Motu Kaikoura: Biodiversity Management Plan March 2012

INTRODUCTION

Purpose of the plan The Biodiversity Management Plan can be seen as a ‘how to’ document that details the methods and timeframes of different tasks that will work towards achieving the objectives and overall vision for the Island that is detailed below. These recommendations and tasks have taken into account the previous actions and successes of the management of Motu Kaikoura thus far. While the Plan covers a period of 10 years, where appropriate some recommendations give consideration to timeframes beyond this scope.

Geographic Situation Motu Kaikoura is a 564 hectare island off the west coast of Great Barrier Island in Auckland’s Hauraki Gulf. Motu Kaikoura is in close proximity to a number of smaller islands and rock stacks and a number of peninsulas of Aotea (Great Barrier Island) (Figure 1).

Figure 1: Motu Kaikoura topography (source: LINZ, Crown Copyright reserved) and aerial view (source: Auckland Council).

This larger landscape context lends a significant influence on the ecosystem processes within the island and therefore management recommendations stated within this document. For these reasons it is important to consider the wider context of the Grey Island group, Broken Islands, Sven Stellin’s peninsula, Glenfern Sanctuary, and other surrounding islands/rockstacks when considering management options for the island. This wider scope will help increase the chances of successfully achieving Motu Kaikoura Trust’s vision for the island. In this manner, the wider areas should be considered as a whole so therefore recommendations below will consider the wider landscape context.

Motu Kaikoura Biodiversity Management Plan 3 History of Use The long history of human occupation and activity has resulted in the natural values of the site becoming degraded and highly modified.

The island has undergone a long history of pre-European burning and vegetation clearance. Most of the island is covered in scrub dominated by kanuka and manuka, but areas of older coastal forest, with pohutukawa, taraire, kohekohe, and puriri, remain in several valleys. Pine forest (maritime pine and radiata pine) is common in the south-east of the island, and pohutukawa trees are common along the coast. Maori are thought to have lived on Motu Kaikoura since the 15th Century. Ngati Wai asserts mana whenua status over the island, a title which dates back to the end of the 17th Century.

Between 1838 and 2004 the island was owned by a number of different families and individuals. Motu Kaikoura was purchased on 13th April 2004 by the Crown, with contributions from ASB Community Trust and 7 of the 8 Auckland Councils (of the time). The island was officially opened to the public in 2005.

In 1859 the first farm was established on Motu Kaikoura, and the island has been heavily grazed since. These grazers have now been removed from Motu Kaikoura, with deer being officially eradicated in 2009. 119 Fallow deer were removed, along with pigs, cats and one rabbit.

Although there are many notable vertebrate pests absent from Motu Kaikoura (including possums, hedgehogs, mustelids, and Norway rats) ship rats and kiore are still present. The presence of mice has never been confirmed. Efforts to eradicate rats on the island began in August 2008, with two aerial bait drops of ‘Pestoff 20R’ (a Brodifacoum based) poison. This poison drop was at first thought successful, but ship rats and kiore are now present. Rats are controlled today using ‘rat motels’ (lured traps and poison baits in plastic bags). Biosecurity measures on the adjacent mainland are in place to minimise further invasion of rats from surrounding areas.

MANDATE

Motu Kaikoura is designated under the Reserves Act 1977 as a Scenic Reserve. The main intent of a Scenic Reserve is to provide an area that public can enjoy whether for landscape, intrinsic value or beauty, and also should: o be open to the public; o preserve native flora and fauna; o eliminate exotic flora and fauna unless their presence is deemed to be of scientific interest or of beauty to the public; o allow development of infrastructure that aids public enjoyment of the reserve; o preserve any historical or archaeological sites (see Appendix 1).

Administration and management of the island was granted to the Motu Kaikoura Trust in April 2004 under an agreement with the Crown. The Trust’s mandate is outlined below: 1) the reserve is to be available for outdoor/environmental education for youth in particular and for the provision of appropriate facilities;

Motu Kaikoura Biodiversity Management Plan 4 2) the Trust shall submit to the Minister for his/her approval a management plan for the reserve within two years after the date of its appointment; 3) the appointment of the Trust as the administering body of the reserve is to be reviewed after seven years; and 4) the Department of Conservation shall provide advice, guidance, technical and related assistance to the Trust.

The intent of a Scenic Reserve and mandate given to the Motu Kaikoura Trust is directly reflected in the thinking behind the recommendations given within this plan.

VISION

To restore the natural environment of Motu Kaikoura to reflect that of the least modified, parallel ecosystem types on Great Barrier Island uniqueness of Motu Kaikoura while ensuring it is available for public use, enjoyment and education.

GOALS

The goals to meet this vision are listed below as: • restoration of the island environment; • ecological, cultural and recreational resources are acknowledged and enhanced; • allow and/or provide for environmental/outdoor education with a focus on youth; • recognise the importance of the island to Ngati Rehua; • aid the restoration of neighbouring islands.

ECOLOGICAL RESTORATION OBJECTIVES

The following objectives will fulfil the vision and goals for Motu Kaikoura: • manage animal pest species to zero density; • manage pest plant species to zero density; • restore the island’s indigenous flora; • restore the island’s indigenous fauna; • recognize and protect features of cultural importance; • encourage public participation in restoration activities.

Guiding Principle - ‘Minimal intervention’

In contrast to many other island restoration projects, the restoration of Motu Kaikoura will follow a minimal intervention approach. This approach recognises that some species may colonise the island naturally, and that some unrecorded species will need time for recovering populations to reach detection levels. Intervention is not considered prudent until a more comprehensive picture of the island’s biodiversity is built up through on-going monitoring. However, a greater level of intervention (e.g.

Motu Kaikoura Biodiversity Management Plan 5 translocation, planting) will be considered if the island’s ecological structure and function are not restored through natural processes.

Motu Kaikoura Biodiversity Management Plan 6 CHARACTERISTICS OF MOTU KAIKOURA

Motu Kaikoura is a large island (564ha) of volcanic origin within the Hauraki Gulf, bounded by Great Barrier Island along its northern, eastern and southern coasts (Figure 2). The islands are, at some points, only a few hundred metres apart and are geologically similar with similar flora and fauna.

Figure 2: Motu Kaikoura viewed from the east (Photo: M. Galbraith)

Detailed descriptions of the characteristics of the island are included in the Motu Kaikoura Management Plan (Motu Kaikoura Trust 2005) and the Kaikoura Island Eradication Operational Plan (Natural Logic Environmental Management 2008). A brief summary of the characteristics of Motu Kaikoura is given below to provide an ecological context for this document.

Geology Geologically, Motu Kaikoura is volcanic in origin with prominent ridges; spurs, andesitic tufts and rock outcroppings. A central NW-NE divide has rocky escarpments and outcrops, all of which are andesitic remnants of a strato volcano. The highest point on the island is Mitre Peak at 205m. The coastline consists of steep cliffs, small beaches; muddy intertidal flats, and rocky shorelines. A few perennial streams, with low summer flows, exist in the larger catchments.

Vegetation The valleys and ridges of the island are predominantly covered in stands of regenerating kanuka and manuka interspersed with a few remnants of mature coastal forest. Large stands of pines are present in the south-east. Prior to their recent eradication, deer, cattle, goats and pigs prevented the development of an understorey. On steeper, more exposed slopes, erosion pans devoid of vegetation developed due to overgrazing. A survey and review of the vascular flora of Motu Kaikoura was undertaken by Cameron (2007). A detailed description of vegetation communities as well as the presence of threatened species is provided and compared with surveys undertaken in the past to document changes over time (see Appendix 2 for species list).

An extensive stand of wilding pines (Pinus pinaster and P. radiata) has established in the south-eastern corner of the island around the lodge and spread to the west and north. A number of environmental weeds have been identified and are currently managed by the Motu Kaikoura Trust.

Motu Kaikoura Biodiversity Management Plan 7

Inter-tidal marine algae were surveyed in June 2007 as part of a wider marine algae survey conducted by Michael Wilcox. Good water clarity allows for an abundant but moderately diverse range of species. A paucity of common red algal species was noted and attributed to a high abundance of kina (Evechinus chloroticus) which are feed on these species as well as the competitive presence of Ecklonia radiata (kelp).

Fauna Birds have been surveyed annually since 2006 (Galbraith & Jones 2010). The current record is 39 bird species on the island, of which 27 species are indigenous and 12 are exotic species (see Appendix 1). Kereru and tui were less common than insectivorous species, and flocks of kaka utilised the south-eastern pine block as a food source, shredding the cones for seeds.

Annual reptile surveys, assisted by the use of artificial cover objects, have been undertaken from 2008 (Martin 2012) (see Appendix 2). Cameron et al. (2007) recorded the presence of moko skink (Oligosoma moco) as well as copper skink (Cyclodina aenea) during a vegetation survey. Martin (2012) reports that moko skink and copper skink are widespread throughout the island in forest and shrubland habitats, and shore skink are present on the boulder beach below Mount Overlook. Gecko species have not yet been confirmed despite extensive searches under logs, rocks and debris, and spotlighting within forest, shrubland, and coastal cliff habitats at night. Many more species of reptile are likely to have been present on Motu Kaikoura prior to human settlement. Forest gecko, Pacific gecko, common gecko, and Duvaucel’s gecko would all have been present, along with ornate skink, striped skink, and egg laying skink. These species may all still be present, albeit in very low numbers. Tuatara were formerly on Great Barrier Island, and may have been present on Motu Kaikoura. Mokohinau skink, green gecko and chevron skink are still present on Great Barrier and their possible presence on Motu Kaikoura cannot be ruled out.

