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Mortimer J.A.,Seychelles Islands Foundation SIF | Mortimer J.A.,University of Florida
Chelonian Conservation and Biology | Year: 2012

Seasonal and temporal-spatial distributions of green turtle (Chelonia mydas) nesting activity were assessed at Aldabra Atoll Seychelles, the second largest green turtle rookery in the Western Indian Ocean (WIO), based on morning counts of fresh turtle tracks conducted during 1980-2011. The datasets used in the analyses are derived from an average of 3-4 surveys per month at two index sites representing ∼30%-42% of total annual nesting during 1980-1989 and ∼58% during 1995-2011; and monthly surveys conducted at another two remote sites, which accounted for an additional 20% of annual nesting (total ∼78%) during 2002-2011. Turtles engaged in year-round nesting during the season defined as December to November and characterized by patterns of high intra- and interannual variation. In some seasons, nesting peaked primarily during February to May, and in others during May to September, but on average during 1995-2011, a clear unimodal pattern emerged with nesting activity greatest during February to September, peaking during April to June, and lowest in November-December. The two Primary Index Sites situated 2.2 km apart on the west coast and separated by a lagoon entrance had mean peak nesting dates that consistently differed by more than a month. Possible explanations for the differences are discussed. At Aldabra, the timing of the 1997-1998 ENSO event coincided with a disruption in normal nesting cycles during 1998 through 2002 and the highest levels of nesting recorded at Aldabra to date during the 2000-2001 season. Comparison of seasonal median peak nesting dates at five green turtle rookeries in the WIO suggests an inverse relationship with latitude among four of them, with those in the lower latitudes peaking during the austral autumn and winter and in the higher latitudes during the austral summer, an indication that temperature may be moderating nesting seasonality in the WIO. © 2012 Chelonian Research Foundation. Source


Mortimer J.A.,Seychelles Islands Foundation SIF | Mortimer J.A.,University of Florida | Von Brandis R.G.,Seychelles Islands Foundation SIF | Von Brandis R.G.,Tshwane University of Technology | And 3 more authors.
Chelonian Conservation and Biology | Year: 2011

When Aldabra Atoll became a nature reserve in 1968, its endangered nesting green turtle (Chelonia mydas) population was the first to be protected in the Indian Ocean. In 1983, Aldabra became a UNESCO World Heritage Site managed by the Seychelles Islands Foundation (SIF). But prior to 1968, its green turtles suffered intense exploitation documented by trade statistics, historical literature, and a scientific study in 1927. Three population surveys conducted just before, during, and shortly after 1968 provide baseline data by which to assess the long-term population recovery monitored since 1980 using a standardized track count protocol. The 52 nesting beaches distributed along the 83-km outer rim of Aldabra were classified into 6 beach groups (WGT, SETT, DDM, DJL, CC, and North), with total beach length of 5.2 km. During Phase 1 (19801994) of the study, 17 index beaches (WGT #117) were monitored 4 times per month and other beaches opportunistically. During Phase 2 (19942008), index beaches (WGT #122 and SETT) were monitored at least 4 times per month and remote beaches monthly. Track counts were converted to estimated egg clutch production using nesting success data. Reproductive output for the atoll rose from a mean annual estimated 20003000 clutches in the late 1960s to 15,669 (SD = 2776) during 20042008, equivalent to a mean estimated 31005225 females nesting annually (assuming an average of 35 egg clutches per female). This represents a 500%800% increase during 40 years of complete protection. During Phase 2, the rate of increase was highest at the Settlement Beach (SETT), which had historically suffered the most intense exploitation. © 2011 Chelonian Research Foundation. Source


Galman G.,French Natural History Museum | Matyot P.A.T.,Island Conservation Society ICS | Voisin J.-F.,Seychelles Islands Foundation SIF
Annales de la Societe Entomologique de France | Year: 2011

The Seychellian species of the genus Cratopus are reviewed, and four new taxa described. The largesized (16-19 mm) C. roberti n. sp. possesses ten elytral striae, small denticules on its foretibiae, the profemoral tooth included, and a metallic squamulose green vestiture with a white stripe at the base and along the sides of the elytra as well as along each side of the prothorax. About 8-10 mm long, C. venustus n. sp. is recognizable from its black, shining integuments, its reduced metallic blue vestiture, its twelve elytral striae of strong punctures, and its careniform 8. and 9. interstriae. C. griseovestitus northislandensis n. ssp. differs from the nominative form C. griseovestitus griseovestitus Linell 1887 by its coriaceous integuments and denser vestiture with golden to green reflections. C. griseovestitus fregata n. ssp. differs from the nominative form by its more or less dark brown integuments, with scattered, very small hairs and squamules. The synonymy of C. parcesquamosus Fairmaire 1893 and C. abbotti Linell 1907 with C. aurostriatus Fairmaire 1892 is confirmed, and an identification key to the Seychellian species of the genus is given. These species can be divided into two sets according to their distribution. One of these sets comprises three species of the griseovestitus group, which have a broad distribution and inhabit coastal areas and low coral islands, and probably arrived fairly recently. The second set comprises six species living in the granitic islands, five of them having their habitat restricted to the interior of one or two islands. They are certainly of much older stock. The Cratopus are folivores at the adult stage, and often polyphagous, and a list of their known host-plants is provided. Source


Frazier J.,Smithsonian Conservation Biology Institute | Matyot P.,Seychelles Islands Foundation SIF
Zootaxa | Year: 2010

Although it was forgotten for over a century, the binomen Testudo dussumieri Gray, 1831, is an available name, and the specimen RMNH 3231 deposited in the natural history museum of Leiden - evidently one of the two original syntypes of T. dussumieri - has been designated as the lectotype of this taxon. Recently several authors have actively promoted this as the name-bearing type for the Aldabra tortoise, escalating debates in which this chelonian has been immersed for nearly two decades. This lectotype designation is highly significant to nomenclatural and taxonomic disputes regarding tortoises (Testudinidae), living and extinct, from the western Indian Ocean; and an attempt has been made in this paper to compile all information relevant to the lectotype as well as to better understand the history of the binomen applied to it. Several critical aspects of the history are uncertain and open to speculation. The provenance of RMNH 3231 is unknown and unlikely to be Aldabra Atoll; the specimen was most likely collected in the granitic Seychelles, between 1823 and 1829. The combination of estimated date and locality of collection raises the possibility that the lectotype is not an Aldabra tortoise, but rather an extinct taxon from the granitic Seychelles. It is concluded that RMNH 3231 is not a suitable name-bearing type for the Aldabra tortoise, and the continued use of the name T. dussumieri will cause persistent nomenclatural and taxonomic confusion and unending debate. Copyright © 2010 © Magnolia Press. Source

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