Biodiversity of New Caledonia
The biodiversity of New Caledonia is of exceptional biological and paleoecological interest. It is frequently referred to as a biodiversity hotspot.[1] The country is a large South Pacific archipelago with a total land area of more than 18,000 square kilometres (6,900 sq mi). The terrain includes a variety of reefs, atolls, small islands, and a variety of topographical and edaphic regions on the largest island, all of which promote the development of unusually concentrated biodiversity. The region's climate is oceanic and tropical.
Location and description
The archipelago is about 1,300 kilometres (810 mi) east of Australia and 1500 km, 1800 km and 1200 km from New Zealand, Papua New Guinea and Fiji respectively. A few lesser islands are closer, but now provide no convenient island-hopping path by which animal species could pass either to or from major mainlands. Some plants, invertebrates, sea mammals, and many flying species as aquatic birds, parrots, and bats have spread to new locations, either under their own power or due to freak events such as storms, or have been transported by humans. Some plant species have colonized new areas by means of seed carried by ocean currents.
Some animal and plant species have reached New Caledonia from surrounding regions and in turn, some New Caledonian species have successfully extended their ranges into the Pacific Ocean area. Other New Caledonian species or their close relatives are found in regions remote from the archipelago. For example, the New Caledonian parakeet is known to be the basal species in the genus
The main island,
The most conspicuous aspects of the New Caledonian marine environment are associated with the surrounding coral reef.
Such circumstances may be expected in general to promote biodiversity, but in the case of New Caledonia, a striking feature is the intense biodiversity in such a small land area. Presumably this is partly due to the edaphic and topographic features that define a number of discrete regions and ecological gradients. However, the local species do not always occupy all the potential niches, leaving the territory vulnerable to certain forms of invasion.[4]
The larger flora include Nothofagus, Beilschmiedia, Adenodaphne, Winteraceae, Myrtaceae, southern sassafras (Atherospermataceae), conifers of Araucariaceae, Podocarpaceae, and Cupressaceae, and tree ferns.[5]
Geologic origins
New Caledonia comprises fragments of the continental crust of
However, the view of the island as a surviving fragment of the Cretaceous period is obsolete. Islands from that time are partly or fully submerged. Most modern New Caledonian
In the Carboniferous and Permian, New Zealand and New Caledonia were on the periphery of Gondwana, which included Africa, South America, Antarctica, India, New Zealand and Australia. Paleomagnetic data locate New Caledonia as originally near the South Pole. In the Triassic and early Jurassic, Gondwana moved northward, warming the eastern margin. New Caledonia separated from
The island soils derived largely from
The native flora evolved many
Ultramafic rocks also contain elevated amounts of chromium and nickel which may be toxic to plants. As a result, a distinctive type of
Often thick,
Early organisms
The marine fauna of the period, separate from that of the southwest Pacific, was distinguished as the "
At the beginning of the Tertiary, New Zealand and New Caledonia moved north to a warmer climate. This led to a long period of evolution in near complete isolation. New Caledonia's natural heritage includes species whose ancestors were present on New Caledonia when it broke away from Gondwana; not only species but entire genera and even families are unique to the island.
Evolution and history
The species of the archipelago of New Caledonia are relicts of a type of vegetation which earlier covered much of the tropics of the Earth, including much of the mainland of Australia, South America, Antarctica, South Africa, and North America. Although tropical cloud forests disappeared during the glaciations, they re-colonized large areas during successive geological eras when the weather was favorable again. At other times they were replaced by more cold-tolerant or drought-tolerant sclerophyll plant communities. Many of the then existing species became extinct because they could not cross the barriers posed by new oceans, mountains and deserts, but others found refuge as species relict in coastal areas and islands.
When the large landmasses became drier and with a harsher climate, this type of forest was reduced to those boundary areas. Although some remnants of archaic rich flora still persisted in coastal mountains and sheltered sites, their biodiversity was reduced. The location of the New Caledonian Islands in the Pacific Ocean moderated these climatic fluctuations, and maintained the relatively humid and mild climate which has allowed these communities to persist to the present day.
The ecological requirements of many of the species are those of the laurel forest, and like most of their counterparts laurifolia in the world, they are vigorous species with a great ability to populate the habitat that is conducive. The geographical isolation and special edaphic conditions helped to preserve it too. Some species are even specialized in nickel hyperaccumulation such as the Sapotaceae Sebertia acuminata.[3]
Some
Extinct species
Numerous species were wiped out by humans before the arrival of Europeans.