Limited bat and invertebrate (marine and terrestrial) information is available for Motu Kaikoura as no formal surveys have yet been undertaken. A single individual of the Great Barrier paua slug (Schizoglosaa novoseelandica) was noted by Cameron (2007) in the remnant of taraire forest on the south-west coast. Further survey work to document the invertebrates of the island is needed. No formal bat surveys have yet been undertaken. Long-tailed bats are present on Great Barrier Island and are good fliers. It is possible that long-tailed bats are periodic visitors to the island.

The Hauraki Gulf, including the outer gulf around Great Barrier Island, is recognised as an important nursery area for marine mammals, such as the common and bottle- nosed dolphins. Research on habitat utilisation, abundance and density of these dolphins is being undertaken by a PhD student from Massey University using Motu Kaikoura as a base.

The Hauraki Gulf is particularly rich area for seabirds, and considered a global hotspot with 25 breeding species, including threatened petrel species. Seabirds are known to enrich terrestrial systems through the transportation of marine nutrients, and can be the ecological ‘drivers’ of terrestrial communities on islands. It is inevitable that, historically, Motu Kaikoura would have held large populations of seabirds. Although seabirds are present in the waters surrounding the island, no

Motu Kaikoura Biodiversity Management Plan 8 burrow-nesting species are known to be present now. Many of the smaller islands and stacks in the vicinity of Motu Kaikoura still support small numbers of seabirds.

RESTORATION OF ECOLOGICAL PROCESSES

Restoration of the island’s natural environment is a principal goal. From an ecological restoration perspective, the key to recommendations in this plan is the restoration of ecological processes, characterised by ecosystem structure (species and complexity) and ecosystem function (biomass and nutrient content). A model of the changes that these characteristics might undergo throughout a restoration process is shown in the following diagram (Van Dyke 2003):

It is recognised that significant constraints prevent Motu Kaikoura reaching an ‘original’ ecosystem as depicted in the diagram. However, the natural recovery of the island is already increasing the magnitude of both ecosystem structure and ecosystem function, perhaps represented by one of the curved trajectories of the diagram. This upward trajectory recognises that, although biomass and nutrient content may be increasing as the vegetation recovers, species and complexity may be responding at a slower rate due to ‘gaps’ in the species’ composition of the island.

The minimal intervention approach will ensure that any processes that are capable of restoring themselves through time will be allowed to do so. Some processes may not be restored through time, e.g. those dependent on species that are unable to reintroduce themselves. Such organisms may need to be translocated to Motu Kaikoura to fill the gaps. This, however, is not within the scope of this current plan.

Motu Kaikoura Biodiversity Management Plan 9 RESTORATION OF FLORA

Current situation Motu Kaikoura was most likely covered by coastal and lowland broadleaf forest with a minor component of mixed conifer species similar to that found on Great Barrier Island and other inner Hauraki Gulf Islands (Gardner-Gee et al. 2007; McEwen 1987; Ogden 2001).

Coastal broadleaf communities, dominated by pohutukawa (Metrosideros excelsa) would have existed along coastal cliffs, bluffs and spurs. Canopy species would have included taraire (Beilschmiedia tarairi), kohekohe (Dysoxylum spectabile), puriri (Vitex lucens), tawapou (Pouteria costata), and kowhai (Sophora microphylla). A dense shrub layer of kawakawa (Macropiper excelsum), rangiora (Brachyglottis repanda) and hangehange (Geniostoma ligustrifolium) would have formed under the canopy. Coastal heathlands were restricted to exposed headlands and rocky outcrops which supported low-canopied speciesand may have included Great Barrier kanuka (Kunzea sinclairii).

At higher altitudes (up to 250m), coastal forest would have given way to lowland podocarp or broadleaved species including kauri (Agathis australis); miro (Prumnopitys ferruginea); tawa (Beilschmiedia tawa); tawaroa (Beilschmiedia tawaroa) and maire (Nestegis lanceolata). Taraire and kohekehe were also still present but at lower abundances. Damper areas would have supported additional species such as houpara (Pseudopanax lessonii) and pigeonwood (Hedycarya arborea). Epiphytes such as Astelia banksii, Collospermum hastatum, Pyrrosia eleagnifolia and Microsorum pustulatum were common.

The present day flora of Motu Kaikoura reflects decades of grazing and clearance that occurred whilst the island was in private ownership. Cameron (2007) undertook the most recent vegetation survey of the island which is estimated to account for 80- 90% of vascular plant species present. The most common vegetation is kanuka (Kunzea ericoides) forest. Until recently, browsing by deer, goats and pigs severely reduced the undergrowth with palatable species absent or only present in inaccessible sites (Bellve 2007). Since the eradication of deer the understorey has significantly increased in diversity and density in many parts of the island.

A few broadleaved forest remnants remain, and these are mostly along the southern parts of the island. Taraire (Beilschmiedia tarairi) and pohutukawa (Metrosideros excelsa) are common. Other canopy species include puriri (Vitex lucens), tawa (Beilschmiedia tawa), mangeao (Listea calicaris) and kohekohe (Dysoxylum spectabile). Areas of regenerating understorey include kawakawa (Macropiper excelsum), ponga (Cyathea dealbata) and mapou (Myrsine australis) as well as fern species (Microsorum scandens and Asplenium spp.). A small area of conifer forest is also present on the eastern side of the island above Houseboat Bay. Species present here include kauri (Agathis australis), miro (Prumnopitys ferruginea), matai (P. taxifolia) and totara (Podocarpus totara) (Cameron, 2007).

Exposed and eroded northern slopes support sparse communities of gumland-type species as well as hakea (Hakea sericea) and Erica baccans. Vegetation, such as manuka and kanuka, which establish at these sites have low stunted growth forms.

Motu Kaikoura Biodiversity Management Plan 10 A number of pest plant species are also present, many of which originate from gardens surrounding the old farm buildings. Further information on pest plants including recommendations for control is given under the Biosecurity section of this document.

To date, 380 vascular plant species have been recorded on Motu Kaikoura (see Appendix 2). Of these species, 68% are native. Thirteen nationally threatened species, 20 regionally threatened and numerous uncommon species are present on the island. Further observations (Young 2010) have revealed an increase in species richness as well as a noticeable regeneration of species (Melicope ternata, Dysoxylum spectabile, Sophora sp.) that were previously restricted by deer browse.

Lichen have been surveyed on Motu Kaikoura annually since 2008. The current species list is 114 (see Appendix 2), considered to be a high number despite the relatively small size of the island and the poor state of the vegetation (Blanchon et al. 2011). Particularly important habitats include the farmhouse orchard, broadleaf forest areas and shaded inland bluffs.

Some of the more unusual species seem to be restricted in their distribution. Eight lichen species found on Motu Kaikoura have been designated as “At Risk” by de Lange et al. (in press). Of these, Teloschistes flavicans (Declining Sp, TO) was only seen once, in the orchard. The other seven species are listed as “Naturally Uncommon”, and include: Degelia durietzii, Parmotrema subtinctorum, Porpidia albocaerulescens, Pseudocyphellaria haywardiorum, Punctelia perreticulata, Ramalina meridionalis and Teloschistes sieberianus. A number of species found on the island are listed as “Data Deficient”, potentially indicating that the list of threatened and uncommon lichens could increase with further research.

The eradication of the deer may result in the recovery of some lichens or recolonisation by others if they were, in fact, being eaten by the deer (Blanchon et al. 2011). Conversely, recovery by grasses and other vascular plants following deer eradication may already be impacting negatively on soil and rock-dwelling lichen (D. Blanchon pers comm.). The farmhouse orchard is a lichen hotspot, and needs to be protected until sufficient smooth-bark indigenous trees are present to act as alternative hosts.

Restoration options Pivotal to the return of ecological processes to Motu Kaikoura is the return of forest community structure, i.e. a thriving, diverse understorey as well as the sustainable regeneration of canopy species. This, in turn, forms the foundation of ecosystem services such as habitat provision and food source for fauna, therefore facilitating ecological processes such as pollination and seed dispersal. At present, most of the island is in an early successional stage represented by the widespread manuka and kanuka scrub. Over time, this scrub will be replaced by a diverse mosaic of coastal vegetation.

The factors that will influence the development of these vegetation communities include the risk of ongoing disturbance by fire competition with weeds, and the relative scarcity of older forest remnants on the island. However, with the removal of deer, there is already firm indication that forest regeneration processes are underway, with seedlings of species such as mangeao, puriri, kohekohe, and taraire

Motu Kaikoura Biodiversity Management Plan 11 widespread on the island, including in areas dominated by maritime pine, radiata pine, manuka, and kanuka. Restoration can involve varying degrees of intervention. In keeping with the current strategic direction set by the Trust, the recommendations regarding the restoration of flora require a low level of intervention.

Monitoring methodology Regeneration of the understorey has been observed and recorded by visitors to the island. This is attributed to the removal of deer and goats and considered a great biodiversity gain for the island. However, little is known in terms of both species composition and distribution of species across the island and ongoing monitoring of vegetation and the regeneration thereof is recommended.

It is suggested that as a minimum, monitoring of the Auckland Botanical Society’s vegetation plots should be undertaken in collaboration with the society. At present the plots (20m x 20m) are monitored every five years as per the following methodology: • five plots located approximately within the scrub; kanuka forest, eroded areas and kauri-associated forest habitats defined by Cameron (2007). • data collected for each plot includes: o Recce inventory; o species list; o canopy and ground cover; o sub-sample of saplings, seedlings (>15cm) and epicormic shoots. • 5 yearly monitoring frequency.

In addition to the five yearly plots, Auckland Botanical Society members visit the island on a regular basis and update the current flora checklist as new species are observed.

Lichen monitoring adhering to the methodology established by (Blanchon et al. (2011) should continue as the availability of research personel and funding permits to track changes associated with the island’s ecological recovery.

Continued pest plant control Current weed control programmes will continue to support the natural regeneration process and should be considered a minimum requirement for ecosystem restoration. Site specific control should be considered in relation to threaten plant / ecosystem management, some examples Crawford’s Bay where kikuyu may threaten strand plants as well as site specific control for the protection for native carrot (Daucus glochidiatus).

