist of remnants of old floodplain terraces which have been raised over
the last 500,000 years by repeated uplifts. These terraces have subsequently eroded into
plateau, rolling and easy landforms. The Southern Hills have a fairly constant elevation
fluctuating around 200-260m a.s.l along the main ridgeline.
A map based on Druce and Atkinson outlining the extent of indigenous vegetation in 1960 has
been reproduced to follow the same ecological boundaries as was mapped as part of this
exercise (Figure 2)1.
The soils of the Southern Hills are almost entirely made up of 6e7. The following descriptions of
the site have been derived from the New Zealand Land Resource Inventory Worksheets (Page
1990) and from Interim Report on Soils of the Wellington Region (Heine 1975). They provide an
overview of the area in relation to similar sites in the Eastern Hutt hills.
4.5
The Land Cover Database (LCDBII) indicates that the Southern Hills comprise of a range of
classes of vegetation. Although the LCDBII approach to marking vegetation communities is
based on topographic imagery, the statistics form a useful part of desktop identification of a site’s
natural values. LCDBII outlines the following vegetation communities and their relative
percentage cover over the site.
Eastern Slopes
(Pinehaven)
Table 1: Geomorphology of the Site
4.3
6e7
Gw – TH+TaS – E+F
0-M8n6m6
TH = Taita Hill Soils
Moderately steep to steep, deeply weathered greywacke hill
country with soils of low fertility. Loess on deeply weathered
greywacke. Central Y-B earths, Taita hill soils.
The main soil group found on class 6e7 landforms are Taita
Hill soils. These are typically found on hilly land of the
eastern Hutt valley. They would have historically had hard
beech forest, (possibly with black beech on dry spurs).
Table 2: LCDBII Vegetation Classes
Vegetation Community
Built-up Area
Urban Parkland / Open Space
Alpine Gravel and Rock
High Producing Exotic Grassland
Low Producing Grassland
Gorse and or Broom
Manuka and or Kanuka
Broadleaved Indigenous Hardwoods
Afforestation
Forest - Harvested
Pine Forest (Open Canopy)
Pine Forest (Closed Canopy)
Other Exotic Forest
Indigenous Forest
Total
Waterbodies
The study area drains to the north into Silverstream Creek and to the south into Black Stream
and the Mangaroa River, before entering the Hutt River. There is a small area of raupo wetland
on this site near Kingsley Heights.
Most of the waterbodies on the site consist of relatively small and steeply incised streams. A
check of the New Zealand Freshwater Fish Database (NIWA, 2007) did not indicate any surveys
from the study area. However, the streams of the Mangaroa River have been surveyed in 1978
and 2004 and have found long-finned eel, redfin bully and brown trout.
However, the Hutt River and other tributaries of the Hutt River in the area which these smaller
streams flow into include a number of freshwater fish, including diadromous species. It is
assumed that the smaller streams of the study area are likely to provide habitat for a number of
indigenous freshwater fish species.
4.4
Total Area
65.3
90.2
25.5
497.8
14.7
249.8
122.8
421.7
6.9
13.9
1.5
67.6
20.3
116.6
1714.6
Percentage of Site
3.8%
5.3%
1.5%
29.0%
0.9%
14.6%
7.2%
24.6%
0.4%
0.8%
0.1%
3.9%
1.2%
6.8%
100%
In terms of the sites indigenous ecological values, Table 1 indicates that 7.2% (122.8 ha) of the
site is covered in Manuka / Kanuka, 24.6% (or 421.7ha) of the site in Broadleaved Indigenous
Hardwoods and 6.8% (116.6 ha) as Indigenous Forest. Based on these figures, one would
assume that approximately 31.4% of the site retains either original or advanced secondary
forest. The Manuka and Kanuka across the site is assumed to have regenerated from pasture
associated with historical vegetation clearance.
Historical Vegetation and Land Use
Hard beech and hard beech–black beech forest is a vegetation type once common on the
Eastern Hutt Hills and unique to the region due to red beech reaching its southern limit in the
North Island near Bawbaw and High Misty at the headwaters of the Pakuratahi River, Rimutaka
Ranges. North of this line red beech and silver beech dominated areas of continuous, uniform
forests. South of this line, in the absence of red beech, a wide variety of vegetation types
occurred depending on soil, climate, and exposure. In this landscape, hard and black beech
would have been locally present on lower fertility soils at middle altitudes (up to 600 m)
particularly on the Taita Hill Soils and Tawai steepland soils common on the eastern Hutt Hills
(Heine 1975).
W08017_MCP_Ecological Values for the Southern Hutt Hills_080718.doc
Current Vegetation and Land Use
Today the extensive areas of hard beech forest that would have existed on the Eastern hills are
considerably modified and are now represented by a large number of small fragments within
1
Vegetation Map of the Hutt Catchment, North Island, New Zealand. Vegetation Survey Map by A.P.
Druce and I.A.E. Atkinson, Botany Division, Department of Scientific and Industrial Research, 19581960.
