A5077583834- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- SAS software applications and methods
- Astrophysical Phenomena and Observations
- Geology and Paleoclimatology Research
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Tree-ring climate responses
- Astrophysics and Cosmic Phenomena
- Ecology and Vegetation Dynamics Studies
- Particle Detector Development and Performance
- Lichen and fungal ecology
- Pleistocene-Era Hominins and Archaeology
- Statistical and numerical algorithms
- Dark Matter and Cosmic Phenomena
- Species Distribution and Climate Change
- Plant Ecology and Soil Science
- Botany and Plant Ecology Studies
- Nuclear Physics and Applications
- Peatlands and Wetlands Ecology
- Magnetic confinement fusion research
- Isotope Analysis in Ecology
- Ionosphere and magnetosphere dynamics
Tallinn University
2015-2024
University of Florence
2024
Istituto Nazionale di Fisica Nucleare, Sezione di Firenze
2024
Nello Carrara Institute of Applied Physics
2024
National Research Council
2024
Aoyama Gakuin University
2005-2023
Tallinn University of Technology
2015-2022
École Pratique des Hautes Études
2021
Université des Sciences et Techniques de Masuku
2021
Universität Innsbruck
2021
1 According to the Prentice-Sugita model, pollen loading (PL) is linearly related distance-weighted plant abundance (DWPA) surrounding a sedimentary basin. Since source trees of far away from basin have much less influence on representation than near basin, correlation between PL and D WPA should approach an asymptote as vegetation sampling area increases. The 'relevant area' for can be defined beyond which does not improve. 2 A simulation experiment using patchy landscapes illustrates this...
Subfossil pollen and plant macrofossil data derived from 14C-dated sediment profiles can provide quantitative information on glacial interglacial climates. The allow climate variables related to growing-season warmth, winter cold, plant-available moisture be reconstructed. Continental-scale reconstructions have been made for the mid-Holocene (MH, around 6 ka) Last Glacial Maximum (LGM, 21 ka), allowing comparison with palaeoclimate simulations currently being carried out as part of fifth...
Quantitative reconstruction of past vegetation is one the primary goals in Quaternary palynology and palaeoecology but still remains difficult. This paper proposes a model, REVEALS, that estimates regional composition using pollen from ‘large lakes’ have small site-to-site variations assemblages even if highly heterogeneous. Once these data been used to quantify within 10 4 -10 5 km 2 , background pollen, parameters crucial for reconstruction, can be estimated smaller-sized sites,...
Abstract A model of pollen deposition on the surface an entire basin is developed to estimate source area, and results are compared with those for a point at center (I. C. Prentice, 1985, Quaternary Research 23, 76-86; 1988, "Vegetation History," (pp. 17-42, Kluwer Academic). This more appropriate approximating area in lake sediment, since mixing water focusing sediment redistribute originally deposited over surface. In general, radius 10-30% smaller than center; difference profound heavier...
Quantitative reconstruction of the area cleared forest in past is essential to assess possible indirect anthropogenic impacts on environment Europe, including climate. We apply a simul ation model pollen dispersal and deposition (1) re-examine relationship between landscape openness, often uncritically inferred from non-arboreal (NAP) percentages alone, (2) predict relevant source pollen, smallest spatial scale vegetation that can be reconstructed records. The simulations use landscapes...
This paper describes the LOVE (LOcal Vegetation Estimates) model for estimating local vegetation composition within relevant source area of pollen. quantifies and then subtracts background pollen (ie, coming from beyond area) in order to arrive at a quantitative reconstruction vegetation. Parameters required applications are counts target sites, these productivity estimates regional 10 4 -10 5 km 2 . Regional is obtained using fossil large sites (≥10 ha) with REVEALS (Regional Estimates...
Abstract Pollen data from China for 6000 and 18,000 14 C yr bp were compiled used to reconstruct palaeovegetation patterns, using complete taxon lists where possible a biomization procedure that entailed the assignment of 645 pollen taxa plant functional types. A set 658 modern samples spanning all biomes regions provided comprehensive test this showed convincing agreement between reconstructed present natural vegetation types, both geographically in terms elevation gradients mountain...
