All over the world, local natural ecosystems are vulnerable to invasion by plants, animals or microbes that originated somewhere else, having evolved in a different ecosystem, with checks and balances imposed there by the other components of that system.
It is difficult to predict which species, having been imported to Norfolk Island on purpose or accidentally by human carriers, are likely to become obnoxious in their new home. Many horticultural introductions such as Hibiscus stay within the confines of the owners’ gardens, but others such as Formosan Lily spread out of control and compromise bushland or roadsides. Norfolk Island’s landscapes have been badly compromised in particular by Hawaiian Holly (Broad-leaved Pepper to Australians), Porpieh (Cherry Guava to Australians) and African Olive. Yet only in a couple of places have the eucalypts spread beyond their plantings.
It is of course far easier to eliminate an invasive species at an early stage of its spread than to wait until it is well-established. Two important clues:
To answer these questions, keen observation and skills in identification are required. For example, Broad-leaved Privet is a serious pest in the hinterland of Brisbane and has the potential to be a serious pest here, but is little-known on the Island because it is not yet widespread!
Explanation of terms
Indigenous or native refers to a species that was certainly or presumably present on Norfolk Island prior to human settlement. (On mainland Australia, indigenous and native have different meanings. Indigenous refers to originally present at a locality, native refers to a species found somewhere on the Australian continent, but not (or not necessarily) at the precise locality. Many ornamental species such as Cootamundra Wattle or Red Flowering Gum are planted widely beyond their indigenous range. Given the small size of Norfolk Island, there is no need to differentiate between these terms here). Many birds such as shearwaters are indigenous to the Island but are also found widely across the region.
Endemic refers to an indigenous species that is not known to be naturally occurring anywhere else on the planet. Norfolk Island Pine is an endemic species.
Introduced, alien or foreign refers to a species that was not known to be on Norfolk Island (or Nepean or Phillip Islands) prior to human settlement. Starlings are an example, as is Kikuyu grass.
Invasive species are introduced species that spread or propagate without human action and compromise native ecosystems or human enterprises. Rats, cats and the noxious weeds are examples.
In 2017 Australia’s Invasive Species Council (with Island Conservation) issued a benchmark report on Norfolk Island’s biosecurity (left cover) and highlighted just how weak the controls were. The press release on 20 November 2017 issued a call to action by the Australian Government. These initiatives followed the earlier biosecurity benchmark report coordinated by Island resident Dr Glynn Maynard.
The Weeds Handbook_NIQS_2014 (right cover) has descriptions and photos of some 50 species of plant that threaten Norfolk’s bush or home or commercial gardens.
Invasive marine species
Dr Ashley Coutts from specialist consultancy Biofouling Solutions has supplied a copy of a recent presentation IMS Survey (2.2MB) to the Society. The team of specialist marine scientists discovered shells of two alien species, Japanese Oyster (Magallana gigas) and New Zealand Greenshell Mussel (Perna canaliculus), with question marks over two other species.
Dr Coutts has advised that it is “Vital that any future changes to port infrastructure incorporates effective biofouling management measures.” Yachties also please note that it is vital that you check your vessel frequently to avoid bringing alien marine passengers to our shores.