Revegetation – future options Limiting factors such as the low abundance of mature native trees could delay natural regeneration in some areas of the island Later successional species are often poorly represented in the soil seed bank and rely on seed dispersal by birds. There is a paucity of these species on Motu Kaikoura and subsequently fewer birds such as kereru and tui are present on the island. This creates a negative feedback loop which limits the spread of seed which is produced by the few remaining broadleaf trees. Spreading seeds collected from forest remnants at specific sites, e.g. within large tracts of manuka scrub, could facilitate the speedy establishment of forest tree species and accelerate the restoration process.

Motu Kaikoura Biodiversity Management Plan 12

Recommended actions for flora:

• Continue the monitoring of flora as described. • Continue pest plant management as described. • Continue support for lichen monitoring, and maintain fruit trees in the farmhouse orchard for specific lichen species. • A revegetation programme is not considered necessary as regeneration is occurring across the island and late successional species will eventually establish over all the island. • Should it become evident from vegetation monitoring data that the recovery of these species is significantly delayed, e.g. after 10 year timeframe of this plan, revegetation opportunities could be reviewed at that time to determine if a different course of action is appropriate.

Motu Kaikoura Biodiversity Management Plan 13 RESTORATION OF FRESHWATER ENVIRONMENTS

Current situation The extent of freshwater habitat Motu Kaikoura is minimal. The main perennial streams are Bradshaw Cove, Houseboat Bay and the valley west of Crawford’s Bay. Three valleys on the southwest coast also have small flows that disappear into coastal sands. The largest wetland area is part of the stream below Top House, which includes a pond area created by an earth dam (Bellve 2005).

Limited information has been collected relating to freshwater species on Motu Kaikoura:

• Ryder (2009) has carried out a study of freshwater invertebrates on the island using the macroinvertebrate community index (MCI). Low scores were calculated for all sampling sites, suggesting both a depauperate aquatic invertebrate assemblage and unsuitable habitat availability.

In comparison, it has been noted that streams and wetlands on Great Barrier Island host more freshwater species than any other offshore island in New Zealand (Maddison & Arkins 2001).

The following freshwater fish species are known to live on Great Barrier Island: • longfin eel (Anguilla dieffenbachia) • shortfin eel (A. australis) • inanga (Galaxias maculatus) • banded kokopu (G. fasciatus) • giant kokopu (G. argenteus) • redfin bully (Gobiomorphus huttoni) • giant bully (G. gobioides) • common bully (G. cotidianus) • bluegill bully (G. hubbsi) • cockabully (Grahamina nigripenne)

It is likely that some of these species, such as longfin eel, short fin eel, banded kokopu, and common bully are present on Motu Kaikoura. Fortunately, Great Barrier Island (and therefore, it is assumed, Motu Kaikoura) is free of invasive freshwater pest fish.

Restoration options Restoration of freshwater environments on Motu Kaikoura is not considered a priority due to a relative lack of permanent aquatic habitats. Further baseline information should be collected (as resources allow) to clarify the nature of species present on the island.

Monitoring methodology • Macroinvertebrate Community Index (MCI) study – sampling of all soft bottomed streams to collect and quantify macroinvertebrates present. This could be carried out at any time of the year, although as streams on the island are generally quite small and shallow, winter may be the best season for this. An MCI study of streams should be carried out at least every two years.

Motu Kaikoura Biodiversity Management Plan 14 • Backpack electrofishing or collapsible minnow nets could be used to sample fish communities – depending on experience and ability of participants. This could be carried out at the same time and locations as the MCI study.

Recommended actions for freshwater environments:

• Support the collection of baseline data. • The reintroduction of freshwater animals to Motu Kaikoura is not recommended. Most freshwater fish species that the island provides appropriate habitat for are either likely to be present, or to naturally disperse to the island with time.

RESTORATION OF INVERTEBRATES

Current situation Approximately five thousand species of land and freshwater invertebrates are thought to live on Great Barrier Island and its outlying islands (Maddison & Arkins 2001). These occur across a wide range of habitats (e.g. sand dunes, wetlands and mature forests).

Limited information exists relating to the invertebrate diversity and distribution on Motu Kaikoura. As the island has experienced considerable disturbance through human activities and suffered from the impacts of vertebrate pests, it is likely that some invertebrate species have been lost from the ecosystem.

Brief studies have been carried out in recent years looking at invertebrate populations on Motu Kaikoura:

• Foster (2011) has carried out research to determine if pest control has benefited invertebrates on Motu Kaikoura. A comparison was made between a study site on Motu Kaikoura where pest control is occurring, and at a site on Great Barrier Island, where there is no pest control. Results showed little difference between the two islands. It is thought that invertebrate populations have not yet recovered from the impacts of predation and that the degraded state of the vegetation is not able to support a diverse invertebrate community.

• Foster (2011) also compared weta populations between these two areas. Occupancy rates in artificial ‘weta boxes’ were found to be much higher on Motu Kaikoura (pests controlled) than on Great Barrier Island (pests not controlled). As a large insect, weta are relatively easy to monitor, and can be an indicator of the health of the invertebrate fauna in general.

• As mentioned above, Ryder (2009) has carried out a study of freshwater invertebrates on the island using the macroinvertebrate community index (MCI). Low scores were calculated for all sampling sites, suggesting both a depauperate aquatic invertebrate assemblage and unsuitable habitat availability.

Motu Kaikoura Biodiversity Management Plan 15

• Galbraith (2009) noted an increase in insectivorous birds (e.g. fantail, grey warbler and silvereye) in a recent ornithological survey on the island. It is thought the reduced predation by rats could have led to this increase in invertebrates and therefore higher insectivorous bird numbers.

Restoration options The species diversity and population dynamics of invertebrates on Motu Kaikoura is not well known at this time. It is recommended that until resources allow, monitoring of weta populations should continue as the main invertebrate monitoring focus. Monitoring of weta occupancy in weta boxes (by volunteers and/or community / school groups) is a relatively simple exercise and can be used as a biological indicator for invertebrate communities on the island as a whole.

A more robust and meaningful programme of invertebrate monitoring could be set up on the island in future, although this will require expert input. It is not recommended that this be initiated at this stage. Any restoration programme designed to eradicate pests will probably necessitate the use of poisons. It is strongly recommended that all poison use should be monitored and where there is a choice the least toxic poison should be used, particularly if there is a risk of invertebrates eating it and passing the poison through a foodchain to other animals.

Species that are absent and unlikely to colonise by natural means may be candidates for translocation in the future (such as large flightless species – weta, giant land snails, and large flightless beetles). Those species unlikely to self-colonise could be investigated beyond the ten-year timeframe of this plan, once monitoring has revealed more about the resident invertebrate community of Motu Kaikoura.

Recommended actions for invertebrates:

• Continue annual weta surveys. • Support the collection of baseline data when resources are available.

Motu Kaikoura Biodiversity Management Plan 16 RESTORATION OF REPTILES

Current situation Reptiles are in decline throughout mainland New Zealand, and predator free offshore islands offer important safe refuges. In the Auckland region, offshore or mainland island refuges are the only place that some reptiles persist, e.g. egg laying skink, moko skink. Table 1 shows the current threat categories (Hitchmough et al. 2010) of reptiles possibly present on Motu Kaikoura.

Table 1: Reptile species and threat categories.

Reptile species Present Detected Possibly Threat status on GBI to date present Auckland green gecko ü ü At risk - declining (Naulitinus elegans) Pacific gecko ü ü At risk - relict (Hoplodactylus pacificus) common gecko ü ü - (Hoplodactylus maculatus) forest gecko ü ü - (Mokopirirakau granulatus) Duvaucel's gecko ü ü At risk - relict (Hoplodactylus duvaucelii) chevron skink ü possible Nationally vulnerable (Oligosoma homalonotum) marbled skink ü possible At risk - relict (Oligosoma oliveri) striped skink ü possible At risk - declining (Oligosoma striatum) ornate skink ü ü At risk - declining (Oligosoma ornatum) egg laying skink 1 possible ü ü At risk - relict (Oligosoma suteri) sighting moko skink ü ü ü At risk - relict (Oligosoma moco) shore skink ü ü ü - (Oligosoma smithi) copper skink ü ü ü - (Cyclodina aenea) rainbow skink ü Introduced (Lampropholis delicata)

Those in the ‘At risk’ category are grouped according to risk type not degree of risk which varies within each category. ‘Declining’ means that current widespread population levels are conservation dependant and still in decline. ‘Relict’ refers to smaller localised populations that exist due to conservation efforts. These rankings indicate that the reptiles present or possibly present on Motu Kaikoura represent regionally and nationally significant species populations.

Reptiles fulfil important ecosystem functions such as pollination and seed dispersal, and sit within the food web as both predators (of invertebrates) and prey species (for birds). They also play an important role in the honeydew cycle. Before modification of Motu Kaikoura and the introduction of animal pests, reptiles would have been

Motu Kaikoura Biodiversity Management Plan 17 widely dispersed across the island occupying different niches such as open rocky shores (shore, moko, & Suter skink), damp forest floors (Chevron and striped skink), seabird burrows (tuatara and Mokohinau skink) and general forest habitats (Pacific, common and Duvaucel's gecko, copper and ornate skink).

Motu Kaikoura has a wide range of habitats that are likely to support the same species as present on nearby Great Barrier, with a few exceptions. • Chevron and striped skink require moist habitat conditions that are not available on the island. • Forest and green gecko may be present but are not usually found on smaller offshore islands (D. Towns, G. Ussher pers comm.) possibly due to lack of constant availability of favoured early successional habitat. It is unclear at this stage whether Motu Kaikoura will be large enough to support such species in the long term. • The Mokohinau skink is a larger skink often associated with seabird presence and therefore unlikely to have persisted or still be present on Motu Kaikoura.

