An ecological island is a term used in

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...

, and increasingly in Australia, to refer to an area of land (not necessarily an actual island) isolated by natural or artificial means from the surrounding land, where a natural micro-habitat exists amidst a larger differing

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syst ...

. In

the term is used to refer to one of several types of nationally protected areas. In artificial ecological islands (also known as mainland islands): * all non-native species (at least

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

species) have been eradicated, * native species are reintroduced and nurtured, and * the natural or artificial border is maintained to prevent reintroduction of non-native species. The ultimate goal is to recreate an ecological microcosm of the country as a whole as it was before human arrival. There is usually provision for controlled public access, and scientific study and research. The definition does not include land within a fence erected to: * protect farm animals from wild predators * protect a specific species from specific predators * exclude farm animals only * exclude native animals (although some native animals,

weka The weka, also known as the Māori hen or woodhen (''Gallirallus australis'') is a flightless bird species of the rail family. It is endemic to New Zealand. It is the only extant member of the genus '' Gallirallus''. Four subspecies are recog ...

for example, may need to be excluded during a species' recovery phase).

Background

The concept of mainland islands was pioneered in

and arose mainly from the particular circumstances of that country's history. For millions of years New Zealand was part of the supercontinent Gondwanaland, which included Australia,

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

, and shared the same

flora Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...

and

fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as ''biota''. Zoo ...

. About 70 million years ago New Zealand became separated, earlier than Australia, South America and Antarctica. About five million years later non-avian

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s became globally extinct leaving the way open to mammals to dominate - except in New Zealand where there were no land mammals (only 3 species of bats and seals). In the absence of mammals,

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s became dominant. Evolutionary processes resulted in a unique assemblage of plants and animals, and New Zealand became a land dominated by birds. Without competition from browsing mammals, birds evolved to occupy niches that mammals occupied elsewhere. Threatened by few

s, many birds had no need to fly and many species became flightless. Birds, reptiles, plants,

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...

s, and bats, all evolved in the absence of terrestrial mammals, and have little defence against alien species. With human colonisation came many accidental or deliberate introductions of mammals and birds. These wrought havoc with native species and many became extinct, many others were reduced in range and number, with some teetering on extinction. Traditionally pacific rats (''Rattus exulans''), Norway rats (''Rattus norveigucus''), ship rats (''Rattus rattus'') cats, ferrets, stoats, and weasels were all considered to be the main culprits in the decline of native species of New Zealand birds, reptiles and insects. More recent information adds hedgehogs and mice to the list. These species have been introduced for a variety of reasons and some inadvertently. The effect remains the same: they have all contributed to the decline of native animals. Possums and deer did the same for the forest. However, New Zealand also includes many offshore islands, some of which contained species rare or extinct on the mainland because introduced pests could not reach them.

Offshore islands

Increasingly over the last hundred years, New Zealand's

Department of Conservation An environmental ministry is a national or subnational government agency politically responsible for the environment and/or natural resources. Various other names are commonly used to identify such agencies, such as Ministry of the Environment, ...

together with many volunteers have developed and perfected world-first methods of clearing some of these islands of all introduced pests, and

island restoration The ecological restoration of islands, or island restoration, is the application of the principles of ecological restoration to islands and island groups. Islands, due to their isolation, are home to many of the world's endemic species, as well as ...

, creating safe havens for the reintroduction of at-risk species, thereby saving them from extinction. These islands are also used to expand the range of rare species so that an ecological disaster on one island would not result in the total extinction of a species. As many species rebound in numbers in the absence of predators the islands act as species reservoirs enabling the periodic removal of some to create breeding colonies on other cleared islands, or on the mainland itself.

Fenced enclosures

Following the example of what had been achieved on offshore islands, groups of New Zealanders decided to create artificial ecological islands on the mainland so that the public could have easier access and learn what New Zealand looked and sounded like before human colonisation. There are excellent projects where alien species numbers are kept down by various methods other than a pest-exclusion fence or the coastline, but these are not generally described as ecological islands. Projects that do meet the criteria, or are aiming to, include: * New Zealand ** 1999

Zealandia Zealandia (pronounced ), also known as ( Māori) or Tasmantis, is an almost entirely submerged mass of continental crust that subsided after breaking away from Gondwanaland 83–79 million years ago.Gurnis, M., Hall, C.E., and Lavier, L.L ...

** 2004 Tawharanui Open Sanctuary ** 2005 Bushy Park ** 2006 Maungatautari Restoration Project ** 2007

Orokonui Ecosanctuary thumb Orokonui Ecosanctuary, called Te Korowai o Mihiwaka in Māori, is an ecological island wildlife reserve developed by the Otago Natural History Trust in the Orokonui Valley between Waitati and Pūrākaunui, New Zealand, to the north of ...

** 2009 Glenfern Sanctuary Charitable Trust ** 2011 Shakespear Regional Park ** 2016

Brook Waimārama Sanctuary The Brook Waimārama Sanctuary is a nearly 700 hectare mainland "ecological island" sanctuary located 6 km south of Nelson, New Zealand. The sanctuary is the largest fenced sanctuary in New Zealand's South Island and the second largest in ...

**Moehau Environment Group * Australia ** 2015 Nangak Tamboree Wildlife Sanctuary

Background

Offshore islands

Fenced enclosures

References

See also