Flora and fauna
[edit]
Plants[edit]
Box-shaped fruit of Barringtonia asiatica, SW Pacific washed up on Blinky Beach
Lord Howe Island is a distinct terrestrial ecoregion known as the Lord Howe Island subtropical forests. It is part of the Australasian realm and shares many biotic affinities with Australia, New Guinea, and New Caledonia. In geological terms at 7 million years old, Lord Howe Island is relatively young and was never part of any continent, its flora and fauna colonising the island from across the sea, carried by the wind, water, or birds, possibly assisted at a geological time when other islands were exposed, enabling island hopping. Nevertheless, it has been sufficiently remote for long enough to evolve endemic species.
Wedding flower (Dietes robinsoniana)
The high degree of endemism is emphasised by the presence of five endemic genera: Negria, Lordhowea, Howea, Lepidorrhachis, and Hedyscepe. Island plants are similar to those of Norfolk Island, the two islands sharing some endemic species, for example, the critically endangered species of creeping vine Calystegia affinis. The combined flora of these two islands is more closely related to that of New Zealand and New Caledonia than to that of Australia. Also, a small but clear link exists with the plants of Vanuatu. The closest mainland affinities are with the vegetation of subtropical southeastern Queensland. A link with Gondwanaland is indicated by the presence of endemic species such as the wedding lily (Dietes robinsoniana) whose only living relatives occur in South Africa.
The flora of the island is relatively untouched, with a large number of rare plants, 44% being endemic to the island. With a diversity of conditions ranging from valleys to ridges, plains, and misty mountain tops, habitat is available for a wide range of plant communities, which have been comprehensively analysed and mapped. Many of the island's unique plants grow on or around the mountain summits, where the height has allowed the development of a true cloud forest and many different microhabitats, from sea level to the summits. With the increased humidity brought by the clouds on Mount Gower and the other mountain tops, the range of endemic plants include mosses, ferns and flowering plants.
One of the best-known plant genera endemic to Lord Howe Island is Howea, an endemic genus of palms (Arecaceae) that are commonly known as kentia palms and are popular houseplants. Mosses include Spiridens muelleri. There are 57 species of ferns, of which 25 are endemic: they are most abundant in the moist environments of the southern island, especially the higher parts of Mount Gower, perhaps the most apparent being the four endemic tree ferns in the genus Cyathea that occur on the southern mountains. Hedyscepe and Lepidorrhachis are the other two palm genera that are also endemic to the island.
Since the rodent eradication program, researchers have observed an increase in the amount of growth and seeds, especially of the "larger, fleshy, fruited plants", previously eaten by rats. As the understorey grows thicker, this in turn will provide habitat for small animals such as snails and insects, which in turn provide food for the birds.
Number of different vascular plants
Total
Indigenous
Endemic
Naturalised
459
241
105 (43.6%)
218 (47.5%)
Communities and special plants[edit]
Little mountain palm (Lepidorrhachis mooreana) on the summit of Mount Gower
Plant communities have been classified into nine categories: lowland subtropical rainforest, submontane rainforest, cloud-forest and scrub, lowland swamp forest, mangrove scrub and seagrass, coastal scrub and cliff vegetation, inland scrub and herbland, offshore island vegetation, shoreline and beach vegetation, and disturbed vegetation.
Several plants are immediately evident to the visitor. Banyan (Ficus macrophylla subsp. columnaris) is a remarkable tree with a buttressed trunk and pendulous aerial roots; it can be seen on the track to Clear Place and near Ned's Beach. Pandanus tree (Pandanus forsteri) has spectacular teepee-like prop roots and pineapple-like fruits that are orange-red when mature, the tough leaves being used for basketry. It occurs in damp areas such as creek beds, and fine specimens can be seen along the Boat Harbour track. Ten species of orchids are on the island, the most noticeable being the bush orchid (Dendrobium macropus subsp. howeanum) on lowland trees and rocks, bearing cream flowers from August to September. Other prominent flowering plants in the summer include, on the mountain slopes, the whiskery red flowers of mountain rose (Metrosideros nervulosa and Metrosideros sclerocarpa), the massed, small, yellow flowers of corokia (Corokia carpodetoides), orange, plump flowers of pumpkin tree (Negria rhabdothamnoides), and white spikes of Fitzgerald tree (Dracophyllum fitzgeraldii). The kava bush has large, aromatic, heart-shaped leaves. After heavy rain, the endemic glowing mushroom Mycena chlorophanos, and Omphalotus nidiformis, can be found in the palm forests.
