Malcolm G. Penn
Natural History Museum
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Publication
Featured researches published by Malcolm G. Penn.
Proceedings of the National Academy of Sciences of the United States of America | 2008
Louise T. Humphrey; Mc Dean; Te Jeffries; Malcolm G. Penn
Recent developments in microspatial analysis of enamel chemistry provide the resolution needed to reconstruct detailed chronological records of an individuals early life history. Evidence of nutritional history, residential mobility, and exposure to heavy metals can potentially be retrieved from archaeological and even fossil teeth. Understanding the pattern and timing of incorporation of each trace element or stable isotope into enamel is crucial to the interpretation of the primary data. Here, we use laser ablation inductively coupled plasma mass spectrometry and ArcGIS software to map variation in calcium-normalized strontium intensities across thin sections of enamel from exfoliated deciduous teeth. Differences in calcium-normalized strontium intensities across each tooth reflect variation in tooth mineralization, implying that sampling location must be taken into account in interpreting results. Chronologically consistent shifts in calcium-normalized strontium intensities in teeth from children with known nursing histories reflect the onset and duration of breastfeeding and the introduction of nonmaternal sources of food. This tool is likely to be valuable for studying weaning and nursing behavior in the past. The distribution of normalized strontium intensities presented here is consistent with a model for the differential incorporation of strontium and calcium into enamel during the secretory and maturational phases of formation.
Economic Botany | 2006
Samuel G. M. Bridgewater; Philippa Pickles; Nancy C. Garwood; Malcolm G. Penn; Richard M. Bateman; Holly Porter Morgan; Nicholas Wicks; Nicodemous Bol
Of the twelve species ofChamaedorea palm recorded for Belize, three are of international economic value because their cut leaves (xaté) are traded in the floricultural industry. Traditionally, Belize has not harvested xaté, the industry being based in Mexico and Guatemala. However, a decline in wild xaté stocks in these countries means Guatemalan leaf harvesters now illegally harvest xaté in Belize. To assess the local abundance of the BelizeanChamaedorea resource, its economic value, and the extent to which it has been illegally harvested, 209 plots measuring 20 meters (m) by 20 m were established in the Greater Maya Mountains (GMM) in western Belize, which includes the Chiquibul Forest Reserve (CFR). We estimate that 37.8 million leaves with a value of U.S.
Systematics and Biodiversity | 2004
Malcolm G. Penn; Alex Monro
0.3 million to xateros have been extracted from the CFR. The standing export value is calculated as U.S.
Biological Reviews | 2009
Richard J. Butler; Paul M. Barrett; Paul Kenrick; Malcolm G. Penn
1.8 million for the CFR and U.S.
Proceedings of the Royal Society of London B: Biological Sciences | 2012
Daniel P. Bebber; Mark A. Carine; Gerrit Davidse; David J. Harris; Elspeth Haston; Malcolm G. Penn; Steve Cafferty; John R. I. Wood; Robert W. Scotland
5 million for the GMM.
Edinburgh Journal of Botany | 2006
S. G. M. Bridgewater; David J. Harris; C. Whitefoord; A. K. Monro; Malcolm G. Penn; D. A. Sutton; B. Sayer; B. Adams; M. J. Balick; D. H. Atha; J. Solomon; B. K. Holst
Abstract This paper describes a new vegetation classification for the Greater Maya Mountains of Belize, focusing primarily on the Chiquibul Forest Reserve. Extensive use is made of GIS, remote sensing, botanical collections and field visits to provide a macro‐ and meso‐scale overview of the vegetation of this region. A total of 32 vegetation classes have been defined, both geographically and structurally, including 11 new classes. Where possible, classes have been compared with earlier classifications. A dominant scaling technique has been used to enable direct comparison between ground truthing data and a supervised Maximum Likelihood Classifier image‐based vegetation classification. The merits of such classifications and the effect of scale are discussed.