Ecoregions
There are several vegetation types, in a variety of niches, landforms and micro-climates where endemic species thrive,
New Caledonia has two terrestrial
In the
The now-fragmentary
New Caledonia's marine environment is characterized by the surrounding
Dry forests
The west coast of New Caledonia has a drier climate and different habitat from the rain forests that cover most of the island. The plant life of the west coast consists of nearly 400 species, including endemic species such as the unique
Rainforest
Mountain forests are mainly located on the lee slopes, where communities are evergreen species of
, and genera such as southern beech (Nothofagus).Many other families of
There are many epiphytes and large, hanging mossy formations, giving a surreal and ghostly effect. Moisture is abundant, creating a moist, hygrophilous environment with great visual appeal, in the form of mists, sprays, ponds and streams that permeate the entire visual field.
Flora
New Caledonia's vegetation is distinguished by the world's highest rate of endemism: 5 families, 107 genera and 3,380 species. Among these are
The palm trees (
Three of the most primitive genera of Araliaceae also occur.
Some New Caledonia plant communities are true living fossils. Flora contains many groups of plants that appear to be remnants of the Gondwanan flora in late Cretaceous - early Tertiary that once covered large parts of Australasia. The flora is exceedingly diverse and includes a level of endemism, per square kilometre, seen almost nowhere else on Earth. Three-quarters of native plant species on New Caledonia are
There are besides 454 species of marine
In contrast, several groups that are well represented in the rest of tropics have only a few species on the Archipelago, such as Melastomataceae with one species, or are absent all together, e.g., Ochnaceae (sensu stricto) and Begoniaceae. Other families, such as Araceae, Boraginaceae, Brassicaceae, Commelinaceae, Gesneriaceae, and Zingiberaceae, are substantially under-represented.
Five families are considered endemic: the
.Some genera originated in the Gondwanian
Many other groups reached New Caledonia after it separated from Australia, which took place as part of a widespread movement of Indo-Malesian elements that expanded into Australasia during the early and middle Tertiary.[20][21] Some of these newer flora speciated intensively and are now among the largest genera on the island. Examples include Phyllanthus, with 111 species, Psychotria with about 85 species, and Eugenia with around 37 species, Flindersia in the family Rutaceae, and Polyosma among others.
Most
Four genera, Araucaria, Libocedrus, Prumnopitys and Retrophyllum that populate the subantarctic Pacific, have endemic species in New Caledonia. The genus Acmopyle (Podocarpaceae), currently present in New Caledonia and Fiji, is a fossil in Patagonia. There are 13 endemic species of Araucaria, including A. rulei and A. columnaris. The island shares some Araucaria species with Australia's Norfolk Island. Many, if not all current populations are relict.
Angiosperms also include many groups of archaic characteristics that appear as vestiges of an old Gondwanan floral background.
The bamboo genus Greslania is endemic to New Caledonia and comprises three or four species. They are found only in the southern part of the island where the soil contains heavy metals such as iron.[citation needed]
Several genera, belonging to primitive families, are endemic or sub-endemic.
The importance of the families of Gondwanan origin, both in the number of species and their abundance in different plant communities contrasts with the low representation in indigenous communities of more modern groups such as the
The groups of Gondwanan origin are the most remarkable flora and include Cunoniaceae, Proteaceae and Myrtaceae. The family of Cunoniaceae has six genera in New Caledonia. Pancheria and Codia are endemic, although the last is known as a fossil in Australia, while Cunonia has 23 endemic species in New Caledonia and one species in South Africa.
The other three genera have a Papuan-Australian (
Proteaceae's two main centers of dispersion are in Australia and Southern Africa; the family is represented in the archipelago by 43 species. They divide into six endemic genera: Beauprea, Beaupreopsis, Garnieria,[22] Kermadecia, Sleumerodendron and Virotia and three non-endemic genera Grevillea, Knightia and Stenocarpus.[23]
Myrtaceae, although basically Gondwanan in origin, currently range throughout the tropical world and have reached the Northern Hemisphere. With 229 species, it is the largest family in New Caledonia. It has two widely distributed genera, Eugenia and Syzygium. The endemic genera are Arillastrum, Cloezia, Myrtastrum, Pleurocalyptus, and Purpureostemon.[24] The genus Melaleuca is represented by six endemic species and one shared with Australia and Papua New Guinea, Melaleuca quinquenervia, known locally as niaouli.[25]
Fauna
The
Today's New Caledonian marine biodiversity has been counted to 9372 species, belonging to 3582 genera and 1107 families. Important groups that contribute include the molluscs (2151 species), fish (1695 species), the
New Caledonia's animal land diversity was similar to that of some oceanic islands, particularly New Zealand and as in these islands, the biodiversity was greater before being inhabited by humans. The island has no native
Endemic species comprise 62 of 69 total. No crocodiles or terrestrial turtles remain on the islands. Two species of snake are found in the Territory, one on Grand Terre and the other on the Loyalty Islands. It is the home to a large number of skinks and geckos.