The palms are the signature plants of the island as the kentia and curly palms especially dominate the landscape in many places, the kentia being of special economic importance. All four species are endemic to the island, often occurring in dense, pure stands, the one that has proved such a worldwide success as an indoor plant being the kentia or thatch palm (Howea forsteriana). This is a lowland palm with drooping leaflets and seed branches in 'hands' of three to five, while the curly palm (H. belmoreana), which occurs on slightly higher ground, has upwardly directed leaflets and solitary 'hands'. Natural hybrids between these species occur on the island and a mature specimen of one is growing in the island nursery. On the mountain sides higher than about 350 m, the big mountain palm (Hedyscepe canterburyana) occurs; it has large, golf ball-sized fruits, while the little mountain palm (Lepidorrhachis mooreana) has marble-sized fruits and is only found on the mountain summits.
Images of native flora[edit]
Kentia palms
Curly palm
Lord Howe bird's nest fern
Asplenium milnei
Lagunaria patersonia
Animals[edit]
No snakes nor poisonous or venomous animals or plants occur, and no dangerous daytime sharks are found off the beaches, although tiger sharks have been reported on the cliff side of the island.
Birds[edit]
Sooty terns are the most abundant breeding seabirds and are common along the east coast.
A total of 202 different birds have been recorded on the island. Eighteen species of land birds breed on the island and many more migratory species occur on the island and its adjacent islets, many tame enough that humans can get quite close. The island has been identified by BirdLife International as an endemic bird area, and the Permanent Park Preserve as an important bird area because it supports the entire population of Lord Howe woodhens, most of the breeding population of providence petrels, over 1% of the world population of another five seabird species, and the whole populations of three endemic subspecies.
Fourteen species of seabirds breed on the island. Red-tailed tropicbirds can be seen in large numbers circling the Malabar cliffs, where they perform acrobatic courting rituals. Between August and May, thousands of flesh-footed and wedge-tailed shearwaters return to the island at dusk each day. From the Little Island Track between March and November, one of the world's rarest birds, the providence petrel, also performs courtship displays during winter breeding, and it is extremely tame. The island was its only breeding location for many years after the breeding colony on Norfolk Island was exterminated in the late 19th century, though a small population persists on the adjacent Phillip Island. The Kermadec petrel was discovered breeding on Mount Gower in 1914 by ornithologist Roy Bell while collecting specimens for Gregory Mathews and the black-winged petrel was only confirmed as a breeder in 1971; its numbers have increased following the elimination of feral cats from the island.
Black noddy on North Beach
The flesh-footed shearwater, which breeds in large numbers on the main island in spring-autumn, once had its chicks harvested for food by the islanders. The wedge-tailed and little shearwaters breed on the main island and surrounding islets, though only a small number of the latter species can be found on the main island. Breeding white-bellied storm petrels was another discovery by Roy Bell. Masked boobies are the largest seabirds breeding on Lord Howe and can be seen nesting and gliding along the sea cliffs at Mutton Bird Point all year round. Sooty terns can be seen on the main island at Ned's and Middle Beaches, North Bay, and Blinkey Beach; the most numerous of the island's breeding seabirds, their eggs were formerly harvested for food. Common and black noddies build nests in trees and bushes, while white terns lay their single eggs precariously in a slight depression on a tree branch, and grey ternlets lay their eggs in cliff hollows.
Three endemic passerine subspecies are the Lord Howe golden whistler, Lord Howe silvereye, and Lord Howe currawong. The iconic endemic rail, the flightless Lord Howe woodhen, is the only surviving member of its genus; its ancestors could fly, but with no predators and plenty of food on the island, this ability was lost. This made it easy prey for islanders and feral animals, so by the 1970s, the population was less than 30 birds. From 1978 to 1984, feral animals were removed and birds were raised in captivity to be successfully reintroduced to the wild. The population is now relatively safe and stable.
Domestic Mallards have colonised Lord Howe Island from New Zealand. They have replaced the Pacific Black Duck through competition and introgressive hybridisation.
