February 2011	ISSUE 3

ISI News Issue 3, February 2011

In this issue:

Editorial The economics of invasions Finding rare things Rabbit management information – online database Managing invasive species in the Juan Fernández Archipelago Restoring Ririwha

A new paradigm in restoration ecology: reintroduction of native bush rats in Australia Pikas as ecosystem engineers: grassland degradation on the Qinghai-Tibetan Plateau, China   Subscribe to ISI News

Editorial

Welcome to the third edition of ISI News. In this ‘communications era’ it seems that we are deluged with fact sheets, newsletters and other snippets of sometimes-interesting information. I find it an increasing challenge to sift out what I need to read, from the rest. I hope this ISI e-newsletter helps by succinctly providing topical and interesting information. I hope too that it complements other news and information sources (such as the informative IslandNet newsletter, for example). Thanks for the feedback from those who appreciated our first issues.

In this edition we feature an article by Robin MacIntosh on the economics of invasions. Economic dimensions – the costs to society of invasive species impacts, and the economic implications of managing them, or not – are increasingly important. There is a pressing need for good economic information to justify management and to quantify its financial benefits. Landcare Research and partners have begun work on quantifying the economics of invasions in the Pacific.

Also on the economic theme ISI recently hosted a visit to New Zealand by Josh Donlan (Director of Advanced Conservation Strategies). Some of you will know Josh through his work with Island Conservation in northwest Mexico, or serving as Chief Scientist for Project Isabela in the Galapagos Islands. He presented seminars around New Zealand on the general theme of ‘innovative conservation financing’. Using real project examples Josh discussed a series of topics including:

• ‘return on investment’ frameworks - where island restoration priorities are set according to available funds and conservation benefits
• ‘flattening the cost curve" - reducing island restoration project costs by applying new models, technology and techniques, and
• leveraging ‘financial engineering’ -  to raise the priority for conservation funding and identify new markets for conservation outcomes in order to incentivise land-user conservation practices and other innovative approaches.

Josh’ seminars were well attended and stimulated some interesting discussions.

As usual we have included summaries of a few projects being undertaken by Landcare Research which are addressing topical research themes. We would be happy to include summaries of any other projects (research, or otherwise) which you feel might be of interest.

Many of you will have noted in a recent Macquarie Island pest eradication project newsletter that the eradication operation discontinued last winter due to poor weather is back on again this winter. This is wonderful news and we wish Keith Springer and his team better luck this time. We also note that another large rodent eradication, on South Georgia Island, is also about to get underway (visit www.sght.org/projects.htm). These are exciting times.

Best wishes,
Alan Saunders
Manager – Invasive Species International

The economics of invasions

Understanding the full extent of the economic impacts of invasives may assist with making the case for management. Assessing the costs of the social and cultural impacts including impacts on health and welfare, income and employment, infrastructure, and ecosystem functioning will provide valuable input to managers wanting to justify management of invasives and quantify its benefits. ‘Towards establishing the economic value of invasive species impacts in the Pacific’ is the title of a joint project between ecologists and economists at Landcare Research, the Pacific Invasives Initiative (PII), IUCN-Oceania and the University of the South Pacific. The project is assisted with funding from a Critical Ecosystems Partnership Fund (CEPF) small grant.

The team would welcome any information regarding biological, socio-economic or economic data that has been collected, either published or unpublished, for the region.

 

The destructive impacts of introduced beavers, Tierra del Fuego. Photo Brent Barret	Ile Lepredour, New Caledonia. Forest destroyed by introduced herbivores. Photo: John Parkes

For further information contact Robin MacIntosh: macintoshr@landcareresearch.co.nz

Finding rare things

New invaders at the border or on the island and the last survivors of eradication attempts are not always easy to detect. Managers often search either proactively or in response to some hint that a pest may be present, and if they find none they are left with uncertainty about whether they just did not look hard enough or there were really none to be found.

However, there is a growing body of research that allows managers to put some hard numbers on the probability that absence of evidence really does mean absence of the pest, or on the extra effort that is required to increase this probability to match the risk and costs of getting it wrong.

ISI staff have been involved with several projects either attempting to specify how much monitoring needs to be applied as part of quarantine systems on islands or on estimating the probability of eradication success after the hunters or trappers stop finding any more animals.

An international symposium on the theme of search and detection was held in Wellington in late 2008 and papers on the theme are about to appear as a special issue on New Zealand Journal of Ecology 35.

