Modern pollen spectra from the east European forest steppe reflect land use patterns rather than a climatic gradient
摘要
Current global warming will very probably change the water balance in the region of the east European forest steppe, affecting farming there. One of the ways to understand the effects of climate change on such systems is to look at how it affected vegetation in the past, which can be reconstructed from fossil pollen data. To understand how pollen samples reflect the forest steppe landscapes, and the potential of the palaeorecords to capture this variety as well as to provide a training set for quantitative reconstructions of vegetation and climate from pollen records, we studied surface samples from the east European forest steppe. Sixty modern pollen samples were collected along a north–south latitudinal gradient in the steppe, mostly from nearly natural environments. The results show that the variability in the surface pollen spectra is connected primarily to land use and secondarily to the local conditions on site, rather than to the latitudinal position on the gradient. The comparably small impact of climate could be explained by the good soil moisture conditions in the south of the study area due to the local relief features. The climate variables such as temperature, precipitation etc. explain from 1.4 to 2.6% of the variance for each one with comparably high correlation among themselves. The minimum arboreal pollen values for the sites with nearly natural vegetation in the ecotone do not go under 33%. The majority of the pollen records from the east European forest steppe show the dominance of pinewoods, as these palynological archives are often located in wetlands of oxbow lakes and rivers where pines and azonal vegetation dominate. Pollen records from higher parts of the landscape such as plateaus would potentially give a better insight into the dynamics of the wooded and open landscapes compared to the records from river valleys.