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Endangered Species Monday | Brachylophus fasciatus.

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Endangered Species Monday | Brachylophus fasciatus

This Monday’s (ESP) Endangered Species Watch Post report I document on a rather “undocumented species” of iguana identified back in the 1800’s. (Photographer unknown)

Identified back the 1800’s, and listed as [endangered] the species was originally identified by French Dr Alexandre Brongniart (5 February 1770 – 7 October 1847) who was a French chemist, mineralogist, and zoologist, who collaborated with Georges Cuvier on a study of the geology of the region around Paris.

Dr Alexandre Brongniart was born in Paris, the son of the architect Alexandre-Théodore Brongniart and father of the botanist Adolphe-Théodore Brongniart. He was an instructor at the École de Mines (Mining School) in Paris and appointed in 1800 by Napoleon’s minister of the interior Lucien Bonaparte director of the revitalized porcelain manufactory at Sèvres, holding this role until death.

The young man took to the position a combination of his training as a scientist— especially as a mining engineer relevant to the chemistry of ceramics— his managerial talents and financial acumen and his cultivated understanding of neoclassical esthetic. He remained in charge of Sèvres, through regime changes, for 47 years.

Commonly known as the Fiji Banded Iguana, Lau Banded Iguana, South Pacific Banded Iguana, or Tongan Banded Iguana the species is unfortunately endangered and nearing extinction within the wild. A reptilian, and member of the iguana family the species has been placed within the order of (Squamata).

Within the past TWO DECADES the species has undergone a decline of some 50% throughout its range. Furthermore species declines are still ongoing with no apparent let up neither, (threats have been noted as significantly severe and widespread).

Without conservation intervention, the degradation observed during the last 20 years is predicted to cause further declines over the next 20 years that approaches 80% and potentially will be found to be even higher with further population analysis. Basically unless conservation efforts are improved or continue then we will lose the species very quickly.

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Image: Fiji Banded Iguana (Credits: Robin Carter) 

Now to some humans this may not seem much to worry about. However let me ask you this. Have you experienced a rather large number of flies bothering you, mosquitoes, insects, and general bugs wreaking havoc with your everyday life? If the answer is “yes”, then maybe you need to be paying attention to my articles. Reptiles loves flies, and without reptiles there will be more flies.

Endemic to Fiji, the species has recently been introduced to Tonga. Among all the islands surveyed for the presence of Lau Banded Iguana, only on the two Aiwa Islands were enough lizards found to estimate a population size, this was estimated to number less than 8,000. That population size is concerning (especially when we take into consideration life span, gestation, and threats). 8,000 can soon turn into 1000 in under five years.

Although there is no official “population size estimates”, its believed from census reports (which I myself do question), within the past 35-40 years the species has undergone (as explained above) a decline of 50%. Discussions with island residents indicate that on most islands the iguanas are now more rare than they had been in the recent past.

Most islands in the region are now inhabited and iguanas were generally found in degraded forests or remnant forest patches, but not in proximity to villages or gardens. Surprisingly, among the uninhabited islands surveyed only one was found to have iguanas present, but this is likely due to the abundance of cats present on the iguana-free islands. It is known that local residents intentionally translocate kittens to these uninhabited islands for rat control.

In summary, a total of 52 islands in the Lau Group and Yasayasa Islands were visited between 2007 and 2011 and iguanas were detected or reported from only 11 islands, with an additional report from one island that was not visited. The sheer fact we only have on ELEVEN ISLANDS instead of FIFTY TWO Fiji Banded Iguanas, just goes to show we have serious problems here that need addressing before its to late.

Iguanas were abundant on only three islands, the two neighbouring Aiwa Islands and Vuaqava, all of which are uninhabited. Goats have recently populated all three of these islands and Vuaqava has a seemingly large cat population (which could be a threat). Most of these 53 islands should have had resident iguana populations. For example, two islands with historic populations, Moce and Oneata, were described by the Whitney Expedition and have since been extirpated. Given these results, it appears that iguanas could be remaining on about 20% of the islands in the region and are abundant on only 5%. 

“SO WHAT ARE THE THREATS?”

The current band at which the Fiji Banded Iguana sits in (in regards to known population levels) is 8,000 120,000 mature individuals. Now that doesn’t mean we have 8,000 or 120,000 mature individuals. The current band basically means what we have “assumed the population” based on very sketchy and rough census estimates. What we do know, is that from the last census conducted only 8,000 were eye balled (meaning that 8,000 were physically witnessed). Further census counts are underway.

Lau Banded Iguanas are sometimes locally kept as pets, and this was observed on three different islands during surveys in 2011. Historically, these iguanas would have been a local food source, similar to the larger extinct species (Lapitaiguana and B. gibbonsi) in the region, but there are no recent records of human consumption. The black market trade in Brachylophus does not include this species and is unlikely to be a threat in the future as its remaining localities are very remote.

