Background
New Caledonia is a group of islands located in the southwestern part of the Pacific ocean, just east of Australia. A notable feature of New Caledonia is that it has limited surface area. The islands are surrounded by bodies of water, and are relatively small in size. Therefore, only a selective amount of species can thrive. Specifically, large fauna do not fair well mainly due to the lack of resources (e.g. large territory) which ultimately restricts increases in population (New Caledonia). However, small fauna, which includes reptiles, are more abundant since conditions are more favorable towards them.
Endemism
The majority of the herpetofauna that inhabit the islands are endemic. Knowing the geological history of New Caledonia is critical in order to understand why high levels of endemism and biodiversity exist. New Caledonia was once part of the continent Gondwana, and it can be inferred that fauna and flora were introduced during or after the late Eocene (Pelletier 2007). During the Pleistocene, sea level variation caused by glaciation and deglaciation periods had an enormous impact on New Caledonian terrestrial species diversity and distribution (NetBiome). As a result, there are 61 known species of reptile that are endemic with an additional 13 species which were recently discovered to be endemic in January 2005 (Intreasures).
Conservation
The herpetofauna flourishes in New Caledonia because of the tropical conditions that determine their distribution. According to WWF, the islands are mainly tropical and subtropical broadleaf forests. Geographically, New Caledonia is situated within the Tropic of Capricorn; therefore, constant exposure to sunlight and warmth are suitable for ectothermic species like reptiles. Yet, there are a few species that are listed as critically endangered in IUCN, which indicates the importance of conservation. Habitat loss and destruction is a serious issue for herpetofauna. Particularly, massive deforestation for wood production and agriculture is a major threat. Today only 1% of the original surface area of dry forests remain while only 21% of rain forests remain (Secretariat of the Pacific Regional Environment Programme). The significance of conservation is that it maintains and stabilizes high levels of endemism. The majority of reptiles and amphibians that inhabit New Caledonian forests occur no where else in the world. Hence, this makes New Caledonia one of the most sensitive places in the world for wildlife because of the fact that concentrated amounts of unique herpetofauna live in a small area.
New Caledonia is a group of islands located in the southwestern part of the Pacific ocean, just east of Australia. A notable feature of New Caledonia is that it has limited surface area. The islands are surrounded by bodies of water, and are relatively small in size. Therefore, only a selective amount of species can thrive. Specifically, large fauna do not fair well mainly due to the lack of resources (e.g. large territory) which ultimately restricts increases in population (New Caledonia). However, small fauna, which includes reptiles, are more abundant since conditions are more favorable towards them.
Endemism
The majority of the herpetofauna that inhabit the islands are endemic. Knowing the geological history of New Caledonia is critical in order to understand why high levels of endemism and biodiversity exist. New Caledonia was once part of the continent Gondwana, and it can be inferred that fauna and flora were introduced during or after the late Eocene (Pelletier 2007). During the Pleistocene, sea level variation caused by glaciation and deglaciation periods had an enormous impact on New Caledonian terrestrial species diversity and distribution (NetBiome). As a result, there are 61 known species of reptile that are endemic with an additional 13 species which were recently discovered to be endemic in January 2005 (Intreasures).
Conservation
The herpetofauna flourishes in New Caledonia because of the tropical conditions that determine their distribution. According to WWF, the islands are mainly tropical and subtropical broadleaf forests. Geographically, New Caledonia is situated within the Tropic of Capricorn; therefore, constant exposure to sunlight and warmth are suitable for ectothermic species like reptiles. Yet, there are a few species that are listed as critically endangered in IUCN, which indicates the importance of conservation. Habitat loss and destruction is a serious issue for herpetofauna. Particularly, massive deforestation for wood production and agriculture is a major threat. Today only 1% of the original surface area of dry forests remain while only 21% of rain forests remain (Secretariat of the Pacific Regional Environment Programme). The significance of conservation is that it maintains and stabilizes high levels of endemism. The majority of reptiles and amphibians that inhabit New Caledonian forests occur no where else in the world. Hence, this makes New Caledonia one of the most sensitive places in the world for wildlife because of the fact that concentrated amounts of unique herpetofauna live in a small area.
Dierogekko inexpectatus
Endemic to Province Nord of New Caledonia, Dierogekko inexpectatus is currently considered to be highly endangered because of it restricted distribution. The species can be found in a small area on the northern end of Poum Massif, northern Grande Terre. Habitat destruction and fragmentation are major threats to the reptile which are consequently causing a significant decrease in population. There are no signs of effective conservation. For example, there are no known protected areas in New Caledonia. Furthermore, the ecological niche that Dierogekko inexpectatus inhabits is very specific. Therefore, methods like replicating its habitat and relocating the species are proven difficult. According to the IUCN, Dierogekko inexpectatus lives in low, closed forests on rocky surfaces. This allows it to find shelter beneath stones by day and climb trees by night.