Experience from other islands show that it can take a long time to detect reptile presence so monitoring is recommended for at least 10 years before any introductions are contemplated. Preliminary surveys of various habitats and locations around the island indicate the presence of small remnant populations of a few skink species – moko, copper and shore skinks (Martin, 2010) (see Appendix 2). Surveys used artificial cover objects (ACOs) and visual encounter surveys (VES). No geckos have yet been seen on the island. All reptiles will have been subjected to predation from pests present on the island (rodents, cats and pigs), from habitat destruction due to farming, fires, and deer browse, or from loss of associated species (such as seabirds and access to burrows). Browsing animals will also have compacted soil and leaf litter, therefore reducing appropriate habitat and burrows.

Restoration options Regeneration of habitat will benefit all forest dwelling reptiles that require deep leaf litter, well developed vegetation, high moisture levels, and good forest structure. Forest regeneration will also provide direct benefits of suitable food resources such as fruit, nectar, honeydew and indirect benefits of increased invertebrates and provision of refuges via flaking bark, tree cavities and detritus material. In coastal areas harakeke (flax; Phormium tenax) and ngaio (Myoporum laetum) could be further established by direct seeding to provide additional refuge and nectar sources. However planting is not recommended within the ten-year life of this plan. The island provides extensive areas of manuka and kanuka which are a favoured habitat for some gecko species.

Rodents are currently the biggest threat to reptiles and population recovery so should be controlled to low densities as outlined in the Biosecurity section. Otherwise, ongoing management requirements are minimal, with a five yearly monitoring programme recommended. Reptile populations respond slowly to predation pressures and so more frequent monitoring is not necessary. Large skinks associated with seabirds could be considered for translocation after a suitable period has elapsed to enable detection of presence and to allow for any establishment of seabird populations – probably a minimum of 10 years.

Motu Kaikoura Biodiversity Management Plan 18 Monitoring methodology As can be seen from Table 2, different species require different detection methods and different habitats lend themselves to different methods. For example ACOs are best placed in partial or full sun so are less effective in areas with a canopy. Skill levels required to check devices also varies with tracking tunnels requiring little skill in terms of baiting and collecting cards but a higher level of skill for card interpretation. Closed foam refuges (CFRs) and ACOs require trained personnel operating under a DOC permit and, in the case of ACOs, quick reflexes to catch animals.

Table 2: Recommended monitoring methods

Monitoring method Reptile species Tracking ACO CFR VES tunnel Pacific gecko ü ornate skink ü ü common gecko ü ü ü Duvaucel’s gecko ü ü ü Suter skink ü ü moko skink ü ü shore skink ü ü copper skink ü ü rainbow skink ü ü green gecko ü

With these factors in mind the following methodology is recommended: • ACO o Continuation of ACO monitoring with existing lines located in various habitat types as per Martin 2010. Recommended frequency = every one to three years, timing = March.

• CFR o Installation of 5 lines of CFRs, with 40 covers on each line approximately 10 metres apart. Two lines to be placed in forest habitat and three lines in coastal habitat. Covers to be nailed to trees at approximately chest height and numbered. If possible covers should be placed on kanuka or manuka trees. Lines to be placed along existing bait station lines for ease of access, in a variety of habitat types. o Year one – all covers checked in early March, six checks every second day. Subsequent years, each line to be checked once only, with repeats of the full methodology every five years. o NB: This methodology matches that used by the Auckland Council for its regional monitoring programme.

• Tracking cards o Existing rodent monitoring tracking tunnels to be used. Cards to be baited with banana, left overnight and collected the next day. o Check every day over 5 day period in March.

Motu Kaikoura Biodiversity Management Plan 19 o Check once a year for the first two years, then every three years thereafter.

Motu Kaikoura Biodiversity Management Plan 20

Recommended actions for reptiles:

• Undertake ongoing regular monitoring as described. • Undertake comprehensive baseline survey of reptiles using appropriate methods (see Table 2) to target different species depending on their behaviour. [NB: Tracking tunnels may have to be replaced by ACO’s if rodent presence is too high causing avoidance by reptiles or masking of presence.] • No translocations to be considered for a minimum of 10 years to allow detection of remnant populations. • Ensure rodents controlled to ≤5% density, zero if possible. • Consider enhancing populations of harakeke and ngaio in coastal areas if suitable gaps and labour resources exist.

RESTORATION OF BIRDS

Current situation Birds undertake important ecosystem functions such as pollination and seed dispersal, and are also an essential part of predator/prey food webs. Large birds like native pigeons are the only remaining dispersers of large-seeded tree species such as tawa (Beilschmiedia tawa), taraire (B. tarairi) and tawapou (Planchonella costata). Seabirds also bring large amounts of marine nutrients ashore which, in the past, drove coastal forest ecosystem fertility and species composition.

Recent surveys (Galbraith & Jones 2010; M. Galbraith, pers obs.) have recorded 37 species, of which 70% are indigenous (26) and 30% (11) exotic (see Appendix 2). Shore and seabirds account for 33% (12), wetland birds 5% (2), and landbirds 62% (23). The avifauna on the island is depauperate compared with mainland Great Barrier Island, which has 62 recorded species. This difference is considered to be due to lower habitat diversity, and the former presence of deer which browsed the understorey.

A lack of ground nesting birds is probably a result of predation over the years by predatory mammals such as rats and feral cats. In the main, insectivorous birds are better represented and herbivorous species are fewer possibly due to the lack of both understorey and mature later successional native vegetation. However, the previous absence of possums and mustelids from the island has most likely allowed a greater suite of bird species to survive compared with most mainland sites.

Table 3 lists the threatened bird species already on the island (Hitchmough et al. 2007). These are mostly seabirds (e.g. Cooks petrel, blue penguin, pied shag, little shag, terns and the gulls), but also shorebirds (variable oystercatcher, and reef heron) and some ground nesting wetland species (brown teal and banded rail). The island already represents an important refuge for these species. Controlling rodents to low densities ≤5% will add further protection.

Motu Kaikoura Biodiversity Management Plan 21 Table 3: Indigenous threatened species present

Common name Latin name Threat classification reef heron Egretta sacra Nationally vulnerable red-billed gull Larus novaehollandiae Nationally vulnerable pied shag Phalacrocorax varius Nationally vulnerable NI Kaka Nestor meridionalis Nationally vulnerable Caspian tern Sterna caspia Nationally vulnerable blue penguin Eudyptula minor At risk - declining white-fronted tern Sterna striata At risk - declining Cooks petrel Pterodroma cookii At risk - relict variable oystercatcher Haematopus unicolor At risk - recovering brown teal Anas chlorotis At risk – recovering little shag Phalacrocorax At risk - naturally uncommon melanoleucos banded rail Rallus philippensis At risk -naturally uncommon

Model situation As habitats improve, and with sustained protection from pest mammals, further colonisation by some bird species from Great Barrier and Little Barrier Islands, and possibly elsewhere, is expected. Significant functional gaps and missing species however, will need to be addressed through reintroductions. This is especially the case for some less mobile forest bird species. Translocations to secure habitat on Motu Kaikoura would also have the potential, at least for those species capable of crossing the narrow channels around the island, to provide a source of birds which can then recolonise nearby Great Barrier. The island is ideally placed to provide future habitat for a wide range of sea and landbird species. A number of species of petrels would have been present historically, and many of these still breed on nearby islands.

Offshore islands in the Hauraki Gulf are important refuges for seabirds. As seabird densities in the Gulf increase following pest removals from a number of their breeding islands, it becomes more important for prospecting birds to have new safe habitats to colonise. This supports a ‘watch and wait’ policy within the lifetime of this plan.

Restoration options Petrel species could self-colonise from nearby islands. Species include black petrel (Procellaria parkinsoni), Cook’s petrel (Pterodroma cookii), grey-faced petrel (P. macroptera), diving petrel (Pelecanoides urinatrix) and fluttering shearwater (Puffinus gavia) (Lovegrove 2001; Halema Jamieson, pers comm.). Translocations or active management of petrels may not be necessary until more suitable habitat is available. For example, Cook’s petrels prefer mature forest, deep free draining soils, and steep slopes with short distances to ridge tops (Rayner et al. 2007). These needs are currently not easily met on Motu Kaikoura.

In the sooty shearwater (Puffinus griseus), another species that could potentially self- colonise, burrow density is correlated with similar abiotic factors, as well as vegetation type, and burrows are more commonly found at sites with tall canopy species of kamahi, rata, manuka or podocarps (Scott et al. 2009). Soft, flexible canopy foliage is essential for safe landing, and a flourishing understorey provides

Motu Kaikoura Biodiversity Management Plan 22 shelter from coastal winds. However, waiting for suitable petrel habitat to develop could take a long time, and this should not preclude experimental use of acoustic luring devices at potentially suitable sites if any already exist.

As petrels and shearwaters have low reproduction rates and delayed maturity (Bell & Sim 1998), rodent control is essential to ensure minimal predation of adults and chicks and thus maximise population recruitment.

Recommended actions for birds:

• Continue regular annual bird monitoring across a variety of habitats. • Control rodent numbers to ≤5% density across the entire island. • For kaka, maintain mature P. pinaster until mature native canopy species are established & more widespread. Pines on the island, particularly P. pinaster currently provide a food source for visiting kaka and their removal should be staged over a period of time. • Control any prickly or spiky or harsh foliage weeds in coastal cliff areas to promote opportunities for petrels to prospect and colonise. • Investigate use of acoustic luring devices at suitable sites to attract missing petrel species. • Draw up a list of species for potential future translocation. Early candidates for reintroduction should include forest species such as robin (in which a Motu Kaikoura population could augment existing translocation initiatives at Glenfern and Windy Hill), and recently extinct species from Great Barrier, such as whitehead.

