Will a revised methodology jeopardise the success of the REP?

The decision to delay implementation until 2019 was announced in the Householder last week (20/02/2018), but what does the revised methodology really mean?

Without the APVMA licence in hand and not knowing what the approval conditions might be, we were unable to plan the final logistics to implement the baiting in 2018. Secondly, although there is a high level of support for the REP, there continues to be opposition within the community. However, based on feedback from some members of the community, an acceptable compromise may be to change the methodology in the settlement area to more bait stations and less hand broadcast. This will largely remove bait in the open within the settlement area, and therefore alleviate people’s concerns relating to this aspect of the operation.

So does a change to less hand broadcasting and more bait stations in so many areas in the settlement reduce the likely success of removing every rodent?

The answer is no, the methodology is still robust and can achieve eradication as has occurred on islands elsewhere. However this change to methodology requires more time and resources on the ground during the eradication and more time invested in planning, to ensure the project meets the required standards.

To understand it more, let’s look at both methods, whilst considering the rodent behaviour outlined below;

1. Mice are territorial, with a home range territory as small as 10m² per mouse
2. Rats and mice are neophobic, which means they are often wary of new objects in the environment, so we need to consider how we present bait stations and bait to rodents.
3. Rats suppress mice, so rats are likely to take the bait first, and when the rats are dead, mice can move in to take the bait next.
4. The bait we will be using is very tasty to rodents, compared to natural food sources it is their version of ‘tasty cake’, so research shows they will select it over other food sources.
5. Rodents need to consume a lethal dose of this bait (approximately 1-2 pellets for both a mouse and a rat) and it can take 2-7 days for the rodent to die.

Click the table below for a comparison of bait stations vs hand broadcast

Therefore both methodologies work for eradication, however this change to methodology requires more time and resources on the ground during the eradication and more time invested in planning, to ensure the project meets the required standards.

Bait stations need to be placed out in the settlement a month before bait is placed inside (from late April 2019) for rats to get used to them. The bait stations need to be baited for four months to six months  (from late May to late September/December) to allow ample time for mice to receive a lethal dose after the rats.

Mice eradicated from Antipodes Island by Million Dollar Mouse

Members of the Lord Howe Island Rodent Eradication Project team, both Ann De Schutter (GIS Officer) and Keith Springer (Aerial Operations Manager) were previously part of the Million Dollar Mouse team www.milliondollarmouse.org.nz, so it is great that they will be bringing their knowledge and expertise to the island. On the 21^st of March it was announced that the eradication of mice was successful from Antipodes Island in the New Zealand Sub Antarctic. Million Dollar Mouse is a joint initiative between DOC and funding partners the Morgan Foundation, WWF-New Zealand, Island Conservation and public supporters. Million Dollar Mouse have achieved one of the most complex eradications ever undertaken despite challenges such remoteness, scale, and difficult terrain.

“This is huge news for conservation both in New Zealand and internationally,” The Minister of Conservation, Hon Eugenie Sage said. “Special plants and wildlife, including 21 species of breeding seabirds, more than 150 species of insects – 17 per cent of them only found on the Antipodes; 21 uncommon plant species and four unique land birds are found on the Antipodes Island.  They can now thrive with mice no longer preying on the insects or competing with the land birds.”

REP team member Ann De Schutter celebrated the success with the team in New Zealand last week.  Ann says “From May – August 2016 we were on island with a team of 13 people for 10 weeks to aerially treat the whole island with Brodifacoum. This eradication project was very ambitious as it was the first project worldwide to specifically target mice on an island of 2,000 ha, with rugged steep coastal cliffs up to 200m high.  For me personally, it is great to know that thanks to the efforts of all those involved, the special species now have a fighting chance.

Letter of Support

Over the course of the project we have received numerous letter’s of support from organisations in support of the project. We will be sharing some of these over the next few newsletters.

Dear Lord Howe Island,

We would like to say how delighted we are that this project of rodent eradication is to be done. We have travelled to many places and seen the wonderful regeneration of indigenous species when these actions are carried out. We humans have been so appallingly irresponsible in our care for our planet. Thank goodness there are a few things being done to rectify a little of the damage. We look forward very much too visiting Lord Howe Island after this is carried out. Knowing of the problem of the rats and mice in the past, we have made no effort to go there but now most definitely will once this has been completed.

Please allow our voice in favour to be heard.

Thankyou.
Yours faithfully,
Barbara and Adam Acworth

Rat impacts on Phillip Island Wheat Grass – Elymus multiflorus ssp. Kingianus

This critically endangered grass is endemic to Lord Howe Island and Phillip Island (off Norfolk Island) with less than 100 plants recorded, so with a seriously low population in a global context, the LHI population is extremely important for its conservation. It is named after Phillip Gidley King, in charge of the first settlement of Norfolk Island and with seed heads which appear similar to ‘ears of wheat’, it is aptly titled. On LHI It is only known from two very small discrete sites between Old Settlement beach and Dawson’s Point where it grows just above the high water mark.

Sue Bower, LHI Board Flora Management Officer, has recently been trying to grow and safeguard some specimens for relocation to the site near Old Settlement beach, but these specimens were being nibbled by either birds or rats. To protect these specimens, Sue recently placed some samples under a wire seed tray away from nibbling creatures, but as can be seen from the below picture this could not stop a rat still feeding on the grass despite the area being baited.

The LHI Board ‘Weed Team’ are maintaining the grass at its known sites by continuing to remove target weeds that would otherwise have potential to disperse into the habitat and smother it, and bait stations have been installed nearby to reduce rat pressure. These techniques are maintaining the grass population currently but the REP will certainly help safeguard and increase its population.

What do the pellets look like?

During the REP, we will be using Pestoff 20 R, a 10mm cylindrical crushed cereal-based composite pellet bait, coloured green – blue. The active ingredient contains 0.002% Brodifacoum.

 We have been asked if the pellets will leave dust and loose cereal in the environment, as you can see from the picture below they are a large, hard pellet designed to be spread by air. There will be a very small amount of dust generated which the NSW Chief Scientist concluded would present no risk to Human Health.

Philip Island Networking Visit

Last week the LHI Board welcomed a team from the Philip Island Nature Parks, Victoria. They were on a study tour to understand how conservation was being delivered on another island in Australia.

Ranger in Charge, Ben Thomas said “We thoroughly enjoyed the trip and got a lot out of it. Your achievements over the last decade are truly inspiring. The way you go about your work is world class”.

Conservation Manager Jessica McKelson said “It’s been really good to see how the previous work has come together – it’s a fantastic place, we have learnt a lot. We wish you every success with the Rodent Eradication Project, the results will be incredible”. We also discussed eco-tourism and how conservation and sustainable tourism are important on our precious islands.