An Ecological Restoration Plan for Maungatautari

Transcription

1 Maungatautari Ecological Island Trust 64 Alpha Street, P.O. Box 476, Cambridge, New Zealand Ph: Fax: mail@maungatrust.org Website: An Ecological Restoration Plan for Maungatautari Working Document Our Vision To remove forever, introduced mammalian pests and predators from Maungatautari, and restore to the forest a healthy diversity of indigenous plants and animals not seen in our lifetime. Working Document last revision September 2004 i

2 Compiled by Joanna C. McQueen Centre for Biodiversity and Ecology Research Department of Biological Sciences The University of Waikato Private Bag 3105 Hamilton CBER Contract Report No. 34 Contributing authors: Chris Smuts-Kennedy 1, Kevin Collier 2, Bruce D. Clarkson 3, Bruce Burns 4, and Roger MacGibbon 5 Prepared for Maungatautari Ecological Island Trust March Ecological advisor to Maungatautari Ecological Island Trust, PO Box 476, Cambridge 2. Freshwater Ecologist, National Institute of Water and Atmospheric Research, PO Box 11115, Hamilton 3. Associate Professor, Centre for Biodiversity and Ecology Research, Department of Biological Sciences, The University of Waikato, Private Bag 3105, Hamilton 4. Scientist, Maanaki Whenua Landcare Research, Private Bag 3127, Hamilton 5. Restoration Ecologist, Natural Logic Ltd, Taupo Reviewed by Matt Maitland, Rotoiti Nature Recovery Project, Department of Conservation. Working Document last revision September 2004 ii

3 Table of Contents Page Use of this plan iv Consultants Brief vi Recommendations vii Summary viii Acknowledgements xi Part 1: Background Information 2 Part 2: Restoration 38 Part 3: Monitoring and Risk Analysis 78 Working Document last revision September 2004 iii

4 Use of this plan This restoration plan is a working document and will need to be adjusted as the project evolves and more information is gained. The use of this plan should recognise its role as a guide to the restoration. In many instances, this plan is the starting point for debates which need to be conducted between scientists, and often the community as well, on how to proceed. This plan has been separated into three parts for ease of use. Part 1 contains the background information for the project and the context in which the project is being undertaken. Part 2 contains the information needed for restoration, including what species to introduce and the timing of introductions. Part 3 contains information on monitoring and a risk assessment for the project. For ease of use, each of these parts has been designed as a stand alone document which can be bound individually or combined to make a total volume. Appendixes are placed at the end of each part to allow binding as a complete document, however the numbering allows binding as a whole. After each main heading, a summary of that section is given in a box. Where a section raises questions that need to be debated or researched, questions are given in a box at the end of the section. Working Document last revision September 2004 iv

5 How the restoration plan fits into the Maungatautari project Restore the diversity, vitality and resilience of the ecosystems of Maungatautari Educational/recreational plan Management Plan Restoration Plan Restore the forest Restore the wildlife Restore waterways Forest ecosystem is self sustainable Connections to landscape Complete fence Appoint project manager for pest control Pre-operation monitoring on mountain Appoint person to manage wildlife Workplans for each species Secure funding and approval for translocations Plant riparian zones Monitor water quality Appoint monitoring coordinator Monitor forest condition and wildlife Locals plant riparian zones and corridors on surrounding land Operation plans for pest control developed Carry out pest control Make wildlife introductions Prove pest-free status Working Document last revision September 2004 Monitor introductions v

6 Consultants Brief A restoration plan for Maungatautari is necessary to detail the timing and co-ordination of implementation of restoration goals and to ensure finances and resources are available when required. The vision for Maungatautari also needs to be incorporated into such a plan. To restore Maungatautari to a largely indigenous, diverse, fully functional, (near) self-sustaining forest, permanently free of mammalian pests and to strengthen the mauri of the forest and protect the mana of the maunga. The restoration plan needs to comprise the following processes: 1. Integrate ideas from experts and groups interested in the restoration process, including iwi. 2. Establish restoration goals 3. Establish measurable success criteria 4. Risk analysis including factors that may limit restoration 5. Steps to ameliorate factors that may limit restoration 6. Management strategies for restoration including: a. Type of eradications/reintroductions b. Timing of eradications/reintroductions c. Monitoring of eradications/reintroductions and checking against success criteria 7. Develop a realistic timeline for restoration goals 8. Develop work plans that can be followed by restoration managers 9. Identify the resource requirements for restoration* 10. Identify the costs of restoration* *these points have not been covered in the plan due to the dynamic and ever changing nature of the restoration process. They are also separate issues to ecological restoration and should be covered elsewhere. Working Document last revision September 2004 vi

