Possums bounce back from Devils on Maria Island

SEPTEMBER 23, 2019

by University of Tasmania

The recent introduction of healthy Tasmanian Devils to Maria Island was initially bad news for the local possum population, a species blissfully ignorant of the predator's existence.

But the ability of the prey species to rapidly modify its foraging behavior is the subject of a new report from the University of Tasmania published in the journal Ecography.

"In response to extinction fears, devils were introduced to Maria Island, where their abundance rapidly increased," according report lead-author and UTAS School of Natural Sciences researcher Calum Cunningham.

"This was really important for safeguarding the devil's future, but it also provided a unique opportunity to research how apex predators structure ecosystems."

And the Maria Island experience could have implications for the "rewilding" of apex predators across the world, according to Mr Cunningham.

"Rewilding is a management approach that aims to restore important ecological processes by introducing species that play important roles."

Mr Cunningham said that declines of large carnivores across the world had reduced the "landscape of fear" that constrains the behavior of other species.

"Our study shows that recoveries of top predators can re-establish missing controls on the behavior of other species," he said.

The Maria Island study used a foraging experiment specifically designed to measure how possums—a key prey species of devils—perceive predation risk. The experiment compared possum behavior before devils were introduced to the island, and again after devils had become very abundant.

Read on

Nature reclaiming suburbs

Possums are moving into abandoned Christchurch suburbs and a very rare bird has returned to the city as wildlife reacts to the earthquakes.

The growing number of possums is just one of many changes in local wildlife in response to population and landscape changes in eastern Christchurch, including tree saplings already sprouting on empty sites and a potential fall in birds such as pukekos.

Landcare Research pest control scientist Janine Duckworth said possums would prosper in the red zone as humans leave.

"It doesn't surprise me that we are seeing more of them as they do try to avoid people. With fewer dogs in the areas that will allow them to move into places they may not have been able to take advantage of in the past. If they are less disturbed, then more young possums will grow into adults," she said.

Richmond resident Rex Collins found a possum the size of a "fox terrier" on the roof of his home. It is the first he has encountered in 16 years of living in the suburb.

"We woke up in the middle of the night to this loud crashing sound on the roof. We have this problem with squatters next door, so we thought it was someone jumping on our roof. We rang the police and they came pretty quickly. They had a good look around and then they found this huge possum," he said.

"He was about the size of a fox terrier in body size. He had these huge big round eyes about the size of $2 coins."

"A lot of wildlife is coming back into the area. The wildlife is taking over again."

Sub5 security officer Rory Garland, who patrols the red zone for Cera, has also seen many possums on his night patrols.

"I have seen about three or four possums. I saw one just sitting in the middle of the road. In the end it went up a power pole."

Read on:  http://www.stuff.co.nz/the-press/news/7464947/Nature-reclaiming-suburbs

Animal pests are destroying New Zealand’s biodiversity

Each day stoats kill an average of 40 North Island brown kiwi chicks. and possums destroy forests and reduce native birdlife numbers.NEWS FROM the Faculty of Agriculture and Life Sciences, Lincoln University
By Janette Busch

Animal pests are destroying New Zealand’s biodiversity

Each day stoats kill an average of 40 North Island brown kiwi chicks. and possums destroy forests and reduce native birdlife numbers.

Cheri van Schravendijk (Te Ati Haunui-a-Papārangi, Ngāti Apa) is working tangata whenua representatives to identify effective biological agents (toxins) from native plants in New Zealand that can be used against introduced mammals. This is part of her doctoral studies as an external student at Lincoln University.

“As a result of exotic animal liberations over the last hundred and fifty years Aotearoa/New Zealand has been left on the brink of significant negative ecological change,” said Cheri.

“Scientific research into the control of these animals has progressed since then but this has often operated in isolation from the communities directly affected by the decisions being made by pest managers.

“Our kaumatua have long understood that tangata whenua have something unique to offer to research and my project is a working example of that.”

Cheri is working primarily with kamatua from Tuhoe who have knowledge (Matauranga) about native plants to identify poisonous plants that could be used to assist in the management and control of animal pests.

“I get really passionate with the ideas around providing greater participation of our people in research which, in turn, provides a broader horizon of opportunities for everyone to participate,” said Cheri.

