POHUTUKAWA TRUST NEW ZEALAND

To rehabilitate the native flora and
fauna of Kawau Island
To promote the conservation of
indigenous species in New Zealand
To achieve sustainable land use on Kawau Island
THE
ECOLOGICAL VALUES OF KAWAU ISLAND
(Operations
Manual Section 6)
Kawau Island is of
considerable long term ecological value to the Rodney District and the
Auckland Region and New Zealand. The Trust’s founder has previously
described Kawau as the “forgotten island” so far as ecological values
are concerned, because Government conservation agencies have placed
emphasis upon the significant historic values of the Island and have
concentrated their resources in that direction.
The
topography provides a unique spectrum of ecosystems in the Hauraki
Gulf and as an island its ecological potential is probably only
surpassed by Hauturu/Little Barrier, and Great Barrier Islands, even
though restoration presents some challenges.
The
Kawau ecosystems for example, range from exposed cliffs and headlands
with remote nesting ledges to sheltered valleys, some with wetlands
terminating in intertidal estuaries, gorges and watercourses with
permanent running water and pools, steep inland stony slopes, large
areas of more moderately sloping land facing in various directions and
flat stony valley floors. The range of physical conditions present
ecosystems related to a variety of wind, sun, shelter, elevation,
gradient, surface and soil characteristics. The Island has two main
soil types, derived from weathering of the sandstones and
conglomerates on the one hand, and the older jasperiod slate rocks on
the other. In general the soils have a paucity of organic matter and
are low in the main plant nutrients due to the environmental situation
existing for many years, with limited vegetation and stripping of
topsoils by water run off. While in elevation Kawau is no match for
Hauturu at over 700 metres, the range of ecosystems presented close to
the mainland will prove to be a very valuable resource, particularly
in the recovery of plants and of native bird numbers as the Trust’s
program advances.
Much
of the land was once farmed or milled for timber, but there are areas
that have never been clear felled and these contain a range of remnant
native trees, some at least 300 years old. In this general respect
Kawau Island is by contrast more that 150 years ahead of Tiritiri
Matangi, and with a much greater range of ecosystems. Kawau therefore
already has considerable potential and value for permanent
restoration.
Remnant native trees and plants are being discovered in the course of
the Trust's project, including some which are rare in the Auckland
District.
While the Trust’s emphasis is on restoration of flora and fauna some
potential is recognised by the community for small scale sustainable
land uses and the restoration concept recognises and enables this to
be accommodated without compromising the restoration goals. The Kawau
Island community initiated the project and has traditionally focussed
on looking after the ecological values. A healthy community structure
with a balance including appropriate sustainable land uses is
encompassed. A most important factor in the plans is that the
community ownership and motivation provides the main resource to very
cost effectively accomplish and retain the restoration goals. The
Trust has developed this aspect as a community culture through
participation open to all, including innovative action to cost
effectively control possum numbers and then to move through serious
wallaby control to eradication, and concurrently to encourage
eco-sourced replanting and provide management provisions in the Rodney
District Plan consistent with the project.
NATIVE
FLORA RESOURCE LIST
(Operations Manual Section 12, May 1996)
Two
stays were made on Hauturu during the 1980’s decade to evaluate the
diversity of native flora and fauna, and the general potential to
restore Kawau Island, to balance the formal view of government
agencies at the time that such a project was neither feasible nor
justifiable.
It
was fully recognised that Hauturu was significantly different to Kawau
due to both the andesitic origin of the land and the range of
elevations, but the stays were well worthwhile and essential to
inspire confidence and action by a group of landowners at the time
when Kawau was recorded to be of little ecological value or
importance.
In
1995 a formal native flora resource list was commenced, to be
progressively compiled as information on native plants growing on
Kawau is collected.
There is still anticipation that rare plants could be discovered on
Kawau in spite of the serious general collapse of the ecosystems.
The starting references used:
“ON THE BOTANY OF KAWAU
ISLAND”
John Buchanan, F.L.S. 2
September 1876.
“REGENERATION POTENTIAL OF NATIVE FOREST
ON
KAWAU ISLAND”
Claire Marie Taylor, A
thesis submitted to University of Auckland, 1990.