5
W08017_MCP_Ecological Values for the Southern Hutt Hills_080718.doc
6
Southern Hills Environmental Management
Study
Ecological Values And Constraints
Prepared for Upper Hutt City Council
July 2008
page 3
Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
deep gullies. Some fragments contain original forest and others contain beech that has
regenerated following fire. Where beech has been removed from these sites, kamahi, kanuka,
and manuka are typically appearing, often through a succession involving gorse. In many areas
of the Eastern Hutt Hills wildling pine is also a dominant feature of this regenerating vegetation.
predominantly hard and black beech forest on loess and deeply weathered greywacke with a
mosaic of kamahi-manuka scrub. The area is fenced by the prison boundary and is much used
by the public.
Blue Mountain Road Scenic Reserve (or Ecclesfield Scenic Reserve) is approximately 5 ha in
area and consists of hard and black beech forest on loess and strongly weathered greywacke
with mixed broadleaved scrub on loess and strongly weathered greywacke. The reserve was
gazetted in 1966 through land donated to the Royal Forest and Bird Protection Society. The
reserve is much used by local residents and their children and has an attractive backdrop to the
residential area of Blue Mountains Road (Wassilieff et al 1986). These two scenic reserves are
largely a contiguous forested unit that provide a range of scenic and recreational values for local
residents.
This lowland-beech forest type is protected in a number of reserves within the Hutt Catchment.
They include Silverstream, Wi Tako, Blue Mountain Road, Mangaroa Hill, Wainuiomata, Lowry
Bay, Hayward’s, Keith George Scenic Reserves. This lowland-beech forest type is also found in
the Stokes Valley recreation reserve, forest blocks within the Eastern Hutt, Whakatikei, and
Pakuratahi water supply areas, and in the southern Tararua Ranges (Eastern Hutt and Marchant
Ridge). Outside the Hutt Catchment, areas of hard beech dominated forest occur in the
Wainuiomata and Orongorongo catchments and within the Rimutaka Forest Park. In addition to
these protected areas, there are a number of unprotected fragments across the study area.
Two other areas recognised as having high ecological values adjacent to the study area include
the Wallaceville Swamp (size unknown, but much reduced from its former extent) and the
Mangaroa Swamp (approximately 241ha). However, these are just on the outside of the study
area and are not discussed in any further detail as part of this exercise.
There are also a number of other unprotected forest remnants and wetland areas on the valley
floors and lower slopes of the study area, particularly within Whiteman’s Valley and the
Mangaroa valley.
4.6
Other protected sites include the Richardson QEII covenant of lowland primary forest (6 ha).
With the exception of the Wi Tako Scenic Reserve and the small QEII covenant, none of the site
is formally protected by the Department of Conservation or other agencies. Overall, despite the
forested nature of these hills and the two smaller scenic reserves, there is very little of this land
protected for its scenic or ecological values.
Historical Site Inventories
An assessment undertaken for BECA in 19942 to prepare a list of significant natural areas for
inclusion in the Upper Hutt City District Plan identified a number of sites of significance.
94 sites were listed in this inventory. However, it is noted that this inventory was a first order
compilation of sites combining and summarising information from published and unpublished
inventories of the Hutt Valley. No attempt to rank the sites was undertaken. The site inventory
only provided a cursory analysis of these extensive forested lands, concentrating instead on
smaller indigenous forests outside Regional Council ownership. We note that the report
concluded with a recommendation for a more comprehensive survey and assessment of the
indigenous flora and fauna of the District.
5.0 SIGNIFICANT NATURAL AREAS
Protected Natural Areas
The site is surrounded by a number of reserves, significant natural areas, and wildlife sites.
Figure 1 shows the location of the study area in relation to significant forested areas and wildlife
habitats in the local area. As outlined above, there are two protected natural areas, both scenic
reserves, located within or on the immediate southern edge of the study area (Wassilieff 1986,
DoC 2002):
A 1995 Ecology and Heritage Verification Study undertaken for Upper Hutt City Council 3 to refine
these sites from the 1994 study established three sites of significance in the study area.
Importantly for the purposes of this 2008 exercise, it is noted that this study did not include ‘all
small sites of young broadleaved second growth or hard and black beech as these vegetations
types were well represented in sites that were included in the Schedule”. These studies did not
include the Scenic Reserves that are located in the southern end of the study area. As an aside,
we note that the 1995 study only recommended 4 sites in the Upper Hutt district for inclusion in
the Schedule of Natural Heritage Areas. None of these are located within the Southern Hills
boundaries.
Blue Mountain Road Scenic Reserve (4.8 ha)
2.
Wi Tako Silverstream Bush Scenic Reserve (70ha)
As has already been identified, a number of scenic reserves are also located in close proximity
to the study area, including the Keith George Scenic Reserve (60 ha), the Silverstream Scenic
Reserve (69 ha) and the Ecclesfield Scenic Reserve (5 ha). In addition, a number of designated
Upper Hutt City Council reserves or other designated areas (e.g. Ministry of Defence-owned
land) are located within the boundaries of the study area as follows, some of which include areas
identified as having indigenous ecological values such as those along the main ridgeline of the
Southern Hills:
In summarising this historic information, the site contains only one particular area having
recognised ecological values from previous site inventories or protected as Scenic Reserves –
the Wi Tako Silverstream Bush Scenic Reserve. Wi Tako Scenic Reserve (59ha) consists of
2
Fuller, S.F. 1994. Resource Description, Ecological Assessment & Inventory of Sites of Biological
Value, Upper Hutt District. Report prepared on contract to Beca Carter Hollings and Ferner for
incorporation into the Upper Hutt City Council District Plan.