List of endemic birds[edit]
Lord Howe silvereye (Zosterops lateralis tephropleurus)
Lord Howe currawong, Strepera graculina crissalis (vulnerable, subspecies of pied currawong)
Lord Howe golden whistler, Pachycephala pectoralis contempta (least concern, subspecies of golden whistler)
Lord Howe silvereye, Zosterops lateralis tephropleurus (vulnerable, subspecies of silvereye)
Robust white-eye, Zosterops strenuus (extinct)
Lord Howe gerygone, Gerygone insularis (extinct)
Lord Howe fantail, Rhiphidura fuliginosa cervina (extinct, subspecies of NZ fantail)
Lord Howe starling, Aplonis fusca hulliana (extinct, subspecies of extinct Tasman starling)
Lord Howe thrush, Turdus poliocephalus vinitinctus (extinct, subspecies of Island thrush)
Lord Howe parakeet, Cyanoramphus subflavescens (extinct)
Lord Howe boobook, Ninox novaeseelandiae albaria (extinct)
Lord Howe woodhen, Hypotaenidia sylvestris (endangered)
Lord Howe swamphen, Porphyrio albus (extinct)
Lord Howe pigeon, Columba vitiensis godmanae (extinct)
Mammals, reptiles and amphibians[edit]
Skeleton of the horned turtle Meiolania platyceps, once native to Lord Howe
Only one native mammal remains on the islands, the large forest bat. The endemic Lord Howe long-eared bat is known only from a skull and is now presumed extinct, possibly the result of the introduction of ship rats.
Two terrestrial reptiles are native to the island group: the Lord Howe Island skink and the Lord Howe Island gecko. Both are rare on the main island, but more common on smaller islands offshore. The garden skink and the bleating tree frog have been accidentally introduced from the Australian mainland. During the Pleistocene the giant terrestrial horned turtle Meiolania platyceps was endemic to the island, but this is currently thought to have gone extinct before human occupation as a result of postglacial sea-level rise.
Invertebrates[edit]
Lord Howe Island stick insect
The Lord Howe stick insect disappeared from the main island soon after the accidental introduction of rats when the SS Makambo ran aground near Ned's Beach on 15 June 1918. In 2001, a tiny population was discovered in a single Melaleuca howeana shrub on the slopes of Ball's Pyramid, has been successfully bred in captivity, and is nearing re-introduction to the main island.[needs update] The Lord Howe stag beetle is a colourful endemic beetle seen during summers. Another endemic invertebrate, the Lord Howe flax snail (or Lord Howe Placostylus), has also been affected by the introduction of rats. Once common, the species is now endangered and a captive-breeding program is underway to save the snail from extinction. An endemic species that is likely to have become extinct due to human-introduced rats was the large rove beetle Hesperus gigas (Lea, 1929) comb. nov. (formerly Cafius gigas Lea, 1929) (Coleoptera: Staphylinidae). The Lord Howe Island wood-feeding cockroach (Panesthia lata) was thought extirpated from the island until a small population was found.
Marine life[edit]
Surge wrasse swimming in the waters of Ned's Beach
Marine environments are near-pristine with a mixture of temperate, subtropical, and tropical species derived from cool-temperate ocean currents in the winter and the warm East Australian Current, which flows from the Great Barrier Reef, in summer. Of the 490 fish species recorded, 13 are endemic and 60% are tropical. The main angling fish are yellowtail kingfish and New Zealand bluefish, while game fish include marlin, tuna, and giant kingfish called "greenbacks". Over 80 species of corals occur in the reefs surrounding the islands. Australian underwater photographer Neville Coleman has photographed various nudibranchs at Lord Howe Island.
Various species of cetaceans inhabit or migrate through the waters in the vicinity, but very little about their biology in the area is known due to a lack of studies and sighting efforts caused by locational conditions. Bottlenose dolphins are the most commonly observed and are the only species confirmed to be seasonal or yearly residents, while some other dolphin species have also been observed. Humpback whales are the only large whales showing slow but steady recoveries as their numbers annually migrating past the island of Lord Howe are much smaller than those migrating along the Australian continent.
Historically, migratory whales such as blue, fin, and sei whales were very abundant in the island waters but were severely reduced in numbers to near-extinction by commercial and illegal hunts, including the mass illegal hunts by the Soviet Union and Japan in the 1960s to 1970s. Southern right and sperm whales were most severely hunted among these, hence the area was called the Middle Ground by whalers. These two were likely once seasonal residents around the island, where right whales prefer sheltered, very shallow bays, while sperm whales mainly inhabit deep waters.
Images of native fauna
Providence petrels on the summit of Mount Gower
Woodhen by Neds Beach Road
Masked booby with chick viewed off Malabar cliffs
Coral skeleton on Little Island Beach
Conservation[edit]
Lord Howe white-throated pigeon (Columba vitiensis godmanae) painted by George Raper, 1790 – now extinct
About 10% of Lord Howe Island's forests have been cleared for agriculture, and another 20% has been disturbed, mostly by domestic cattle and feral sheep, goats, and pigs. As a result, 70% of the island remains relatively untouched, with a variety of plants and animals, many of which are endemic, and some of which are rare or threatened. Two species of plants, nine terrestrial birds, one bat, and at least four invertebrates have become extinct since 1778. Endemism at the generic level includes the palms Howea, Hedyscepe and Lepidorrhachis, a woody daisy Lordhowea insularis, the tree Negria, the leech Quantenobdella howensis, three annelid worm genera (Paraplutellus, Pericryptodrilus and Eastoniella), an isopod shrimp Stigmops, a hemipteran bug Howeria, and a cricket Howeta.