Black Rats (Rattus rattus) and feral cats (Felis catus) are the main mammalian predators threatening the persistence of iguanas and are capable of causing local extinctions in a relatively short time period. Fortunately, mongoose has not been introduced to the Lau Group yet, and maintaining it free of them is an important biosecurity issue. On a few islands, free-roaming domestic pigs (Sus scrofa) were observed to cause major disturbance in small forest patches, turning large areas to bare mud that is no longer suitable for iguana nesting.

Even in the absence of goat herding, forest burning is widespread and is increasingly one of the biggest threats to iguana habitat and their persistence. Continued deforestation on the small islands where Lau Banded Iguanas remain is predicted to cause additional local extinctions over the next 40 years. In particular, on the large islands of Lakeba and Vanua Balavu where iguanas should have been numerous, there has been significant forest loss through deforestation, burning, and fragmentation.

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Image: Fiji Banded Iguana (Photographer unknown). 

Additional threats to the native forests include further development of urban and village areas, plantation agriculture, and logging. In particular, harvesting Vesi Tree (Intsia bijuga) for use in traditional carving on several islands (for example, Kabara) has significantly reduced the native forest. Forest conversion to Caribbean Pine plantations is also significant, especially on Lakeba.

Proposed development of tourism resorts, on the smaller islands in particular, has significant impacts on these habitats, possibly leading to losses of entire iguana populations as has been observed elsewhere in Fiji. Finally, proposed new cruise ship routes to the remote Lau islands will require construction of new infrastructure and is likely to be a source of invasive species from Viti Levu unless strict biosecurity measures are enforced.

The impact of the recent introduction and spread of the invasive alien Common Green Iguana (Iguana iguana) in Fiji are not yet known for this species but have been shown to have significant detrimental effects everywhere they have been introduced. Eradication for this invasive now appears unlikely, and it is possible the Green Iguana will continue to spread to other well-forested islands despite eradication efforts. Green Iguanas are vastly more fecund and aggressive than native iguanas and may have significant effects on remnant small island populations.

At minimum, this introduction has caused considerable confusion in the local education programmes aimed at protection of Banded Iguanas versus eradication of the Green Iguanas, since juveniles of the latter appear superficially similar. The northern Lau Islands are very close to Qamea where the Green Iguana was first introduced and are at high risk of invasion.

Irruptions of invasive alien Yellow Crazy Ants (Anoplolepis gracilipes) are known to occur on many of the southern Lau islands. Even though these ants were introduced to Fiji over 100 years ago, it is not understood what causes populations to periodically irrupt in huge numbers on some islands. When Crazy Ants irrupt, the entire ground surface, shrubs, and trees are entirely covered with ants and it has been observed that native skink and gecko abundance drops greatly during this time.

The impact of aggressive ant irruptions on iguana reproduction and recruitment is not known, but is likely to suffer similarly to other lizards. Lau Banded Iguanas are sometimes locally kept as pets, and this was observed on three different islands during surveys in 2011 (as explained above).

Historically, these iguanas would have been a local food source, similar to the larger extinct species (Lapitaiguana and B. gibbonsi) in the region, but there are no recent records of human consumption. The black market trade in Brachylophus does not include this species and is unlikely to be a threat in the future as its remaining localities are very remote.

Listed as endangered, the current future is not as yet known. However what we do know is that the Fiji Banded Iguana does not inhabit the ground it once did. Threats are wide, and the species has undergone a large population decline.

Thank you for reading. 

Dr Jose C. Depre PhD. MEnvSc. BSc(Hons) Botany, PhD(NeuroSci) D.V.M.

Environmental, Botanical and Human Science.

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Endangered Species Monday: Dasyurus maculatus

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Endangered Species Monday: Dasyurus maculatus

This Mondays Endangered Species Watch Post (ESP) I focus a little attention onto the Spotted-tailed Quoll. D. maculatus was identified back in 1792 by Dr Robert Kerr (1755 – 11 October 1813) Dr Kerr was a scientific writer and translator from Scotland. Dr Kerr was born in Roxburghshire as the son of a jeweler. He studied medicine at the University of Edinburgh and practiced at the Edinburgh Foundling Hospital as a surgeon. (Image adult Quoll) 

Dr Kerr translated several scientific works into English, such as Antoine Lavoisier’s work of 1789, In 1792, he published The Animal Kingdom, the first two volumes of a four-tome translation of Professor Linnaeus’ Systema Naturae, which is often cited as the taxonomic authority for a great many species. (He never did start the remaining two volumes.) Please note, the Spotted-tailed Quoll is described as ‘two subspecies’ and will be noted as such during this short article.

Listed as near threatened, D. maculatus has been wrongly named by some writers as the ‘Tiger Quoll’. The species shows no resemblance to that of a Tiger nor shows any familiar behavioral traits too. There is no mention of a ‘Tiger Quoll’ within conservation literature too. So I wish to put that name to bed now.

From 1996 the species [and sub-species] was listed as vulnerable, a further 2008 evaluation of the carnivorous marsupial saw conservation NGO’s submit data to the Red List of which the Spotted-tailed Quoll now qualifies for the criteria of (near threatened). Endemic to the island of Australia the species exists as explained as two sub-species.

