Above picture:  The MFM Project was at the 6th SANAP Research Symposium.  From left: John Cooper, Ria Olivier (Antarctic Legacy of South Africa), Robyn Adams and Sue Jackson; photograph by Greg Hofmeyr

The South African National Antarctic Programme (SANAP) recently held its 6th Research Symposium in the Houw Hoek Hotel, in a country setting near Grabouw in the Western Cape.  The meeting was attended by 177 scientists from all the disciplines involved with Antarctic, sub-Antarctic and Southern Ocean research within South Africa.  Among those present were representatives of the South African National Research Foundation, the South African Polar Research Infrastructure and the South African Department of Science and Innovation.  Oral and eposter presentations, along with associated meetings and events, were held over five days from 27 November to 1 December.  The meeting was hosted by the University of Stellenbosch with Ria Olivier, Principal Investigator, Antarctic Legacy of South Africa, efficiently leading the Organizing Committee.

Sue Tonin presents her plenary lecture, backed by MFM pull up banners; photograph by Robyn Adams

To kick off the last full day of the symposium, the Mouse-Free Marion (MFM) Project’s Assistant Project Manager, Sue Tonin, gave an invited 30-minute plenary lecture entitled “Eradicating Invasive House Mice Mus musculus from Marion Island: Gains and Challenges” to a full audience.  Her abstract follows:

“This conservation management action is a once-off eradication of introduced and increasingly damaging House Mice that are driving Marion Island into a state of ecological crisis by eating and burrowing into plants and preying on invertebrates and seabirds.  Because of their isolation, islands host unique species assemblages that contribute disproportionately to global biodiversity; because they often lack indigenous terrestrial predators, these biotas are particularly vulnerable to invasive alien species.  Approximately 5% of the plant species on Marion Island appear to be endemic to the Prince Edward Islands group, as are some of the insects eaten by mice on Marion Island (three weevil and one moth species).   Several species of the native invertebrate fauna have been reduced to tiny proportions of their pre-mouse populations, thereby altering nutrient cycling and other key ecological processes. Marion Island is a globally significant breeding island for 28 seabird species.  Left unchecked, mouse impacts are expected to lead to the local or functional extinction of 19 of these within an estimated 30-100 years.

Removal of invasive alien predators from islands is a highly effective biodiversity conservation tool.  Preparations to eradicate House Mice from Marion Island commenced with a feasibility study in 2015.  Subsequent planning has been informed by best practice principles and guidelines developed over decades on similarly invaded islands owned by New Zealand, Australia, Mexico, the USA, France, and other member states of the EU, amongst others.

The eradication is being planned and will be undertaken by the Mouse-Free Marion (MFM) Project partnership between BirdLife South Africa and the Department of Forestry, Fisheries and the Environment (DFFE), assisted by many organisations and individuals. Custom-formulated rodenticide bait will be broadcast from helicopters, the only approach that has proven successful for large oceanic islands.  Comprehensive bait coverage of every part of the island, essential for success, will be guided by advanced GPS tracking and GIS mapping.

With the passage of time and methodological advances, since the 1960s, larger and larger islands have been targeted for the eradication of alien mammals. From Horn et al. 2022, New Zealand Journal of Ecology 46: 3500

Successful eradications of House Mice from Southern Ocean islands include Macquarie Island (12 875 ha), Antipodes Island (2025 ha), Coal Island (1189 ha), Enderby Island (710 ha), Ile Chateau (220 ha), and parts of South Georgia Island (4 932 ha of which had mice).  A powerful motivator is the dramatic population recoveries of seabirds and other fauna following mouse removal on these islands.  At 30 000 ha, Marion is by far the largest island on which such an eradication will be attempted in a single operation.  We are closely examining failed mouse eradication attempts such as those on Gough and Midway Islands to incorporate lessons learned there into our planning. Assessment of risks, including those to non-target species, is critical to maximise the MFM Project’s chances of success and is applied to every phase of planning and execution.  Assessing and monitoring the ecological outcomes of the mouse eradication initiative will require a long-term monitoring framework, which makes use of pre-eradication baseline data against which post-baiting monitoring can be compared.”

Support for Sue’s plenary in the appreciative audience came from Robyn Adams, MFM Communications Officer and Project Assistant, and John Cooper, MFM News Correspondent.

A sylvan setting in the Western Cape mountains proved a pleasant venue for the 6th SANAP Research Symposium

The Symposium ended on Antarctica Day with a themed Antarctic Breakfast, followed by a Closing Ceremony.

With profound thanks to Ria Olivier, Antarctic Legacy of South Africa, University of Stellenbosch.

 

John Cooper, News Correspondent, Mouse-Free Marion Project, 18 January 2024

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A Northern Giant Petrel in late evening light on Marion Island; photograph by Stefan Schoombie, poster design by Michelle Risi

The Mouse-Free Marion Project is a registered non-profit company (No. 2020/922433/08) in South Africa, established to eradicate the invasive albatross-killing mice on Marion Island in the Southern Ocean.  The project was initiated by BirdLife South Africa and the South African Department of Forestry, Fisheries and the Environment.  Upon successful completion, the project will restore the critical breeding habitat of over two million seabirds, many globally threatened, and improve the island’s resilience to a warming climate.  For more information or to support the project please visit mousefreemarion.org.