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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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