Vegetation history, fire history and lake development recorded for 6300 years by pollen, charcoal, loss on ignition and chironomids at a small lake in southern Kyrgyzstan (Alay Range, Central Asia):

摘要: Analyses of pollen, microscopic charcoal, loss on ignition (LOI) and chironomids in the sediment small sub-alpine lake Kichikol (2541 m a.s.l.; 39°59'N, 73°33'E; Alay Range, Kyrgyzstan) provide new data to reconstruct vegetational lacustrine history during past 6300 years. From 6300—5100 calibrated 14C years BP (cal. yr BP) semi-deserts with Chenopodiaceae Ephedra rather open Juniperus stands persisted around lake. At 5100—4000 cal. dense forest established. Around 4000 retreated was probably restricted north-facing slopes, as is case today. Changes hydrology are inferred from lithological properties, pollen aquatic plants remains invertebrates. The development suggests a step-wise increase humidity mid late Holocene, major shifts recorded at 5000 BP. beginning record very shallow, possibly temporary pond. An initial rise water-table registered c. BP, followed by second near present levels These hydrological could be related an westerly moisture transport Mediterranean region consequence late-Holocene weakening Central Asian High Indian monsoon systems. Moderate human impact after 2100 indicated Plantago lanceolata-type slight charcoal accumulation rates. Considering general course climate well we conclude that composition natural or quasi-natural.