7 Recommendations 1. That MEIT carries out best practice monitoring methods for mammalian pests, whilst acknowledging the shortcomings of these methods, so that the pest-free status of Maungatautari can be shown. 2. That MEIT encourages and/or assists in research into low density pest monitoring to provide a permanent solution to pest detection over large areas with minimum cost and labour. 3. That MEIT establishes permanent monitoring programmes so that changes in biodiversity and ecosystem functioning can be measured both pre and post fence construction and pest elimination. 4. That MEIT carries out extensive surveys of plants and animals on the mountain, especially with the goal to determine whether any remnant populations of species proposed for re-introduction still exist and whether introductions of other native species will impact these populations. 5. That MEIT establishes restoration goals for the two enclosures. For example, are they to be a part of the larger goal of returning the mountain to its original condition, or are they a safe haven for endangered species that would not necessarily have lived on the mountain in the past? 6. That MEIT does not work in isolation but establishes links with other similar restoration projects (such as Karori Sanctuary) to increase the body of knowledge on this type of restoration work and prevent mistakes from being repeated. 7. That MEIT follows the species introductions outlined in this restoration plan and/or makes introduction decisions based on sound scientific knowledge and consultation with the appropriate experts to ensure success is not compromised by wrong choices. 8. That MEIT records all activities that have been carried out on the mountain so that successes and failures can be analysed in the correct context. 9. That MEIT employs a mountain caretaker who is based on the mountain and who is intimately involved in the day to day running of the restoration (such as bird feeding/monitoring etc.). 10. That MEIT shortly begins the process of making workplans (following the DOC standard operating procedure for translocations) for each planned species introduction and begins dialogue with the appropriate recovery groups to ensure access to the appropriate species. 11. That MEIT encourages research into the ecological impacts of wasps and any other exotic invertebrates on the mountain. 12. That MEIT encourages research into species and communities about which little is known of their biology and structure. 13. That MEIT keeps a database of biota known to exist on the mountain which is available to all. Working Document last revision September 2004 vii

8 14. That MEIT encourages activities (such as planting) that provide connections from the mountain to the surrounding landscape. 15. That MEIT constructs a comprehensive risk management strategy for the project, including both risks to both the ecological and management sides of the project. Summary The aim of this restoration is to reactivate the major successional processes likely to have operated in pre-human times (before the arrival of mammalian pests), so that Maungatautari reaches his own ecological balance. Some species introductions may fail and others may exceed our expectations, but, so long as best practice techniques were used in the translocation, the restoration can be deemed a success. MEIT can give the mountain the appropriate ingredients to restore itself, but cannot control the dynamic balance that results. This is a trial on a grand scale as we do not know what will happen once mammals are removed from a place which they have long inhabited. We do not know how ecosystem balance will be found with the removal of these pests, but a reduced animal fauna to replace them with. We do not know how important extinct species such as the moa were on influencing ecosystem processes. We can only wait to see how the mountain responds and watch and learn. To be successful, a restoration programme must have a restoration goal, active intervention to restore plants and/or animals formally present and monitoring of progress (Atkinson 1988). This document presents a restoration plan to ensure the successful restoration of Maungatautari. In summary: Part 1. Background information The New Zealand flora and fauna evolved in the absence of mammalian predation and were ill equipped to deal with terrestrial mammals when they arrived. There have been many extinctions since the arrival of exotic mammals and biodiversity losses are continuing today through predation and habitat fragmentation. The challenge now is to halt this decline and the Maungatautari project offers a way forward in this regard. Located in the middle of the Waikato Basin, Maungatautari represents a significant area of forest remaining here. The bird fauna is now quite depleted and there are a number of mammalian predators present including possum, deer, goats, ship rats, mice, ferrets, stoats, hedgehogs, pigs and cats. Maungatautari was once a high point in a large area of coniferbroadleaved forest, but today it represents nearly half of the forest remaining in the district. Many birds, invertebrates and reptiles that are now extinct or gone from the area would have lived in the forests. Restoration is necessary to restore degraded habitats. Only a fraction of the original fauna remains on Maungatautari and the flora Working Document last revision September 2004 viii

9 has been subjected to intense browsing pressure in the past. Introduced pests, even in very low numbers, can cause the extinction of much of our fauna. After eradication, a fence has the potential to exclude these pests permanently from the mountain and thus allow the recovery of fauna and flora no longer seen on mainland New Zealand. The large area enclosed will allow substantial ecological gains to be made, including an increase in the numbers of native animals on the mountain. A restoration plan is required to ensure the timing and sequencing of reintroductions are carefully planned and to ensure restoration goals are adhered to. Restoration of Maungatautari will aim to return the original ingredients to the mountain so that Maungatautari will reach an ecological balance. The goal is to Restore the diversity, vitality and resilience of the ecosystems of Maungatautari, as close as possible to the original condition, to re-create self-sustaining communities of indigenous plants and animals. Missing plants include: White mistletoe, woodrose Missing animals include: Bellbirds, whiteheads, kaka, weka, takahe, kiwi, kakapo, kokako, saddleback, north Island robin, hihi, kakariki, long-tailed cuckoo, rifleman, petrels, snipe, short-tailed bat, tuatara, Cylodina alani, McGregors skink, Whitakers skink, Oligosoma infrapunctatum, green gecko, forest gecko, common gecko, Pacific gecko, striped gecko, Duvaucel s gecko, Leiopelma waitomoensis, L. markhami, L. hamiltoni, Archey s frog, Hochestter s frog, Mahoenui giant weta, wetapunga, Middle Island tusked weta, weevils, stag beetles, banded and short-jawed kokopu. Part 2 Restoration Translocations and release of indigenous plants and animals must adhere to the Department of Conservation standard operating procedure for the transfer of indigenous fauna and flora. Planting should be restricted to any large areas of pasture encompassed within the fence and to riparian zones surrounding the mountain. Plantings should be sourced from the Maungatautari forest and be species that are naturally replaced in succession. Animals suitable for translocation to the mountain include: weka, takahe, kiwi kakapo, kokako, hihi, Cook s petrel, Mahoenui weta, tuatara, Whitaker s skink, and Archey s frog. The appropriate timing for introducing these animals is discussed. All introductions must be accompanied by the appropriate research and a plan detailing the introduction to ensure maximum chances of success and to ensure permission is gained from the Department of Conservation for the translocation. A timeline for the project is given. Part 3 Monitoring and Risk Assessment Failure to monitor steps and rates of progress in a restoration programme may result in loss of significant information that could Working Document last revision September 2004 ix