3
Boffa Miskell. 1995. Ecology and Heritage Verification Study. Contract 565B. Prepared for Upper Hutt
City Council. The ecological component of this report was undertaken by M. Wassilieff for Boffa Miskell.
W08017_MCP_Ecological Values for the Southern Hutt Hills_080718.doc
1.
1.
7
Proposed Scenic Reserve , Southern Hills ridgeline, Wallaceville Road (UHC 3)
W08017_MCP_Ecological Values for the Southern Hutt Hills_080718.doc
Southern Hills Environmental Management 8Study
Ecological Values And Constraints
Prepared for Upper Hutt City Council
July 2008
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Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
Fendalton Scenic Reserve, Fendalton Crescent (UHC 37)
4.
Gentian Park Timberlea Recreation Reserve (UHC 38)
Table 3: Vegetation Communities
5.
Maidstone Park (UHC 50)
6.
Southern Hills ridgeline Local Purpose Reserve (UHC 70)
7.
Rimutaka Prison, Freyberg Road Extension (COR 1)
8.
Trentham Miliatary Camp (DEF 1)
9.
Wallaceville Animal Research Centre (MAF 1)
Trend2
H
A
S
0.3% �
M
H
A
S
Primary beech forest remnants and advanced secondary
beech forest: Predominantly secondary beech forest
surrounding remnant beech trees and kamahi dominant.
Occasional younger podocarps in wetter areas. Occasional
older pine over forest canopy with wilding pine scattered
throughout. Refer photos 1, 2, 4 & 7.
213.74 13.9% �
Secondary mixed broadleaved scrub and low forest:
Mixed broadleaved species dominated by mahoe, fivefinger,
tarata, karamu, kanuka, gorse, mamaku, rewarewa with
some kamahi. Some isolated remnant beech trees and
occasional older pines present. Refer photos 5 & 6.
79.17 5.2%
5
Recommended Areas for Protection (RAP)
A Protected Natural Areas Programme (PNAP) survey has not been conducted for the area.
6
Overall, we consider that the Southern Hutt Hills area is unusual in having retained a relatively
high proportion of indigenous vegetation close to adjacent developments.
7.
8.
4.98
Mixed kanuka and gorse scrub: Kanuka with gorse,
manuka and some broadleaved shrub species present and
occasional scattered pines. Mahoe, mamaku and other early
successional broadleaved species often present in the
gullies. Refer photos 7 & 9.
176.65 11.5%
Manuka on wet soils: Predominantly manuka on wet soils
with areas of gorse and open pasture. Refer photo 8.
0.46 0.0%
Gorse monoculture: Predominantly younger gorse with
some kanuka, manuka and broadleaved species, particularly
in gullies and lower wetter slopes. Refer photos 4, 9 & 10. 133.57 8.7%
Agriculture and built-up area:
�
�
H
H
L
I
�
�
H
H
L
I
�
�
M
M
M
I
H
M
L
S
�
L
A
H
D
�
M
A
H
S
�
H
H
L
S
�
�
432.68 28.2%
9.
Plantation pine: A mix of older established pine plantation
(including established wilding pines) and more recent pole
and/or sapling pine surrounded by gorse. Hangehange,
fivefinger, kamahi, mahoe, rangiora, karamu gorse, bracken
and silver tree fern in understorey and gullies. Refer photos
1, 7 & 10.
179.79 11.7%
10. Raupo wetland: Raupo dominated wetland with blackberry,
gorse and pasture grasses surrounding.
1.6 0.1%
6.0 ASSESSMENT AND EVALUATION OF THE EXISTING
ENVIRONMENTAL VALUES
Vegetation Communities
The vegetation of the Southern Hills area consists of a complex mosaic of remnant and
advanced secondary forest, regenerating scrub, pine plantation, gorse and pasture typical of the
highly modified eastern Hutt hills. Its variety reflects repeated fires, planting and harvesting of
exotic conifers, and the influence of browsing by goats and possums. Table 1 outlines the
W08017_MCP_Ecological Values for the Southern Hutt Hills_080718.doc
H
3
Forest Parks
6.1
313.08 20.4% �
Lowland podocarp forest: Predominantly kahikatea with
rimu, matai and occasional tawa and titoki. Refer photo 3.
4
The site lies some 10 km north west of the Rimutaka Forest Park. The nearest large protected
forest is the Wainuiomata/Orongorongo Water Supply catchment which is approximately 10 km
to the south.
Primary beech forest: Predominantly red and black beech
forest with mixed podocarp with varying degrees of
modification. Older pines often intermixed. Mixed
understorey of beech and kamahi with supplejack, toru,
pigeonwood, toru, beech, silver tree fern, karamu and
occasional tawa. Kahikatea are present and dominant in
some areas with isolated swamp maire. Includes some
smaller areas of lowland podocarp forest on flat areas and
lower slopes. Refer photos 1, 2, 4, 6 & 7.