Papers of interest to managers of rats on islands include a paper by Frith Jarrad on the effort required to detect an invading rat with a high degree of certainty – in this case on Barrow Island in Western Australia where it would cost the oil company Chevron a lot of money if rats established.

Papers on detection devices are presented by Amy Yackel Adams for kiore on Aguiguan Island, by Peter Sweetapple for anything that chews cardboard (with a little peanut butter) in New Zealand and by Julie Savidge on the ability of dogs to detect brown tree snakes on Guam.

The lesson is that to be 100% sure that a pest is absent we would have to search everywhere with an infallible detection system – both being unlikely, so ‘How sure can we be and is it enough?’ are the key questions these papers are leading to.

Determining these questions and the end point of eradications are described by Dave Ramsey for the eradication of cats on San Nicolas Island in California and by Mandy Barron for feral pigs in reserves in Hawaii. The cat paper illustrates the need to plan before the operation starts on how to collect the control data (catch per unit effort) and other monitoring data (camera traps) so it can be used to inform managers when they should stop and declare success.

These sorts of eradications with successive culls of the population provide information as they go along, but others (the one-hit aerial baiting for island rodents) provide no intrinsic information on success or failure. At the moment managers can look for survivors soon after the event but unless they can search the whole island all this tells them is that the operation has failed and not where remedial action is required – unless that is just a repeat dose of the failed baiting.

An area for future research is whether a detection array can cover the whole island with sufficient power to focus remedial action on a cost-effective way.

For further information contact John Parkes: parkesj@landcareresearch.co.nz

Rabbit management information – online database

Landcare Research has established an online database of information about the wild rabbits and their management.

The European rabbit is an invasive species in many countries throughout the world, indeed just recently a report by CABI named the rabbit as Britain’s most costly invasive species – the estimated 40 million rabbits costing Britain more than £260m a year in damage to crops, businesses and infrastructure.

The rabbit was introduced to New Zealand in the mid-1800s. Spreading rapidly it soon became a serious problem affecting agriculture and natural ecosystems. New Zealand has a long history of research into the rabbit problem, initially by the Animal Ecology Division of DSIR, and later by a dedicated Rabbit Research Group within the Ministry of Agriculture and Fisheries (now the Ministry of Agriculture and Forestry). From 1990-95 a Rabbit and Land Management Programme (R&LMP) was implemented in the worst rabbit prone areas of the South Island that involved land owners and managers and included extensive monitoring of rabbits and their impacts. After the end of the R&LMP in 1995 little research was carried out on rabbits in New Zealand until the illegal introduction of Rabbit Haemorrhagic Disease (RHD) in 1997.

In 2009, because of increasing rabbit impacts with the waning effectiveness of RHD in some areas, Landcare Research was funded to research improvements in conventional control of rabbits in New Zealand. As part of this research programme the new website has been launched, providing a searchable database of published and unpublished articles and references relevant to wild rabbits and their control.

Checkout the site at http://rabbits.landcareresearch.co.nz/

To date, over 3000 references (most from Australia and New Zealand, but including a number from other countries) are included, and cover a range of topics including basic rabbit biology, ecology, population monitoring, and control methods. The references span almost a century of research and management. Many of the references can be downloaded via the website.

The database was developed as a resource not just to ensure all available information and knowledge was available for research, but also that it was accessible to rabbit managers, farmers and the public.

This work was contracted by the NZ Foundation for Research Science and Technology as part of Landcare Research’s Small Mammal Pest Control research programme.

For further information contact Aaron McGlinchy: mcglinchya@landcareresearch.co.nz

Managing invasive species in the Juan Fernández Archipelago

A recent feasibility study commissioned and funded by Island Conservation and led by ISI addresses the conservation of a global biodiversity hotspot. The Juan Fernández Archipelago is a group of three oceanic islands approximately 700 km west of the Chilean mainland.

Home to around 700 people, the islands are perhaps most famous for their earlier human inhabitant Alexander Selkirk, who was stranded there for four and a half years and inspired Daniel Defoe’s classic novel Robinson Crusoe.

High levels of endemism among its plants and animals make the Juan Fernández Archipelago a Mecca of global biodiversity. Over 60% of the plants, including several genera and one entire family, are endemic. In addition, six of the seven native land birds are single-island endemics. Some, such as the Másafuera rayadito and Juan Fernández firecrown, are critically endangered.

