Last Glacial Maximum climate of the former Soviet Union and Mongolia reconstructed from pollen and plant macrofossil data

International audienceAn improved concept of the best analogues method was used to reconstruct the Last Glacial Maximum (LGM) climate from a set of botanical records from the former Soviet Union and Mongolia. Terrestrial pollen and macrofossil taxa were grouped into broad classes - plant functional types (PFTs), defined by the ecological and climatic parameters used in the BIOME1 model. PFT scores were then calibrated in terms of modern climate using 1245 surface pollen spectra from Eurasia and North America. In contrast to individual taxa, which exhibit great variability and may not be present in the palaeoassemblages, even in suitable climates, PFTs are more characteristic of the vegetation types. The modified method thus allows climate reconstruction at time intervals with partial direct analogues of modern vegetation (e.g. the LGM). At 18 kBP, mean temperatures were 20-29 degrees C colder than today in winter and 5-11 degrees C colder in summer in European Russia and Ukraine. Sites from western Georgia show negative, but moderate temperature anomalies compared to today: 8-11 degrees C in January and 5-7 degrees C in July. LGM winters were 7-15 degrees C colder and summers were 1-7 degrees C colder in Siberia and Mongolia. Annual precipitation sums were 50-750 mm lower than today across northern Eurasia, suggesting a weakening of the Atlantic and Pacific influences. Reconstructed drought index shows much drier LGM conditions in northern and mid-latitude Russia, but similar to or slightly wetter than today around the Black Sea and in Mongolia, suggesting compensation of precipitation losses by lower-than-present evaporation

Dynamics and evolution of Turgay‐type vegetation in Western Siberia throughout the early Oligocene to earliest Miocene—a study based on diversity of plant functional types in the carpological record

peer reviewedBased on ecospectra of 66 published carpofloras we study dynamics and evolution of Turgay vegetation in Western Siberia during the early Oligocene to earliest Miocene. The ecospectra are obtained using a Plant Functional Type (PFT) classification system comprising 26 herbaceous to arboreal PFTs. The carpofloras originate from seven floristic levels covering the time‐span from the Rupelian to early Aquitanian. Key elements of these levels are documented based on original collection materials. Although impacted by local edaphic conditions, the ecospectra can be interpreted in terms of changing vegetation. Our data show that warm temperate mesophytic, mixed conifer‐broad‐leaved deciduous forest assemblages persisted throughout the Oligocene and earliest Miocene in this core area of Turgai type vegetation. This is in line with comparatively stable climate conditions persisting in the studied time‐span, showing a minor temperature decline and coeval moderate increase in seasonality and precipitation. Concurrently, the reconstructed ecospectra contradict significant continental drying throughout the Oligocene and earliest Miocene. Spatial variability of the proportions of PFTs within the single floristic horizons primarily reflects local edaphic conditions. High diversities of PFTs characteristic for swamp vegetation are mainly confined to the early Oligocene and have a regional focus. Our results indicate that taxonomical diversity, particularly concerning mesic herbs and deciduous shrubs and trees, increased towards the end of the Oligocene. This increase in biodiversity probably can be attributed to an increase in rainfall and extension of terrestrial habitats after the final retreat of the Paratethys

Last glacial maximum biomes reconstructed from pollen and plant macrofossil data from northern Eurasia

International audiencePollen and plant macrofossil data from northern Eurasia were used to reconstruct the vegetation of the last glacial maximum (LGM: 18,000 +/- 2000 C-14 yr BP) using an objective quantitative method for interpreting pollen data in terms of the biomes they represent (Prentice Et al., 1996). The results confirm previous qualitative vegetation reconstructions at the LGM but provide a more comprehensive analysis of the data. Tundra dominated a large area of northern Eurasia (north of 57 degreesN) to the west, south and east of the Scandinavian ice sheet at the LGM. Steppe-like vegetation was reconstructed in the latitudinal band from western Ukraine, where temperate deciduous forests grow today, to western Siberia, where taiga and cold deciduous forests grow today. The reconstruction shows that steppe graded into tundra in Siberia, which is not the case today. Taiga grew on the northern coast of the Sea of Azov, about 1500 km south of its present limit in European Russia. In contrast, taiga was reconstructed only slightly south of its southern limit today in south-western Siberia. Broadleaved trees were confined to small refuges, e.g. on the eastern coast of the Black Sea, where cool mixed forest was reconstructed from the LGM data. Cool conifer forests in western Georgia were reconstructed as growing more than 1000 m lower than they grow today. The few scattered sites with LGM data from the Tien-Shan Mountains and from northern Mongolia yielded biome reconstructions of steppe and taiga, which are the biomes growing there today

Factors which influence the consumption of street foods and fast foods in South Africa-a national survey

<p>Abstract</p> <p>Background</p> <p>Very little is known about street food and fast food consumption patterns in South Africa despite this being a large sector of the national economy in terms of employment provided and sales of food. The objective of this study was to determine the use of street foods and fast foods purchased by South Africans living in different provinces and geographic areas.</p> <p>Methods</p> <p>A cross-sectional survey was conducted. Structured interview-administered questionnaires in 11 official languages were conducted at the participants' homes. A nationally representative sample (n = 3287) was drawn from all ethnic groups, and provinces including participants 16 years and older. Logistic regression was done to evaluate factors impacting on fast food consumption.</p> <p>Results</p> <p>Frequent (2 ≥ times/week) street food consumption ranged from 1.8% in Northern Cape to 20.6% in Limpopo; frequent (2 ≥ times/week) fast food consumption ranged between 1.5% in North West Province to 14.7% in Gauteng. The highest intake of street food was in the medium socio-economic category (14.7%) while the highest intake of fast foods was in the high socio-economic category (13.2%). Overall, fruit was the most commonly purchased street food by all ethnic groups over the previous week although this practice was highest in black participants (35.8%). Purchases of soft drinks ranged from 4.8% in whites to 16.4% in blacks and savoury snacks from 2.3% to 14.5% in whites and blacks, respectively. Consumption of fast foods and street foods were influenced by a number of socio-demographic factors including ownership of major home appliances. Frequent fast food consumers had a significantly higher dietary diversity score (4.69; p < 0.0001) while frequent street food consumers had a significantly lower score (3.81; p < 0.0001).</p> <p>Conclusions</p> <p>A large percentage of the population purchase street foods and fast foods. This is of some concern when one notes the high prevalence of soft drink consumption in terms of its association with obesity and non-communicable diseases. These findings need to be taken into consideration when evaluating dietary patterns and nutritional adequacy of population diets.</p