A5011715369- Geology and Paleoclimatology Research
- Pleistocene-Era Hominins and Archaeology
- Amazonian Archaeology and Ethnohistory
- Ecology and Vegetation Dynamics Studies
- Isotope Analysis in Ecology
- Archaeology and ancient environmental studies
- Plant Diversity and Evolution
- Pacific and Southeast Asian Studies
- Species Distribution and Climate Change
- Plant and animal studies
- Evolution and Paleontology Studies
- Conservation, Biodiversity, and Resource Management
- Wireless Communication Networks Research
- Fire effects on ecosystems
- Antenna Design and Analysis
- Environmental and Cultural Studies in Latin America and Beyond
- Tree-ring climate responses
- African Botany and Ecology Studies
- Power Line Communications and Noise
- Antenna Design and Optimization
- Speech and Audio Processing
- Cassava research and cyanide
- Polar Research and Ecology
- Radio Wave Propagation Studies
- Sensor Technology and Measurement Systems
University of Amsterdam
2016-2025
The Open University
2013-2022
University of Bath
1974-2020
Lorentz Center
2020
Vrije Universiteit Amsterdam
2020
University of Roehampton
2020
Utrecht University
2020
Leiden University
2020
Pyramid Technical Consultants (United States)
2019
Great Basin College
2019
Impacts of global climate change on terrestrial ecosystems are imperfectly constrained by ecosystem models and direct observations. Pervasive transformations occurred in response to warming associated climatic changes during the last glacial-to-interglacial transition, which was comparable magnitude projected for next century under high-emission scenarios. We reviewed 594 published paleoecological records examine compositional structural vegetation since glacial period project magnitudes...
Individual processes shaping geographical patterns of biodiversity are increasingly understood, but their complex interactions on broad spatial and temporal scales remain beyond the reach analytical models traditional experiments. To meet this challenge, we built a spatially explicit, mechanistic simulation model implementing adaptation, range shifts, fragmentation, speciation, dispersal, competition, extinction, driven by modeled climates past 800,000 years in South America. Experimental...
While large-scale pre-Columbian human occupation and ecological disturbance have been demonstrated close to major Amazonian waterways, less is known of sites in terra firme settings. Palaeoecological analyses two lake districts central western Amazonia reveal long histories land use. At both locations, activity was centred on one the lakes, while others were either lightly used or unused. These indicate that scale impacts these settings localized probably strongly influenced by presence a...
The accurate and consistent identification of fossil pollen is essential to allow robust inferences be drawn with regard past climate vegetation change. Identifications are best achieved through the direct inspection reference material. Most substantial collections held at prestigious universities in Europe or United States America which can restrict access for researchers trying advance palynology less developed countries. Digital imaging fast spreading internet means that it now possible...
Abstract. An improved understanding of present-day climate variability and change relies on high-quality data sets from the past 2 millennia. Global efforts to model regional modes are in process being validated against, integrated with, records vegetation change. For South America, however, full potential for evaluating improving models has hitherto not been sufficiently acknowledged due an absence information spatial temporal coverage study sites. This paper therefore serves as a guide...
The high tropical Andes host one of the richest alpine floras world, with exceptionally levels endemism and turnover rates. Yet, little is known about patterns processes that structure altitudinal latitudinal variation in plant community diversity. Herein we present first continental‐scale comparative study diversity on summits Andes. Data were obtained from 792 permanent vegetation plots (1 m 2 ) within 50 summits, distributed along a 4200 km transect; summit elevations ranged between 3220...
Significance Our results identify the prime driver of climate variation in Africa’s low latitudes over past 620 ky—the key time frame for evolution our species. Warming and cooling tropical Pacific Ocean paced by insolation changes modulated Walker circulation, driving opposing wet–dry states eastern western Africa. We show that effects glacial/interglacial cycles were not predominant source environmental change most continent. patchwork driven low-latitude processes should therefore be a...