Area
(%)
2
Covenants
There is one Queen Elizabeth II private covenant within the study area, the Richardson
covenant, which protects a 6ha remnant of lowland primary forest.
Exotics1
A small number of large beech forest remnants have been identified within the site in different
historic inventories. The majority of these remnants have not been named or mapped, but have
simply been shown on maps and plans and are often referred to in the context of adjacent
reserves. They are not identified in the District Plan unless protected or identified as Council
reserves. In addition, the adjacent Mangaroa Swamp and the Wallaceville Swamp have been
identified in various historic inventories, but are not included within the Upper Hutt City District
Plan.
NAT1
Unprotected Natural Areas
Regen1
1
Area
(ha)
Exotic
Community Name
Induced native
3.
vegetation communities of the study area and these are also shown in Figure 3 and illustrated in
photographs in Figure 5.
20 native
Proposed Amenity Reserve, Southern Hills ridgeline, near Gorrie Road (UHC 5).
10 native
2.
TOTAL:
Regen / Nat / Exotics1 H = High,
9
�
1536 100%
M
= Medium,
L
= Low,
A
= Absent Trend2 D = Deteriorating,
S
= Steady,
I
= Improving
W08017_MCP_Ecological Values for the Southern Hutt Hills_080718.doc
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Southern Hills Environmental Management
Study
Ecological Values And Constraints
Prepared for Upper Hutt City Council
July 2008
page 5
Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
6.2
Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
native seed to young shrublands and scrub and cleared sites following development-related
disturbance or harvest of the pine plantations.
Wildlife Corridors
The original forests once found on the Eastern Hutt hills now occur as a series of fragments, a
number of which are located along the Southern Hills. Many of these fragments are protected
within the protected natural area network. Within this fragmented landscape the forests of the
study area contribute to a habitat continuum extending along most of the Eastern Hutt hills and
on through to the extensive indigenous forests of the Orongorongo, Pakaratahi, Hutt and
Whakatikei/Akatarawa catchments. They therefore have value as wildlife corridor and could
potentially have higher value once the landfill has been retired and the land is rehabilitated.
The most important wildlife corridor in the district is the Hutt River and its tributaries. Despite the
significant urbanisation of the lower sections of the Hutt River it remains in surprisingly good
condition due largely to its extensive forested headwaters. The continued health of this river
relies on the wise management of its headwaters and the maintenance of migratory pathways
across publicly owned and private lands.
The ecologically fragmented site contains only a small percentage of its original forest.
However, those fragments that remain are considered representative of much of the original
forest that would have covered many of the surrounding hillsides and are significant. Many of
the remnant beech trees are adjacent to or in close proximity to relatively well advanced
secondary forest and scrub, with isolated remnant trees within these areas. Beech regeneration
is becoming well advanced indicating both the advanced nature of natural regeneration and the
future potential of these areas as forest and as habitat.
7.0 ECOLOGICAL CONSTRAINTS AND OPPORTUNITIES
The resource information that has been collected for this site allows the identification of physical
and biological constraints as well as areas where there are no constraints to development. As
illustrated in Figure 4, there are a wide range of ecological opportunities and constraints in the
area, largely defined by the presence and or absence of remnant indigenous vegetation. The
historical pattern of vegetation clearance and subdivision and development has meant that large
areas of the flat to moderately steep land have been cleared and in many areas the primary
vegetation is confined to steeper land and / or gullies, with some larger ecological units being
protected for their scenic or recreational value. There are some exceptions to this however, as
recognised by the widespread extent of primary and advanced secondary forest across the site.
Irrespective of their size, forest remnants are important for a wide range of reasons. They
provide bird corridors and "stepping stones" linking larger forest areas; they often contain
vegetation which typifies the area but may no longer occur as large forests; they provide a seed
source for regeneration; contribute to the biodiversity of the area; they may act as refuges for
rare or threatened plants, birds, lizards or insects; and they contribute to the urban landscape.
As has been outlined previously, the study area is part of a number of recognised wildlife
corridors, including being part of between nine regionally important wildlife sites (after Parrish
1984).
10.
No 35 (Blue Mountain Bush – moderate high value forested site)
11.
No 29 (Wi Tako Silverstream Bush – moderate high value forested site) to south east
12.
No 25 (Keith George Memorial– moderate high value forested site) to south west
13.
No 28 (Belmont Bush – potential value forested site)
14.
No 32 (Quarry Bush – potential value forested site)
15.
No 38 (Stokes Valley Bush – moderate high value forested site)
16.
The Hutt River
17.
Heretaunga Wildlife Refuge. The Royal Wellington Golf Course is a wildlife refuge,
initially gazetted in the 1920s under the Animal Protection and Game Act (1921) and was
then re-gazetted as a wildlife refuge under the Wildlife Act 1953 (DoC R27103).
18.
The following sections discuss the varying levels of ecological constraint and the areas of each
are provided in Table 4 below and Figure 4.
Table 4: Ecological Constraints of the Site.