Sub species (1) Dasyurus maculatus maculatus was formerly distributed in south-eastern Queensland (as far north as Bundaberg and as far west as Chinchilla), eastern New South Wales, Victoria, South Australia, Tasmania (including some of the Bass Strait Islands. Maxwell et al. (1996) reported that in south-east Queensland this particular sub-species has undergone a range contraction indicated to be in excess of 30% over the last 25 years and is now rare in most areas.

Sub species (2) D. m. gracilis formerly occurred throughout the latitudinal range of the Wet Tropics World Heritage Area of north Queensland. It is now apparently extinct from the Atherton and Evelyn Tablelands, and there are few sightings south of 17o45’S. This represents a decline in extent of occurrence of approximately 20%.

Populations are decreasing of which there remains an estimated ‘20,000’ mature individuals. Populations in south-east Queensland, western Victoria (Otways and far south-west of Victoria), and coastal areas of southern New South Wales are known to be declining too. Populations in north-eastern Queensland are small, fragmented, and are <1,000 individuals. Tasmanian population numbers appear to be stable.

There is some evidence of a decline in distribution or in numbers in remaining suitable habitat (e.g., in the Otway Range), and the species is mostly uncommon (although it is present in good numbers in some areas, such as the Marengo and Chaelundi Forests).

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Image: Spotted-tailed Quoll (juvenile) 

Threats

The reasons for decline of D. m. maculatus are a combination of habitat loss and fragmentation, possible disease at the beginning of the 20th century, competition with foxes and feral cats, predation by foxes and dogs, and impact of widespread strychnine baiting for dingoes.

Most recently threats include non-target mortality from trapping and poisoning (there is a long-standing concern that Quolls are being killed by the use of 1080 poisoning, but this has not been confirmed and is currently the focus of a number of investigative trials).

Direct persecution is significant as they are attracted to caged birds and do not necessarily take flight when discovered. Estimated forest loss as a result of clearing within its former range in south-east Queensland is over 70%, with the majority of loss occurring over the last 20 years.

The species uses a large number of den sites throughout the year and activities that reduce the number of den logs are likely to be significant. In Tasmania this taxon is naturally rare, possibly as a result of competition with D. viverrinus, Sarcophilus harrisii, and feral cats. Road mortality could be a significant factor where high speed roads and good habitat coincide, as Quolls are attracted to feed on the carcasses of road-killed animals.

D. m. gracilis is susceptible to factors which increase juvenile and/or adult mortality, or which otherwise decrease breeding success. Such factors may include habitat clearance, logging, introduced species including cane toad, and direct killing at chicken pens, at houses, and on roads.

Conservation actions are underway with more planned soon that will work to evaluate the current species size, habitat loss, food sources and protective areas needed Etc.

Spotted-tailed Quolls are generally nocturnal and rest during the day in dens. However, juveniles and females with young in the den can be seen during the day and may leave their dens when it is light out. Quoll dens take the form of underground burrows, caves, rock crevices, tree hollows, hollow logs, or under houses or sheds. Quolls move by walking and bounding gaits. Trails are not particularly important for Quoll, although they forage and scent mark along runways and roads.

Facts

Size of the Quoll depends on the species. They can reach 14 to 29.5 inches in length and 3 to 15.4 pounds of weight.
Quoll is covered with coarse coat that can be grey, brown or black in color. Basic color of the fur is enriched with prominent white spots. Quoll has pointed snout and pink nose. Its powerful jaw is equipped with sharp teeth. Tail is long and bushy. Quoll has sharp claws on the front and hind feet that are used for holding the food, climbing and digging underground burrows.

Quolls are nocturnal animals (active during the night). Even though Quolls are agile climbers, they spend majority of their life on the ground. Quolls can consume both animals and plants. Diet is mainly based on small mammals (such as rabbits), small birds, snakes and insects. They occasionally eat fruit and nuts.
Main predators of Quolls are crocodiles and snakes. Quolls live in the underground burrows, inside the hollow trees or caves. Quoll is territorial animal.

Male’s territory overlaps with territories of several nearby females. They share communal latrines. Quoll is solitary creature which gathers with other Quolls only during the mating season.
Mating season of Quolls takes place during the winter. Pregnancy lasts only couple of weeks and ends with up to 30 miniature babies (they weigh less than one gram).

Babies spend first 8 weeks of their life inside the mother’s pouch. After that period, babies are big enough to leave the pouch and ride on the mother’s back. Young Quolls are ready for independent life at the age of 6 months. Female’ pouch is not a true pouch. It forms out of the fold of skin on the stomach after successful mating. Pouch contains only 6 teats, which means that only 6 babies out of 30 will be able to survive and complete their development. Quolls reach sexual maturity at the age of one year. Quolls have short lifespan. They can survive from 2 to 5 years in the wild, depending on the species.

Contrary to popular belief Quolls or as some people refer to this documented species as the ‘Tiger Quoll’ are not rare. The species and entire genera are in fact nocturnal, so while your asleep they’ll most likely be happily wondering through your garden or local parks and nature reserves. However the species is threatened and decreasing with a population size of some 20,000.

Thank you for reading.  

Dr Jose Depre. 

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