Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
LanguageLanguage
-
SubjectSubject
-
Item TypeItem Type
-
DisciplineDiscipline
-
YearFrom:-To:
-
More FiltersMore FiltersIs Peer Reviewed
Done
Filters
Reset
23,156
result(s) for
"Oliver, S. J."
Sort by:
Status and trends in the international wildlife trade in Chameleons with a focus on Tanzania
by
Burgess, Neil D.
,
Kadigi, Reuben M. J.
,
Pavitt, Alyson T.
in
Analysis
,
Animals
,
Animals, Wild
2024
Chameleons (family Chamaeleonidae) are a distinctive group of reptiles, mainly found in Africa, which have high local endemism and face significant threats from the international wildlife trade. We review the scale and structure of international chameleon trade, with a focus on collection in and exports from Tanzania; a hotspot of chameleon diversity. Analysis used data from the CITES Trade Database 2000–2019, combined with assessment of online trade, and on-the-ground surveys in Tanzania in 2019. Between 2000 and 2019, 1,128,776 live chameleons from 108 species were reported as exported globally, with 193,093 of these (from 32 species) exported by Tanzania. Both global and Tanzanian chameleon exports declined across the study period, driven by decreased trade in generalist genera. Whilst the proportion of captive-bred individuals increased across time for the generalist taxa, the majority of range-restricted taxa in trade remained largely wild-sourced. For Tanzanian exports, 41% of chameleons were from one of the 23 endemic species, and 10 of the 12 Tanzanian endemic species in trade are categorised as threatened with extinction by IUCN. In terms of online trade, of the 42 Tanzanian species assessed, there was evidence of online sale for 83.3% species, and 69% were actively for sale with prices listed. Prices were on average highest for Trioceros species, followed by Kinyongia , Rieppeleon , Rhampholeon , and Chameleo . Field work in Tanzania provided evidence that the historic harvest of endemic chameleon species has been higher than the quantities of these species reported as exported by Tanzania in their annual trade reports to CITES. However, we found no field evidence for trade in 2020 and 2021, in line with Tanzanian regulations that applied a blanket ban on all exports of live wild animals. Literature evidence, however, suggests that illegal trade continued to Europe from seizures of Tanzanian chameleon species in Austria in 2021.
Journal Article
The global distribution of tetrapods reveals a need for targeted reptile conservation
2017
The distributions of amphibians, birds and mammals have underpinned global and local conservation priorities, and have been fundamental to our understanding of the determinants of global biodiversity. In contrast, the global distributions of reptiles, representing a third of terrestrial vertebrate diversity, have been unavailable. This prevented the incorporation of reptiles into conservation planning and biased our understanding of the underlying processes governing global vertebrate biodiversity. Here, we present and analyse the global distribution of 10,064 reptile species (99% of extant terrestrial species). We show that richness patterns of the other three tetrapod classes are good spatial surrogates for species richness of all reptiles combined and of snakes, but characterize diversity patterns of lizards and turtles poorly. Hotspots of total and endemic lizard richness overlap very little with those of other taxa. Moreover, existing protected areas, sites of biodiversity significance and global conservation schemes represent birds and mammals better than reptiles. We show that additional conservation actions are needed to effectively protect reptiles, particularly lizards and turtles. Adding reptile knowledge to a global complementarity conservation priority scheme identifies many locations that consequently become important. Notably, investing resources in some of the world’s arid, grassland and savannah habitats might be necessary to represent all terrestrial vertebrates efficiently.
The global distribution of nearly all extant reptile species reveals richness patterns that differ spatially from that of other taxa. Conservation prioritization should specifically consider reptile distributions, particularly lizards and turtles.