10 avoid further mistakes or enable successful programmes to be repeated. Monitoring must be carried out continuously for both pest and reintroduced species. Vegetation and bird monitoring should be carried out routinely using permanent plots and 5-minute bird counts. The mountain should be protected from mammalian pests by the fence, but rigorist pest monitoring will need to be carried out to ensure there are no breaches or failures of eradication. Weeds must be removed and other pests (e.g. exotic invertebrates) must be managed. People must be managed to ensure they do not impact on the restoration and a separate management plan should be written for visitors. Surrounding landowners should be encouraged to plant native forest corridors to provide connections from Maungatautari to the surrounding landscape. A preliminary risk analysis is given. Working Document last revision September 2004 x

11 Acknowledgements We wish to acknowledge the helpful advice received from the following people: Jillana Robertson John Innes Tony Beauchamp (advice on weka) Avi Holzapfel Peter Maddison (invertebrate studies) Liz Grove Elizabeth Bell (advice on shearwater introductions) Carolyn King Paul Jansen (advice on kiwi) John McLennan (advice on kiwi) Keri Neilson Colin Miskelly (advice on snipe) The landowners around Maungatautari for the history of the area Members of the Maungatautari Science and Research Committee Catherine Beard for colouring the vegetation map. Working Document last revision September 2004 xi

12 Part 1. Background Information Celmisia gracilenta (Photo B.D. Clarkson) Working Document last revision September

13 Table of Contents Part 1. Background Information Introduction Characteristics of Maungatautari Reserve area Climate Geology Landforms and soils Flora Vegetation types Fauna Birds Terrestrial invertebrates Reptiles Frogs Fish and aquatic invertebrates Introduced mammals Pre-historic Maungatautari Vegetation Birds Terrestrial invertebrates Fish and aquatic invertebrates Reptiles and amphibians Restoring Maungatautari Why restore Maungatautari? Maungatautari biodiversity losses Mainland islands Ecological benefits Benefits of pest removal The pest proof fence Pest removal The need for a restoration plan What biotic community should we restore to Maungatautari? Goals and restoration targets The ecological goal Ecological objectives Missing plant and animal species Flora Fauna Missing birds Missing mammalian species Missing reptile species Missing terrestrial invertebrate species Missing fish species. 28 References.. 29 Appendix 1: Common and scientific names used.. 33 Appendix 2: Introduced mammals on Maungatautari Working Document last revision September

14 1. Introduction The New Zealand flora and fauna evolved in the absence of mammalian predation and was ill equipped to deal with mammals when they arrived. There have been many extinctions since the arrival of mammals and biodiversity losses are continuing today through predation and habitat fragmentation. The challenge now is to halt this decline and the Maungatautari project offers a way forward in this regard. The New Zealand land mass split from Gondwanaland around 80 million years ago, leaving the flora and fauna here to evolve through a long period of isolation. Animal groups such as terrestrial mammals failed to reach this isolated land mass (apart from three species of bats). This long period of isolation led to a high degree of endemism in the flora and fauna; about 82% of the flora is endemic (Dawson 1988). Both plants and birds evolved in the absence of mammalian predators. Many plants failed to develop defence mechanisms to mammalian predation, such as toxins or spines. Many birds lost the ability to fly and began to nest on the ground. Some birds and insects expanded their niches to fulfil the roles carried out by mammals elsewhere, for example, the weta became the ecological equivalent of a mouse (Field 2001). Ancient animals and plants, such as tuatara and tawari, relicts from Gondwanaland, survived here when they disappeared from the rest of the world. This led to a New Zealand fauna and flora which commonly has low fecundity, long nesting period (or slow seedling growth) and high longevity. Many birds also have large eggs, long incubation periods, long family periods, year round fidelity with a single mate, no migration, early pair bonding and flightlessness. Many plants have attractive foliage or bark and shallow feeding roots (Mark 1984). The long isolation of New Zealand and the unique adaptations of the flora and fauna have meant that the plants and animals were especially vulnerable to new changes. The arrival of humans has had dramatic impacts on the indigenous biodiversity. The arrival of Polynesians ( A.D.) brought to the vulnerable New Zealand fauna, a rat (Rattus exulans) and dog (now extinct). They also carried out massive deforestation through burning and unsustainable hunting. Forty five species of bird went extinct, including all moa species (Mark 1984). The arrival of Europeans from around 1850 brought about an even bigger wave of destruction. Two-thirds of the forest has been lost, and wetlands, dunelands and coastal areas have been extensively modified. A vast range of plants and animals (including possums, goats, deer, rats, stoats and feral cats) were introduced, many of which have become pests (including some 200 plant species) and many that have contributed to extinctions. Extinctions since human arrival in New Zealand in the last years have included (New Zealand's Biodiversity Strategy 1998): Thirty-two percent of indigenous land and freshwater birds Working Document last revision September