W08017_MCP_Ecological Values for the Southern Hutt Hills_080718.doc
Level of Constraint
Dominant Vegetation communities
(ha)
(%)
A
High constraints
1. Primary beech forest
2. Primary beech forest remnants and advanced
secondary beech forest
9. Raupo wetland
10. Lowland podocarp forest
533
34.7%
3. Secondary mixed broadleaved scrub and low forest
4. Mixed kanuka and gorse scrub
5. Manuka on wet soils
256
16.7%
6. Gorse monoculture
7. Agriculture & built-up area
8. Plantation pine
746
48.6%
1536
100%
C
As has been outlined above, the Southern Hills are characterised by a large number of forest
remnants, connected by regenerating native shrublands, gorse and pine. The area is recognised
as an important corridor for the movement of birds from the Hutt Catchment through Upper Hutt
and into the eastern Hutt hills. In particular, the dominant ridgeline extends to the Hutt River and
provides a short hop for birds travelling from the western to the eastern Hutt Hills. Wildlife
movement within the beech remnants of the site will be important in the future to distributing
Moderate constraints
Minimal or no ecological
constraints
TOTAL AREA:
11
Area
Key
B
Mangaroa and Wallaceville Swamps
Area
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Southern Hills Environmental Management Study – Ecological Values & Constraints DRAFT
High Ecological Constraints - ‘NO GO’
•
•
stormwater, hydrology and vegetation buffering on surrounding areas.
Predominantly remnant native forest or advanced secondary regenerating beech forest
which is largely unmodified, prime wildlife habitat, high bird diversity, weed-free and
Table 4 outlines the extent of each of the above constraints. This constraints information is
illustrated visually in Figure 4 and the following text.
locally significant. This category also includes a small raupo wetland.
•
No development should be permitted within these areas, other than properly designed
Based on the ecological constraints maps outlined above, the site can be broken down into
approximately 65% developable area (or 1,002 ha), that being the area with limited or no
ecological constraints or moderate ecological constraints.
and formed recreational tracks / trails (tree roots, special plants, drainage).
•
Consideration should be given to formal protection of these areas, particularly the larger
and more ecologically diverse areas, and the ability to link them with surrounding
Taking into account the historical vegetation patterns that have shaped the Southern Hills, we
consider the site has substantial future potential to accommodate a range of development types
that continue to retain and enhance the ecological values of the site. A number of possibilities
exist that can be implemented to ensure the area’s natural values can be protected and
managed in the long-term.
reserves and/or corridors.
•
Consideration should be given to the possible effects of sediment management,
Consideration should be given to potential adverse effects of adjacent development and
any stormwater discharge into these areas. If future development extends to the edges of
these areas, a suitable buffer of vegetation must be maintained to protect forest margins
from edge effects of wind, weeds and desiccation.
•
Consideration should be given to building set-backs from the edge of these areas.
7.1
The existing pattern of residential development in the Southern Hills is very mixed, but generally
concentrated along spurs, flatter areas and the leading ridgeline. Development densities also
differ greatly in the area – from the more intensive residential development on the lower spurs
and valleys surrounding Mt Marua in the north to the less dense ‘forested’ residential
development around Blue Mountains Road, where limited vegetation has been removed to form
house sites.
Moderate Ecological Constraints – Limited Development
•
Generally these consist of areas of secondary regenerating vegetation typically located in
steeper areas, gully floors and headwaters with occasional remnant trees, mostly beech.
Regeneration ranges from early successional natives of kanuka and mahoe scrub
through to more advanced regenerating low forest with occasional forest trees of
Initial fieldwork as part of this project has illustrated that some of the more recent development,
particularly around the Mt. Marua northern end of the study area, has resulted in the retention of
the site’s more important ecological features. In these areas, remnant and advanced secondary
vegetation has been retained and incorporated into buffer areas between residential sections
and as part of walkways and other landscape features (refer photo 11). However, it is
considered that this is in part due to the topography and steeply incised streams of the area
where indigenous vegetation remnants have been retained, rather than solely for amenity values
or to protect indigenous flora and fauna.
rewarewa, kamahi and beech. These areas provide good habitat for wildlife and have
moderate to high botanical values.
•
Consideration should be given to protecting remnant trees as part of any development
and establishing reserves and habitat corridors to connect smaller areas.
•
Areas of younger regenerating broadleaved scrub and kanuka-dominated scrub provide
limited opportunities for lower density residential development and roading.
•
Establishment of residential boundaries and preferred building sites etc. should have
Similarly, the residential area of Chatsworth Road provides a good example of more established
low- medium density residential development adjacent to areas of high ecological values within
the Southern Hills. Within this residential area, a large number of remnant trees have been
retained and incorporated into landscape plantings. This situation, combined with other
established plantings, provides a good ecological buffer between residential homes and forest
remnants as well as providing habitat for native birds.
some ecological input.
•
Consideration should be given to adverse ecological effects associated with edge effects
and changes in hydrology associated with development within these areas.
•
A large portion of the areas marked as having moderate ecological constraints at the
northern end of the Southern Hills is already formally protected by Council reserve
There is also evidence to suggest that those areas of high ecological values adjacent to high
density residential development have not been adversely affected or hindered by such
development. Photo 12 illustrates a wetter area of kahikatea and swamp maire that is actively
regenerating adjacent to Gentian Street, a 1970’s development (UHC 38, Gentian Park
Timberlea Recreation Reserve). Recognising these values is an important component of
ensuring their protection and enhancement.
contribution covenant.