Journal Article
Late Quaternary reptile extinctions: size matters, insularity dominates
2016
Aim: A major Late Quaternary vertebrate extinction event affected mostly large-bodied 'megafauna'. This is well documented in both mammals and birds, but evidence of a similar trend in reptiles is scant. We assess the relationship between body size and Late Quaternary extinction in reptiles at the global level. Location: Global. Methods: We compile a body size database for all 82 reptile species that are known to have gone extinct during the last 50,000 years and compare them with the sizes of 10,090 extant reptile species (97% of known extant diversity). We assess the body size distributions in the major reptile groups: crocodiles, lizards, snakes and turtles, while testing and correcting for a size bias in the fossil record. We examine geographical biases in extinction by contrasting mainland and insular reptile assemblages, and testing for biases within regions and then globally by using geographically weighted models. Results: Extinct reptiles were larger than extant ones, but there was considerable variation in extinction size biases among groups. Extinct lizards and turtles were large, extinct crocodiles were small and there was no trend in snakes. Lizard lineages vary in the way their extinction is related to size. Extinctions were particularly prevalent on islands, with 73 of the 82 extinct species being island endemics. Four others occurred in Australia. The fossil record is biased towards large-bodied reptiles, but extinct lizards were larger than extant ones even after we account for this. Main conclusions Body size played a complex role in the extinction of Late Quaternary reptiles. Larger lizard and turtle species were clearly more affected by extinction mechanisms such as over exploitation and invasive species, resulting in a prevalence of large-bodied species among extinct taxa. Insularity was by far the strongest correlate of recent reptile extinctions, suggesting that size-biased extinction mechanisms are amplified in insular environments.
Journal Article
The rapid assembly of an elliptical galaxy of 400 billion solar masses at a redshift of 2.3
2013
An observation of a rare merger of two massive submillimetre bright galaxies that is forming stars at an unexpectedly high rate of 2,000 solar masses a year shows that such mergers can indeed form the most massive elliptical galaxies by about redshift 1.5.
A massive starburst merger
Multi-wavelength observations of the HXMM01 system, a pair of lensed star-forming galaxies first identified in the Herschel Multi-tiered Extragalactic Survey (HerMES), provide a view of a galactic merger taking place about 11 billion years ago, a period when most of the massive elliptical galaxies existing today were formed. Such events are short-lived on cosmological timescales so are rarely observed. The merging galaxies are forming stars at a rate of 2,000 solar masses per year. The gas reservoir is likely to be exhausted within about 200 million years, by which time a massive elliptical galaxy will have been produced.
Stellar archaeology
1
shows that massive elliptical galaxies formed rapidly about ten billion years ago with star-formation rates of above several hundred solar masses per year. Their progenitors are probably the submillimetre bright galaxies
2
at redshifts
z
greater than 2. Although the mean molecular gas mass
3
(5 × 10
10
solar masses) of the submillimetre bright galaxies can explain the formation of typical elliptical galaxies, it is inadequate to form elliptical galaxies
4
that already have stellar masses above 2 × 10
11
solar masses at
z
≈ 2. Here we report multi-wavelength high-resolution observations of a rare merger of two massive submillimetre bright galaxies at
z
= 2.3. The system is seen to be forming stars at a rate of 2,000 solar masses per year. The star-formation efficiency is an order of magnitude greater than that of normal galaxies, so the gas reservoir will be exhausted and star formation will be quenched in only around 200 million years. At a projected separation of 19 kiloparsecs, the two massive starbursts are about to merge and form a passive elliptical galaxy with a stellar mass of about 4 × 10
11
solar masses. We conclude that gas-rich major galaxy mergers with intense star formation can form the most massive elliptical galaxies by
z ≈
1.5.
Journal Article
Geochronology and physical context of Oldowan site formation at Kanjera South, Kenya
2019
Oldowan sites in primary geological context are rare in the archaeological record. Here we describe the depositional environment of Oldowan occurrences at Kanjera South, Kenya, based on field descriptions and granulometric analysis. Excavations have recovered a large Oldowan artefact sample as well as the oldest substantial sample of archaeological fauna. The deposits at Kanjera South consist of 30 m of fluvial, colluvial and lacustrine sediments. Magneto- and biostratigraphy indicate the Kanjera South Member of the Kanjera Formation was deposited during 2.3–1.92 Ma, with 2.0 Ma being a likely age for the archaeological occurrences. Oldowan artefacts and associated fauna were deposited in the colluvial and alluvial silts and sands of beds KS1–3, in the margins of a lake basin. Field descriptions and granulometric analysis of the sediment fine fraction indicate that sediments from within the main archaeological horizon were emplaced as a combination of tractional and hyperconcentrated flows with limited evidence of debris-flow deposition. This style of deposition is unlikely to significantly erode or disturb the underlying surface, and therefore promotes preservation of surface archaeological accumulations. Hominins were repeatedly attracted to the site locale, and rapid sedimentation, minimal bone weathering and an absence of bone or artefact rounding further indicate that fossils and artefacts were quickly buried.