Systematics and Biodiversity | 2009
Malcolm G. Penn; Clive Moncrieff; Samuel G. M. Bridgewater; Nancy C. Garwood; Richard M. Bateman; Ivis Chan; Percival Cho
The significance of co‐evolution over ecological timescales is well established, yet it remains unclear to what extent co‐evolutionary processes contribute to driving large‐scale evolutionary and ecological changes over geological timescales. Some of the most intriguing and pervasive long‐term co‐evolutionary hypotheses relate to proposed interactions between herbivorous non‐avian dinosaurs and Mesozoic plants, including cycads. Dinosaurs have been proposed as key dispersers of cycad seeds during the Mesozoic, and temporal variation in cycad diversity and abundance has been linked to dinosaur faunal changes. Here we assess the evidence for proposed hypotheses of trophic and evolutionary interactions between these two groups using diversity analyses, a new database of Cretaceous dinosaur and plant co‐occurrence data, and a geographical information system (GIS) as a visualisation tool. Phylogenetic evidence suggests that the origins of several key biological properties of cycads (e.g. toxins, bright‐coloured seeds) likely predated the origin of dinosaurs. Direct evidence of dinosaur–cycad interactions is lacking, but evidence from extant ecosystems suggests that dinosaurs may plausibly have acted as seed dispersers for cycads, although it is likely that other vertebrate groups (e.g. birds, early mammals) also played a role. Although the Late Triassic radiations of dinosaurs and cycads appear to have been approximately contemporaneous, few significant changes in dinosaur faunas coincide with the late Early Cretaceous cycad decline. No significant spatiotemporal associations between particular dinosaur groups and cycads can be identified – GIS visualisation reveals disparities between the spatiotemporal distributions of some dinosaur groups (e.g. sauropodomorphs) and cycads that are inconsistent with co‐evolutionary hypotheses. The available data provide no unequivocal support for any of the proposed co‐evolutionary interactions between cycads and herbivorous dinosaurs – diffuse co‐evolutionary scenarios that are proposed to operate over geological timescales are plausible, but such hypotheses need to be firmly grounded on direct evidence of interaction and may be difficult to support given the patchiness of the fossil record.
Bulletin of The Natural History Museum. Entomology Series | 2002
Anthony John Shelley; L.M. Hernández; Malcolm G. Penn
Discovering biological diversity is a fundamental goal—made urgent by the alarmingly high rate of extinction. We have compiled information from more than 100 000 type specimens to quantify the role of collectors in the discovery of plant diversity. Our results show that more than half of all type specimens were collected by less than 2 per cent of collectors. This highly skewed pattern has persisted through time. We demonstrate that a number of attributes are associated with prolific plant collectors: a long career with increasing productivity and experience in several countries and plant families. These results imply that funding a small number of expert plant collectors in the right geographical locations should be an important element in any effective strategy to find undiscovered plant species and complete the inventory of the world flora.
Ecography | 2017
Stephen J. Brooks; Angela Self; Gary D. Powney; William D. Pearse; Malcolm G. Penn; Gordon L.J. Paterson
Covering an area of 177,000 hectares, the region known within Belize as the Chiquibul Forest comprises the country’s largest forest reserve and includes the Chiquibul Forest Reserve, the Chiquibul National Park and the Caracol Archaeological Reserve. Based on 7047 herbarium and live collections, a checklist of 1355 species of vascular plant is presented for this area, of which 87 species are believed to be new records for the country. Of the 41 species of plant known to be endemic to Belize, four have been recorded within the Chiquibul, and 12 species are listed in The World Conservation Union (IUCN) 2006 Red List of Threatened Species. Although the Chiquibul Forest has been relatively well collected, there are geographical biases in botanical sampling which have focused historically primarily on the limestone forests of the Chiquibul Forest Reserve. A brief review of the collecting history of the Chiquibul is provided, and recommendations are given on where future collecting efforts may best be focused. The Chiquibul Forest is shown to be a significant regional centre of plant diversity and an important component of the Mesoamerican Biological Corridor.
Memorias Do Instituto Oswaldo Cruz | 2001
Anthony John Shelley; Apa Luna Dias; Marilza Maia-Herzog; C. A. Lowry; Pr Garritano; Malcolm G. Penn; M Camargo
Abstract The purpose of this investigation was to model the distribution of the fishtail xate palm (´Chamaedorea ernesti‐augusti) and to investigate the effectiveness of using geostatistical techniques to map its distribution. The leaves of the Central American xate palm C. ernesti‐augusti are now extensively cut for the flori‐cultural industry; across its range, populations are being over‐harvested. In Central America, the Greater Maya Mountains (GMM), Belize are widely believed to be an abundance ‘hotspot’ for this species. In total, 220 sample sites were systematically located throughout the GMM, based on a fixed distance interval using the accessible track/road network. Species counts and environmental data were collected from each 20 m × 20 m plot. Statistical analyses were carried out using GenStat and Arc‐GIS. We used several semivariogram models, within bespoke GenStat procedures, to map the log‐transformed xate abundance data. Validation of models used the official GenStat Kcross‐validation procedure. Of the six models investigated in detail, the ‘Bounded Linear’ model outperformed all others and most effectively represented the spatial distribution of C. ernesti‐augusti. Environmental factors were found to have low statistical significance for the distribution of the xate palm. The predicted map shows that the geographic abundance was dominated by low xate counts; xat´ abundance values for this region appear to have been consistently overestimated in the literature. Our study showed the effectiveness of using local modelling techniques to map xate abundances and reveal local abundance hotspots. It highlighted areas needing further survey work and the need for collecting more environmental data to improve the prediction of plant distribution in this region using niche and/or co‐kriging modelling approaches. Our study suggested that the xate resource in Belize needs a careful conservation approach.