The Lord Howe Island Group is a group of
islands of volcanic origin in the Pacific Ocean. These
islands are located around 700 km northeast of Sydney.
The islands of the group were discovered in 1778, and
they were inscribed as a World Heritage Site in 1982.
In 2007 the Lord Howe Island Group was also added
to the National Heritage List, in recognition of the
significance of its national heritage. The island is home
to a large number of endemic animal and plant species,
some of which are endangered. The islands support a
large nesting colony of sea birds. A number of species
recorded in the region are endangered or rare. The
waters surrounding the islands have a unique mixture
of both tropical and temperate species. Besides, the
reef present in the particular site is the southernmost
coral reef in the world, and it is a very rare example of
the transition between algal and coral reefs. The major
threat to the biodiversity in the region is the impact
of some invasive species. These invasive species were
brought to this region after the first human settlement
was established.
The Lord Howe Island Group is situated off New
South Wales, Australia (location- S310 33 56 E1590 5 18).
This is a group of irregularly crescent-shaped islands in
the Tasman Sea, between Australia and New Zealand.
Lord Howe Island is situated 700 km off the east coast
of Australia, in the Pacific Ocean. The islands of this
group are examples of isolated oceanic islands that
originated due to volcanic activities that occurred 2000
m under the sea. Lord Howe Island is built adjacent
to the boundary between two major physiographic
features of the region, the Lord Howe Rise and the
Tasman Basin.
Apart from Lord Howe Island itself, the group has several smaller islands (including Admiralty Islands, Blackburn (or Rabbit) Island, Mutton Bird Island, Gower Island and Ball's Pyramid) (Auld & Hutton 2004). The site provides important breeding grounds for colonies of sea birds and a habitat for conserving threatened species. The site is a habitat for many endemic species, such as the flightless Lord Howe woodhen (Gallirallus sylvestris), once known as one of the rarest birds in the world, and the Lord Howe Island phasmid (Dryococelus australis), the world's largest stick insect, which was feared to be extinct until its rediscovery on Ball's Pyramid. A rare combination of Australian, New Zealand, and New Caledonian floral elements is seen in the Lord Howe Island Group (Green 1994). The flora of this region shows a high level of endemism, and they form floristic assemblages unique to this island group.
The five plant genera endemic to the site are Negria, Lordhowea and three palm genera, Howea, Hedyscepe and Lepidorrachis.The diversity of invertebrates of the site is rich. Around 1600 species have been recorded, including 157 land and freshwater snails, 515 beetles, 27 ants, 183 spiders, 21 earthworms, 137 butterflies and moths and 71 springtails. The level of endemism in this region is high. A large number of invertebrate species from the region have been listed as endangered (for example, the Lord Howe flax snail (Placostylus bivaricosus), the earthworm Pericryptodrilus nanus, the Lord Howe Island wood-feeding cockroach (Panesthia lata) and the Lord Howe Island phasmid (Dryococelus australis).
The Lord Howe Island Group is grandiose in its
topographic relief and has an exceptional diversity of
spectacular and scenic landscapes within a small area,
including sheer mountain slopes, a broad arc of hills
enclosing the lagoon and Balls Pyramid rising abruptly
from the ocean. It is considered to be an outstanding
example of an island system developed from submarine
volcanic activity and demonstrates the nearly complete
stage in the destruction of a large shield volcano. Having
the most southerly coral reef in the world, it demonstrates
a rare example of a zone of transition between algal and
coral reefs. Many species are at their ecological limits,
endemism is high, and unique assemblages of temperate
and tropical forms cohabit. The islands support extensive
colonies of nesting seabirds, making them significant
over a wide oceanic region. They are the only major
breeding locality for the Providence Petrel (Pterodroma
solandri), and contain one of the world's largest breeding
concentrations of Red-tailed Tropicbird (Phaethon
rubricauda).
The Lord Howe Island Group is an outstanding example of the development of a characteristic insular biota that has adapted to the island environment through speciation. A significant number of endemic species or subspecies of plants and animals have evolved in a very limited area. The diversity of landscapes and biota and the high number of threatened and endemic species make these islands an outstanding example of independent evolutionary processes.
Lord Howe Island supports a number of endangered endemic species or subspecies of plants and animals, for example the Lord Howe Woodhen, which at time of inscription was considered one of the world's rarest birds. While sadly a number of endemic species disappeared with the arrival of people and their accompanying species, the Lord Howe Island Phasmid, the largest stick insect in the world, still exists on Balls Pyramid. The islands are an outstanding example of an oceanic island group with a diverse range of ecosystems and species that have been subject to human influences for a relatively limited period.
The major threats to this region are the
introduction of new pests; invasions of weeds; habitat
clearing and modification; trampling, browsing and
grazing by domestic stock; and climate change (Brown
and Baker 2009). The exotic species are spread in
the island followed the human settlement, and has
catastrophic effect on the native biota (Hutton et al.
2007).
Fishing and increasing tourism are increasing the pressure on the region. The major threat to the vascular flora of the region is the introduction of foreign species that eventually become naturalized. Such invasive species found here include Psidium cattleianum, Pittosporum undulatum, Chrysanthemoides monilifera, Ageratina adenophora, Asparagus aethiopicum, Asparagus plumosus and Lilium formosanum. These serve as the biggest threat to the vascular flora of the region. Phytophthora cinnamomi is a widespread exotic pathogen species that is severely impacting plant communities across various environmental ranges (Environment Australia 2001).
Two invasive rodent species, the house rat (Mus musculus) and the ship rat (Rattus rattus), pose a serious threat to the biodiversity of the region. These species have caused the extinction of around 20 species of bird, invertebrate and plant (Wilkinson & Priddel 2011). Many measures have been taken by the authorities to eradicate the population of rodents in the region.The site faces threats from climate change, rising oceanic temperatures and the increase in marine debris.
There are other threats to the marine environment that are beyond the control of the local authorities. These require both national and international responses. Coral bleaching is one of the impacts of climate change in the region, and it is likely to worsen in the future with rising oceanic temperatures. The Lord Howe Island Board, under the statutory framework of the Lord Howe Island Local Environment Plan (2010), handles the onground management of the terrestrial component of the property.
