Modern pollen-vegetation-climate relationships and pollen productivity estimates for common East Siberian taxa

2021 ◽  
Author(s):  
Rongwei Geng ◽  
Andrei Andreev ◽  
Stefan Kruse ◽  
Yan Zhao ◽  
Ulrike Herzschuh ◽  
...  
Keyword(s):  
Field Survey ◽  
Source Area ◽  
Soil Samples ◽  
Lake Surface ◽  
East Siberia ◽  
Climate Conditions ◽  
Modern Pollen ◽  
Pollen Productivity ◽  
Paleoclimate Reconstructions ◽  
R Value

<p>East Siberia is an ideal area for investigating the relationships between modern pollen assemblages and vegetation under the extremely cold and dry climate conditions. These relationships are the basis of paleovegetation and paleoclimate reconstructions from fossil pollen records. Pollen productivity estimates (PPE) are required for reliable pollen-based quantitative vegetation reconstructions. Here, we present a new pollen dataset of 48 moss/soil and 24 lake surface sediment samples collected from Chukotka and Yakutia. Generally, tundra and taiga vegetation sites can be well distinguished in the surface pollen assemblages from East Siberia. Moss/soil and lake samples have mostly similar pollen assemblages but contents of some pollen taxa may vary significantly in different sample types. We classified drone images based on field survey to obtain high-resolute vegetation data. Pollen counts in moss/soil samples and vegetation data can? be used in the Extended R-Value (ERV) model to estimate the relevant source area of pollen (RSAP) and the PPEs of major plant taxa. The result of PPE calculation for most common taxa (Alnus, Betula, Cyperaceae, Ericaceae, Larix, Pinus and Salix) can be used to improve vegetation reconstructions.</p>

scholarly journals Key parameters for landscape evolution and anthropogenisation estimation in the Kamchia River downstream region (Eastern Bulgaria)

2021 ◽  
Vol 5 (1) ◽  
pp. 86-93
Author(s):  
Stoyan Ivanov Vergiev ◽  
Mariana Filipova-Marinova ◽  
Daniela Toneva ◽  
Todorka Stankova ◽  
Diyana Dimova ◽  
...  
Keyword(s):  
Source Area ◽  
Critical Parameters ◽  
Vegetation Composition ◽  
Pollen Data ◽  
Plant Abundance ◽  
Pollen Type ◽  
Modern Pollen ◽  
Downstream Region ◽  
Pollen Productivity ◽  
Gis Environment

Pollen productivity еstimate (PPE) and relevant source area of pollen (RSAP) are critical parameters for quantitative interpretations of pollen data in palaeolandscape and palaeoecological reconstructions, and for analyses of the landscapes evolution and anthropogenisation as well. In light of this, the present paper endeavours to calculate PPE of key plant taxa and to define the RSAP in the Kamchia River Downstream Region (Eastern Bulgaria) in order to use them in landscape simulations and estimations. For the purposes of this research, a dataset of pollen counts from 10 modern pollen samples together with corresponding vegetation data, measured around each sample point in concentric rings, were collected in 2020. Three submodels of the Extended R-Value (ERV) model were used to relate pollen percentages to vegetation composition. Therewith, in order to create a calibrated model, the plant abundance of each pollen type was weighed by distance in GIS environment. The findings led to the conclusion that most of the tree taxa have PPE higher than 1 (ERV3 submodel). Cichoriceae, Fabaceae and Asteraceae have lower PPE.

Relative pollen productivity estimates and changes in Holocene vegetation cover in the deciduous forest of southeastern Quebec, Canada

Botany ◽  
2018 ◽  
Vol 96 (5) ◽  
pp. 299-317 ◽  
Author(s):  
Michelle A. Chaput ◽  
Konrad Gajewski
Keyword(s):  
Vegetation Cover ◽  
Deciduous Forest ◽  
Source Area ◽  
Species Level ◽  
Vegetation Survey ◽  
Pollen Data ◽  
Regional Estimates ◽  
Pollen Productivity ◽  
R Value ◽  
Reveals Model

The Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model was used to quantify Holocene changes in vegetation cover in the deciduous forest of southeastern Quebec, Canada. The Extended R-Value (ERV) model was used to obtain relative pollen productivity estimates (PPEs) for eight tree taxa and to determine the relevant source area of pollen (RSAP) for lakes in this ecosystem. Modern vegetation was estimated using pollen data from 16 small (<0.5 km2) lakes and a species-level vegetation survey of southern Quebec. The RSAP was estimated to be within 1600 m of the lakes. Tsuga, Fagus, and Quercus were the most productive taxa, and Populus and Acer were the lowest. Reconstructed changes in absolute vegetation cover show a high abundance of Picea followed by Populus in the early Holocene. The reconstructed values for Populus suggest that it was widely distributed across the landscape. Abies and Acer were dominant on the landscape during the late to mid-Holocene, and an increase in Picea during the Neoglacial is more significant than in percentage diagrams. The REVEALS results provide estimates of land-cover change that are more realistic and informative than the use of pollen percentages alone.