15 Eighteen percent of sea birds Three out of seven frogs At least twelve invertebrates such as snails and insects One fish, one bat and perhaps three reptiles About eleven plants At least 1000 taxa of indigenous plants, animals and fungi are threatened with extinction in New Zealand (Saunders and Norton 2001). The challenge now is the stop this decline in our biodiversity. Projects such as the restoration of Maungatautari are an important part of restoring our biodiversity and ensuring no further decline occurs. Located in the centre of the North Island, close to the townships of Cambridge, Te Awamutu, Tirau and Putaruru (Fig. 1.), the mountain provides an opportunity to increase the biodiversity of the Waikato basin with community involvement. To be successful, a restoration programme must have a restoration goal, active intervention to restore plants and/or animals formerly present and monitoring of progress (Atkinson 1988). This document presents a working restoration plan to ensure the successful restoration of Maungatautari. Mt. Maungatautari Figure 1. The location of Maungatautari in the Waikato in the North Island of New Zealand (NZMS Topographical Maps). Working Document last revision September

16 2. Characteristics of Maungatautari Located in the middle of the Waikato Basin, Maungatautari represents a significant area of forest here. The bird fauna is now quite depleted and there are a number of mammalian predators present including possum, deer, goats, ship rats, mice, ferrets, stoats, hedgehogs, pigs and cats Reserve area The Maungatautari scenic reserve (2,390ha) and adjoining Maori and private land constitute about 3,200ha of native forest surrounded entirely by farmland. The area of Maungatautari mountain currently in forest or regenerating native bush is 3363ha (derived from cadastral information provided by Environment Waikato and Waipa District Council) (MacGibbon 2001). Maungatautari reserve was originally set aside in 1927 when it recognised to be of value for climatic and conservation purposes (MacGibbon 2001) Climate The Waikato Basin receives about 2,000 hours of bright sunshine a year and days of fog (de Lisle 1967). The average temperature is around 14 0 C (de Lisle 1967). Rainfall averages cm per year on high ground compared to approximately cm per year on the surrounding flats Geology Maungatautari volcano lies in the southeast of the Middle Waikato Basin, separated from other volcanoes and mountain ranges in the region, and being regarded as a separate volcanic complex (Cole 1978). At 797m above sea level, it is a highly eroded andesite cone (Clarkson 2002) of lower Pliocene age. Made mainly of andesite lava, it is surrounded by a ring-plain of lahar (Cole 1978). The rocky outcrops represent exposures of lava in the central part of the complex (Cole 1978) Landforms and soils The topography of Maungatautari ranges from strongly rolling slopes at the base of the mountain to steep to very steep slopes near the peaks and in the gullies. The soils are a mixture of yellow-brown silt and clay loams which have developed from volcanic ash, and stony red-brown clay loams derived from the parent rock (MacGibbon 2001). The plastic quality of these soils renders them inherently unstable. Mudflows are a distinct possibility on cleared or disturbed land. The streams on the southern, eastern and northern slopes of Maungatautari flow into the Waikato River. Those on the western slopes flow into the Waipa River, before joining the Waikato approximately 200 kilometres further downstream. Working Document last revision September

17 2.5. Flora The forest canopy appears to have remained largely intact throughout the period of human occupation, surviving clearance for agriculture. Some rimu and to a lesser extent tawa and kahikatea were removed for milling from at least 1948 (Gudex 1963) and this continued through at least until the 1980s (MacGibbon 2001). The forest progresses from lowland rimu/tawa forest to upland forest at around 600 metres above sea level, dominated by tawari-kamahi and tawheowheo (Clarkson 2002). Tawari is dominant on the slopes to the south of Maungatautari trig, but kamahi is abundant on the summit as a consequence of forest clearance (Clarkson 2002b). In the lower reaches of the upland forest, tawa is important, and scattered emergent miro are present. On some upper slopes, emergent Hall s totara (Podocarpus hallii) are a feature. The understory commonly consists of Coprosma grandifolia, toro, five-finger (Pseudopanax arboreus), raukawa and horopito (Clarkson 2002b). Alseuosmia macrophylla, a fragrant flowered shrub is abundant in places. Epiphytes commonly include filmy ferns and kidney fern (Trichomanes reniforme). Ferns such as crown fern (Blechnum discolor) and Microlaena avenacea are common on the ground, along with hook-seeded sedges (Uncinia spp.) (Clarkson 2002b). The rocky spurs contain an interesting mix of vegetation, with hedge-like tawheowheo dominating over a shrub layer with mingimingi and a ground layer including Blechnum procerum. The open habitats have an interesting assemblage of small shrubs, sedges, orchids and herbs (Clarkson 2002b), including Morelotia affinis, Orthoceras novae-zeelandiae, Pomaderris ericifolia, Luzula decipiens, Celmisia gracilenta, Rytidosperma gracile, Leptospermum scoparium, Gonocarpus cf. incanus & monanus, and Racomitrium lanuginosum. Vegetation surveys have been carried out by Gudex (1963) and Clarkson and Boase (1986). Gudex (1963) found 191 indigenous vascular taxa and this list has subsequently been added to, making a total of 249 indigenous vascular taxa in 2002 (Clarkson 2002a). The flora of Maungatautari is generally typical of that found in the Waikato region (Clayton-Greene 1976). What is of special interest here, is the absence of species from the upland zone of Maungatautari, which are typically found on other mountains in the region. Missing species include Coprosma colensoi, Raukaua simplex, mountain flax, Hebe macrocarpa, Dracophyllum traversii and D. latifolium. It is important to note that these species are not missing due to browsing pressure, but have never been recorded on the mountain. This is probably because Maungatautari is relatively isolated from other mountain regions. The physical environment of the Waikato basin probably acted as a barrier to the dispersal of many higher-altitude species (Clayton-Greene 1976) and thus lowland vegetation simply expanded its range. The absences of these species are what make the flora of Maungatautari special. Parts of the mountain have not been thoroughly surveyed, including considerable areas on private land. The relatively low impact of pests, timber extraction and land clearance means that Maungatautari is probably more diverse and in better health than many remaining areas in the region (MacGibbon 2001). The few Working Document last revision September