Minimal or no ecological constraints
•
Areas entirely dominated by exotic plants where no or minimal ecological constraints
exist.
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Management and Protection of Natural Values
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Accordingly, with the combination of views, established forested areas and privacy, we assume
that these types of developments close to areas of ecological value are attracting a premium
price and will continue to provide a good model for future development demand. Although it is
our recommendation that areas identified as having high ecological constraints are excluded
from development, it is important to reiterate that these areas should be recognised as providing
a number of important and saleable benefits, including the following:
•
walkways, large areas of reserve and public space across the Southern Hills and other adjacent
areas.
It is our recommendation that a long-term goal be developed for the Southern Hills that combines
areas of high ecological values, open space, reserves and recreation areas.
Attracting a certain type of homeowner who would pay a premium to live in close
7.3
association with the bush (e.g. some forested areas of Eastbourne, Khandallah and
The study area also contains a large amount of land with moderate ecological constraints and
limited or no ecological constraints. Although there are less ecological values in these areas
currently, the dynamics of the wider site ensure that these areas have high potential for future
ecological values. The natural regeneration of these hills is dynamic as a result of the
surrounding seed sources and bird corridors and can rapidly transform from gorse and kanuka
through secondary scrub and forest. In many areas, natural beech regeneration was observed.
Silverstream).
•
Increased privacy to residential areas.
•
Attracting bird life through providing good habitat, insects, seeds and flowers at various
times of the year.
•
Could be used for public walkways to connect different remnants within the wider area
Providing opportunities for future regeneration across the site, particularly within areas identified
as having moderate ecological constraints, will assist in the wider site’s ecological integrity
through providing additional buffering of areas of high ecological value and enhancing ecological
connectivity between these areas. As has been outlined above, these areas also have
recreational and open space benefits for the wider Hutt Valley.
and other adjacent reserves. There is a possibility that the provision of public walkways
through the forest could decrease the need for footpaths as part of the roading
requirements in the area, minimising future development costs.
•
Future ecological potential
Could be used to minimise reserve contributions and ongoing costs associated with the
maintenance of these areas.
•
The current vegetation would substantially reduce the flow of stormwater from major
7.4
rainfall events (via the multi-canopy layers within the catchment of pine, native forest,
Pines are dominant in many areas of the site. While as a general rule it is recommended that
pines be removed in the long-term, it is noted that there are some areas of the Southern Hills
where the large areas of pine in the area and the forest types that have established around some
of the older pines give the area a certain characteristic. In addition, the pines provide habitat for
native fauna (mostly birds) and good edge buffering and shelter from adjacent native forest.
regenerating understorey plants and leaf litter) that would otherwise require more
substantial stormwater controls.
•
Some less sensitive areas of regenerating forest could be used for locating infrastructure
such as stormwater and sewage treatment and disposal facilities.
There are a range of options in relation to management of the pines in the area that could be
implemented as part of any controls on residential subdivision in the Southern Hills, including:
In addition to the above benefits, it is our experience that residential developments adjacent to
areas of high ecological value generally attract conservation-minded residents who tend to be
well organised and often get involved voluntarily in the ongoing management and decisionmaking of the area. In other similar residential developments in New Zealand a range of
resident-led conservation projects have led to substantial environmental gains through
community care groups, guardians, restoration projects and stream-care groups. These
initiatives combined with vesting of large areas of native forest in council reserves or
conservation covenants could save substantial ongoing management and maintenance costs
and responsibilities and ensure the long-term protection of the area.
7.2
•
Harvesting and removal of some of the larger areas of block plantation pine.
•
Removal of some of the more established pines where possible to enable natural forest
regeneration.
•
Landscape management of many areas of older pine.
•
Protection of some large areas of pine where they provide buffering or are so tightly
intermixed with vegetation communities having high ecological values.
Pine control can be expensive and because of its size and stature can also be damaging to
underlying vegetation and remnant trees. In certain areas of the site, there is potential for
development contributions to be used to manage pines and restore areas following their
removal. Ongoing thought will need to be given to long-term control or some thinning of areas
of pine with high public use, as like with the Wellington Town Belt, there are safety issues that
will need ongoing consideration. In addition, wind effects may add to this problem if housing is
adjacent to older pines on prominent windswept ridges. Natural succession in the place of the
Ecological corridors and networks
Given the Southern Hills proximity to existing reserves and backdrop to the densely populated
Upper Hutt city area, the site has a range of recreational values. We see great potential for
development contributions to work towards a common goal for the study area – one that links to
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Pine Management
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removed pines is expected to be relatively rapid given the conditions and adjacent seed sources
(although some thought would need to be given to invasive weeds.
•
Any roading should be carefully designed to avoid areas identified as having high
ecological values.