Dierogekko kaalaensis
Only known to be located in Kaala massif, north-western Grande Terre, Dierogekko kaalaensis is highly endangered because of its limited range. Threats include mining activities and wild fires which ultimately results in a decline in population. There is also habitat degradation caused by non-endemic species such as ungulates (deer and pig) while rodents and feral cats continue to exert more pressure on the species. The IUCN states that Dierogekko kaalaensis inhabits humid forests at low to mid-elevations, montane forests at high elevations, and rocky maquis shrublands at all elevations. Nocturnal by nature, the reptile is highly arboreal. However, during the day, Dierogekko kaalaensis finds shelter beneath rocks and stones.
Dierogekko koniambo
Found in Koniambo massif and adjacent lowlands, northwestern Grande Terre, Dierogekko koniambo is endangered mainly because of nickel mining and clearings for agricultural production. Yet, wildfires particularly in maquis shrublands are threats to the species. As a result, there is evidently a significant reduction in population. The IUCN states that this species lives in rocky maquis shrublands and sclerophyll forests at low elevations near Vavouto. It also inhabits maquis shrublands and closed montane forest at mid to high elevations on the Koniambo massif. It is considered nocturnal and arboreal. It seeks shelter beneath stones by day and climbing onto trees by night.
Dierogekko nehoueensis
Endemic to Dôme de Tiébaghi massif and adjacent lowlands, northern Grande Terre, Dierogekko nehoueensis are highly endangered due to introduced ungulates, mining activities, and an invasive species of ants known as Wasmannia auropunctata which has an tremendous negative impact on the gecko. Thus, the small areas it inhabits not only shows that they are vulnerable to intense human use but also to intrusive species of animals. Dierogekko nehoueensis inhabits gallery forests on floodplains in Rivière Nehoué. At Dôme de Tiébaghi, it can be found in closed forests and maquis shrublands. Like the other aforementioned geckos, Dierogekko nehoueensis is nocturnal and arboreal. It shelters itself from the sun by hiding under rocks and comes back out by night to climb on vegetation.
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Dierogekko poumensis
Located mainly in Poum massif, northern Grande Terre, Dierogekko poumensis is threatened by mining. Specifically, the IUCN claims that current plans to mine the plateau of Poum Massif for the next decade would translate to approximately a 25% reduction of Dierogekko poumensis' habitat range which is home to some of the densest populations. Dierogekko poumensis predominantly occupies rocky maquis shrublands and low closed forests. Nocturnal and arboreal, Dierogekko poumensis hides by slipping through rock crevasses to avoid high temperatures produced by the sun and emerges by night.
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Dierogekko thomaswhitei
According to the Reptile Database, Dierogekko thomaswhitei can be measured up to 45 mm SVL which is considered to be a relatively large gecko. Beige with dark brown stripes, the gecko is able to find its niche in Ouazangou-Taom massif, north-western Grande Terre. It occupies rocky maquis shrublands at mid to high elevations and low closed montane forests. However, it is labeled as highly endangered because of active mining and wildfires in the lower elevation areas.
Oedodera marmorata
Distinguishable by its swollen neck, Oedodera marmorata is also noted to have a marbled dorsal pattern. Historically, populations of Oedodera marmorata suffered from mining, but this threat is currently subsiding. However, unstable wildfires mainly pose a serious risk on the gecko. The IUCN states that there were three major wildfires in the past decade. In addition, increasing human populations also have an adverse impact on Oedodera marmorata. If these threats continue, IUCN predicts that there will be a 50% reduction within three generations. The habitats of Oedodera marmorata are maquis shrublands and closed forests which are located in Dôme de Tiébaghi massif. However, unlike the other geckos, Oedodera marmorata finds shelter in bark or tree holes instead of rocks. Also, it forages through twigs and foliage on canopies at nighttime.
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Nannoscincus exos
Endemic to Tnâno massif in the north-eastern ranges of Grande Terre which is near Hienghène, Nannoscincus exos living in mid to low elevations are critically endangered because of Wasmannia auropunctata. According to IUCN, these invasive ants are known to decimate lizard populations. However, Nannoscincus exos living in high elevations in closed forests are highly susceptible to habitat loss from agricultural clearings and wildfires. Furthermore, introduced ungulates degrade Nannoscincus exos' habitat by disturbing leaf litter on the forest floors and lowering humidity which translates to desiccation.
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Nannoscincus hanchisteus
A single population of Nannoscincus hanchisteus is known to only occupy space that is less than 100 km², meaning that their habitat is highly specialized. Specifically, Nannoscincus hanchisteus is found in closed sclerophyll forests which are located on the Pindaï Peninsula on the northwestern coast of Grande Terre. The skink depends on moist environments; hence, it is commonly found under stones and leaf litter where it forages. Some threats include prolonged droughts, predation by rodents, and invasive species. However, major concerns include wildfires and degradation by livestock and invasive ungulates because they ruin the moisture that Nannoscincus hanchisteus heavily depends on.
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