18 weed species that are present are largely confined to the forest margins where they occur Vegetation types The vegetation types present on Maungatautari have been mapped by the New Zealand Forest Service (Fig. 2) to the scale of 1 inch to 1 mile (McKelvey 1963, Nicholls 1963). The forest of Maungatautari is predominately occasional rimu with abundant tawa. Rimu-rata/tawa-rewarewa-mangeao-kamahi is the main forest type below 610m (Nicholls 1963). Other forest types present include thinbarked totara-kamahi-tawari forest; miro/tawa-kamahi-tawari forest; rimu/rata/tawa-pukatea forest; rata/tawa-rewarewa forest; rewarewa-kamahi forest; manuka-kanuka scrub; scrub hardwoods and tree-fern scrub Fauna Based on the presence of kokako, long tailed bat, possibly short tailed bat and a wide variety of the more common forest birds, surveys of Maungatautari undertaken by the Wildlife Service in the mid 1970 s assigned a national habitat ranking of high to outstanding to the forest (Wildlife Service Fauna Survey Record Sheets, Department of Conservation). Kokako are no longer found in the forest but is it likely that they persisted until the early 1980 s (Garland pers.com). Saddleback, North Island robin and hihi all disappeared from the forest in the 1800 s or early 1900 s (MacGibbon 2001). Kiwi, kaka and kakariki all disappeared by the mid 1900 s (MacGibbon 2001) Birds In the summer of 2002, twenty-two bird species were recorded at Maungatautari (Innes et al. 2002). Of these, half were native, including fantail, grey warbler, kereru, bellbird, tui and kingfisher. Exotic species recorded included blackbird, chaffinch and magpie Terrestrial invertebrates Preliminary invertebrate information has been collected by Peter Maddison, and several hundred species have been found, including a number that have not been described previously (P. Maddison pers.comm). Exotic invertebrate pests are likely to include at least three species of introduced wasps Reptiles There is no information to date on the reptile populations on Maungatautari. Working Document last revision September

19 manuka-kanuka scrub, Scrub hardwoods, tree-ferns Rata/tawa-rewarewa Rimu-rata/tawa-rewarewa Rimu-rata/tawa-kamahi Miro/tawa-kamahi-tawari Thin-barked totara-kamahi-tawari Rimu/rata/tawa-pukatea Rewarewa-kamahi Figure 2. The vegetation types present on Maungatautari (McKelvey 1963, Nicholls 1963). Working Document last revision September

20 Frogs There is no information to date on any native frog populations on Maungatautari. The introduced Australian frogs Litoria aurea and/or L. raniformis are likely to be present, especially around the bush margins. They are also likely to travel through the bush looking for new breeding ponds Fish and aquatic invertebrates Preliminary surveys have found the following native fish species are present on Maungatautari: Crans bully, shortfin eel, longfin eel. Fish populations of migratory species are likely to be limited by restricted access to and from the sea on both sides due to dams along the Waikato River preventing fish passage and from the high turbidity of the water in the Waipa. In addition to high turbidity, other habitat changes such as elevated water temperature may limit the fish fauna able to penetrate upstream to Maungatautari tributaries. Thus fish present are likely to be those that can maintain self-sustaining populations while confined to the upper reaches of the streams. Trout are the only alien fish species known to be present, and they are most likely to be confined to the lower reaches of the mountain tributaries. Other than records of koura, little is known of the aquatic invertebrates found in Maungatautari streams Introduced mammals Further information on the mammals present at Maungatautari can be found in Appendix 2. Mammal Possum Goats Pigs Deer Ship rats Mice Stoats Ferrets Cats Hedgehogs Impacts Eat eggs and young birds; strip foliage from trees; carry TB Eat understory vegetation preventing forest regeneration Disturb ground; eat invertebrates, roots, frogs, lizards, ground nesting birds Eat understory vegetation preventing forest regeneration Eat fruit, invertebrates, eggs; can eat enough seed to cause regeneration failure Eat seeds, invertebrates Eat birds, eggs, mice, rats, rabbits, invertebrates, carrion Eat small mammals, birds, eggs Eat small mammals, birds, eggs Eat invertebrates, seeds, lizards, frogs, eggs, young birds The table above addresses the impacts of each animal in isolation; the impact of these species as a guild could be considered to be much greater. Changes in the guild structure from the removal of some of these animals may also significantly change the impacts of the remaining animals to a greater or lesser degree. Working Document last revision September