There is already a number of forestry or older farm access roads
across the Southern Hills. A number of these roads are well placed in terms of their
ridgetop location, topography, size and gradient etc. and with minimal upgrading could
8.0 RECOMMENDED DEVELOPMENT CONTROLS
continue to be used to service future residential subdivision. Utilising existing tracks
wherever possible reduces the need for substantial vegetation clearance, earthworks,
As part of future development of the Southern Hills areas, we have a number of
recommendations to ensure that the locally significant ecological values of the site are
recognised and the more valuable areas are protected and maintained. These are as follows:
•
disposal areas and any possible adverse effects associated with major earthworks.
•
access roads as part of any landuse consents for the Southern Hills. Conditions could
Development of an integrated management framework that covers staging of
include requirements for sediment/flocculation ponds, timing of earthworks and
development across the wider site, pine removal, and which provides rules and guidelines
construction, ongoing downstream mitigation and sediment control, monitoring water
for management by future landowners.
•
Than consent conditions be imposed in relation to any earthworks and construction of
quality and a management plan for downstream riparian environments, particularly where
As part of this management framework, a long-term goal should also be developed for the
earthworks are close to the Black Stream, Mangaroa River and the Hutt River.
Southern Hills to protect high areas of high ecological value as part of a broader network
of open space, reserves, ecological values and recreation areas – the ‘Town Belt’
concept.
•
9.0 SUMMARY AND CONCLUSIONS
Part of this ‘Town Belt’ concept to develop an integrated framework for open space and
protected areas across the site, it is recommended that Council require the establishment
The Southern Hills lie on moderately steep to steep hill country with some areas of rolling land
confined to ridgelines. There is a mix of vegetation types across the site, from pasture, gorse
and pine through to primary beech forest and areas of mixed lowland podocarp forest.
of either reserve contributions or conservation covenants to protect areas identified as
having high ecological value. These areas could either be managed by Upper Hutt City
Council or through body corporate structures.
•
The site’s topography and vegetation mean that ecological constraints affect approximately 51%
of the site (or 789 ha). Most importantly, 35% of the site (or 533 ha) is identified as having high
ecological constraints. In general, these areas recognised as having high ecological value are
primarily remnant or advanced secondary beech forest with one small raupo wetland. These
vegetation communities are considered to be locally significant and therefore are considered “no
go” in terms of development. A number of these areas are already formally protected through a
various reserves or designations and require no further protection. However, there are still
larger areas of vegetation that are considered to warrant some level of protection from
development – or as a minimum their incorporation within a larger network of designated or
formally protected open space or reserve areas across the Southern Hills.
Any development in close proximity to areas identified as having high or moderate
ecological constraints should require as a minimum an independent ecological
assessment to ensure those areas are protected from any adverse effects and to ensure
thought is given to their long-term maintenance and enhancement. Alternatively, we
would recommend the development of resource consent assessment criteria that require
ecological input or matters of discretion that require consideration of ecological values,
rarity and representativeness of vegetation and values as habitat and/or corridors.
•
Appropriate resource consent conditions or covenants are imposed as part of any
development surrounding areas of high ecological value.
With the exception of those areas identified as having high ecological values, we consider that
limited development is suitable over much of the site. In those areas identified as having
moderate ecological constraints (17% of the site, or 256 ha), some development is considered
appropriate so long as it recognises the particular ecological values unique to the site and that
the design, layout and density of any development is undertaken appropriately and in a manner
that does not adversely effect on areas having high ecological values. The remainding 49% of
the site (or 746 ha) is considered to have either low or no ecological constraints and is therefore
considered to be suitable for a number of development opportunities. However, given the wider
ecological values of the Southern Hills it is recommended that any such development is required
to consider a long-term integrated goal for the wider Southern Hills and that any potential
adverse effects of development on the sites ecological values is taken into consideration.
These could include
requirements for buffer areas or building set-backs, restrictions on vegetation removal,
minimum lot sizes, limitations on future pruning or modification, stormwater and grey
water disposal, appropriate garden plants and species, weed control obligations, fires etc.
•
Depending on the nature of development and whether reserve contributions are to be
maintained by Council or by body corporate structures, appropriate conditions could also
be imposed whereby each lot owner pays an annual amount towards ongoing
management, maintenance and possibly enhancement of areas identified as having high
ecological values.
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Comparing the extent of current vegetation communities across the Southern Hills to a detailed
vegetation map prepared in 1960, illustrates a surprising situation whereby almost all the primary
beech forest remnants have been retained. In a lot of areas these primary forest remnants have
been increased in size by surrounding regeneration, much of which is now becoming well
advanced with some primary forest species present. This situation is considered relatively
unusual given a significant proportion of the land is privately owned and close to urban
development.
10.0 REFERENCES
DEPARTMENT OF CONSERVATION 1996: Conservation Management Strategy for Wellington 1996-2005.
Wellington Conservancy Management planning Series No 2. 2 Vols.
DRUCE, A.P.; ATKINSON, I.A.E. 1960: Map of the Vegetation of the Hutt Catchment. Unpublished map redrawn
and revised by G. Stephenson 1974. On file, Wellington Regional Council.
Overall, there are large areas of the study area that would be suitable for residential
development and associated infrastructure of the nature proposed. It is our opinion that limited
residential development that is sensitive to the site’s ecological features would certainly be an
appropriate use of the area in the long-term.
DRUCE, A.P. ; ATKINSON, I.A.E. 1960. Vegetation Map of the Hutt Catchment, North Island, New Zealand.