RESTORATION OF INDIGENOUS MAMMALS

Current situation New Zealand has few native mammals and bats are the only terrestrial native mammals present. There are only two living species, the long-tailed bat (Chalinolobus tuberculatus) and the short-tailed bat (Mystacina tuberculata). Both species are threatened with extinction and considered a high priority for conservation.

Although bats remain widely distributed across New Zealand, populations are patchy with extremely low numbers in many areas. C. tuberculatus is found in native, regenerating and exotic forests, but M. tuberculata inhabits only old-growth native forest. Both species are recorded from islands. Long-tailed bats are known from Great Barrier Island, while there are no known records of short-tailed bat for Great Barrier. It is reasonable to assume that the long-tailed bat was a part of the original fauna of Motu Kaikoura.

Motu Kaikoura Biodiversity Management Plan 23 Habitat requirements Native bats are largely found within old growth forests around New Zealand. They utilise hollows in old-age trees as roosts and actively select the largest trees for roosting sites, usually in mature lowland forest. It has been found however, that they will inhabit fragmented/regenerating native forest, and may utilise exotic plantations. It can be assumed that if bats are present in native forested areas, that they will be present in adjacent exotic plantations (Borkin & Parsons 2010).

Restoration options It is improbable that the long-tailed bat would have would have survived the historical degradation of vegetation on Motu Kaikoura. However, since the species is present on Great Barrier Island, and Motu Kaikoura does have extensive areas of pine, there is a possibility that some bats, possibly commuting between the islands, utilise the area of pine trees on Motu Kaikoura.

To date, bat surveys on Motu Kaikoura have consisted of non-systemmatic sampling carried out during bird survey trips using a hand-held call detector. The surveys were carried out at dusk in open areas beside old pine trees, specifically around the airfield and the old farmhouse. These surveys have not produced evidence of bats, although the old-growth pine forest has potential to be a suitable habitat.

Monitoring methodology • a 3-night survey using automatic bat detectors undertaken along transects in spring / summer (Oct-Feb) would provide a suitable baseline data to assess the presence of bats on the island; • research to determine the presence and abundance of suitable food species.

Recommended actions for bats:

• Undertake regular monitoring for bats as described. • Support research of the status of suitable food species for bats. • The reintroduction of bats to Motu Kaikoura is not recommended at this time if no bat population is found as suitable native habitat on the island is limited (options for translocation could be reconsidered in the future once natural regeneration of coastal forest species has occurred).

Motu Kaikoura Biodiversity Management Plan 24 Marine mammals The Hauraki Gulf has been identified as an important nursery area for native marine mammals, in particular, common dolphins (Dept of Conservation 2006). Further research will be undertaken by a PhD student from Massey University to determine habitat utilisation, abundance and densities of common and bottle-nosed dolphins. Motu Kaikoura will serve as a base for the research.

Recommended actions for marine mammals:

• Support/collaborate on research as resouces allow.

Motu Kaikoura Biodiversity Management Plan 25 BIOSECURITY

Pest plants Pest plants present on the island originate from previous gardens, the presence of livestock, wind dispersed seed from Great Barrier or from being attached to or within birds. Fortunately the lack of habitat on the island means that many weeds present on Great Barrier are absent from Motu Kaikoura, such as - wandering Jew (Tradescantia fluminensis), sweet pea shrub (Polygala myrtifolia), kahili ginger (Hedychium gardnerianum), climbing asparagus (Asparagus scandens), jasmine (Jasminum polyanthum) and Japanese honeysuckle (Lonicera japonica).

Pest plants considered in this plan are environmental weeds only and do not include pasture, grass or annual weed species. Control of weeds has been undertaken by the Auckland Council Biosecurity Team and the Motu Kaikoura Trust. Auckland Council has implemented pest plant surveys and control work on the Island for the past five years and have documented infestations of environmental weed species as listed below in Table 4 (Cox 2010).

Also present are wilding peaches (Prunus persica), prickly hakea (Hakea sericea), gorse (Ulex europeaus), macrocarpa (Cuppressus macrocarpa) and large areas of two pine species (Pinus pinaster and P. radiata). Some infestations such as moth plant, hakea, and pines are quite widely dispersed, but most occur only in localised sites. The implication of current distribution is that most species are can be eradicated in the short to medium term. Council efforts to date have already resulted in the eradication of three pest plant species - Cape honey flower (Melianthus major), smilax (Asparagus asparagoides) and aloe (Aloe arborescens).

Table 4: Pest plants present on the island 2010 (Cox 2010)

Common name Latin name arum lily Zantedeschia aethiopica black passionfruit Passiflora edulis buttercup bush Senna septemtrionalis Chinese privet Ligustrum sinense cotoneaster Cotoneaster sp. elephant's ear Alocasia brisbanensis hydrangea Hydrangea macrophylla Madeira vine Anredera cordifolia monkey apple Syzygium smithii moth plant Araujia sericifera pampas Cortaderia sp. periwinkle Vinca major mist flower Ageratina sp. Australian sedge Carex longebrachiata Mexican daisy Erigeron karvinskianus

Motu Kaikoura Biodiversity Management Plan 26

Pest plant control recommendations (see Appendices 3):

• Continued annual surveying of the island (both on foot and by boat) by experienced people is recommended. The focus of surveys should be key flowering times such as early summer for moth plant. To increase efficiency and progress more rapidly with surveys and control work it is recommended that the annual Auckland Council visit is augmented with either Motu Kaikoura Trust members or DOC staff. Any new species of pest plants detected during future surveys need to be added to the future actions list of the corresponding year’s report. • Manage pines as per the recommendations of the pine management plan – see Appendix 3. The larger areas of maritime pine are to be removed progressively as they provide a food source for kaka; regular surveillance of controlled areas to prevent regeneration essential. • In eroded areas prickly hakea and gorse are common as a result of previous fires. Control is not recommended within the life of this plan as these plants will eventually become shaded out by native tree species. Gorse control is not necessary unless it impedes access or is present where it will not be shaded out by taller native vegetation (e.g. on rock outcrops). • Macrocarpa should be controlled where access to light may give it an advantage over native species. • All other pest plants should be controlled regularly as per the recommendations of the latest Auckland Council report (Cox 2010) – see Appendix 3. Note that some weeds such as pampas are located in inaccessible steep areas and will require either aerial spraying (which could be carried out in conjunction with DOC) or control by a specialised abseiling team.

Pest Animals An aerial-based pest animal eradication undertaken in 2008 was initially thought to be successful. However, after nine months, rodents were detected and it appears from DNA evidence (Fewster et al. 2011) that kiore and ship rats may now be present. The adjacent mainland is only 120m away at the closest point and this poses a significant risk. Ship rats are capable swimmers, however, kiore and mice are thought to be poor swimmers and unlikely to be able to cross to the island from the mainland of Great Barrier unassisted.

Despite trapping and baiting efforts to contain reinvading rats on the shoreline, rodents are found throughout the island as evident from recent surveys and trapping results (Hamilton 2011; Mitchell 2010; Scarlett 2011). It is possible that more deer than anticipated were present on the island at the time of the bait application, and that these animals consumed enough bait to create gaps in bait cover. In these gaps, rodents will not have been exposed to bait or to enough bait for a lethal dose. While it is possible one or more species of rodents may have survived the poison drop, it is equally plausible they have re-invaded the island by swimming, via flotsam, or as stowaways on vessels.

To date there have been no further sightings or sign of deer, pigs, cats or rabbits. Rodents appear to be the only animal pests still present. It is unknown whether other

Motu Kaikoura Biodiversity Management Plan 27 pests are present on Motu Kaikoura - current reptile survey efforts have not detected rainbow skinks; surveillance of Argentine ants on Great Barrier Island following their discovery in 2006 has identified their persistence at specific localised sites (Great Barrier Island Charitable Trust 2010).

Pest animal control recommendations (see Appendix 4):

Other animal pests • Early detection is paramount in preventing other pests from establishing on the island. Border security measures as recommended below should minimise the arrival of pests, including mice, rainbow skinks and Argentine ants, and on-going reptile monitoring should reveal the presence of rainbow skinks. People carrying out rodent control will be covering the island intensively, so should all be trained in recognising Argentine ant colonies and all animal scats and footprints. If any pests or suspected sign (other than rodents) are found the Trust must be informed immediately so that a control programme can be initiated.

Border control Maintain existing biosecurity controls at border and pre-border to minimise the likelihood of any pest arriving:

• Pre border: - Arrivals from Great Barrier and surrounding islands should be checked for presence of all ship rats, kiore, mice, rainbow skinks, Argentine ants and weed seeds. All footwear must be cleaned and sprayed with trigene for prevention of kauri die-back. - Arrivals from outside of Great Barrier should additionally be checked for Norway rats, possums, mustelids, and hedgehogs. - Inspect all materials/machinery/equipment before arrival to ensure no stowaways are present. Undertake preventative treatment if available, e.g. bait for Argentine ants, control treatment for rainbow skinks. - No plant material or soil mixes are to be taken to the island as they constitute a major biosecurity risk.

• At border: - Undertake biosecurity check of all visitors and their luggage either in the biosecurity shed on the wharf, or in the biosecurity shed on the runway. - Ensure all food arriving at the island is packed in rodent-proof containers. - Remove all leftover food scraps containing seeds from the island. Undertake visual inspections of all equipment before unloading.

Motu Kaikoura Biodiversity Management Plan 28 REFERENCES

Bell, E.A. and J.L. Sim. 1998. Survey and monitoring of black petrels on Great Barrier Island 1997. Science for Conservation 78. Department of Conservation, Wellington.

Blanchon, D., C. Elliott, I. Ennis, G. Hayward, M. Galbraith and G. Aguilar. 2011. A lichen species list for Motu Kaikoura, Fitzroy Harbour, Great Barrier Island. Auckland Botanical Society Journal 66(2): 102-107.