scholarly journals Isolation of entomopathogenic nematodes in an apple orchard in Southern Brazil and its virulence to Anastrepha fraterculus (Diptera: Tephritidae) larvae, under laboratory conditions

2017 ◽  
Vol 77 (1) ◽  
pp. 22-28 ◽  
Author(s):  
E. Foelkel ◽  
M. Voss ◽  
L. B. Monteiro ◽  
G. Nishimura
Keyword(s):  
Entomopathogenic Nematodes ◽  
Abiotic Factors ◽  
Integrated Control ◽  
Weather Conditions ◽  
Apple Orchard ◽  
Soil Samples ◽  
Similar Frequency ◽  
Promising Alternative ◽  
Climate Conditions ◽  
Anastrepha Fraterculus

Abstract Entomopathogenic nematodes (EPNs) are a promising alternative to integrated control in many fruit pests. Few studies were made on the relationship of Anastrepha fraterculus natural population with native EPNs population and other biotic and abiotic factors. The aim of this work was to verify the occurrence of endemic nematodes in an apple orchard, concerning environmental conditions and technical procedure, and access isolates virulence to A. fraterculus larvae. The experiment was conducted during a year taking monthly soil samples from an apple orchard, with and without fallen fruits just above the soil. Samples were baited with Tenebrium molitor and A. fraterculus larvae in laboratory. Canopy and fallen fruits were sampled to access the pest infestation. Seventy three EPN isolates were captured, in 23.2% soil samples, more with T. molitor than with A. fraterculus baits. From the 20 isolates tested against A. fraterculus, only five were pathogenic, and they were identified as Oscheius sp. The nematodes were captured during all seasons in a similar frequency. Soil and weather conditions, presence of fruit over the orchard soil, and A. fraterculus pupae in the fruits had no significant influence on the capture. As a conclusion, nematodes of the genera Oscheius are found in an apple orchard of Porto Amazonas constantly along the year, independently of fluctuations in A. fraterculus population, climate conditions and presence of fruit over the soil. Some of the isolates are pathogenic to A. fraterculus.

Pollen Taphonomy in a Canyon Stream

1987 ◽  
Vol 28 (3) ◽  
pp. 393-406 ◽  
Author(s):  
Patricia L. Fall
Keyword(s):  
Surface Soil ◽  
Pollen Grains ◽  
Close Correlation ◽  
Soil Samples ◽  
Alluvial Deposits ◽  
Modern Pollen ◽  
Pollen Types ◽  
Pollen Rain ◽  
Arid Steppe ◽  
Turbulent Water

AbstractSurface soil samples from the forested Chuska Mountains to the arid steppe of the Chinle Valley, Northeastern Arizona, show close correlation between modern pollen rain and vegetation. In contrast, modern alluvium is dominated by Pinus pollen throughout the canyon; it reflects neither the surrounding floodplain nor plateau vegetation. Pollen in surface soils is deposited by wind; pollen grains in alluvium are deposited by a stream as sedimentary particles. Clay-size particles correlate significantly with Pinus, Quercus, and Populus pollen. These pollen types settle, as clay does, in slack water. Chenopodiaceae-Amaranthus, Artemisia, other Tubuliflorae, and indeterminate pollen types correlate with sand-size particles, and are deposited by more turbulent water. Fluctuating pollen frequencies in alluvial deposits are related to sedimentology and do not reflect the local or regional vegetation where the sediments were deposited. Alluvial pollen is unreliable for reconstruction of paleoenvironments.

Prediction of soil organic and inorganic carbon concentrations in Tunisian samples by mid-infrared reflectance spectroscopy using a French national library

2020 ◽  
Author(s):  
Tiphaine Chevallier ◽  
Cécile Gomez ◽  
Patricia Moulin ◽  
Imane Bouferra ◽  
Kaouther Hmaidi ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Prediction Models ◽  
Reflectance Spectroscopy ◽  
Soil Samples ◽  
Infrared Reflectance ◽  
Least Squares Regression ◽  
Mid Infrared ◽  
Climate Conditions ◽  
Infrared Reflectance Spectroscopy ◽  
Soil Database