21 3. Pre-historic Maungatautari Maungatautari was once a high point in a large area of coniferbroadleaved forest, but today it represents nearly half of the forest remaining in the district. Many birds, invertebrates and reptiles that are now extinct would have lived in the forests Vegetation The Waikato Region comprises seven ecological districts. Maungatautari Mountain lies within the Maungatautari ecological district, which covers the low hill country surrounding three old volcanic cones in the central Waikato. Rimutawa forest was once dominant in this district, covering all of the higher hill country, with a smaller area of montane forest on the summit of Maungatautari (Harding 1997). Dense podocarp forest would have dominated the lower altitude country, occurring mostly along the Waikato River valley (Harding 1997). Maungatautari was once a high point in a large area of conifer-broadleaved forest rising above the wetland areas of the Waikato Basin (Leathwick et al. 1995). Tall forest would have covered most of the region, except for extensive areas of bogs and deep swamps (Nicholls 2002). The arrival of Maori to the region in 1500AD coincided with large fires and the destruction of large tracts of the tall forest, which was replaced by scrub and fern lands. It is likely that the vegetation on Maungatautari largely escaped burning (Clayton-Greene 1976). By 1873, the landscape was in the process of being modified into the pasture we see around us. Allom (1873) describes some of the landscape in the journal of his travels to Maungatautari. We now had an ordinary Maori track for some miles in an easterly direction, through rich, undulating, uncultivated land, as we approached the western slopes of Maungatautari. Turning then a little to the left, we ascended one of the long ferny spurs of the Whanake mountain, an offshoot from Maungatautari and pushing through a small patch of bush, arrived at the summit (Allom 1873). Today, Maungatautari provides a forested backdrop to surrounding pasture lands and is a significant area of forest in the district (Table 1), representing nearly half of the forest remaining here. Table 1. The proportion of indigenous vegetation in the Maungatautari Ecological District (87,041 ha) in 1840 and today (adapted from Leathwick et al. 1995). Date Primary Forest (% Secondary forest and land area) Scrub (% land area) Working Document last revision September

22 3.2. Birds Kiwi, kaka, kakariki, hihi, saddleback, kokako, and North Island robin and many other species (see below) would all have been present in the forest of Maungatautari before the introduction of mammalian pests (Worthy and Swabey 2002). The birds that used to live on Maungatautari can be inferred from fossil remains from caves near Waitomo (Worthy 1984). These fossils provide a good indication of what species were likely to have been present at Maungatautari because podocarp forest was present over Waitomo at the time. The forest fauna would have included weka, snipe-rail, takahe, adzebill, kiwi, Eyle s Harrier, laughing owl, kakapo, sub-antartic snipe, kokako, moa, stout-legged moa, Mappin s moa, little bush moa, slender bush moa, giant moa (Worthy 1984), New Zealand hawk (goshawk), giant owlet-nightjar, New Zealand raven and New Zealand wrens (Holdaway 1989). Petrel and snipe species would also have been present throughout the mainland, including inland regions such as Maungatautari (Holdaway 1989: Worthy and Holdaway 1993). It is also thought that black petrels bred in numerous localities in the North Island (Worthy and Holdaway 1993) and until the mid 20 th century, burrows could be found in deep soil within forest (Oliver 1955), including on Maungatautari (G. Taylor pers. comm.). Three species of bats would have been the sole representatives of the mammalian fauna Terrestrial invertebrates Large, flightless, conspicuous endemic invertebrates evolved in New Zealand in the absence of mammalian predators. These species would have been widespread over the New Zealand mainland in the past, including giant weta, large flightless weevils and stag beetles (Meads 1994). Fossil insect species recovered in Waitomo caves included one ground beetle, a zopherid and three weevil species (approaching 20mm in length), all now extinct (Worthy 1984). Maoripahmborus fairburni, Plocamostehus planiusculus and Mecodema crenaticolle were also found (Worthy 1984) Fish and aquatic invertebrates Fish would have had an uninterrupted passage to the sea and migratory species such as koaro, banded kokopu, red fin bullies, torrent fish and possibly shortjawed kokopu would probably have been present (K. Collier, pers. comm.). Aquatic invertebrates, with the exception of the freshwater shrimp, are nonmigratory and communities in Maungatautari streams are unlikely to have been affected by downstream activities. However populations of koura may have declined due to mammal predation. Trout can also adversely affect the aquatic invertebrate fauna, but densities of trout in these mountain streams are likely to be low (K. Collier, pers. comm). Working Document last revision September