Borkin, K.M. and S. Parsons. 2010. The importance of exotic plantation forest for the New Zealand long-tailed bat (Chalinolobus tuberculatus). New Zealand Journal of Zoology 37(1): 35-51.

Cameron, E.K. 2007. The Vascular Flora of Motu Kaikoura, FitzRoy Harbour, Great Barrier Island. Auckland Botanical Society Journal 62 (1): 78-95.

Cox, H. 2010. Kaikoura Island weed control and survey 2010. Auckland Regional Council, Auckland. de Lange, P.J., D.J. Galloway, D.J. Blanchon, A. Knight, J.R. Rolfe, G.M. Crowcroft and R. Hitchmough. 2012. Conservation status of New Zealand lichens. New Zealand Journal of Botany (in press).

Department of Conservation. 2006. Marine mammals of the Hauraki Gulf. Department of Conservation, Christchurch.

Dodd, A. and V. Tanner. 2007. Kaikoura Island archaeological survey. Department of Conservation, Auckland.

Fewster, R.M., S.D. Miller and J. Ritchie. 2011. DNA profiling - a management tool for rat eradication. pp 426-431 In: Veitch, C. R., M.N. Clout and D.R. Towns (eds.) Island invasives: eradication and management. IUCN, Gland.

Foster, K. 2011. Effect of ship rat (Rattus rattus) eradication on the terrestrial invertebrate biodiversity of Motu Kaikoura: a comparison with a non-rodent controlled site. Unitec Institute of Technology, Auckland (unpublished student report).

Galbraith, M. and G. Jones. 2010. Bird fauna of Motu Kaikoura, New Zealand. Notornis 57: 1-7.

Gardner-Gee, R., S. Graham, R. Griffiths, M. Habgood, S. Heiss Dunlop and H. Lindsay. 2007. Motuora native species restoration plan. Department of Conservation/Motuora Restoration Society, Auckland.

Great Barrier Island Charitable Trust. 2010. Great Barrier Island State of Environment Report. On-line report, www.gbict.co.nz.

Motu Kaikoura Biodiversity Management Plan 29 Hamilton, O. 2011. Distribution and density of ship rat (Rattus rattus) on Motu Kaikoura, Hauraki Gulf, following reinvasion after eradication. University of Auckland, Auckland (unpublished student report).

Hitchmough, R., L. Bull and P. Cromarty (comp.). 2007. New Zealand Threat Classification System lists - 2005. Department of Conservation, Wellington.

Hitchmough, R.A., J.M. Hoare, H. Jamieson, D. Newman, M.D. Tocher, P.J. Anderson, M. Lettink and A.H. Whitaker. 2010. Conservation status of New Zealand reptiles, 2009. New Zealand Journal of Zoology 37(3): 203 - 224.

Lovegrove, T. 2001. Birds. pp. 147-162 In: Armitage, D. (Ed.) Great Barrier Island. Canterbury University Press, Christchurch.

McEwen, M. (Ed.). 1987. Ecological regions and districts of New Zealand. Department of Conservation, Wellington.

Maddison, P. and A. Arkins. 2001. Land and freshwater invertebrates. pp. 104-117 In: Armitage, D. (Ed.) Great Barrier Island. Canterbury University Press, Christchurch.

Martin, T. 2012. Preliminary survey and monitoring of herpetofauna, Motu Kaikoura 2008-2011. Wildland Consultants Contract Report No. 2791. Wildland Consultants, Auckland.

Mitchell, M. 2010 Report on Motu Kaikoura rat monitoring. Auckland Council, Auckland (unpublished report).

Motu Kaikoura Trust. 2005. Motu Kaikoura management plan, Draft 24. Motu Kaikoura Trust, Auckland.

Natural Logic Environmental Management. 2008. Kaikoura Island Eradication Operational Plan. Unpublished report.

Ogden, J. 2001. Major ecosystems. pp. 52-81 In: Armitage, D. (Ed.) Great Barrier Island. Canterbury University Press, Christchurch.

Rayner M. J., M.N. Clout, R.K. Stamp, M.J. Imber, D.H. Brunton and M.E. Hauber. 2007. Predictive habitat modelling improves the population census accuracy of a burrowing seabird: a study of the endangered Cook’s petrel. Biological Conservation 138: 235-247.

Ryder, T. 2009. The effect of canopy cover and seasonal variation on freshwater fauna in streams on Kaikoura Island. Unitec Institute of Technology, Auckland (unpublished student report).

Scarlett, 2011. Update from Will Scarlett – Caretaker. Kaka Comments 10. Motu Kaikoura Trust Supporters, Auckland.

Motu Kaikoura Biodiversity Management Plan 30 Scott, D, H. Moller, D. Fletcher, J. Newman, J. Aryal, C. Bragg and C. Charelton. 2009. Predictive habitat modeling to estimate petrel breeding colony sizes: sooty shearwaters (Puffinus griseus) and mottled petrels (Pterodroma inexpectata) on Whenua Hou Island. New Zealand Journal of Zoology 36: 291-306.

Van Dyke, F. 2003. Conservation Biology: foundations, concepts, applications. McGraw-Hill, New York.

Young, M. 2010. Botanical Report December 2009. Kaka Comments, Motu Kaikoura Trust Supporters’ Newsletter 8: 4.

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Motu Kaikoura Biodiversity Management Plan 32

APPENDICES

Biodiversity Management Plan April 2012

Motu Kaikoura Biodiversity Management Plan 33

Motu Kaikoura Biodiversity Management Plan 34 APPENDIX 1: ARCHAEOLOGICAL SITES

Management of archaeological sites A detailed archaeological survey was undertaken by Dodd & Tanner (2007) and shows that Motu Kaikoura has a number of archaeological sites representing both Maori and European occupation although the landscape has undergone significant modification over time (see list included). In particular, the island’s World War II heritage is well preserved with a complete outpost including tracks, structures and roads.

Although management of these sites is mostly passive, potential adverse effects may arise during natural restoration of the island. Identified threats include damage by vegetation (including planting) and increased proximity of foot traffic on or around sites as a result of improved access.

Knowledge as to the location of archaeological sites is important to reduce the likelihood of damage during other restoration activities including the development of a track network across the island.

To this end, a map of significant archaeological sites should be compiled for ease of reference when undertaking other restoration activities. Specific recommendations regarding the management of Motu Kaikoura’s archaeological landscape are presented in by Dodd & Tanner (2007) as below and a list of known sites is included in the Motu Kaikoura Management Plan 2005-2015.

Recommendations from Dodd & Tanner (2007):

Motu Kaikoura Biodiversity Management Plan 35

Motu Kaikoura Biodiversity Management Plan 36 APPENDIX 2: FLORA AND FAUNA LISTS

Dicotyledons (135) Ageratina adenophora* Hakea sericea* Anagallis arvensis* Haloragis erecta Apium prostratum Hebe macrocarpa Apium "white denticles" Hebe pubescens subsp rehuarum Aster subulatus* Hedycarya arborea Atriplex prostrata* Helichrysum lanceolatum Avicennia marina var. resinifera Hoheria populnea Beilschmiedia tarairi Hydrocotyle moschata Beilschmiedia tawa Hydrocotyle elongata Beilschmiedia tawaroa Hypericum japonicum Brachyglottis kirkii Knightia excelsa Brachyglottis repanda Kunzea ericoides Callitriche muelleri Kunzea ericoides x sinclairii Callitriche stagnalis* Kunzea sinclairii Carmichaelia australis Leontodon taraxacoides* Celmisia major! (AK 11741) Leptecophylla juniperina Centella uniflora Leptospermum scoparium Cirsium vulgare* Leucopogon fasciculatus Clematis cunninghamii Leucopogon fraseri Clematis paniculata Linum sp Conyza bilbaoana* Litsea calicaris Coprosma grandifolia Lobelia anceps Coprosma macrocarpa Lotus ? suaveolens* Coprosma repens Macropiper excelsum subsp excelsum Coprosma rhamnoides Melianthus major* Coprosma robusta Melicope ternata Coprosma robusta x macrocarpa Melicytus ramiflorus Coriaria arborea Metrosideros excelsa Corynocarpus laevigatus Metrosideros perforata Cotoneaster glaucophyllus* Muehlenbeckia complexa Cotula australis Myoporum laetum Crassula sieberiana Myrsine australis Dichondra repens Nasturtium sp Disphyma australe Nestegis apetala Dodonaea viscosa Nestegis lanceolata Drosera auriculata Olearia furfuracea Dysoxylum spectabile Oxalis rubens Einadia triandra Ozothamnus leptophyllus Elaeocarpus dentatus Parietaria debilis Entelea arborescens Parsonsia heterophylla Erica baccans Passiflora edulis* Eruca vesicaria subsp sativa*! Pelargonium inodorum Erythrina x sykesii* Peperomia urvilleana Eucalyptus spp Physalis peruviana* Euchiton gymnocephalus Phytolacca octandra* Euphorbia peplus* Pimelea aff urvilleana Galium propinquum Pittosporum crassifolium Geniostoma rupestre var. ligustrifolium Pittosporum umbellatum Geranium robertianum* Plantago lanceolata* Geranium solanderi "coarse hairs" Pomaderris kumeraho Gonocarpus incanus Pomaderris phylicifolia var ericifolia Hakea gibbosa* Pouteria costata

