What is a “Native Species?” – A feral stray Australian?
Many of environmental concerns of outdoor recreationists hinge around the preoccupation of DOC, councils, and other agencies, in preserving “native species” (often at the expense of acclimatised/exotic species), and the methodologies used to do this. An ethnic cleansing mentality often dominates. These attempts to recreate the mythical year of 1769 (Cook’s arrival), or c1250 (initial Maori settlement), ecosystems are often based on the belief that ecosystems are, or were, static entities.
New Zealand agencies define native species as those which have evolved “on shore” or have self-introduced since the “Gondwanaland continental break up”. No assistance by man is the other aspect of their definition.
Our advocates for natives however have “Poster Species”. The Kauri however is a native of Queensland and New Guinea. Podocarps, which include Rimu, Kahikatea and Totara, are part of a plant family found from Indochina and the Philippines, across Australasia to South America. Our species were no doubt gifted to us when we broke free from Australia c70 million years ago but may in fact be later arrivals. The Southern beech family have a similar distribution.
Manuka is also a native of Australia. The Sophora (Kowhai) are found from South East Europe across southern Asia to Australia, New Zealand and the Americas. Most of our sea birds are also shared with other countries notably the southern black backed gull; probably the most widespread vertebrate in the southern hemisphere after humans and the house mouse. Our iconic hawk is correctly known as the Australasian Hawk.
Many fishers and hunters rightly bristle when “chardonnay conservationists”, and some farming hierarchy, blame trout for the demise of “native” species (and even for the waterway pollution near dairy pastures). The whole basis of “ecology” is that it involves a whole raft of biological systems in dynamic equilibrium.
Native fish face far greater threats from habitat destruction, the effects of excessive water abstraction, glyphosate (and other extensively used herbicides disrupting their food chains), excess nitrates and phosphates in run-off, industrial poisons and human waste, all entering their habitat. The “extinct” grayling still occurs in Australia and as an amphidromous species could well have swum the Tasman originally to get here. It had largely disappeared in New Zealand before introduced trout and salmon entered their rivers.
In simple English, all species within biological systems are constantly changing and adjusting to both environmental variations, and to changes within interacting species.
Classic deliberate introductions by humans include our common earthworms, bees, oaks, eucalyptus species, rye grass, wheat, canola, Pinus radiata, kiwi fruit, blackbirds, sparrows, chickens, goats, sheep, cattle, deer, opossums and mustelids (ferrets, stoats and weasels), etc., therefore they can never get “native” status. The opossums and mustelids were actually deliberately imported by past governments.
The protected colony of white herons in South Westland is not a unique remnant of a population that once roamed widely, but a relatively recent “invasion” from Australia; like so many of our native birds. The strong winds and sea currents of the Tasman Sea are primarily from the west to east. They bring us numerous surprises.
In 2012 Australian pelicans were reported from Northland to Taranaki; up to 18 at a time. This phenomenon of uninvited Australian immigrants is not unusual, but once here they become “natives”. Their favourite food is listed as the native kahawai, also present in/around Australia where it is sold as “Australian salmon”.
Other 21st Century refugees from Australia include the plumed whistling ducks, royal spoonbills, and gull-billed terns. In the 1970s spur-winged plovers appeared in Southland following strong trans-Tasman winds. They spread rapidly throughout the country predating on many small bird species, including natives. They are now major bird-strike worries for our airports.
The common white/silver/wax-eye first made an appearance on the West Coast after a period of high winds in the 1800s. It obviously thrived and is now a nationwide “native”. The common white-faced heron is also an “Aussie” refugee. The black swan was re-introduced from Australia to replace the closely related black swan which was hunted to extinction. There are also 20th Century records of the Australian black swan self-introducing itself to Aotearoa.
Our iconic swamp hen, the pukeko, has only been here about as long as Maori. The first colonists supposedly rafted across on flood debris from South East Australia where it is quite common. Remnants of a ship which ran aground, was abandoned in S. E. Australia in 1855, and then floated across the Tasman Sea ended up at Ship Creek on the West Coast. The pukeko’s potential rafting journey is thus not too unreasonable. There may well have been several such pukeko introductions. They arrived in Australia from New Guinea about a thousand years ago. This species is also present in a wide range of Pacific Islands and some Maori tribal traditions, including Aotea, claim that they introduced it to NZ on the Horouta Waka. Despite the lack of clear evidence either way it is classed as a native. Its presence on the Kermadec and Chatham Islands poses interesting questions however.
The native long finned eel is also present in Australia from whence it probably strayed. Several of our other freshwater species have very close relatives across the ditch also, as do many arthropod species. The common galaxiid (inanga or whitebait) occurs across the southern hemisphere including S.E. Australia. This brings us back to the definition of a native. Is it just a feral stray Australian refugee?