These outstanding natural values have led the Juan Fernández to be designated as a national park and a UNESCO biosphere reserve. However, this unique place is under severe threat from the impacts of invasive plants and animals. Weeds are displacing native plants, altering entire communities and threatening many species with extinction. Invasive rodents are impeding forest regeneration through their consumption of seeds and seedlings. Goats, rabbits and cattle disperse seeds of introduced species, consume native plants and cause severe erosion. Feral and domestic cats, as well as coatis (a South American relative of the raccoon), prey upon critically endangered native birds.

As a result of these and other impacts, the archipelago has been listed by the IUCN as one of the world’s most threatened protected natural areas.

Commencing in May 2010, ISI led a team of scientists investigating whether – and how – the impacts of invasive species can be managed in the Juan Fernández. The feasibility study took a broad approach, considering invasive plants, mammals, birds and invertebrates. Members of the study team visited the archipelago in May and again in November 2010 to see first-hand the impacts of invasive species, and to consult with the local community and management agencies.

The team concluded that invasive species management is achievable but will require a multi-faceted approach. Because a wide variety of invasive species are present, they will be interacting with one another. Without a comprehensive, multi-species approach, attempts to manage one pest could exacerbate the impacts of others. For example, removal of goats and rabbits could trigger a proliferation of weeds.

There are also logistical and socio-political challenges inherent in managing invasive species on inhabited islands. For example, the use of some eradication tools may be restricted by real or perceived safety risks, and communities or individuals may oppose eradication of some species that they view as useful or desirable. It is imperative that the local community is engaged in, and supportive of, the proposed management.

Biosecurity will also be a major consideration. While many of the invasive animals and some of the plants may be able to be eradicated, it would be unwise to attempt this unless the risk of reintroduction is minimal.

The feasibility study has recommended a phased approach starting with the establishment of biosecurity measures, followed by a capacity-building phase (during which knowledge and techniques are developed through adaptive management of priority sites and species), an eradication and control phase, and finally a restoration phase with planting of native species to encourage a rapid recovery of habitat and communities.

Managing diverse communities of invasive plants and animals on inhabited islands represents a major challenge in the ever-advancing field of island eradication. However, as much of the world’s biodiversity is found on such islands, it is a challenge to which we must rise.

For more information contact Al Glen: glena@landcareresearch.co.nz

Restoring Ririwha

Introduced rat species have significant impacts on seabird populations around the world through their predation on eggs and chicks. This is particularly so for breeding colonies on islands.

One example of such predation occurs on Ririwha, an island owned by Ngā Uri o Whakakii, a hapū (Māori sub-tribe) of Ngāpuhi, off Whangaroa Harbour, in Northland, New Zealand. The island has remnant populations of burrowing petrels and also kiore (Polynesian rat) and Norway (brown) rats, the former in large numbers.

The hapū, via the Ririwha Restoration Trust, asked Landcare Research’s Phil Lyver and Chris Jones to determine the effect of rats on egg survival and breeding success of oi (grey-faced petrel) populations and to develop population models to predict the recovery of oi in the absence of rats. This work is in line with Ngā Uri o Whakakii’s plan to eradicate rats from Ririwha to allow the restoration of its native plants and animals.

The island has, until recently, been used for farming and is still stocked with sheep, which are maintained to help manage the introduced grasses, kikuyu in particular, that cover much of the island. Small remnants of native vegetation persist in gullies and around the coastal margins.

Oi are of cultural significance to northern iwi, and once formed the basis of widespread customary harvest. However, their present numbers make such harvest unsustainable. Restoration of the small remaining oi populations on Ririwha is likely to be achieved only by removing the rats.

It is hoped that the knowledge gained by Chris and Phil from this work (and from the eventual rodent eradication programme) will complement the team’s other research on sustainable harvesting of oi on the Aldermen Islands and Moutohora (Whale Island), and will guide the management of the birds’ recovery on Ririwha.

The team is looking at how egg survival and breeding success of oi vary in both time and space relative to the presence of rats. Prior to the proposed island-wide eradication of rats, the researchers have set up trapping grids, including 120m-wide buffer zones, over two remnant breeding colonies to remove all rats while the birds are laying and incubating. Breeding success of oi is being monitored using fibre-optic cameras, or ‘burrowscopes’, which allow observers to detect breeding birds, eggs or chicks deep inside the birds’ burrows.

Results from the trapped areas will be compared with those obtained from similar grids in other colonies where the rats are monitored but not trapped.