23 3.5. Reptiles and amphibians Fossilised tuatara remains have been found in Waitomo (Worthy 1984), indicating that they are likely to have been present on Maungatautari in the past. A diverse range of geckos and skinks would also have been present including Cylodina alani, C. macgregori, and C.whitakeri, C. aenea, C. ornata and Oligosoma striatum. O. infrapunctatum was possibly present in open areas such as the rocky outcrops (Towns et al. 2002). O. homalototum may also have been present: fossil evidence and their present distribution suggest they may have been widespread across the mainland (Towns et al. 2002). Leiopelmatid frogs were widespread on both islands (Holdaway 1989). Leiopelma hamiltoni, L. waitomonensis, L. markhami and L. hochstetteri have been found in cave deposits at Waitomo (Worthy 1987). From the abundant remains found in caves whose entrances were once within forest, it can be assumed that frogs were once a major feature of the pre-human forest (Holdaway 1989). 4. Restoring Maungatautari Restoration is necessary to restore degraded habitats. Only a fraction of the original fauna remains on Maungatautari and the flora has been subjected to intense browsing pressure in the past. Introduced pests, even in very low numbers, can cause the extinction of much of our fauna. A fence offers a way to exclude these pests permanently from the mountain and thus allow the recovery of fauna and flora no longer seen on mainland New Zealand. The large area enclosed will allow substantial ecological gains to be made, including an increase in the numbers of native animals on the mountain Why restore Maungatautari? Ecological restoration is the active intervention and management to restore or partially restore biotic communities, both their plants and animals, as fully functioning systems (Atkinson 1988). Ecological restoration is carried out to provide habitats for threatened plants and animals and/or to replace or repair plant/animal communities that have either been lost or degraded in structure and function (Atkinson 2003) Maungatautari biodiversity losses 1 Despite Maungatautari potentially having a more intact forest canopy and vegetation less damaged by pests compared to other remaining forested areas, it is not necessarily a fully functioning forest ecosystem. Introduced pests, even in low numbers, have caused the local extinction of many indigenous animal species. Kiwi, saddleback, kakariki, kaka, hihi, weka, kokako and many other birds have long gone from Maungatautari, and tuatara, a variety of Working Document last revision September

24 frogs and lizards, giant weta and an unknown array of invertebrates no longer inhabit the mountain. The continued presence of mammalian pests eliminates any opportunity for recolonisation by natural or other means. Even low numbers of pests can cause extinctions, e.g. the presence of less than one stoat per 100 hectares is enough to ensure the native saddleback never returns. The clearance of forest from much of the Waikato basin (and New Zealand) has left a fragmented and patchwork mosaic of indigenous forest across the landscape. Most of the patches are simply too small now to sustain anything like their original biodiversity even if all foreign influences were removed. Some, including Maungatautari are probably large enough to sustain much of the biological diversity of the past, but their isolation means it is unlikely that they will ever regain, by natural means, species that have been lost Mainland Islands 1 Offshore islands have been a focus of threatened species management over the last 40 years. The relatively undamaged state of their forests, their isolation from reinvasion by pests, and the development of technology that has enabled the complete eradication of pests, including rats and mice, from those islands has meant that sensitive threatened animal species such as the kakapo, takahe, saddleback, hihi, kiwi, and tuatara have been reintroduced and managed in relatively natural conditions. However, due to their limited size, it will not be possible to sustain all or even the majority of New Zealand s remaining indigenous biodiversity on offshore islands alone. There is a need to achieve real conservation outcomes at mainland sites. On the mainland, pest control began with Government deer control in the 1950 s and 1960 s, but has only become widespread and intensive in the last eight years (Atkinson 2001). The most intensive level of ecological restoration on the mainland occurs at mainland islands. Mainland islands aim to control animal numbers to as low a level as possible in order to sustain and restore the natural character of the conservation estate (Norton 2000), however reinvasion by mammalian pests cannot be prevented. Using toxic aerial baits, control of 90-95% of possums and rabbits can be achieved, but reinvasion from surrounding areas is rapid (Veitch 1994). In addition, when pest numbers are low, natural foods regenerate and control with baits is made more difficult with control usually having to wait until a time when food supplies are again low (Veitch 1994). The reduction in one prey species can also cause population explosions in other species e.g. mice after the removal of stoats or rats, or alternatively, predators can prey-switch, possibly resulting in the higher mortality of native species e.g. stoats put more effort into hunting birds after rat removal (Veitch 1994). This means that very sensitive plants and animals such as tuatara, stitchbird, kakapo and takahe can presently only survive on pest-free offshore islands. The public has few opportunities to view these species in their natural habitats. Despite the fact that complete pest elimination has not been achieved in mainland islands, there have been some important achievements recorded so far. In several 1 adapted from (MacGibbon 2001) Working Document last revision September

25 locations bird-breeding success has increased noticeably following pest control. At Trounson Kauri Park north of Dargaville (one of the six Department of Conservation Mainland Islands), kiwi nest success of 80% has been achieved. This is one of the highest survival rates achieved amongst kiwi in recent times. There has also been a dramatic increase in kaka chick survival in the Rotoiti Nature Recovery Project (within the Nelson Lakes National Park) compared to other sites. Recorded changes in the number and condition of monitored plants in response to herbivore control have been dramatic in several areas, notably at Paengaroa where threatened plants such as the tree daisy Olearia gardinerii are now flourishing. The development of Mainland Islands, in concept and practice, has directed conservation and biodiversity management on a positive course. However, there are many challenges to be overcome if gains are to be made on a national scale. It is now recognised that if conservation benefits are to be sustained, management must be focused on ecosystem processes as well as on individual species (Saunders and Norton 2001). Mainland Islands are expensive to establish and maintain ($165/ha/year on average in the 1998/99 year (Saunders and Norton 2001). Many more Mainland Islands are necessary to make a difference on a national scale, but Department of Conservation resources alone will not be sufficient. There is a need for greater public participation if biodiversity decline is to be arrested. This increased participation is necessary not only in the form of support and voluntary assistance, but most importantly in the form of land, funding and commitment to on-going management. One of the most pressing practical challenges (and costs) is how to minimise the rate and likelihood of pest reinvasion into a managed Mainland Island. Persistent, on-going ground-based use of traps and poisons to create a buffer around the island and to remove invaders from within is the current practice. Pest-proof fencing offers considerable potential in this regard. Maungatautari is an entirely community driven project. The mountain is an outstanding feature of the landscape and thus many people have strong emotional ties to it. Maori have had strong connections to the mountain since 1400, where it was a strategic defence position and a source of abundant food (Clark and Tairi 1992). These connections have spurred the formation of a trust (Maungatautari Ecological Island Trust) to raise money for the conservation of their mountain. Putting conservation effort into an ecosystem such as Maungatautari requires a change in the philosophy in the way in which conservation dollars are spent in New Zealand. Currently, relatively robust ecosystems receive little in the way of funding (with the exception of mainland islands), with most funding seemingly being spent on saving species on the brink of extinction. The Maungatautari Ecological Island concept represents a new vision in conservation spending. Money is largely coming from private backers and money is being put into an area of relatively high ecosystem health to really enhance what is there before it becomes further degraded. If enough of these projects can be scattered around New Zealand, there should be a real improvement in halting biodiversity losses. Working Document last revision September