Using criteria set by a tangata whenua advisory roopu – Ngā Matapopore – Cheri undertook an extensive review of native plants that resulted in the selection of tutin, a highly toxic compound found in the ‘loco weed’, tutu as a potential toxic agent.
Tutu is the a common name of Mäori origin for plants in the genus Coriaria that are native to New Zealand.

Currently, Cheri is assessing the potential of tutin as a new rat and possum toxin.

“Any potential new toxin should ideally have a low secondary poisoning risk, particularly for native wildlife, breakdown quickly in the environment, have an antidote, be humane in use and, importantly, be accepted by the local community,” she said.

Cheri had no intention of being a scientist before she went to university.

“I wanted to be either a teacher or a cop! But I have a strong interest in environmental science and a strong connection to the resilience of the relationship between the environment and people. This became even more important to me since I’ve had my children and thought about the legacy I would be leaving for them,” said Cheri.

Cheri says that science itself is a way (a tool) for exploring those connections at a more refined/detailed level which can then assist local communities in their decision making around the management of their natural resources.

“ I’ve found science to be an interesting ‘filter’ to look at the natural world through. It offers another perspective for our people to consider, and when coupled with matauranga Maori, can be a very empowering form of information collection and evaluation.”

Cheri’s study is supervised by Dr Shaun Ogilvie, Director of Eco Research Associates Ltd, Dr James Ross and Professor Charles Eason from the Centre for Wildlife Management and Conservation at Lincoln University.

http://business.scoop.co.nz/2012/04/02/animal-pests-are-destroying-new-zealands-biodiversity/#respond

Shocking images: possums and stoats eat kea chicks

Cameras catch predators invading defenceless nests

November 2010: New evidence shows possums are eating New Zealand's native parrot, the kea. Researchers using nest-cameras have for the first time witnessed the gruesome reality inside defenceless kea nests invaded by stoats and possums in South Westland.

Brent Barrett, from the Department of Conservation, says large numbers of kea nests are failing in the wild but it is only now that camera equipment has been able to uncover what's going on.

‘We are just midway through the breeding season and of 11 nests we've had under surveillance three have been devastated by stoats and possums. That's a loss of six chicks.'

Mr Barrett said photos and videos have been posted on YouTube under the key words ‘possums eat parrots' so that people can see for themselves exactly what is going on in kea nests.


Grisly surprise to see such a prolonged and tormented death.
‘We have never been able to look at kea nests in this way before and it was a grisly surprise to see photos of a possum eating a nearly fledged kea and video showing the prolonged and tormented death of chicks attacked by stoats,' Mr Barrett said.

‘Possums have previously been filmed killing an adult kaka but until now we were completely unaware of their direct impact on kea nests,' he said. ‘This constitutes a huge risk to our lowland populations as nearly all of our nests are being visited by possums.'

Mr Barrett said it has been distressing to discover that just how long it takes chicks to die during a prolonged attack by stoats.

‘One attack lasted two-and-a-half hours with the stoat remaining in the recesses of the nest hole and repeating its assault on the two dying chicks. One chick died at the end of the torment but the other lived for 40-hours with its injuries before disappearing. The mother was also injured.'

The stoat predation footage was captured at a nest south of Fox Glacier and the possum was photographed in Okarito Forest.

This is what happens when predators are not controlled

‘The YouTube footage is unpleasant stuff to watch, but it shows what's going on in places where predators are not controlled,' Mr Barrett said.

The kea research team is monitoring nests in the Okarito Forest and in the area from the Copland Valley to the Paringa River, south of Fox Glacier. These areas are steep and thickly forested making it difficult to track wild kea and carry camera equipment and large batteries around in.

‘We are all relieved that the effort is worth it, but saddened by the graphic nature of what we have found,' Mr Barrett said.

Researchers are also monitoring trees for signs of excessive fruiting which would trigger a chain of events starting with a rat plague and ending with a plague of stoats.

‘We are still in the process of gathering this information, but at the moment it looks like we may have a moderate rimu fruiting coming up,' Mr Barrett said.

http://www.wildlifeextra.com/go/news/kea-possum.html