The island Île des Pins is home to the crested gecko
The island of Grande Terre has the greatest variety of reptiles, including the giant gecko (
Before the arrival of Europeans, the only
The world's highest biodiversity of Volutomitridae is in waters off New Caledonia.[31]
Tropical invertebrates make up the bulk of the endemic fauna. They include
Mites,
Birds
There are twenty two endemic species of terrestrial birds, three endemic genera and one family. The
The best-known animal species is the
The other terrestrial endemic birds are
Threats
New Caledonia's biodiversity is threatened by many factors..
Deforestation from logging, mining, uncontrolled fires, agriculture, urban development and tourism all increase pressure on these fragile ecosystems by destroying vital habitat. Hunting is a problem in remote areas. Some species are at risk from overexploitation as medicinal plants.
Deforestation alone could cause the extinction of complete genera and orders across the restricted region with an accompanying loss of genetic and phylogenic information. For example, the reproductive structures of primigenia group of Amborella are true flowers that have a unique and provide an anatomical bridge between the structures seen for cone-bearing and flower-bearing plants. Its order is found only in New Caledonia.
The mining industry is focused on the island's rich nickel deposits, which comprise about one fourth of world reserves. In consequence, mining poses serious threats to its ecology.
The dry zone is the area most degraded by human activity, largely occupied by Colonial buildings fronting fine beaches and the infrastructure of the nickel industry.
Despite these threats, no species are known to have become extinct since 1500. Two species, the
The biodiversity of native tree species has protected against invasive introduced tree species, as has happened on other Pacific islands. The government created protective parks and reserves.
Preservation
New Caledonia is considered a conservation priority by many environmental organizations, which have lobbied to preserve the islands' unique ecosystems. To date they have failed to achieve definitive protection for New Caledonia's remaining natural areas. For instance, all attempts to grant them UNESCO World Heritage Site-status protection failed, due to opposition by regional governments and mining and development interests. Mining continues to expand in sensitive areas, although mining companies perform minimal rehabilitation after a mine closes. However, even when taking such rehabilitation efforts into account, mining activity devastates the local biodiversity. World Heritage Site-status would limit mining activity in areas of ecological importance, affecting employment and government revenues.
Grass-roots conservation efforts have been tentative at best, and invariably failed when in direct conflict with mining and other development projects. Recent efforts to increase habitat protection met with strong official opposition, and violence against the proponents. Notably, Bruno Van Peteghem, recipient of the 2001 Goldman Environmental Prize, used the local court system to force government leaders to obey laws protecting the country's coral reefs. After winning in court, his home was firebombed, and his family was repeatedly threatened.[34] Ultimately, the head of government, Jacques Lafleur, succeeded in silencing Van Peteghem, forcing him into de facto exile by arranging the termination of his employment with the national airline.
The entirety of New Caledonia's EEZ is officially a Marine protected area, the Natural Park of the Coral Sea. Levels of protection within the EEZ differ, 2.4% is highly protected, with economic activities including fishing and mining being legal in the remainder. On 18 October 2023 the government announced the highly protected area would be expanded to cover 10% of the EEZ.[35]
Gallery
Landscapes
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Des Tortues bay (Bay of the turtles), in Bourail coast
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Ouaieme river mouth
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Construction of a tailings storage area Goro Nickel Mine, Kwe West Bassin
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Mangrove in Creek salé
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River Néra plaine
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Vegetation surrounding river Néra
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Roche percée beach
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Poindimié Creek
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Savanna withNiaoulitrees in the north of west coast, in Malabou
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Mont Panie Vista
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Aerial photographs of Annibal reef and islets
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Maquis minierbush in Tiébaghi Mountain (Koumac)
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Casuarina collina (iron wood) and Acacia spirorbis (false guaiac) about seven years in a rehabilitation of mining lands - Commune of Montdore - South Province
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Agathis lanceolata plantation
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Araucaria columnaris habitat
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Araucaria columnaris with Laysan albatross. Located in Midway Atoll, Commodore Ave cul de sac residences Sand Island.