26 The concept of restoring Maungatautari should be seen as an extension of the Department of Conservation s mainland island network. Technology now means we can create an island by placing an artificial barrier (fence) around the mountain and the area inside can be kept pest free. Pests can be completely eliminated without the perpetual need for poisons, which may have harmful affects on our environment Ecological benefits 2 The Maungatautari restoration project is different from the majority of mainland island and conservation management projects currently being undertaken in New Zealand because of the plan to eradicate all mammalian pests on a permanent basis. Eradication will be assured by the construction of a pest proof fence that will prevent pest reinvasion. This project differs from the one other significant fenced mainland island, the Karori Wildlife Sanctuary, by its size. Maungatautari encompasses 3363ha of private and public forest, whereas the Kaori Sanctuary covers 250ha. It is because of these differences that the Maungatautari project offers the potential for more comprehensive ecosystem-focused restoration than has been achieved anywhere on the New Zealand mainland. Permanent mammalian pestfree status will create the opportunity for the successful reintroduction of endemic plant and animal species that would otherwise not be possible even in areas where pests could be maintained at very low levels using conventional pest control methods. There are a number of benefits to be gained from eliminating mammalian predators from Maungatautari (from Smuts-Kennedy (1998)): 1. Many populations of native birds, lizards and invertebrates will increase 2. Increase in fruiting due to larger number of pollinators (e.g. tui, kaka) 3. Increased plant regeneration due to less seed predation and increased seed dispersal 4. Potential to become an internationally significant conservation site 5. Potential for Maungatautari to become a source of native plants and animals into the surrounding landscape, thus greatly increasing the biodiversity of the surrounding district. The following attributes of Maungatautari make it an ideal location for ecosystem restoration: 1. Despite being in the centre of some of the most developed and fertile farmland in New Zealand, the forest canopy on Maungatautari has remained largely intact with most of the original tree species still present. 2. Maungatautari escaped the long duration of damage from exotic browsing introduced mammals that so greatly damaged much of this country s indigenous forest. Possums did not occur in large numbers until the 1970 s, and 1080 poisoning in 1997 and 2002 reduced their numbers 2 adapted from (MacGibbon 2001) Working Document last revision September

27 substantially. Deer, goats and pigs have never occurred in large numbers on the mountain and so palatable species have managed to persevere, leaving the forest more floristically diverse than other forests in the region. Enough of the basic ingredients are present to contemplate ecosystemfocused restoration, compared to many mainland forests, which have been impacted so greatly that natural restoration would be unlikely even with all pests removed. 3. At 3363ha, the forest, when all pests are removed, is sufficiently large and diverse to be able to sustain functioning ecosystems and viable natural populations of many native bird, reptile and invertebrate species, including many of the native species that previously occupied the forest. 4. The roughly oval shape of the forest is desirable, having a minimum edge to interior ratio. 5. The mountain and the project provide an unparalleled opportunity to monitor the changes that occur as a consequence of complete mammalian pest removal in a large area, and learn more about the ecology of both pests and native species Benefits of pest removal 3 In order to restore functional, self-sustaining near original ecosystems, complete mammal pest eradication is necessary. If pests are present, even in very low numbers, some indigenous species, especially some sensitive endemic species, may not survive. Many plants and animals have been severely reduced in forested areas because of predation by and in some cases competition from, introduced pests. The complete removal of mammalian pests from Maungatautari can be expected to lead to a significant natural resurgence of many species, particularly invertebrates and highly palatable plants. Kokako breeding success has been shown to be closely related to the intensity of pest control (Innes et al. 1999), and this relationship is also likely for many other bird species. Effective pest control leads to greater breeding success and the greatest gains are made when pest levels are reduced to zero or very near zero (Innes et al. 1999). Numerous studies (e.g. Mark and Baylis 1975, Allen et al. 1984, Mark et al. 1991, Allen et al. 1994, Bockett 1998) have shown the impact of mammalian pests on vegetation. Browsing can reduce the density of the undergrowth, reduce recruitment of seedlings and can change the composition of the forest by selectively removing the most palatable species The pest proof fence Restoration projects that include a predator proof fence are an opportunity to bring sensitive native animals back to the mainland as there is potential for permanent exclusion of mammalian predators. Exclusion of pests using fences may be a cost-effective and sustainable strategy for the ongoing management of introduced 3 adapted from (MacGibbon 2001) Working Document last revision September