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Posts tagged “Invasive species

Endangered Species Monday: Archaius tigris

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Endangered Species Monday: Archaius tigris

This Mondays Endangered Species watch Post (ESP) I document on yet another African species of wildlife that hunting revenue is not helping to preserve. The Tiger Chameleon was identified back in 1820 by Dr Heinrich Kuhl (September 17, 1797 – September 14, 1821) was a German naturalist and zoologist. Kuhl was born in Hanau. He became assistant to Coenraad Jacob Temminck at the Leiden Rijksmuseum van Natuurlijke Historie. (Image: Credited to Henrick Bringsoe, A tigris). 

In 1817 he published a monograph on bats, and in 1819 he published a survey of the parrots, Conspectus psittacorum. He also published the first monograph on the petrels, and a list of all the birds illustrated in Daubenton’s Planches Enluminées and with his friend Johan Coenraad van Hasselt (1797–1823) Beiträge zur Zoologie und vergleichenden Anatomie (“Contributions to Zoology and Comparative Anatomy”) that were published at Frankfurt-am-Main, 1820.

Commonly known as the Tiger Chameleon or Seychelles Tiger Chameleon the species is currently listed as [endangered] which is not uncommon as like many Chameleons within the Seychelles their range is shrinking by the year or being overrun by invasive botanical species.

Endemic to the Seychelles the species has been listed as endangered since 2006 of which populations trends are unknown. Much documentation often cites the species at “comparatively” low density, however one must not take this as factual until a true population count is seen. It has been alleged that for every [five hectares] there is possibly 2.07 individuals which isn’t good ‘if true’ since the island is only 455 km2.

From what we know the species remains undisturbed where there aren’t invasive Cinnamon trees identified as the Cinnamomum verum. However where C. verum is spreading the Tiger Chameleons habitat is under threat from this invasive plant. There is a negative correlation between Chameleon density and the presence of cinnamon, suggesting this invasion is detrimental to chameleon populations. Negative correlation is a relationship between two variables such that as the value of one variable increases, the other decreases.

The Tiger Chameleon’s main endemic range on the Seychelles islands is Mahé, Silhouette and Praslin. A historical record from Zanzibar (Tanzania) is erroneous. It occurs from sea level to 550 m asl, in areas of the islands that have either primary or secondary forest, or in the transformed landscape if there are trees and bushes present. Although they are currently estimated to have a restricted distribution on each island (following survey transects conducted by Dr Gerlach if anecdotal observations from transformed landscapes (e.g. degraded areas outside the areas surveyed) are valid, then the distribution would be larger than mapped at present.

To date the only [non-active] conservation actions that I am aware of are within the Vallee de Mai on Praslin which is currently not a protected national park. Fortunately the species is protected to some degree in the Morne Seychelles, Praslin and Silhouette National Parks. The primary threat within non-protected areas is as explained invasive Cinnamon which seems to be posing similar threats to both small reptilians, insects and birds on the islands and mainland Madagascar.

While the species has been in the past used as a trade animal it was alleged that there were no Cites quotes since 2000 – 2014. However from 1997 – 2013 a total of twelve live specimens were legally exported [despite the species threatened at risk status]. Cites allowed the twelve species to be exported for use within the pet trade which I myself find somewhat confusing. Two specimens were exported to Germany in 1981 with the remainder [10] sent to Spain. I am a little perplexed as to why these twelve specimens were legally exported, furthermore I have found no evidence or follow up data that would satisfy me in believing this export was even worthwhile for the species currently losing ground within their natural habitat.

From 1981 -2010 a further 98 dead specimens were legally exported for scientific zoological projects. Then in 1982 a single live specimen was legally exported with Cites permit for experimental purposes. While I cannot [again] locate any evidence or reason as to why this single specimen was exported alive – I must make it clear that Cites is sympathetic to Huntington Life Science’s and various other animal experimental laboratories. However this doesn’t prove that Cites has exported to anyone of these experimental research centers, it is merely my assumption.