Journal Article
Differential effects of local habitat and landscape characteristics on bird communities in Mediterranean afforestations motivated by the EU Common Agrarian Policy
by
Universidad de Alcalá. Departamento de Ciencias de la Vida
,
Carrascal, Luis M
,
Sánchez Oliver, Juan Salvador
in
Afforestation
,
Agricultural land
,
Animal populations
2014
We investigated the effects of local habitat structure and surrounding landscape characteristics (proportion of land use types and connectedness) on species density and composition of bird communities inhabiting the interior of young tree plantations on former cropland in central Spain, which were motivated by the Common Agrarian Policy. Variation of species density (number of species/0.78 ha) among tree plantations showed different environmental associations across seasons: local habitat was more important than landscape characteristics during winter, whereas they were similarly important during spring. Species density increased with the development of the tree layer in winter and with the presence of urban areas around tree plantations and cover of the herbaceous layer within them in the breeding season. We identified 15 species that exhibit high relative abundance in woodland habitats within the Mesomediterranean region of Central Spain that were absent in both seasons in the studied tree plantations, which were an attractive habitat for urban exploiter species but an unfavorable habitat for the regional forest species pool except for forest generalist species. Composition of bird assemblages was more related to local habitat structure than to landscape characteristics around tree plantations and was rather similar in winter and spring seasons. The very different effects of local habitat and landscape characteristics on bird communities make difficult suggesting management practices with positive effects for all avifauna species during the entire year. We conclude that the small size and low maturity of the studied tree plantations do not contribute to enhancing the bird diversity value of current CAP aids to afforest former cropland with pines in the Mediterranean region.
Journal Article
Global Protected Areas as refuges for amphibians and reptiles under climate change
2023
Protected Areas (PAs) are the cornerstone of biodiversity conservation. Here, we collated distributional data for >14,000 (~70% of) species of amphibians and reptiles (herpetofauna) to perform a global assessment of the conservation effectiveness of PAs using species distribution models. Our analyses reveal that >91% of herpetofauna species are currently distributed in PAs, and that this proportion will remain unaltered under future climate change. Indeed, loss of species’ distributional ranges will be lower inside PAs than outside them. Therefore, the proportion of effectively protected species is predicted to increase. However, over 7.8% of species currently occur outside PAs, and large spatial conservation gaps remain, mainly across tropical and subtropical moist broadleaf forests, and across non-high-income countries. We also predict that more than 300 amphibian and 500 reptile species may go extinct under climate change over the course of the ongoing century. Our study highlights the importance of PAs in providing herpetofauna with refuge from climate change, and suggests ways to optimize PAs to better conserve biodiversity worldwide.
The effectiveness of protected areas under climate change is debated. Here, the authors analyse the potential effectiveness of protected areas for conserving over 70% of extant amphibian and reptile species under present and future climate scenarios.
Journal Article
A dust-obscured massive maximum-starburst galaxy at a redshift of 6.34
2013
A massive starburst galaxy with 100 billion solar masses of gas is identified at a redshift of 6.34; a ‘maximum starburst’ converts the gas into stars at a rate more than 2,000 times that of the Milky Way.
A massive starburst galaxy unveiled
The physical properties of the first massive starburst galaxies in the Universe provide important clues as to patterns of early cosmic structure formation. But as regions of intense star formation tend to be shrouded in dust, the search for such systems at very high redshift has been a major challenge. Now a massive starburst galaxy has been identified at a redshift
z
= 6.34, just 880 million years after the Big Bang when the Universe was one-sixteenth of its present age. Line-emission data reveal the presence of 100 billion solar masses of gas, equivalent to at least 40% of the galaxy's baryonic (visible matter) mass. The galaxy hosts an intense starburst, converting gas into stars at a rate more than 2,000 times that of the Milky Way. These findings are consistent with the theory that massive galaxies form via extreme starbursts in the early Universe.