Motu Kaikoura Biodiversity Management Plan 37 Pseudognaphalium luteo-album agg Solanum americanum Pseudopanax arboreus Sonchus ? asper* Pseudopanax lessonii Sophora microphylla (S. chathamica) Rhabdothamnus solandri Spergularia marginata Rubus cissoides Stellaria sp Sagina procumbens* Tetragonia trigyna Samolus repens Ulex europaeus* Sarcocornia quinqueflora Verbascum thapsus* Scandia rosifolia Veronica plebia* Schefflera digitata Vicia narbonensis*! (AK 76198) Senecio hispidulus Vinca major* Senecio jacobaea* Vitex lucens Senecio lautus Vittadinia australis! (WELT herbarium) Senecio minimus Wahlenbergia violacea Siegesbeckia orientalis* Weinmannia silvicola Solanum aviculare

Monocotyledons (55) Acianthus sinclairii Isolepis cernua Alocasia brisbanensis* Isolepis ? prolifer Arthropodium cirratum Juncus australis Astelia banksii Juncus effusus*Juncus edgariae Astelia solandri Lachnagrostis billardierei Bulbophyllum pygmaeum Lachnagrostis filiformis Carex breviculmis Lepidosperma laterale Carex flagellifera Microlaena polynoda Carex inversa Microlaena stipoides Carex lambertiana Morelotia affinis Carex longebrachiata* Oplismenus hirtellus subsp. imbecillis Carex ? ochrosaccus Orthoceras novaezeelandiae Carex pumila Phormium tenax Carex virgata Poa anceps Collospermum hastatum Pterostylis alobula Cortaderia selloana* Rhopalostylis sapida Cortaderia splendens Ripogonum scandens Cyperus ustulatus Rytidosperma racemosum Cyrtostylis oblonga Rytidosperma sp Dactylis glomerata Schoenus tendo Dianella nigra Sporobolus africanus* Earina autumnalis Thelymitra sp (not longifolia) Earina mucronata Thelymitra longifolia or aff longifolia Ficinia nodosa Triglochin striatum Gahnia lacera Uncinia uncinata Gahnia setifolia Winika cunninghamii Genoplesium pumilum Zantedeschia aethiopica*

Gymnosperms (5) Mosses (7) Agathis australis Bryum dichotomum Cupressus macrocarpa* Camylopus introflexus Pinus pinaster* Hypnodendron sp Pinus radiata* Leucobryum candidum Prumnopitys ferruginea Ptychomnion aciculare Rhynchostegium tenuifolium Thuidium furfurosum

Motu Kaikoura Biodiversity Management Plan 38 Fungi (9) Amanita muscaria* Gymnopilus junonius Biscogniauxia capnodes var rumpens Lachnum sp Cyclomyces tabacinus Pycnoporus coccineus Favolaschia calocera* Xylaria bypoxylon Ganoderma sp

Lichen (114) Baeomyces heteromorphus Parmelia testacea Buellia stellulata Parmelina conlabrosa Calicium hyperelloides Parmelina labrosa Caloplaca acheila Parmelinopsis afrorevoluta Caloplaca litoralis Parmotrema austrocetratum Candelariella vitellina Parmotrema cetratum Canoparmelia pustulescens Parmotrema crinitum Chrysothrix candelaris Parmotrema grayanum Cladia aggregata Parmotrema mellissii Cladia retipora Parmotrema perlatum Cladonia confusa Parmotrema reticulatum Cladonia capitellata Parmotrema subtinctorum Cladonia chlorophaea Peltigera nana Cladonia floerkiana Pertusaria subplanaica Coccocarpia palmicola Physcia erumpens Collema kauaiense Physcia poncinsii Degelia durietzii Poeltiaria turgescens Dirinaria applanata Porina exocha Flavoparmelia haywardiana Porpidia albocaerulescens Fuscodermia limbatum Pseudocyphellaria aurata Heterodermia chilensis Pseudocyphellaria carpoloma Heterodermia japonica Pseudocyphellaria chloroleuca Heterodermia leucomela Pseudocyphellaria crocata Heterodermia microphylla Pseudocyphellaria dissimilis Heterodermia obscurata Pseudocyphellaria haywardiorum Heterodermia speciosa Pseudocyphellaria montagnei Hypogymnia subphysodes Pseudocyphellaria multifida Jackelixia ligulata Pseudocyphellaria pickeringii Lecanora intumescens Pseudocyphellaria poculifer Lecidella elaeochroma Pseudocyphellaria rubella Leiorreuma exaltatum Pseudocyphellaria wilkinsii Lepraria cf. eburnea Punctelia borreri Lepraria incana Punctelia perreticulata Leprocaulon arbuscula Punctelia subflava Leptogium aucklandicum Pyrenula sp. Leptogium cyanescens Pyxine subcinerea Leptogium denticulatum Ramalina australiensis Leptogium propaguliferum Ramalina celastri Lichina pygmaea Ramalina meridionalis Megalaria maculosa Ramalina peruviana Megalospora atrorubicans subsp. australis Rhizocarpon geographicum Megalospora gompholoma subsp. gompholoma Stereocaulon corticatulum Menegazzia aucklandica Stereocaulon ramulosum Menegazzia neozelandica Stereocaulon vesuvianum Pannaria araneosa Sticta fuliginosa Pannaria crenulata Sticta lacera Pannaria immixta Sticta latifrons Pannaria aff patagonica Sticta martinii Pannaria subcrustacea Sticta squamata

Motu Kaikoura Biodiversity Management Plan 39

Sticta subcaperata Thelotrema lepadinum Strigula delicata Xathoparmelia australasica Strigula fossulicola Xanthoparmelia furcata Teloschistes flavicans Xanthoparmelia isidiigera Teloschistes sieberianus Xanthoparmelia scabrosa Teloschistes xanthorioides Xanthoparmelia verrucella Tephromela atra Usnea angulata Thalloloma subvellata Usnea rubicunda

Reptiles (3) Oligosoma aenea Copper skink Oligosoma smithi Shore skink Oligosoma moco Moko skink

Birds - indigenous (27) Birds - introduced (12) Anas aucklandica Brown teal Acrotheres tristis Indian myna Ardea novaehollandiae White-faced heron Carduelis carduelis Goldfinch Chrysococcyx lucidus Shining cuckoo Carduelis chloris Greenfinch Circus approximans gouldi Australasian Emberiza citrinella Yellowhammer harrier Fringilla coelebs Chaffinch Egretta sacra Reef heron Gymnorhina tibicen Australian magpie Eudyptula minor Blue penguin Passer domesticus House sparrow Gerygone igata Grey warbler Phasianus colchicus Ring-necked pheasant Haematopus unicolor Variable Prunella modularis Dunnock oystercatcher Synoicus ypsilophorus Brown quail Hemiphaga novaeseelandiae NZ pigeon Turdus ericotrum Song thrush Hirundo tahitica Welcome swallow Turdus merula Blackbird Larus dominicanus Black-backed gull Larus novaehollandiae Red-billed gull Morus serrator Australasian gannet Nestor meridionalis North Island kaka Ninox novaeseelandiae Morepork Phalacrocorax melanoleucos Little shag Phalacrocorax varius Pied shag Prosthemadera novaeseelandiae Tui Pterodroma cookii Cook’s petrel Rallus philippensis Banded rail Rhipidura fuliginosa North Island fantail Stercorarius parasiticus Arctic skua Sterna caspia Caspian tern Sterna striata White-fronted tern Todiramphus sanctus Kingfisher Vanellus miles Spur-winged plover Zosterops lateralis Silvereye

Motu Kaikoura Biodiversity Management Plan 40 APPENDIX 3: PLANT PEST CONTROL RECOMMENDATIONS

Species Recommended future actions Control aim arum lily Revisit known sites and retreat any Eradicate within 5 (Zantedeschia surviving/new plants. This treatment should be years aethiopica) done at the same time as elephant’s ear (with 3g metsulfuron+150ml glyphosate+10ml penetrant/10L) black Continue re surveying known sites. Cut and Eradicate within 10 passionfruit stump treat (with either Vigilant gel, 200ml years Control to zero (Passiflora glyphosate/1L or 1g metsulfuron/1L or 100ml density – will always edulis) Tordon/1L or 100ml triclopyr 600 EC/1L or reinvade from GBI 200ml Banvine/1L) buttercup bush Physically remove small plants as and when Eradicate within 10 (Senna found. years septemtrionalis) Cut and stump paint (2g metsulfuron/L or 100mls Tordon BK/10L). Chinese privet Re-check area where Chinese privet was found Eradicate within 5 (Ligustrum in Bradshaw Cove (if necessary cut and stump years Control to zero sinense) treat with 1g metsulfuron/1L). density Treat all plants as and when found. cotoneaster Target during resurvey of areas or surveying of Eradicate within 10 (Cotoneaster new areas – note it is possible that plants could years Control to zero sp.) have been missed, as the adult plants found in density previous years were well above head height (i.e. were part of the canopy). It is still likely that there are more mature cotoneaster trees on Kaikoura. Treat plants from summer – autumn either by cut and painting (with Vigilant gel or 5g metsulfuron/1L) or by frill bark and paint (with 5g metsulfuron/1L). elephant's ear Resurvey and treat (spray with 3g Eradicate within 5 (Alocasia metsulfuron+150ml glyphosate+10ml years brisbanensis) penetrant/10L) hydrangea Monitor for re-growth along with other species at Eradicate within 5 (Hydrangea the Top House and treat any new plants. Use years macrophylla) Vigilant gel to treat regrowth and new plants. Kikuyu Spray with glyphosate as required. Control only in (Penisetum localised areas clandestinum) where threatened habitats or native species present. Madeira vine Regular checks of both sites removal of any Eradicate within 10 (Anredera tubers found. years cordifolia) Further checks up stream of the Crawford Bay site to look for a possible parent site. monkey apple Continue to check for resprouts. Cut & stump Control to zero (Syzygium paint (5g metsulfuron/1L). density smithii)

Motu Kaikoura Biodiversity Management Plan 41 moth plant Survey for plant during flowering season (Jan- Control to zero (Araujia Feb). This should include going to good vantage density sericifera) points on the island and going around the island by boat and using binoculars to look for moth plant in the canopy. Control seedlings at known sites and search for new seedlings in vicinity. This species is likely to follow the same pattern of distribution as found on neighbouring Great Barrier, i.e. often widely dispersed sites with no obvious pattern of distribution. Ongoing surveillance to find any new sites is very important to keep this species in check. pampas Continue to treat accessible locations of pampas Control to zero (Cortaderia sp.) especially around the two house sites. Spray density summer-autumn (150ml haloxyfop (selective) + 50ml crop oil/10L). Treat more inaccessible areas in spring and do follow up survey and control in February (when it’s flowering). Aerial spraying may be required to reach cliffs/ steep coastal areas of pampas. Some native toetoe was also seen therefore good identification skills will be required by whoever treats the pampas. Aerial control will probably be needed in some areas; this could be timed to coincide with DOC control work on Great Barrier (George Wilson, DOC pers comm.). periwinkle The site needs to be regularly treated i.e. every Eradicate within 10 (Vinca major) 3 months and should be able to be eradicated years with a concerted effort and spray program. Treat with 300ml glyphosate + 20ml penetrant/10L.

