Duncan W. Thomas
A5067517189- Ecology and Vegetation Dynamics Studies
- Plant and animal studies
- Forest ecology and management
- Plant Diversity and Evolution
- African Botany and Ecology Studies
- Species Distribution and Climate Change
- Plant Water Relations and Carbon Dynamics
- Animal Ecology and Behavior Studies
- Mediterranean and Iberian flora and fauna
- Traditional and Medicinal Uses of Annonaceae
- Axial and Atropisomeric Chirality Synthesis
- Plant Parasitism and Resistance
- Plant and Fungal Species Descriptions
- Remote Sensing and LiDAR Applications
- Botany and Plant Ecology Studies
- Forest Management and Policy
- Fire effects on ecosystems
- Botanical Research and Applications
- Remote Sensing in Agriculture
- Molecular spectroscopy and chirality
- Genomics and Chromatin Dynamics
- Chemical synthesis and alkaloids
- American Environmental and Regional History
- Alkaloids: synthesis and pharmacology
- Genetic and phenotypic traits in livestock
Oregon State University
2012-2025
Washington State University Vancouver
2015-2024
National Museum of Natural History
2020
ForestGEO
2006-2020
Universiti Brunei Darussalam
2020
Washington State University
2014-2017
Smithsonian Tropical Research Institute
2006
University of California, San Francisco
2005
Wellcome Sanger Institute
2003-2004
Corvallis Environmental Center
1997
Abstract Aim To examine the contribution of large‐diameter trees to biomass, stand structure, and species richness across forest biomes. Location Global. Time period Early 21st century. Major taxa studied Woody plants. Methods We examined large density, biomass using a global network 48 (from 2 60 ha) plots representing 5,601,473 stems 9,298 210 plant families. This was assessed three metrics: largest 1% ≥ 1 cm diameter at breast height (DBH), all DBH, those rank‐ordered that cumulatively...
Species spatial turnover, or beta-diversity, induces a decay of community similarity with geographic distance known as the distance-decay relationship. Although this relationship is central to biodiversity and biogeography, its theoretical underpinnings remain poorly understood. Here, we develop general framework describe how influenced by population aggregation landscape-scale species-abundance distribution. We utilize data from three tropical forests show that rare species have weak...
Summary The relationship between species richness and ecosystem function, as measured by productivity or biomass, is of long‐standing theoretical practical interest in ecology. This especially true for forests, which represent a majority global biodiversity. Here, we conduct an analysis relationships tree richness, biomass 25 forest plots area 8–50 ha from across the world. data were collected using standardized protocols, obviating need to correct methodological differences that plague many...
Maintaining tree diversity Negative interaction among plant species is known as conspecific negative density dependence (CNDD). This ecological pattern thought to maintain higher in the tropics. LaManna et al. tested this hypothesis by comparing how changes with intensity of local biotic interactions tropical and temperate latitudes (see Perspective Comita). Stronger specialized seem prevent erosion biodiversity forests, not only limiting populations common species, but also strongly...
Both habitat filtering and dispersal limitation influence the compositional structure of forest communities, but previous studies examining relative contributions these processes with variation partitioning have primarily used topography to represent environment. Here, we bring together data on both soil resource within eight large (24–50 ha) tropical plots, use decompose community into fractions explained by spatial, topographic variables. resources account for significant approximately...
Abstract Numerous studies have shown reduced performance in plants that are surrounded by neighbours of the same species 1,2 , a phenomenon known as conspecific negative density dependence (CNDD) 3 . A long-held ecological hypothesis posits CNDD is more pronounced tropical than temperate forests 4,5 which increases community stabilization, coexistence and diversity local tree 6,7 Previous analyses supporting such latitudinal gradient 8,9 suffered from methodological limitations related to...