Massive present-day early-type (elliptical and lenticular) galaxies probably gained the bulk of their stellar mass and heavy elements through intense, dust-enshrouded starbursts—that is, increased rates of star formation—in the most massive dark-matter haloes at early epochs. However, it remains unknown how soon after the Big Bang massive starburst progenitors exist. The measured redshift (
z
) distribution of dusty, massive starbursts has long been suspected to be biased low in
z
owing to selection effects
1
, as confirmed by recent findings of systems with redshifts as high as ∼5 (refs
2–4
). Here we report the identification of a massive starburst galaxy at
z
= 6.34 through a submillimetre colour-selection technique. We unambiguously determined the redshift from a suite of molecular and atomic fine-structure cooling lines. These measurements reveal a hundred billion solar masses of highly excited, chemically evolved interstellar medium in this galaxy, which constitutes at least 40 per cent of the baryonic mass. A ‘maximum starburst’ converts the gas into stars at a rate more than 2,000 times that of the Milky Way, a rate among the highest observed at any epoch. Despite the overall downturn in cosmic star formation towards the highest redshifts
5
, it seems that environments mature enough to form the most massive, intense starbursts existed at least as early as 880 million years after the Big Bang.
Journal Article
Drugs in oral fluid Part I. Validation of an analytical procedure for licit and illicit drugs in oral fluid
2005
A qualitative and quantitative analytical method was developed and validated for the determination of 49 licit and illicit drugs in oral fluid. Small oral fluid samples, volume 1mL, were collected from volunteers using a modified Omni-Sal device and the analytes were extracted from an oral fluid/buffer mixture using a single Bond Elut Certify solid phase extraction cartridge. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-repetitive full scan mass spectrometry (GC-MS) were used in parallel to analyze the extracts for the targeted drugs. Extracts were analyzed by GC-MS in their underivatized form and as their pentafluoropropionyl derivatives. Deuterated internal standards were used for quantification of drugs of abuse by LC-MS-MS to minimize matrix effects. Methadone-d(9) and tumoxetine were used as the internal standards for quantification of non-derivatized and derivatized analytes respectively by GC-MS. Linearity was demonstrated over the range 5-200 ng/mL and limits of detection were less than 4 ng/mL for each drug analyzed. The method demonstrated acceptable recoveries for most of the analytes and good intra- and inter-day precision. Acquisition of data by repetitive full scan GC-MS allows the addition of further analytes to the target menu.
Journal Article
Extinct, obscure or imaginary: The lizard species with the smallest ranges
by
Chirio, Laurent
,
Colli, Guarino
,
LeBreton, Matthew
in
accessibility
,
anthropogenic activities
,
Anthropogenic factors
2018
Aim: Small geographic ranges make species especially prone to extinction from anthropogenic disturbances or natural stochastic events. We assemble and analyse a comprehensive dataset of all the world's lizard species and identify the species with the smallest ranges–those known only from their type localities. We compare them to wide-ranging species to infer whether specific geographic regions or biological traits predispose species to have small ranges. Location: Global. Methods: We extensively surveyed museum collections, the primary literature and our own field records to identify all the species of lizards with a maximum linear geographic extent of <10 km. We compared their biogeography, key biological traits and threat status to those of all other lizards. Results: One in seven lizards (927 of the 6,568 currently recognized species) are known only from their type localities. These include 213 species known only from a single specimen. Compared to more wide-ranging taxa, they mostly inhabit relatively inaccessible regions at lower, mostly tropical, latitudes. Surprisingly, we found that burrowing lifestyle is a relatively unimportant driver of small range size. Geckos are especially prone to having tiny ranges, and skinks dominate lists of such species not seen for over 50 years, as well as of species known only from their holotype. Twothirds of these species have no IUCN assessments, and at least 20 are extinct. Main conclusions: Fourteen per cent of lizard diversity is restricted to a single location, often in inaccessible regions. These species are elusive, usually poorly known and little studied. Many face severe extinction risk, but current knowledge is inadequate to properly assess this for all of them. We recommend that such species become the focus of taxonomic, ecological and survey efforts.
Journal Article