Abstract Members of the Chenopodiaceae are the most dominant elements in the central Asian desert. The different genera and species within this family are common in desert vegetation types. Should it prove possible to link pollen types in this family to specific desert vegetation, it would be feasible to trace vegetation successions in the geological past. Nevertheless, the morphological similarity of pollen grains in the Chenopodiaceae rarely permits identification at the generic level. Although some pollen classifications of Chenopodiaceae have been proposed, none of them tried to link pollen types to specific desert vegetation types in order to explore their ecological significance. Based on the pollen morphological characters of 13 genera and 24 species within the Chenopodiaceae of eastern central Asia, we provide a new pollen classification of this family with six pollen types and link them to those plant communities dominated by Chenopodiaceae, for example, temperate dwarf semi‐arboreal desert ( Haloxylon type), temperate succulent halophytic dwarf semi‐shrubby desert ( Suaeda , Kalidium , and Atriplex types), temperate annual graminoid desert ( Kalidium type), temperate semi‐shrubby and dwarf semi‐shrubby desert ( Kalidium , Iljini , and Haloxylon types), and alpine cushion dwarf semi‐shrubby desert ( Krascheninnikovia type). These findings represent a new approach for detecting specific desert vegetation types and deciphering ecosystem evolution in eastern central Asia.
A 2.0 m thick sediment profile from Kikar Tal, Raebareli District is studied for the pollen assemblage to infer the vegetation and climate variability scenario during the Holocene period. Four distinct palynozones were demarcated based on the palynological succession in the core sediment. However, the radiocarbon dates for the profile could not be procured; therefore, the lake profile is corroborated with the chronology of adjacent lake ‘Chaudhary–Ka–Tal’, Raebareli District. It is envisaged that during 8,000–7,200 cal yrs BP, (Pollen Zone KT–I), forest groves with Holoptelea, Acacia, Madhuca indica, Syzygium and Prosopis as major tree taxa were present in the adjoining area of the lake. The forest groves were interspersed with wider stretches of open vegetation comprising grasses, Tubuliflorae, Liguliflorae, Chenopodiaceae/Amaranthaceae, etc. and shrubs of Adhatoda vasica and Acanthaceae. This vegetation scenario reflects that the region was under a warm and humid climate during that time. The existence of lake is also envisaged by the presence of aquatic elements, Lemna and Typha. Subsequently, during 7,200–4,200 cal yrs BP (Pollen Zone KT–II), the forest groves became more diversified and dense in composition as evidenced by the expansion of most of the existing trees as well as presence of Emblica officinalis, Aegle, Adina cordifolia, Symplocos and Sapotaceae and thickets of Adhatoda vasica and Mimosa pudica. This significant change in the vegetation mosaic as a whole implies the initiation of a warm and more–humid climatic condition, owing to climate amelioration. The encounter of Cerealia and concomitant cropland weeds, viz. Cheno/Am. Cannabis sativa, Brassica, etc. suggests that the vicinity of the lake was under agrarian practice and other anthropogenic activities. The ground flora was still dominated by grasses; however, it also turned more profuse than before. The increasing trend of Cerealia coupled with concomitant cropland weeds signifies the augmentation in Cereal–based agrarian practice owing to favourable climatic condition. The lake expanded as manifested by the increase in aquatic elements, such as Typha, Potamogeton and Lemna during this period. During the time bracket of 4,200–1,800 cal yrs BP (Pollen Zone KT–III), the arboreals reveal a decrease in their frequency and diversity of major tree taxa with incursion of Moringa and Bombax ceiba suggesting warm and moderately humid climate with reduced monsoon. The last zone (Pollen Zone KT–IV), from 1,800 cal yrs BP–Present, elucidates open grassland vegetation corresponding to reduced monsoon precipitation, with the shrinkage of lake area. The presence of Cerealia and other culture pollen taxa suggests the prevalence of intense agrarian practice in the vicinity of the lake.
This paper presents the results of plant macro–remain analysis from Iron Age–Historic settlement sites in Ganga Plain. The plant remains affirm the presence of distinct agricultural economy based on cereals (Oryza sativa, Hordeum vulgare, Triticum aestivum, Triticum sphaerococcum), pulses (Lathyrus sativus, Vigna sp., Macrotyloma uniflorum), oil–fibre yielding (Sesamum indicum, Gossypium sp.) and minor millets (Panicum sp., Setaria sp.). Relative dates based on ceramics from individual site provide secure chronology for the sites between 1200 BCE to 300 CE. Also analyzed pollen and non–pollen palynomorphs from Biland–Khera (200 BCE–300 CE) cultural sediment to investigate palaeovegetation and palaeoenvironment around the settlement.
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