As well as being used to compare breeding success of oi in the presence and absence of rats in the same season, the untrapped areas will eventually be used to compare the breeding success of oi over time as the rat eradication programme (under the guidance of John Parkes) gets underway.

The breeding performance of oi will be monitored for 3 years and the resulting data will be used in simple stage-based population growth models to predict the trajectory of the birds’ recovery.

The project is in its early stages, but the team has already carried out rat trapping at the two removal sites (c. 2 ha) for the 6 weeks of the oi breeding season when eggs and young chicks are most vulnerable to predation by rats. In just over 12,000 trapnights, over 400 kiore were removed from the two grids. Both the researchers and the hapū are keen to find out how much this has contributed to the breeding success of oi in those small colonies as a forerunner to future island-wide eradication of rats, and both groups have high hopes for the ongoing restoration of Ririwha and its native biodiversity.

The Trust’s long-term vision is one of co-existence of people and native species to maintain historical and traditional practices in and around the island. Mike Sheehan of the Trust believes that such restorative initiatives provide a continuity of past and future practices that will, in turn, allow for new and developing technologies to stimulate growth and new opportunities.

This work is funded by the Foundation for Research, Science and Technology (Programme C09X0908: Te Hiringa Tangata - Bicultural Restoration of Coastal Forests using Sea Birds).

For further information contact: Chris Jones, jonesc@landcareresearch.co.nz

This article originally appeared in volume 17 of Landcare Research’s vertebrate pest management newsletter, Kararehe Kino.

A new paradigm in restoration ecology: reintroduction of native bush rats in Australia

Landcare Research’s Roger Pech and Andrea Byrom are advisors on a collaborative project funded by the Australian Research Council (ARC) entitled ‘The return of the native: reintroductions, reinvasions, and a new paradigm in restoration ecology’.

The project, run by Profs Peter Banks (University of New South Wales) and Chris Dickman (University of Sydney), aims to restore bush habitats in Sydney Harbour National Park, remove invasive black rats (Rattus rattus) and ultimately reintroduce the native bush rat (Rattus fuscipes).

The project is a fascinating blend of theoretical concepts and practical outcomes: because the presence of native species can often reduce an ecosystem’s susceptibility to invasion, both competition theory and invasion biology predict a role for reintroductions in the control of invasion processes.

Intact assemblages are more robust to invasion by new species than disturbed ones because niches are filled and competitive processes prevent establishment. The reintroduction of common native species has the potential to make a major contribution to the control of invasive species, by preventing them from both establishing in the first place and re-establishing after control.

The aim is to transform Australia’s native wildlife from victims of invasive pests to active defenders that slow or prevent the invasion process. Peter and Chris are working with Andrea and Roger to further develop some of these theoretical concepts, because they apply to both the ARC project and the IMI programme.

More information on the bush rat reintroduction project can be found at: http://www.sydneybushrats.com/

This article originally appeared in the first edition of the Invasive Mammal Impacts (IMI) Programme newsletter.

Pikas as ecosystem engineers: grassland degradation on the Qinghai-Tibetan Plateau, China

Roger Pech and Andrea Byrom’s skills and experience have also been in demand in China. Both were recently awarded visiting professorship for senior international scientists to the Chinese Academy of Sciences. Their host institute was the Northwest Institute of Plateau Biology in Xining, Qinghai Province, in north-western China, where they spent a month with colleague Professor Zhang Yanming in May 2010.

The researchers were investigating the ecological processes likely to regulate populations of a small hamster-like lagomorph, the plateau pika (Ochotona curzoniae), a burrowing species inhabiting the Tibetan Plateau at altitudes 3200–5200m.

The pika is considered a keystone species in alpine meadow ecosystems. Its grazing and burrowing activities influence plant species composition as well as the movement of nutrients and water through the soil profile. The plateau pika is also a primary prey for native bird and mammal predators, and its burrows are used as nest sites by small passerines. However, pikas compete with livestock for scarce forage and their burrowing activities are thought to contribute to soil erosion and, ultimately, landscape degradation.

Research on the population dynamics of plateau pikas is essential both for their conservation as a keystone species and for their management as a pest species.

This article originally appeared in the first edition of the Invasive Mammal Impacts (IMI) Programme newsletter.

Plateau pikas in their native habitat. Photo: Andrea Byrom	Handling a plateau pika. Photo: Roger Pech	Grassland on the Tibetan Plateau. Photo: Andrea Byrom