Motu Kaikoura Biodiversity Management Plan 42 PINE MANAGEMENT PLAN

For the purposes of pine management, Motu Kaikoura is divided into 12 areas (Pine Control Areas A-L) on a catchment basis shown in Figure 3.

Figure 3: Pine Control Areas

Stage 2 control area

Stage 1 of the pine management plan (Pine Control Areas A-H) focused on poisoning outlying stands in the north and west of Kaikoura Island, whilst leaving the core infestation in the south intact. Stage 1 has now been implemented for several years, and only scattered pines that are difficult to access remain. Significant follow-up control will be required in the Areas A-H as further regeneration will occur, both from seeds released from dead and dying trees, and seed from the main southern infestation (Areas I-K).

Systematic searches of Areas A-H should occur at least 3 yearly to control pine regeneration before trees reach seeding age.

Stage 2 will be implemented once the initial control of pines is completed within Areas A-H. In each year, areas for pine control will be mapped and identified by surveying on foot. Control of pines within Stage 2 (Areas I-L) will focus for the first two years on areas with a dense understorey of indigenous species. By controlling pines where indigenous regeneration is advanced, additional recruitment of pines, and therefore follow-up control work, will be minimised. It is expected that the initial

Motu Kaikoura Biodiversity Management Plan 43 control of pines within the main infestation will occur in steeper gullies where species such as mamaku (Cyathea medullaris), ponga (Cyathea dealbata) and hangehange (Geniostoma rupestre) are abundant.

In areas with a dense pine canopy and a sparse understorey of indigenous species, thinning trials will also be conducted to determine if a reduction in canopy density will hasten the succession to indigenous forest and shrubland. It is expected that regeneration will be facilitated by pine control, but the optimum thinning density is unknown.

Thinning trials should be established with four 1ha sites, consisting of three treatment densities and a control: A. control area, no poisoning; B. poisoning 1 in 2 canopy pines; C. poisoning 1 in 3 canopy pines; D. poisoning 1 in 4 canopy pines.

Annual monitoring can occur simply and effectively within the sites by the establishment of photo-points.

Two years following the establishment of the thinning trials, indicative results can be used to determine if regeneration is occurring most rapidly within untreated areas, or areas where 50%, 33% or 25% of the canopy trees were poisoned. Ongoing control, with the eventual aim of eradication, can then be rolled out throughout the remainder of Areas I-L according to the best determined method. If regeneration of indigenous species is not facilitated by the poisoning of canopy pines in the above proportions, then pines will be removed progressively within areas of advanced understorey regeneration only.

HEALTH AND SAFETY NOTE: Dead and dying pines in high-use areas pose a significant health and safety hazard. For this reason, no pines standing within 25m of tracks, building, or the coast should be poisoned. Pines in these situations should be assessed on a site-by-site basis to determine an acceptable method of control.

Motu Kaikoura Biodiversity Management Plan 44 APPENDIX 4: ANIMAL PEST CONTROL RECOMMENDATIONS

Method of control Target all rodent species (ship rats, kiore) and aim to contain to ≤5% relative abundance (as measured by rodent monitoring, see iv. below) by establishing a 100m x 100m grid of bait stations. Baiting to occur in pulses as per timetable in Table 5.

Table 5: Baiting timetable for Motu Kaikoura

Year one Install, bait and refill as installation of track network proceeds

Year two Habitat Pesticide May All stations Brodifacoum Aug All stations Brodifacoum Nov All stations Brodifacoum Jan, Mar Coastal stations Brodifacoum

Year three onwards May All stations Brodifacoum Aug All stations Diphacinone Nov All stations except Diphacinone coastal Nov, Jan, Mar Coastal stations Diphacinone alternating yearly with brodifacoum

Coastal habitat is preferred by rodents due to the amount of food resource available, so coastal stations will need to be checked and baited more intensely than elsewhere. It is important that coastal areas be maintained at ≤5% presence as a first priority. An indicative bait line layout using ridge lines and contours is provided in Figure 4. It is important that there are two concentric coastal bait lines as they will be checked more frequently than internal lines.

Figure 4: Guideline for bait station line pattern.

Motu Kaikoura Biodiversity Management Plan 45 Pesticide Pesticide has been chosen on the basis of knockdown effect (brodifacoum), reduction of secondary poisoning to native fauna (diphacinone), low cost (brodifacoum), minimal environmental impacts (diphacinone) and for variety and appeal to rodents over time. Changing pesticide type and pulsing of baiting are industry best practice methods. Cereal baits should be used, pre-packed in 200g quantities in plastic bags. Initial bait take will be high, so 2-3 bags per station will be required for the first pulse. Subsequent pulses should only require 1-2 bags per station and bait amount is to be judged on previous take at that station, therefore a system of recording bait take is recommended.

Timing Timing of bait pulses is based on successful projects elsewhere in the region where similar climatic conditions allow rat densities to remain high year round with no marked drop off during winter (Gilbert 2011; Martineaux 2010). The aim of beginning the baiting cycle in autumn is to control rats to zero density by spring and thereby minimise the potential breeding population during most favourable climatic conditions, i.e. spring/summer. Note that a pulse is a one-off placement of bait.

Monitoring • Undertake regular rodent monitoring to track success of pesticide programme and use the results to modify programme if necessary. • Tracking tunnels need to be permanently set out in 5 lines of 10 as per standard protocols (i.e. tunnels to be 50m apart, and lines are to be at least 200m apart). Suggested monitoring line placement is shown in Figure 5. Cards baited with peanut butter are to be placed in tunnels for one fine night in the beginning of May, August, December and March.

Figure 5: Suggested rodent monitor line placement

Motu Kaikoura Biodiversity Management Plan 46 • Results are calculated as a percentage of presence, i.e. if 10 cards show rat prints that equals a 20% detection percentage and indication of relative abundance. The monitors in May and August will provide information regarding the density of rodents present and the bait loading amount required for subsequent baiting i.e. how many grams of bait to place in each station. The monitor in January will determine whether any additional baiting needs to occur across all sites before the next scheduled baiting in May. • Adaptive management is encouraged and if there are concerns that rodent numbers are high, e.g. during a warm dry winter, a rodent monitor should be undertaken and if results are >5%, baiting may need to occur ahead of the pulsing timetable. • Any adjustments to the monitoring timetable should be discussed with the Biosecurity Advisor Animal Pests at Auckland Council.

Adjustments to monitoring timing may be desirable to synchronise with the other Great Barrier Island projects but the priority will be to best inform the Motu Kaikoura project.

Analysis of monitoring results If rodent presence cannot be contained to 5% by December of year three, density of stations in coastal areas may need to be increased to 100m x 50m, i.e. place additional stations along existing lines. As internal habitat and food sources improve through regeneration of native flora and fauna, it may be necessary in install further bait stations in such locations.

Surrounding areas and creation of buffer The focus of baiting should always be on the island itself. However if resources permit it would be desirable to minimise reinvasion from the closest point (i.e. the adjacent Stellin property) and to maintain existing traps and bait devices on surrounding islands in the Grey group, and on Nelson and Motuhaku Islands (see Figure 6).

Figure 6: Proposed buffer zone (from Mitchell 2011)

Motu Kaikoura Biodiversity Management Plan 47 Based on evidence available regarding Norway rat incursions across open waters (Russell et al. 2008), the main risk period of reinvasion by swimmers is from December through to April. Control should be initiated two months prior to this period initially to effect some control before the main risk period starts – refer to Table 6.

Table 6: Baiting timetable for buffer zone

Year one Pesticide Establish bait stations Brodifacoum

Year two Oct – Dec (Where stations could be filled monthly) Brodifacoum Feb, Apr Brodifacoum

Year three and onwards Oct – Dec Brodifacoum Feb, Apr Brodifacoum

Timing also is scheduled to avoid conflicts of labour resource with the island baiting. The number of ecological restoration projects in the surrounding areas mean it is important to be collaborative when implementing such a buffer to encourage an effective and efficient means of not only protecting Motu Kaikoura from reinvasion, but also Kotuku peninsula and the Broken Islands. All these projects would benefit from collaboration.

References:

Gilbert, J. 2011. Newsletter 19. Windy Hill Rosalie Catchment Trust.

Martineaux, A. 2010. Management and predator control in a ‘Mainland Island’ ecosystem: assessment of rodent control efficiency. Université Paul-Cezanne Aix-Marseille, Marseille (unpublished student report).

Mitchell, M. 2011. Kotuku Peninsula rat control plan. Auckland Council, Auckland (unpublished report).

Russell, J.C., D.R. Towns, M.N. Clout. 2008. Review of rat invasion biology: implications for island biosecurity. Science for Conservation 286. Department of Conservation, Wellington.

Motu Kaikoura Biodiversity Management Plan 48