“THE NATIVE TREES OF NEW
ZEALAND”
T. J. Salmon. D.Sc.
F.R.S.N.Z., F.R.P.S. 1980.
Members of the Trust
provided locations of some of the
remaining species on
Kawau in a 1995 survey and it is expected
that more discoveries
will be made as the restoration proceeds.
Other methods in use include:
1.
To encourage the Auckland Botanical Society to make field trips to
Kawau at the invitation of the landowners and report species
identified.
2.
To investigate sponsoring a graduate completing a Masters degree in
botany who may add to the content and accuracy of the list.
PURPOSE.
The
purpose of the native flora resource list and identification of
localised ecosystems is to enable development of site specific
revegetation plans to authentically augment natural regeneration using
ecosourced seeds and plants.
The
native flora resource list presently includes both plants which are
known to be growing on Kawau and those thought to be, but not yet
confirmed.
The objective is to compile an inventory of plants in the following
categories:
1.
Serious weed species (see Section 11).
2.
Native plants which will provide the resource for natural (assisted)
regeneration and eco-sourced propagation.
3.
Plants which are rare or endangered on Kawau (due to limited numbers)
even though they may be more common in other locations.
4.
Plants which exist on Kawau and are rare or endangered at least in the
Auckland Region and possibly in New Zealand.
The
main Kawau Island forest trees and shrubs identified are shown below.
Some on the list are represented by very few known specimens and
except for Kanuka, the natural regeneration of every one of them is
prevented by wallaby browsing.
Kanuka (Kunzea ericoides) is the dominant species on the island
where pasture has reverted to forest under the influence of wallaby
browsing because Kanuka seedlings are the only species on the list
completely unpalatable to browsing wallabies. Kanuka is also a climax
species on some exposed coastal sites on Kawau Island.
Beach (hard
beach) Nothofagus truncata
Cabbage tree
Cordyline australis
Cabbage tree (dwarf
cabbage tree) Cordyline pumilio
Coprosma rhamnoides
Coprosma rhamnoides
Five finger
Pseudopanax arboreus
Houpara Pseudopanax
lessonii
Hinau
Elaeocarpus dentatus
Kauri Agathis
australis
Kanuka Kunzea
ericoides
Kahikatea
Dacrycarpus dacrydioides
Karaka Corynocarpus
laevigiitas
Kowhai Sophora spp
Karo Pittosporum
crassifolium
Kohukohu Pittosporum
tenuifolium
Kawakawa Macropiper
excelsum
Karamu Coprosma
robusta and C. lucida
Lacebark Hoheria
popuinea
Miro Prumnopitys
ferruginea
Mapou (Red Matipo)
Myrsene australis
Manuka Leptospermum
scoparium
Matai Prumnopitys
taxifolia
Mahoe Melicytus
ramiflorus
Mangeao Litsea
calicaris
Maire (white maire)
Nestegis lanceolata
Mamangi Coprosma
arborea
Nikau Rhopalostylis
sapida
Pohutukawa
Metrosideros excelsa
Puriri Vitex lucens
Pigeonwood Hedycarya
arborea
Puka Griselina
lucida
Rewarewa Knightia
excelsa
Rimu Dacrydium
cupressinum
Ramarama Lophomyrtus
bullata
Rangiora
Bracyglottis repanda
Totara Podacarpus
totara
Tawaroa (large leaf
tawa) Beilschmiedia tawaroa
Tawa Beilschmiedia
tawa
Taraire
Beilschmiedia taraire
Titoki Alectryon
excelsus
Tanekaha
Rhopalostylis sapide
Towai
Weinmennia silvicola
Tawapou
Pouteria costata
Toatoa Haloragis
erecta
Taupata Coprosma
repens
Wineberry
Aristotelia serrat
Link:
Auckland Regional Council ecological restoration guide.
http://www.arc.govt.nz/environment/natural-environments/restoring_nature/ecological-restoration.cfm
Pohutukawa Trust New Zealand
Registered Office
24 Umere Crescent
Ellerslie
Auckland
Ó
Copyright 1951-2005 E.R. Weaver
Pohutukawa
Trust New Zealand
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Kawau Island History
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