Vegetation Survey Map by A.P. Druce and I.A.E. Atkinson, Botany Division, Department of Scientific and
Industrial Research, 1958-1960.
FULLER, S. A., WASSILIEFF, M. C. 1993: An Inventory of Biological and Geological Sites in the Wellington
Region. Unpublished report. Prepared for the Wellington Regional Council. 33 pp. incl. Appendices.
FULLER, S.A. 1993: Wetlands in the Wellington Region. Wellington Regional Council Policy and Planning Dept
report; WRC/PP-G-93/16 32 pp.
DRAFT
FULLER S.A. 1995: Resource Description, Ecological Assessment & Inventory of Sites of Biological Value Upper
Hutt District. Prepared for Upper Hutt City Council. April 1995
Matiu Park
Senior Ecologist / Planner
Boffa Miskell Limited
HITCHMOUGH, R. 2002: New Zealand Threat Classification System lists—2002. Threatened species occasional
publication 23. Biodiversity Recovery Unit, Department of Conservation, Wellington. 210 p.
McEWEN, M. 1987: Ecological Regions and Districts of New Zealand. Booklet to accompany Sheet 3: Central
New Zealand from Eastern Wairarapa in the North Island to Akaroa in the South Island. New Zealand
Biological Resources Centre. Publication No. 5. Department of Conservation, 3rd Revised Edition.105 p.
NIWA: New Zealand Freshwater Fish Database. National Institute of Water & Atmospheric Research
PAGE, M. J. 1990: New Zealand Land Resource Inventory, land use capability extended legend of the Wellington
Region. Technical Report 26 DSIR Land Resources.
PARRISH, G. R. 1984: Wildlife and Wildlife Sites of the Wellington Region. New Zealand Wildlife Service,
Department of Internal Affairs. Fauna Survey Unit Report No. 38. Pp 56 plus maps.
STEPHENSON, G. 1977: Wildlife and Wildlife Areas in the Wellington Region. Wellington Regional Planning
Authority, Wellington New Zealand. Report 77.31. Pp. 96.
WASSILIEFF etal' 1986: Wassilieff, M.C.; Clark, D.J.; Gabites, I. 1986: Scenic Reserves of the Lower North
Island. Biological Survey of Reserves No.14. 297 p.
WELLINGTON REGIONAL COUNCIL 1995: Regional Freshwater Plan for the Wellington Region. Publication No.
WRC/PP-G-95/58.
WELLINGTON REGIONAL COUNCIL 1995: Regional Policy Statement for the Wellington Region. Publication No.
WRC/PP-G-95/28. May 1995.
WELLINGTON REGIONAL COUNCIL, 1984: Biological Resources of the Wellington Region. Wellington Regional
Council, Queen Elizabeth II National Trust, N. Z. Biological Resources Centre.
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page 11
page 12
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Photo 1:
Photo 2:
Primary beech forest (Vegetation Community 1) intermixing with beech forest More detailed photo illustrating primary beech forest (Vegetation Community
remnants and advanced secondary beech forest (Vegetation Community 3)
1) intermixing with beech forest remnants and advanced secondary beech
and areas of plantation pine.
forest (Vegetation Community 3)
Photo 4:
Primary beech forest remnants and advanced secondary beech forest
(Vegetation Community 3) intermixing with primary beech forest (Vegetation
Community 1) and gorse (Vegetation Community 7).
Photo 5:
Photograph illustrating secondary mixed broadleaved scrub and low forest
(Vegetation Community 4) intermixing with isolated remnant beech trees.
Photo 3:
Lowland podocarp forest (Vegetation Community 2) on the lower slopes
of the Southern Hutt Hills above the northern extent of the historical Wallaceville Swamp.
Photo 6:
Secondary mixed broadleaved scrub and low forest (Vegetation Community
4) intermixing with pimary beech forest (Vegetation Community 1).
page 15
Photo 7:
Mixed kanuka and gorse scrub (Vegetation Community 4). This photo illustrates the complex nature of the various vegetation types across some areas
of the Southern Hutt Hills with primary beech forest (Vegetation Community
1) intermixing with beech forest remnants and advanced secondary beech
forest (Vegetation Community 3) and areas of plantation pine.
Photo 8:
Photo illustrating manuka on wet soils (Vegetation Community 6) looking up
the Mangaroa and Wallaceville Swamps.
Photo 9:
Photo illustrating a large area of gorse monoculture (Vegetation Community
7) in the central area of the Southern Hutt Hills. A number of smaller beech
forest remnants, patches of kanuka and small areas of secondary beech forest are also visible.
Photo 10:
Plantation pine (Vegetation Community 9) near Alexander Road. Areas of
gorse monoculture and mixed kanuka and gorse scrub are also visible.
Photo 11:
Photograph illustrating vegetation that has been retained as part of the
development of Mt. Marua. secondary mixed broadleaved scrub and low
forest (Vegetation Community 4) intermixing with isolated remnant beech
trees.
Photo 12:
Small stand of mixed kahikatea and swamp maire regenerating within the
Southern Hutt Hills area adjacent to older residential development, Gentian
Street.
page 16