The Lord Howe Island Board instigated an extensive biological and environmental survey (published in 1974), which has guided the island conservation program. A group of scientists including director of the Australian Museum, Frank Talbot, and others from the Royal Botanic Gardens, the National Parks and Wildlife Service, and the CSIRO undertook an environmental survey of the island in 1970, reporting on environmental degradation there.
In 1981, the Lord Howe Island Amendment Act proclaimed a "Permanent Park Preserve" over the north and south ends of the island. Administration of the preserve was outlined in a management plan for the sustainable development of the island prepared by the NSW National Parks and Wildlife Service, which has a ranger stationed on the island. The island was cited under the UNESCO World Heritage List in 1982.
Offshore environmental assets are protected by the Lord Howe Island Marine Park. This consists of a state marine park managed by the Marine Parks Authority of New South Wales in the waters out to three nautical miles around the island and including Ball's Pyramid. It also includes a Commonwealth Marine Park extending from 3 to 12 nautical miles out and managed by the federal Department of the Environment and Heritage. In total the Marine Park covers about 3,005 km2 (1,160 sq mi).
Feral animals and plants[edit]
Pigs and goats were released on the island as potential food sources in the early 1800s; the goats destroyed shrubs and grasses used as nesting sites and the pigs ate eggs and chicks and disturbed the land by rooting for food. Several birds have become extinct on the island since the arrival of humans. The first round of extinctions included the Lord Howe swamphen or white gallinule, the white-throated pigeon, the red-crowned parakeet, and the Tasman booby, which were eliminated by visitors and settlers during the 19th century, either from overhunting for food or protection of crops. Black rats were released from provisioning whaling ships in the 1840s and mice from Norfolk Island in 1860. In 1918, the black rat was accidentally introduced with the shipwreck of the S.S. Makambo, which ran aground at Ned's Beach. This triggered a second wave of extinctions, including the vinous-tinted thrush, the robust white-eye, the Lord Howe starling, the Lord Howe fantail and the Lord Howe gerygone, as well as the destruction of the native phasmid and the decimation of palm fruits. Bounties were offered for rats and pig tails and 'ratting' became a popular pursuit. Subsequent poisoning programs have kept populations low. The Lord Howe boobook may have become extinct through predation by, or competition with, the Tasmanian masked owl, which was introduced in the 1920s in a failed attempt to control the rat population. Stray dogs are also a threat, as they could harm the native woodhen and other birds.
Invasive plants such as Crofton weed and Formosa lily occur in inaccessible areas and probably cannot be eradicated, but others are currently being managed. In 1995, the first action was taken to control the spread of introduced plants on the island, chiefly ground asparagus and bridal creeper, but also cherry guava, Madeira vine, Cotoneaster, Ochna, and Cestrum. This has been followed by weeding tours and the formation of the Friends of Lord Howe Island group in 2000. Programs have also been started to remove weeds from private properties and re-vegetate some formerly cultivated areas. An environmental unit was created by the board and it includes a flora management officer and a permanent weed officer. Weeds have been mapped and an eradication program is in place, supported by improved education and quarantine procedures.
Introduced species that harmed Lord Howe's native flora and fauna, namely feral pigs, cats, and goats, were eradicated by the early 2000s.
In July 2012, the Australian federal Environment Minister Tony Burke and the New South Wales Environment Minister Robyn Parker announced that the Australian and New South Wales governments would each contribute 50% of the estimated A$9 million cost of implementing a rodent eradication plan for the island, using the aerial deployment of poison baits. The plan was put to a local vote and is considered controversial. Around 230 woodhens were captured before the rodent eradication commenced in early 2019. Following the successful eradication of the rodents, all woodhens and currawongs were released across the island in late 2019 and early 2020.
In 2023 the island was declared rodent free, which is a globally significant conservation milestone.
A recovery program has restored the Lord Howe woodhen's numbers from only 20 in 1970 to about 250 birds four years before the rodent baiting program. There were 1,100 in the 2023 survey.
Climate change[edit]
According to an analysis by eminent Australian academic Tim Flannery, the ecosystem of Lord Howe Island is threatened by climate change and global warming, with the reefs at risk from rises in water temperature. The first international conference on global artificial photosynthesis as a climate-change solution occurred at Lord Howe Island in 2011, the papers being published by the Australian Journal of Chemistry.