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Image: Archaius tigris

No other trade is reported out of the Seychelles, although re-export of specimens imported to Germany and Spain has been reported to Switzerland and South Africa, respectively (UNEP-WCMC 2014). This species is present and available in limited quantities in the European pet trade, and illegal trade and/or harvest may occur on a limited basis. ‘A’ report handed to myself from an [anonymous 2014] officer from the office of UNEP states that a population of some 2,000 specimens has been recorded [2014] however there is yet again no census historical data to back these claims/report up. I again must point out that if its proven there are no fewer than [2,000 Tiger Chameleons] remaining in the wild and, Cites is allowing export then Cites is going to come under immense pressure from International Animal Rescue Foundation Africa because exporting live animals for pet trade at such ‘alleged’ depressed populations – is neither helping the species nor supportive of conservation practices.

Threats

The main threat is habitat degradation as a result of the invasion by alien plants species, especially Cinnamomum verum, principally on Mahé and Praslin. Cinnamon is displacing other vegetation, it is present all over the islands and it is the fastest growing, heaviest seeding plant in most areas and is changing the composition of the forests. Currently it makes up 70-90% of trees in Seychelles forests, reaching >95% in some areas. For Archaius tigris, the cinnamon trees provide a normal structure of vegetation, but the invaded forests support a massively diminished insect population, somewhere in the region of 1% of normal abundance. This excludes invasive ants which are the only common invertebrates associated with cinnamon.

In addition, the cinnamon produces a denser canopy than native trees, giving deeper shade which excludes forest floor undergrowth (other than cinnamon seedlings), and this also is a factor in the reduced insect abundance. The Chameleons are found on cinnamon and in cinnamon invaded areas, as long as there is a wide diversity of other plants and a dense undergrowth. In fact, rural gardens can provide habitat for the Chameleons, because these tend to be more diversity in terms of flora, and therefore can support invertebrate fauna.

Dr Jose C. Depre

Environmental and Botanical Scientist.

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Endangered Species Friday: Alopecoenas kubaryi

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Endangered Species Friday: Alopecoenas kubaryi

This Fridays Endangered Species watch Post (ESP), I document on the Caroline Ground Dove scientifically identified as Alopecoenas kubaryi. The species was discovered and named back in 1880 by explorer Friedrich Hermann Otto Finsch (8 August 1839 – 31 January 1917, Braunschweig) was a German ethnographer, naturalist and colonial explorer. Since new data has emerged in relation to the species that Hermann identified, the bird has since been correctly renamed and placed into the correct specie table (please read more below). (Image: Alopecoenas kubaryi: Author unknown). 

Listed as vulnerable populations are continuing to decline, and with such a small population size its quite likely this rather beautiful and peaceful little bird will soon meet the criteria for endangered listing on the threatened species list very soon.

Endemic to Micronesia there are no fewer than 250-999 ‘mature individuals’ remaining if that, (that’s incredibly depressed for a bird listed as vulnerable). This sadly equates to exactly 375-1500 individuals in total. In theory I’m perplexed as to why this beautiful bird hasn’t been re-categorized as critically endangered. Should the wild population continue to decrease at the rate it currently is there will be no time left to re-list this bird or, implement much stronger and professional conservation efforts that are already seen today.

As explained the species is native to the Federated States of Micronesia which is an independent sovereign island nation and a United States associated state consisting of four states – from west to east, Yap, Chuuk, Pohnpei and Kosrae which are situated and spread across the Pacific ocean. The Caroline Ground Dove (common name) is located mostly within the Pohnpei region.

From 1983-1984 within the Pohnpei region populations were said to be as high as 841 mature individuals. That would have equated back then to roughly just over 3,000 individuals in total. Back in 1994 another census was undertaken in relation to the species current population trend within the birds stronghold of Pohnpei.

Unfortunately the survey recorded a staggering decrease in overall population rates within the lowlands. Meanwhile back in 2001 a further survey was conducted which again showed a dramatic decline in population trends. A conservationist by the name of Dr Baker ‘alleged’ in 1951 that the Caroline Ground Dove populations have always been depressed.

I personally disagree with this statement and if populations were ‘surveyed’ to be declining then why wasn’t extreme conservation measures implemented back then to protect the species stronghold and establish a type of nature reserve to increase population sizes? Furthermore and as I have explained why hasn’t the species been listed as (critically endangered?). The evidence is more than clear that populations rather than being (small) have in fact (declined). Conservation efforts that are currently underway too are in my opinion way to late.

