Pollen dispersal in a mountainous area based on pollen analysis of four natural trap types from Lugu Lake, southwest China

Abstract

AbstractPalynological analysis of 24 samples from four types of natural pollen traps (Lugu Lake bottom sediments, surface soil, bark samples, and moss cushions) in four sites at different altitudes from the Lugu Lake area, southwest China, has been undertaken to investigate pollen dispersal and deposition in a mountainous area and assist with the interpretation of fossil pollen analysis. Detailed comparisons between the palynological assemblage and the modern vegetation in the Lugu Lake region have been carried out. Preliminary interpretations of the correlation between pollen assemblage and vegetation at the different vertical vegetational zones can be recognized by the percentages of the main taxa, and most of the pollen taxa except Pinus are expected to be underrepresented. Exotic pollen grains can be transported over mountains more than 70 km away by wind. Upslope or downslope transport of pollen grains is crucial when reconstructing palaeoclimate in mountainous areas. We summarize the altitudinal distributions of modern woody plants whose pollen grains are present at three sites, and reveal that pollen grains are more readily carried uphill than downhill. These findings have important implications regarding the reconstruction of vegetation in mountainous regions and the interpretion of palaeoelevations.