Invasive Species
A conference was held at the University of Auckland on 19 to 23 February 2001 by the Invasive Species Specialist Group of the IUCN Species Survival Commission.
Eradication of Island Invasives: Practical Actions and Results Achieved includes 37 pages of abstracts of papers and posters presented at the conference.
The Pest Management Strategy 2021-2026 was produced by the Norfolk Island Regional Council to guide its operations.
The honey bee population on Norfolk Island is unique from a pest and disease perspective. No other honey bee population in the world has fewer pests and pathogens. This important finding was confirmed in 2022 by a survey by Dr John Roberts of CSIRO. The report recommended that ongoing surveillance in Norfolk Island as part of the National Bee Pest Surveillance Program be resourced. Read the report here. The report can also be found on the Department’s website: Norfolk Island bee pest survey 2021–2022. The Department has summarised the results as follows:
“Honey bees are an important part of the ecosystem and culture of Norfolk Island. Honey bees support food security through reliable pollination services as well as producing honey and hive products. Having access to up-to-date information on bee pests and diseases is critical to maintaining the Island’s bee biosecurity.
In December 2022 and April 2023, Dr John Roberts visited Norfolk Island to conduct surveys of the honey bee population. Under the guidance of Norfolk Island’s beekeepers, Dr Roberts collected samples from bees, honey and hives to test for pests and diseases. He sampled 67 bee colonies (approximately 50% of all managed colonies) and inspected and tested for 16 pests and diseases.
The key findings of the survey are:
The report made three recommendations:
In 2012-2014 the Department of Agriculture conducted a comprehensive survey of the plant and animal pests and diseases of the Island, coordinated by resident Glynn Maynard. The report is publicly available.
Supporting data
The data amassed during the survey have been published open access as appendices to the following paper:
Maynard, G V, B J Leschi and S F Malfroy. 2018. “Norfolk island quarantine survey 2012-2014 – a comprehensive assessment of an isolated subtropical island“. Proceedings of the Linnean Society of New South Wales Vol. 140: 7-243.
Madeira Vine (Anredera cordifolia) is a South American invader with bright green fleshy leaves and tubers growing both underground and at nodes along the trailing stems. There are numerous patches within the Hundred Acres reserve. The first photo is of a new patch heading up the nearest tree.
Once established, manual control is a painstaking task that must be repeatedly frequently to remove freshly sprouted bulbils before their tendrils generate strings of new ones. Also, it is very easy to mistake the worthy native spinach Tetragonia for Madeira Vine. In the second photo, a spinach is peeking out from the Madeira vine near the stick.
For several years the Flora and Fauna Society offered a reward for collection of stems of the introduced Formosan Lily. These lilies are a very invasive weed and in some places, infestations have totally precluded any native species from continuing to thrive in their native habitat. They will grow in sun and shade, in wet and dry conditions, and on flat land, slopes and steep cliffs.
Windy conditions are perfect for the ripened seed pods to disperse their thousands of seeds.
A number of parents have expressed concern at the number of lilies, making it easy for their little collectors to see the purpose and so to get great results. We hope this results in a better understanding as to why this problem needs to be tackled soon in a strategic manner across the Island. If we allow all the soil and water, sun and shade to be used by white lilies that don’t belong here, we are denying the natives the ability to survive in the only place they know, and belong.
Members understand that we are not removing the problem, but are simply reducing the size of the population, which has the potential to expand exponentially if left unchecked.
If we are to preserve the island’s all-important native plants we need to make sure they have some space to grow. Without the native plants, we could lose our native insects and our unique bird species and the wonderful experiences we all enjoy through being in our precious environment.
Corms of Formosan Lily
Results
We have had fantastic results from our collectors in the three years 2017-2019. The project offered a bounty for Formosan Lilies collected in bundles of 50. Bounty 10c per stem + prizes of $100, $50 and $75 for the most stems collected.
In the summer season 2016-2017, a total of 257 bundles @ 50 stems bringing to a total of 12,850 plants were collected. With only a single flower per plant this has prevented the spreading of notionally at least 15,420,000 new plants. With some plants having been seen to have 12 flowers the potential increases to 805,040,000! Thanks so much to the collectors and their support teams for participating in this important project.
There was again a fantastic response in the 2018 Great Lily Hunt, resulting in the prevention of a possible 383+ million seeds germinating to make new plants. Due to the wet weather conditions at the time of the collection, some participants were also able to easily remove the bulbs along with the stems, making it a wonderful bonus number of possible future plants now not in the landscape.