The Caroline Ground Dove is commonly known by the locals as; Caroline Ground-dove; Caroline Islands Ground-Dove or the White-fronted Ground Dove. Caroline Ground Dove’s scientific identification back in the 1880’s was put into the wrong (specie) listing commonly known as Gallicolumba kubaryi. However the bird has since been entered into the correct specie list, now known as Alopecoenas kubaryi.  The genera remains the same.

Caroline Ground Doves are known to inhabit tropical or sub-tropical rain-forest of which their preferred habitat is normally within Hibiscus trees. The dove takes a preferential liking to the specie of Hibiscus known scientifically as Hibiscus tiliaceus. Unfortunately the areas from which the bird specie resides is normally within and/or around human settlements which sadly poses a direct threat to the bird due to habitat destruction from human settlements. The dove can also be located in lowland, mangrove and montane rain-forests too.

In the region of Chuuk the Caroline Ground Dove is normally seen inhabiting agricultural areas (again this can pose a significantly high threat) to the bird in general. Reports have also stated that some small populations were located on islets which would indicate coastal habitat is also preferred by the Caroline Ground Dove. Within the region of Weno where habitat is said to be degraded spotters have confirmed the bird may also prefer degraded habitat too.

Diet normally consists of seeds, worms, snails and insects. A. kubaryi normally nests in dense forest at around 180 meters inland. Within the Chuuk province conservationists have confirmed that nests with eggs in have been surveyed from the months of; February, April, June and September. So we know the species normally mates and nests all year round. However unlike other doves that normally lay in the region of 1-3 eggs within a clutch, the Caroline Ground Dove is only known to produce one egg per clutch. Again I question why the species hasn’t been listed as (critically endangered). How much evidence does one need?

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 Image: Alopecoenas kubaryi

Threats

On Pohnpei, predation by introduced species (mainly rats Rattus spp. and cats) and excessive hunting may have caused some depletion. Habitat loss is also a major issue. Overall, there was a reduction of undisturbed upland forest on Pohnpei of over 60% from 1975-1995.

The majority of the island’s forests have been, to varying degrees, converted or at least degraded to mixed forest (native species mixed with lowland secondary species), largely attributable to the cultivation of sakau (kava) Piper methysticum as a major cash-crop. The fragmentation of such forest by sakau clearings also introduces and encourages the spread of invasive species in isolated areas throughout the forest.

Although efforts over the past 20 years to reduce the amount of clear-cutting for sakau plantations have resulted in the slowing of native forest conversion rates, the trend remains negative. On Chuuk, the only remaining semi-original forest remains in tiny remnants on the higher reaches of a few islands.

Traditional leaders have been encouraged to adopt a programme to plant sakau in the lowlands, but resistance is high because the plant grows best on wet mountain slopes and is less likely to be pilfered in more remote areas. Watershed Forest Reserve boundary lines have been laid down and enforced in Madolenihmw and Uh on Pohnpei.

Proposed conservation actions (already now underway) and past conservation actions are in my expert opinion not good enough nor will they prevent this bird from going extinct within five years to seven years max. I do find it somewhat odd that the United States Fish and Wildlife Service haven’t steeped in here to increase more help. But then these islands really are not run by the United States Government. I personally believe the specie will be extinct in five years. Sadly not enough is being done to preserve this stunningly beautiful dove.

Thank you for reading. 

Dr Jose Carlos Depre. 

Environmental and Botanical Scientist. 

info@international-animalrescue-foundation.org.uk

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Endangered Species Monday: Alaena margaritacea

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Endangered Species Monday: Alaena margaritacea

This Mondays (ESP) Endangered Species Watch Post we take a brief glance at South Africa’s most endangered species of butterfly. Generically identified as Alaena margaritacea the species was primarily located by Dr Harry Eltringham FRS (18 May 1873, South Shields – 26 November 1941, from Stroud) whom was an English histologist and entomologist who specialized in Lepidoptera. (Image: unknown photographer) 

Dr Eltringham had been awarded a Master of Science (Cantab and Oxon) and a Doctor of Science (Oxon). He worked at the Hope Department of Entomology. He wrote Histological and Illustrative Methods for Entomologists OCLC 03655743, The Senses of Insects, London, Methuen (1933) and on Lepidoptera Nymphalidae: Subfamily Acraeinae. Lepidopterorum Catalogus 11:1-65 with Karl Jordan (1913) and On specific and mimetic relationships in the genus Heliconius.