Abstract The manifestation of major climatic events such as the timing deglaciation and whether, or not, Younger Dryas affected Andean systems has garnered considerable recent attention. Even Holocene is rapidly emerging a time interest in Neotropical palaeoclimatology palaeoecology. Neotropics now revealed some temperature change with precipitation:evaporation ratios fluctuating markedly. Major changes lake level, ice‐accumulation, vegetation are indicative both precipitation regimes....
Abstract. The biomisation method is used to reconstruct Latin American vegetation at 6000±500 and 18 000±1000 radiocarbon years before present (14C yr BP) from pollen data. Tests using modern data 381 samples derived 287 locations broadly reproduce potential natural vegetation. strong temperature gradient associated with the Andes recorded by a transition high altitude cool grass/shrubland mixed forest mid-altitude temperate rain forest, tropical dry, seasonal low altitudes. Reconstructed...
The updated inventory of the Latin American Pollen Database (LAPD) offers a wide range new insights. This paper presents systematic compilation palynological research in America. A comprehensive publications peer-reviewed and grey literature shows major expansion studies over last decades. includes 1379 cores sections with paleoecological data more than 4800 modern samples from throughout continent. Through years, pollen datasets extend increasing spans time show improved taxonomic temporal...
Terrestrial fossil pollen records are frequently used to reveal the response of vegetation changes in both regional and global climate. Here we present a record from sediment cores extracted Lake Bosumtwi (West Africa). This covers last c. 520 thousand years (ka) represents longest terrestrial Africa published date. The assemblages dynamic change which can be broadly characterized as indicative shifts between savannah forest. Savannah formations heavily dominated by grass (Poaceae) (>55%)...
Abstract Aim The climate variability hypothesis (CVH) predicts that locations with reduced seasonal temperature variation select for species narrower thermal ranges. Here we (a) test the CVH by assessing effect of latitude and elevation on ranges Andean vascular plant communities, (b) assess tropical alpine plants vulnerability to warming based their traits. Location High Andes. Taxon Vascular plants. Methods Temperature data 505 from communities 49 summits, were extracted 29,627...
Sporopollenin, which forms the outer wall of pollen and spores, contains a chemical signature ultraviolet-B flux via concentrations UV-B absorbing compounds (UACs), providing proxy for reconstructing UV irradiance through time. Although Fourier transform infrared (FTIR) spectroscopy provides an efficient means measuring UAC concentrations, nitrogen-containing have potential to bias aromatic hydroxyl bands used quantify standardise abundances. Here, we explore presence possible influence...
Anthropogenically elevated CO2 (eCO2) concentrations have been suggested to increase woody cover within tropical ecosystems through fertilization. The effect of eCO2 is built into Earth system models, although testing the relationship over long periods remains challenging. Here, we explore relative importance six drivers vegetation change in western Africa past ~500,000 years (moisture availability, fire activity, mammalian herbivore density, temperature, temperature seasonality, CO2) by...
A reconstruction of past environmental change from Ecuador reveals the response lower montane forest on Andean flank in western Amazonia to glacial-interglacial global climate change. Radiometric dating volcanic ash indicates that deposition occurred ~324,000 193,000 years ago during parts Marine Isotope Stages 9, 7, and 6. Fossil pollen wood preserved within organic sediments suggest composition altered radically The presence Podocarpus macrofossils ~1000 meters below limit their modern...
Abstract Question: Is the modern patchy distribution of highly biodiverse Polylepis woodlands a consequence human activity or natural fluctuations in environmental conditions? What are consequences changing climate for tree genus ? Location: High central tropical Andes. Methods: We characterized ecological baseline conditions over last ca. 370 000 years through: (i) examination fossil pollen records (Salar de Uyuni and Lake Titicaca) (ii) review autecological information concerning ....
Sporomorphs (pollen and spores) have an outer wall composed of sporopollenin. Sporopollenin chemistry contains both a signature ambient ultraviolet-B flux taxonomic information, but it is currently unknown how sensitive this to standard palynological processing techniques. Oxidation in particular known cause physical degradation sporomorphs, expected that should concordant impact on sporopollenin chemistry. Here, we test by experimentally oxidizing Lycopodium (clubmoss) spores using two...