In 2019 Society representatives, Liz Nobbs-Hewson and Bev Buffett presented certificates and cheques to students who participated in the Hunt. Total prize money was $4362.50, made up of a Community Grant from Norfolk Island Regional Council of $2500 with the balance of $1862.50 funded by Norfolk Island Flora & Fauna Society. Over 40,000 Formosan Lily plants were collected, preventing at least 86 million new plants being produced. Another fantastic effort!
In 2020 $5715 was paid in prizes. The Society thanks Norfolk Island Rotary and Foodlands for $2500 each in sponsorship.
Seeds of Formosan Lily
In 2021 the Society decided to review the project seek to have it mainstreamed into the official work program of the Council.
Raw ingredient of tasty jam and jelly on the Island, and free of the fruit fly that in Australia beats humans to the ripening fruit, it has another valuable use. The timber is durable and widely used for tool handles and garden stakes. Yet Norf’k could do without this pest. From small bushes to dense thickets where it grows tall and straight, it is ubiquitous on the Island.
African Boxthorn, Lycium ferocissimum, is a Weed of National Significance in mainland Australia. It’s a localised nuisance on Norfolk Island. Spines thick enough to penetrate car tyres can inflict painful puncture wounds in human flesh.
The photograph of Boxthorn covering slopes on the the Hundred Acres Reserve demonstrates both its ability to smother all desirable vegetation and also the need for very careful planning of control measures. Abrupt removal of the boxthorn would run the risk of irreversible soil erosion. However, boxthorn also tends to suppress the growth of grasses nearby and grasses are very good for protecting the surface of the soil from raindrop and wind erosion.
Myrtle Rust is a fungal pest that slipped through Australia’s weak biosecurity defences. In 2017 Australia’s Invasive Species Council published a note about its arrival on Norfolk Island and on 17 May 2017 issued a press release:
“Over the past six months myrtle rust has been detected on both Lord Howe Island and Norfolk Island. Australian authorities have responded poorly to both outbreaks.
On Lord Howe Island, Lord Howe Island Board staff swung quickly into action to try to eradicate infected plants but received little support from the NSW government’s primary industry and environment departments beyond advice. Lord Howe Island Board staff had to rely on their own limited resources because myrtle rust is now considered “endemic” in NSW.
On a recent visit to Norfolk Island our CEO Andrew Cox discovered that myrtle rust had been found on planted rose apples (Syzygium jambos) six months ago. No public information about the detection has been released, and the federal agriculture department is still determining a response. The new Norfolk Island Regional Council seemed unaware of the arrival. Thankfully there are no native myrtles on the island.
Myrtle rust outbreaks on these two iconic islands should have been prioritised at state and federal levels. Once established, the rust could spread to other offshore islands and possibly to mainland New Zealand. Last month myrtle rust was found at Raoul Island, about 1000 km northeast of New Zealand and a similar distance east of Norfolk Island.”
Norfolk Island Conservation Volunteers (NICV) was formed in July 2020 under the auspices of the Norfolk Island Flora & Fauna Society Inc., and with the support of Norfolk Island Regional Council and Norfolk Island National Park.
The Coral Berry Crusade
The first NICV project, and the only project to date, has been tackling a heavy infestation of the very invasive coral berry (Rivina humilis) in 100 Acres Reserve. This South American native had established itself in the reserve over many years, and had become the dominant ground cover. Quick-growing and with numerous very hardy seeds produced per plant, its dominance was affecting other native ground cover, and also the slower growing seedlings of native trees and bushes, out-competing them for space, light, water and nutrients.
In its first year, NICV was able to make one full sweep through the reserve and was well into its second or in some spots, third sweep, aiming to catch the coral berry before fruiting and thus progressively exhaust the seed bank. This strategy has been extremely successful so far, with coral berry now replaced by a delicate native herb, Parietaria debilis, as the dominant ground cover. Prior to this, P. debilis had become very scarce in the reserve.
In addition to coral berry, NICV has been pulling up other known weeds as encountered. These have included African boxthorn, silky oak, lantana, tomato, guava, ochna, cape gooseberry, black olive, Hawaiian holly, Morning Glory vine, Madeira vine, chickweed and milkweed.
As the work on coral berry now appears to be approaching maintenance phase, NICV is discussing options of extending into other reserves and the National Park, or remaining in 100 Acres but becoming more systematic in tackling the other weed species found there.