In recent years many species have “hitched” a ride here and become established. Some came attached to ships, planes, etc., and some in imported goods. None of them asked to come here. Why are the actions, and their consequences, of humans classed as unnatural?
Does this go back to the old creationist religious doctrine that man was created in God’s image so is somehow extra special? Tell that to the next great white shark who happily eats a human. Perhaps this is why “pest control” is often pursued with such a “religious fervour”.
In 1824 the flax trading (and former convict transport) brig “Elizabeth Henrietta” ran aground on Ruapuke Island in Foveaux Strait. The ship’s mice scrambled/swam ashore. They may only have swum a few metres, rather than the whole Tasman Sea, but they were not placed there by man. It was our first recorded introduction of mice. Ship rats probably swam ashore from Cook’s ships in 1769 and Norway rats from the first whalers in the Bay of Islands only a decade or so later.
These species are blamed for the decline of some native plant and animal species, but how different is that from the introductions of pukeko (which possibly displaced both takahe and kakapo), or the spur winged plovers, or even the long finned eel?
Current concern is with myrtle rust affecting pohutukawa trees, but it is a natural introduction carried on the trans-Tasman winds. Does that not make it a “native”?
The dynamic equilibrium of 1769 is interesting in that Maori had already been in residence for over 500 years. As cohabiters they had the kiore (Polynesian rat) and the kuri (dog). Both rats and dogs are blamed for the decline of many native birds, yet kiore and kuri had reached a balanced equilibrium with native species by this time. Most bird species now classed as endangered did not decline rapidly until Europeans arrived. Maori, with the kiore and kuri, had done most of their damage several hundreds of years earlier.
The comparison between c1250 and post 1769 is interesting in itself. Several publications have covered studies comparing the browsing of Moa, prior to their disappearance in the 15th century, with the current browsing by deer. Moa browsing can be determined by their coprolites (fossilised faeces). Plant species consumed by deer and Moa are almost identical in species composition and preference.
A logical conclusion is that the plant species regime in the NZ bush from c1500 to 1769 changed dramatically after the removal of the Moa and that deer have simply reversed that change. This is simplistic but has a huge element of logic and evidence to support it as an example of the dynamic equilibrium.
The reality is that the destruction of so-called native habitats by humans is the primary cause of endangered species plight. Almost all of New Zealand’s habitat destruction has been in the interests of farming and the associated service-centred urbanisation. The “Pest Free NZ” initiative is a deliberate diversionary tactic to deflect criticism from farming and industrial practices. Predators have an important role in every ecosystem yet we are indoctrinating our children to believe that we need a “predator free New Zealand. It is just one step further for an “exotic free NZ”. The most invasive exotic is Homo sapiens. Biology textbooks are full of examples of weird species composition dynamics that result from predator removal.
We need to be vigilant about every attempt to demonise exotics. Such demonising actions are diversionary. The decline of native trees, birds, frogs, bats, whitebait, tuna (eels), mud fish, and other aquatic and terrestrial mahinga kai is primarily the result of habitat destruction. The presence of “pest” exotics is usually a factor in habitats so degraded or mismanaged by urban sprawl and farming activities that they are at a tipping point. Attacking the predator, or a particular exotic, species is like blaming race horse for its jockey’s lack of skill.
If we took trout, as an example, out of an aquatic ecosystem today we would trigger another round of dramatic species composition adjustments. Bullies and aquatic invertebrates may initially appear to benefit. The losers would be native eels, terns, gulls, koura and cormorants, etc., that feed on juvenile trout and salmon and their ova. So when can a species be considered native? To say “never” if it is human assisted, is to ignore the values of the current reasonably stable non-agricultural or non-urbanised ecosystems.
New Zealand needs to seriously reconsider its preoccupation with pre c1250 environments and look more at focussing on preserving the whole habitat of those species with cultural values (both Maori and Pakeha), or of biodiversity importance, whether they be “native” or not. Both Maori and subsequent migrant ethnicities are “exotics”.
The microscopic organisms and “creepy looking” invertebrate species deserve as much consideration as our attractive native trees and “pretty” native birds. We have to get away from the nature study approach of trying to save nature one species at a time and focus on whole habitats. Many native bird species happily nest in exotic trees. These habitats will in the 21st Century naturally be a mixture of so-called natives and exotics. We need to ignore the King Canutes of native fauna and flora purity. We cannot recreate that snapshot of our environment that people paint of pre-human times; unless we plan to remove all the people, bees and earthworms too.
Rex N. Gibson
Rex is an Ecologist and a spokesperson on environmental issues for the New Zealand Federation of Freshwater Anglers Inc.