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Fluctuations in bog surface wetness (BSW) over an 86-year period were reconstructed using fine-resolution analyses of testate amoebae, plant macrofossils and peat humification from Fagelmossen, an ombrotrophic bog in western Sweden. Results were compared with local instrumental temperature and precipitation data and reconstructed values of total seasonal water table deficit using an age–depth model based on spheroidal carbonaceous particle analysis and a historically dated, geochemically typed tephra layer. Statistically significant correlations between decadal means of the fine-resolution data and climate parameters lend support to the notion that a climate signal may be present in those data, enhancing confidence in the peat-based record to address pressing research questions on abrupt climate change. All three proxies were correlated most significantly with annual precipitation, plant macrofossils only when correlations were time-lagged by 10 years, suggesting that precipitation, rather than temperature, is the primary driver of the BSW record at Fagelmossen. However, plant macrofossils also correlated significantly with annual temperature when time-lagged by 10 years. The correlation of individual physical and biological proxies with climate parameters on different time-scales, coupled with the significant correlation of plant macrofossil results with annual temperature in addition to annual precipitation, may bring into question the use of composite curves of BSW that combine results from multi-proxy studies. The correlations reported here partly support those from other similar studies, but highlight that regional variability may be greater than previously hypothesised and that it may not be possible to apply a single explanation of climatic forcing where bog surface wetness reconstructions are concerned. |
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