An investigation into the ecological effects a medieval settlement had on the White Loch of Myrton, Scotland using diatom analysis

Abstract

This study aims to use palaeoecological methods to investigate the effects a crannog had on the White Loch of Myrton, Scotland. Diatom analysis was the main form of analysis to reconstruct the ecological changes of the lake and a was used to infer total phosphorus levels using a transfer function. The species richness was calculated using the Shannon Index and the degree of floristic change measured using Square Chord Dissimilarity. A Detrended Correspondence Analysis was undertaken and the main driver of variation in the diatom assemblages was found to be total phosphorus, which increased in the crannog phase. The crannog caused a decrease in the ecological wellbeing of the lake and changes include a decrease in species diversity and shifts in species composition to eutrophic tolerant diatom species, such as Stephanodiscus spp. The recovery trajectory is convoluted, though there is evidence of some recovery and the post-crannog ecosystem can be described as hybrid. To support the reconstructions given by the diatom analysis, a multiproxy study was undertaken where Ti, Si and LOI550 were investigated, though more proxies and a higher resolution would have strengthened the study further.