RESPONSES OF PEATLAND TESTATE AMOEBAE TO MANIPULATED HYDROLOGICAL CONDITIONS WITHIN EXPERIMENTAL MICROCOSMS

Future environmental planning and management is dependent upon knowledge of palaeoclimates, which requires inference from high-resolution proxy indicators. Testate amoebae are abundant in ombrotrophic peatland and are good proxy indicators of Holocene palaeoenvironmental change. The recognised link between peatland, hydrology and climate greatly influences the distribution of microorganisms such as testate amoebae. Modem data conceming the testate amoebae taxa-hydrology relationship is needed to model transfer functions and reconstmct palaeoclimates using fossil data. The use of experimental microcosms for ecological research holds great potential for understanding of this relationship. The principle aim of this study involved testing the use experimental microcosms for determining hydrological tolerances and optima of common testate amoebae taxa. Samples were collected from a typical raised mire located within Northumberland National Park (UK). Methodology involved assigning a number of Sphagnum peat moss samples to three microcosm water table treatments. Sub-samples were taken from the microcosms before, after and mid-way through a ten-week experimental period in order to observe changes to the species assemblage in response to the different water table treatments. Results revealed a very low testate amoebae survival rate, however, a number of problems were encountered conceming the methodology and identification of the living population. Detrended Correspondence Analysis (DCA) indicated that the testate amoebae species assemblages responded to the manipulated water tables, this involved the changing frequency of a number of key species throughout the experimental period. It may be possible to observe statistically significant results if the experimental period was extended and the living population was more clearly identifiable. This research has demonsfrated that there is potential for experimental microcosms in studying the modem ecology of testate amoebae and future work employing such methodology may improve the use of this proxy, thus providing enhanced palaeoreconstructions.Faculty of Scienc