Commonly known as the Wolkberg Zulu butterfly and identified back in 1929 the species stands within ‘threatened’ status of which has qualified for vulnerable listing. Endemic to a wee small town of South Africa the butterfly is from the family Lycaenidae which is the (second largest family of butterflies on the planet), hosting some 5,000 species and, constitutes 30% of the butterfly species on Planet Earth.

A. margaritacea is known to inhabit grassy slopes adjoining afromontane forest in the Haenertsburg area of the Limpopo Province near the Wolkberg. Populations trends are currently not known however we do know that flora alien (non-native botanical specimens) are placing the only two known colonies of Wolkberg Zulu butterflies within that area in [extreme danger], back in 2013-2014 a second colony was located to the joy of many.

To give you a clearer image of just how threatened the species is (any such habitat disturbance within their known range could see extinction occur within days rather than months or years).

However its not all doom and gloom yet. There is hope, even within a country that’s habitat is slowly being destroyed by agriculture, aquaculture and urbanization. Three years ago the species was believed to have gone extinct. However an intensive search was mounted by members of the Lepidopterists’ Society of Africa.

Despite being identified back in 1929 the species has only ever been known to occur in one single location: a small town in northern South Africa in Polokwane within the town of Haenertsberg. The wingspan is 24–27 mm for males and 28–30 mm for females. Adults are on wing from late December to early January. There is one generation per year. Lepidopterists’ Society of Africa spokesperson Naturalist Andre Coetzer stated that as yet none has been able to locate a third colony (2014).

The species has a habit of settling very frequently and for very long periods … which makes searching for the butterfly a tedious, challenging task involving long treks over rocky terrain while combing and scrutinizing the grass and undergrowth. And there’s another problem: the Wolkberg Zulu has an extremely short flight period (the ‘winged’ adult part of its life cycle) – just three weeks in December and early January that also happens to fall right in the middle of the rainy season. All of this easily explains why no one has found another colony of this elusive and endangered butterfly in the last 80 years. Until now… Please read more here to learn more on the butterfly. For fuether information please contact the organisation directly – click here

A typical liquid diet consists of nectar from flowers but also eat tree sap, dung, pollen, or rotting fruit. They are attracted to sodium found in salt and sweat too.

The word Lepidoptera is derived from the Latin words “lepido” meaning scale, and “ptera” meaning wings. Lepidoptera literally means scale wings, referring to the minute scale-like structures on the wings of both butterflies and moths. We are unsure as to how many Wolkberg Zulu Butterflies actually live within the two colonies, there could be anything from 100-200 (random guess). Which is why we please ask all our readers to make a donation to the Lepidopterists Society of Africa to secure more projects.

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Image: Wolkberg Zulu butterfly

For now we remain skeptical and whether there will be more colonies located. We are praying for more colonies to be located. The Department of Environmental Affairs must do more to protect their lands from invasive botanical species to ensure future survival of all flora and fauna. Not forgetting establishing a funding program, protected and manned area to secure their South Africa’s critically endangered butterfly. Failing this we’ll lose South Africa’s most rarest butterfly known to humankind.

Threats 

The only known threat to be placing the species in direct danger are that of alien botanical species. Habitat destruction is not known to be problematic within the region although agriculture and human disturbance could very well become a problem. For more information on alien invasive species please see click here for further information.

Unfortunately folks we do not have a video to show of this amazing video but hope one is made available soon. Video footage of this amazing yet so very rare butterfly would be wonderful to view. Please don’t forget to check out the links above and, donate if you can to the group Lepidopterists’ Society of Africa.

Thank you for reading.

Dr Jose C. Depre.

Chief Environmental and Botanical Scientist.