&lt;p&gt;Mid-Infrared Reflectance Spectroscopy (MIRS, 4000&amp;#8211;400 cm&lt;sup&gt;-1&lt;/sup&gt;) is being considered to provide accurate estimations of soil properties, including soil organic carbon (SOC) and soil inorganic carbon (SIC) contents. This has mainly been demonstrated when datasets used to build, validate and test the prediction model originate from the same area A, with similar geopedological conditions. The objective of this study was to analyze how MIRS performed when used to predict SOC and SIC contents, from a calibration database collected over a region A, to predict over a region B, where A and B have no common area and different soil and climate conditions. This study used a French MIRS soil dataset including 2178 soil samples to calibrate SIC and SOC prediction models with partial least squares regression (PLSR), and a Tunisian MIRS soil dataset including 96 soil samples to test them. Our results showed that using the French MIRS soil database i) SOC and SIC of French samples were successfully predicted, ii) SIC of Tunisian samples was also predicted successfully, iii) local calibration significantly improved SOC prediction of Tunisian samples and iv) prediction models seemed more robust for SIC than for SOC. So in future, MIRS might replace, or at least be considered as, a conventional physico-chemical analysis technique, especially when as exhaustive as possible calibration database will become available.&lt;/p&gt;

scholarly journals INVESTIGATION OF FAILURES AND VERTICAL DISPLACEMENTS OCCURRING AT THE CHOREMI VILLAGE, NEAR THE MEGALOPOLIS’ MINES

2017 ◽  
Vol 50 (2) ◽  
pp. 625
Author(s):  
E. Avramidou ◽  
E. Psychari ◽  
D. Kanaris ◽  
P. Tzampoglou ◽  
C. Loupasakis
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Laboratory Tests ◽  
Slope Failure ◽  
Field Survey ◽  
Soil Samples ◽  
The West ◽  
Vertical Displacements ◽  
Mineralogy Analysis ◽  
The Village

The current study investigates the catastrophic phenomena affecting Choremi village, at the west boundaries of the Megalopolis’ mines. For this purpose, field survey was carried out, failures in the houses were recorded, the level of aquifer was measured and soil samples were collected for the conduction of laboratory tests and mineralogy analysis. The conclusions of the investigation were verified by slope stability analysis. By evaluating all available data, it is clear that the displacements damaging the village occur due to slope failure and swelling of the clay formations of the narrow study area.

scholarly journals Comparison of spatial downscaling methods of general circulation model results to study climate variability during the Last Glacial Maximum

2018 ◽  
Vol 11 (7) ◽  
pp. 2563-2579 ◽  
Author(s):  
Guillaume Latombe ◽  
Ariane Burke ◽  
Mathieu Vrac ◽  
Guillaume Levavasseur ◽  
Christophe Dumas ◽  
...  
Keyword(s):  
Climate Variability ◽  
Last Glacial Maximum ◽  
General Circulation ◽  
Climate Conditions ◽  
The Past ◽  
Temperature And Precipitation ◽  
Interpolation Technique ◽  
Paleoclimate Reconstructions ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. The extent to which climate conditions influenced the spatial distribution of hominin populations in the past is highly debated. General circulation models (GCMs) and archaeological data have been used to address this issue. Most GCMs are not currently capable of simulating past surface climate conditions with sufficiently detailed spatial resolution to distinguish areas of potential hominin habitat, however. In this paper, we propose a statistical downscaling method (SDM) for increasing the resolution of climate model outputs in a computationally efficient way. Our method uses a generalised additive model (GAM), calibrated over present-day climatology data, to statistically downscale temperature and precipitation time series from the outputs of a GCM simulating the climate of the Last Glacial Maximum (19 000–23 000 BP) over western Europe. Once the SDM is calibrated, we first interpolate the coarse-scale GCM outputs to the final resolution and then use the GAM to compute surface air temperature and precipitation levels using these interpolated GCM outputs and fine-resolution geographical variables such as topography and distance from an ocean. The GAM acts as a transfer function, capturing non-linear relationships between variables at different spatial scales and correcting for the GCM biases. We tested three different techniques for the first interpolation of GCM output: bilinear, bicubic and kriging. The resulting SDMs were evaluated by comparing downscaled temperature and precipitation at local sites with paleoclimate reconstructions based on paleoclimate archives (archaeozoological and palynological data) and the impact of the interpolation technique on patterns of variability was explored. The SDM based on kriging interpolation, providing the best accuracy, was then validated on present-day data outside of the calibration period. Our results show that the downscaled temperature and precipitation values are in good agreement with paleoclimate reconstructions at local sites, and that our method for producing fine-grained paleoclimate simulations is therefore suitable for conducting paleo-anthropological research. It is nonetheless important to calibrate the GAM on a range of data encompassing the data to be downscaled. Otherwise, the SDM is likely to overcorrect the coarse-grain data. In addition, the bilinear and bicubic interpolation techniques were shown to distort either the temporal variability or the values of the response variables, while the kriging method offered the best compromise. Since climate variability is an aspect of the environment to which human populations may have responded in the past, the choice of interpolation technique is therefore an important consideration.

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