Abstract. The major objectives of this paper are: (1) to review the pros and cons scenarios past anthropogenic land cover change (ALCC) developed during last ten years, (2) discuss issues related pollen-based reconstruction land-cover introduce a new method, REVEALS (Regional Estimates VEgetation Abundance from Large Sites), infer long-term records pollen data, (3) present project (LANDCLIM: LAND – CLIMate interactions in NW Europe Holocene) currently underway, show preliminary results...
Abstract We present quantitative reconstructions of regional vegetation cover in north‐western Europe, western Europe north the Alps, and eastern for five time windows Holocene [around 6k, 3k, 0.5k, 0.2k, 0.05k calendar years before ( bp )] at a 1° × spatial scale with objective producing descriptions suitable climate modelling. The REVEALS model was applied on 636 pollen records from lakes bogs to reconstruct past 25 plant taxa grouped into 10 plant‐functional types three land‐cover...
8000 years ago, prior to Neolithic agriculture, Europe was mostly a wooded continent. Since then, its forest cover has been progressively fragmented, so that today it covers less than half of Europe's land area, in many cases having cleared make way for fields and pasture-land. Establishing the origin current, more open land-cover mosaic requires long-term perspective, which pollen analysis offers key tool. In this study we utilise compare three numerical approaches transforming data into...
Abstract. Quantitative reconstructions of past land cover are necessary to determine the processes involved in climate–human–land-cover interactions. We present first temporally continuous and most spatially extensive pollen-based land-cover reconstruction for Europe over Holocene (last 11 700 cal yr BP). describe how vegetation has been quantified from pollen records at a 1∘ × spatial scale using “Regional Estimates VEgetation Abundance Large Sites” (REVEALS) model. REVEALS calculates...
Models based on generalized plant physiological theory represent a promising approach for describing vegetation responses to environmental drivers large scales but must be tested their ability reproduce features of real vegetation. We the capability model (LPJ-GUESS) simulate structural and compositional dynamics under various disturbance regimes at transition between prairie, northern hardwoods, boreal forest in Great Lakes region United States. LPJ-GUESS combines detailed representations...
Pollen productivity estimates (PPE) are one of the critical parameters for a quantitative recon struction past vegetation from fossil pollen records. Modern and data were collected in traditional landscapes southern Sweden to derive PPE most characteristic plant taxa. The 42 selected sites assumed be good analogues historical prehistorical grasslands. A sampling method vegetation, designed produce abundance different distance classes, allowed use distance-weighted around surface sites. 11...
In this paper we use a simulation approach to explore the effect of variation in taxon parameters and landscape patterning on relevant source area pollen. We Prentice-Sugita model, assume constant atmospheric conditions basin morphology, take reductionist behaviour pollen dispersal deposition simple scenario. Individual factors within scenario (pollen fall speed, relative productivity, size basic unit mosaic, patch size, rarity individual taxa overall number present landscape) are varied...
Abstract The REVEALS model was developed to reconstruct quantitatively regional vegetation abundance (in a 10 4 –10 5 km 2 area) from pollen assemblages in large lakes (≥100–500 ha). This corrects for biases percentages caused by inter‐taxonomic differences productivity and dispersal. paper presents the first case study validate REVEALS, using empirical data southern Sweden. Percentage cover of modern Skåne Småland, two contrasting regions, predicted with 26 key taxa, surface sediments...
Abstract The Landscape Reconstruction Algorithm (LRA) overcomes some of the fundamental problems in pollen analysis for quantitative reconstruction vegetation. LRA first uses REVEALS model to estimate regional vegetation using data from large sites and then LOVE composition within relevant source area (RSAP) at small by subtracting background estimated composition. This study tests training forest hollows northern Michigan (35 sites) northwestern Wisconsin (43 sites). In Michigan, surface...
Anthropogenic land cover change (ALCC) is the most important transformation of Earth system that occurred in preindustrial Holocene, with implications for carbon, water and sediment cycles, biodiversity provision ecosystem services regional global climate. For example, anthropogenic deforestation Eurasia may have led to feedbacks climate system: both biogeophysical, regionally amplifying winter cold summer warm temperatures, biogeochemical, stabilizing atmospheric CO 2 concentrations thus...