内蒙古草原中东部现代表土植硅体组合与植被关系

对内蒙古中东部14个典型植被表土样品进行植硅体分析，同时将其结果作对应分析。结果表明：圆型和齿型在表土组合中占优势。圆型具有超代表性且在针茅草原和羊草草原表土组合中含量超过50％。针茅哑铃型和脊哑铃型在克氏针茅草原以及退化草原表土组合中含量偏高，可指示干的草原生境以及草原退化。蒿属块型表现为低代表性，即便是在冷蒿灌丛表土中，蒿属块型含量也较低。沙地云杉林和榆树灌丛生境特殊，它们的表土植硅体组合特征明显，前者以光滑块型、粗糙块型、规则多边型以及十字型等为主，后者以多铃型、三铃型、哑铃型以及简单哑铃型为特征。高山草甸和山杨林表土与研究区其它植被表土的相似性低。另外，研究区全新世古土壤剖面样品与表土样品的对应分析表明内蒙古中东部表土植硅体分析为恢复研究区全新世草原植被演化提供了参照物。

PHYTOLITH RECORD OF SURFACE SAMPLES FROM CENTRAL EASTERN INNER MONGOLIA AND THEIR RELATIONSHIP TO THE MODERN VEGETATION

Phytolith analysis of fourteen surface samples from central eastern Inner Mongolia was carried out, and the results were tested by correspondence analysis. The results reveal that rondels and crenates are dominant in all surface samples. Rondels are over represented, and exceed 50% in the Aneurolepidium chinese-dominated and Stipa grandis-dominated grasslands. In the Stipa krylovii-dominated grassland and degenerated grassland, Stipa bilobates and keeled rondels are common, and can be used as indictors of both dry habitat and grassland degeneration. The phytolith production of Artemisia species is low, and Artemisia blocky type phytoliths are not common even in Artemisia frigida shrubbery. The correspondence analysis of phytoliths in soils from different habitats indicates that two particular habitats are extremely different from all the rest: Ulmus pumila and Picea meyeri woodlands. The phytolith types that define these two habitats are Panicoid grass forms for Ulmus pumila (multilobates, trilobates, bilobates, and simple bilobate), and arboreal blocky forms and polyhedrons for Picea meyeri (multifaceted polyhedrals, psilate blocky type, polyhedron, and scabrate blocky type; and one grass type: a cross). The distinctiveness of each of these samples suggests that they would be easily identifiable in a soil record. Meadow grassland and Populus davidiana forest samples are less related to other samples. A correspondence analysis combining surface samples with Taipusi profile samples demonstrates that phytolith analysis of surface samples can provide modern analogue for the reconstruction of Holocene grassland change.