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Sea snake (Laticauda sp) in Lighthouse Amédée islet
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Livestock in Koumac
Coral reef fish
A few examples of coral reef fish; all photographs here are from New Caledonian specimens.
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Naso unicornis
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Sufflamen fraenatum
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Balistoides conspicillum
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Epinephelus areolatus
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Epinephelus coeruleopunctatus
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Epinephelus fasciatus
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Epinephelus merra
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Epinephelus polyphekadion
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Aulostomus chinensis.
See also
References
- doi:10.1038/35002501; Received 22 September 1999
- ^ Présentation - L'Outre-Mer
- ^ a b c d e "New Caledonia: Biodiversity". netbiome.org. Archived from the original on 15 April 2013. Retrieved 27 March 2012.
- ^ Fujiwara, Kazue and Elgene O. Box (1999)."Evergreen Broad-Leaved Forests in Japan and Eastern North America: Vegetation Shift under Climatic Warming" in Conference on Recent Shifts in Vegetation Boundaries of Deciduous Forests F. Klötzli, G.-R. Walther, eds. Birkhauser, Basel.
- ^ a b c Heads, Michael. "Biogeographical affinities of the New Caledonian biota: a puzzle with 24 pieces". Journal of Biogeography (J. Biogeogr.) (2010) 37, 1179–1201
- ^ McLoughlin, Stephen. "The breakup history of Gondwana and its impact on pre-Cenozoic floristic provincialism." Aust. J. Bot. (2001) 49, 271–300
- Published online 2 September 2008
- ^ Dossier > La flore de Nouvelle-Calédonie - Première partie
- ^ Golightly, J.P. (1981): Nickeliferous Laterite Deposits. Economic Geology 75, 710-735
- Sao Paulo, 119-135
- ^ "Mbg: Diversity, Endemism, and Extinction in the Flora and Vegetation of New Caledonia".
- ISBN 978-0-226-77142-7
- ISBN 978-0-226-77142-7
- ^ New Caledonia, p. 26, at Google Books By Leanne Logan, Geert Cole
- ^ "New Caledonia dry forests". Terrestrial Ecoregions. World Wildlife Fund. Retrieved 10 August 2011.
- ^ Dossier > La flore de Nouvelle-Calédonie - Deuxième partie
- ISBN 978-1-84246-182-2.
- S2CID 19753649.
- ^ (Holloway, 1979; Jaffré et al., 1993)
- ^ "MBG New Caledonia: Origin of the New Caledonian Flora".
- ^ Garnieria spathulifolia Brongn. & Gris. "Garnieria — The Plant List". Theplantlist.org. Retrieved 26 March 2012.
- ^ "Proteaceae (Famille)". Endémía - Faune & Flore de Nouvelle-Calédonie. Retrieved 28 March 2012.
- ^ "Myrtaceae (Famille)". Endémía - Faune & Flore de Nouvelle-Calédonie. Retrieved 28 March 2012.
- ^ "Melaleuca (Genre)". Endémía - Faune & Flore de Nouvelle-Calédonie. Retrieved 28 March 2012.
- ^ "Lagoons of New Caledonia: Reef Diversity and Associated Ecosystems". UNESCO World Heritage Centre. Archived from the original on 27 December 2016. Retrieved 18 December 2016.
- ^ (Vacelet et al. 1992, Roux et al. 1991)
- .
- ^ Payri and Richer de Forges 2007, www.ird.nc/biodec
- ISBN 84-87334-20-2
- ^ BirdLife International (2006) "New Caledonia's most wanted Accessed 21 April 2008.
- ^ Tolmé, P. (2002) ""Little Scum" Takes On Big Mining[permanent dead link]". National Wildlife 40 (4)
- ^ Elizabeth Claire Alberts (27 October 2023). "New Caledonia expands strictly protected coverage of its swath of the Pacific". Mongabay. Retrieved 26 November 2023.
External links
- Website of the Botanical Conservatory of New Caledonia
- Website for l'Association Endemia (in French): A thorough presentation of New Caledonian diversity
- Tentative steps towards rehabilitation of areas destroyed by mining
- New Caledonian ecosystems and their threats described
- Efforts to protect ecosystems from fire
- Australian efforts to publicise damage by mining
- Threat to reef ecosystems described
- Birdlife International: New Caledonia
- WWF: New Caledonia Program Moist Forests
- WWF: New Caledonia Program Dry Forests
- Conservation International: Biodiversity Hotspots
- Missouri Botanical Garden: New Caledonia's Flora
- Grasshoppers from New Caledonia