Reconstruction of hydrology, vegetation and past climate change in bogs using fungal microfossils

Water is one of the most important environmental factors defining the niche of terrestrial fungi, and fungi preserved in ombrotrophic peat deposits have the potential to indicate past variations in surface wetness and vegetation composition. This study aimed to assess the potential of fungal microfossils for palaeoclimate reconstructions. The environmental preferences of fungi were evaluated by assessing the relationships among fungal types, the peat-forming vegetation, the occurrence of fire, and water table status in fossil and modem samples from two raised bogs in northern England and Denmark.

The microfungi which showed consistent patterns among the three datasets examined in the study were generally indicators of relatively dry (hummock-like) conditions, and the abundance of most of the abundant fungal types observed reflected the prevalent vegetation type more than the direct influence of local moisture conditions. A number of fungal microfossils were identified which can be used to consistently provide a qualitative reconstruction of past conditions on the surface of the bog, and accurately indicate shifts between relatively dry and wet local conditions. Spores, in general, provided more information about local moisture conditions than vegetative mycelia. Some of the more abundant types, particularly Type 12 spores, showed a characteristic distribution with water table depth, which was consistent between the two different sites examined in the study. These fungal types can form the basis of future quantitative reconstructions of past water table and therefore climate in ombrotrophic bogs.