ABSTRACT A recent increase in published studies of lianas has been paralleled by a proliferation protocols for censusing lianas. This article seeks to uniformity liana inventories providing specific recommendations the determination which taxa include, location diameter measurement points on individual stems, setting minimum stem cutoffs, treatment multiple‐stemmed and rooted clonal groups, noncylindrical stems. Use more uniform may facilitate comparison independently collected data sets...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnti-HIV Michellamines from Ancistrocladus korupensisMichael R. Boyd, Yali F. Hallock, John H. Cardellina II, Kirk P. Manfredi, W. Blunt, James B. McMahon, Robert Buckheit Jr., Gerhard Bringmann, Manuela Schäffer, Gordon M. Cragg, Duncan Thomas, and Johnson G. JatoCite this: J. Med. Chem. 1994, 37, 12, 1740–1745Publication Date (Print):June 1, 1994Publication History Published online1 May 2002Published inissue 1 June...
ABSTRACT Aims With the aim of understanding why some world's forests exhibit higher tree beta diversity values than others, we asked: (1) what is contribution environmentally related variation versus pure spatial and local stochastic to assessed at forest plot scale; (2) resolution are these beta‐diversity components more apparent; (3) determines in observed across regions/continents? Location World‐wide. Methods We compiled an unprecedented data set 10 large‐scale stem‐mapping plots...
Large tropical trees and a few dominant species were recently identified as the main structuring elements of forests. However, such result did not translate yet into quantitative approaches which are essential to understand, predict monitor forest functions composition over large, often poorly accessible territories. Here we show that above-ground biomass (AGB) whole can be predicted from large relationship is proved strikingly stable in 175 1-ha plots investigated across 8 sites spanning...
Tropical tree communities are shaped by local-scale habitat heterogeneity in the form of topographic and edaphic variation, but life-history stage at which associations develop remains poorly understood. This is due, part, to fact that previous studies have not accounted for widely disparate sample sizes (number stems) result when trees divided into size classes. We demonstrate observed structuring a community directly related number individuals community. then compare relative importance...
Long-term surveys of entire communities species are needed to measure fluctuations in natural populations and elucidate the mechanisms driving population dynamics community assembly. We analysed changes abundance over 4000 tree 12 forests across world periods 6-28 years. Abundance all large consistent with models which temporal environmental variance plays a central role. At some sites we identify clear drivers, such as fire drought, that could underlie these patterns, but at other there is...
Abstract. Advances in forest carbon mapping have the potential to greatly reduce uncertainties global budget and facilitate effective emissions mitigation strategies such as REDD+ (Reducing Emissions from Deforestation Forest Degradation). Though broad-scale is based primarily on remote sensing data, accuracy of resulting stock estimates depends critically quality field measurements calibration procedures. The mismatch spatial scales between inventory plots larger pixels current planned...
Summary Tree size shapes forest carbon dynamics and determines how trees interact with their environment, including a changing climate. Here, we conduct the first global analysis of among‐site differences in aboveground biomass stocks fluxes are distributed tree size. We analyzed repeat censuses from 25 large‐scale (4–52 ha) plots spanning broad climatic range over five continents to characterize biomass, woody productivity, mortality vary diameter. examined median, dispersion, skewness...
Abstract Organisms of all species must balance their allocation to growth, survival and recruitment. Among tree species, evolution has resulted in different life‐history strategies for partitioning resources these key demographic processes. Life‐history tropical forests have often been shown align along a trade‐off between fast growth high survival, that is, the well‐known fast–slow continuum. In addition, an orthogonal proposed tall stature—resulting from survival—and recruitment success,...
SUMMARY The mycorrhizal status of a group caesalpinioid legumes in lowland rain‐forest Korup National Park, SW Cameroon, was examined. Species ten genera, Anthonotha, Aphanocalyx, Berlinia, Didelotia, Gilbertiodendron, Julbernardia, Microberlinia, Monopetalanthus, Tetraberlinia (tribe Amherstieae) and Afzelia Detarieae) were ectomycorrhizal. These species not uniformly distributed the forest, three large emergent Microberlinia bisulcata A. Chev., bifoliolata (Harms) Hauman, T. moreliana...
Background DNA barcoding of rain forest trees could potentially help biologists identify species and discover new ones. However, barcodes cannot always distinguish between closely related species, the size completeness barcode databases are key parameters for their successful application. We test ability rbcL, matK trnH-psbA plastid markers to at two sites in Atlantic central Africa under assumption that a database is exhaustive terms content, but not necessarily haplotype diversity within...