Assessing ecological effects of peatland use with testate amoebae

Abstract

Due to their ability to store carbon in the form of peat, peatlands play a key role in the carbon cycle. Besides carbon accumulation, peatlands release dissolved organic matter to surface waters in their catchments, emit methane, and nitrous oxide. Hence, they can strongly affect the global climate. In addition, peatlands provide habitat for wildlife, help in water regulation, and store valuable palaeoenvironmental information. As most ecosystems, peatlands are affected by anthropogenic activities such as mining, peat extraction, forestry and agriculture. Due to the increasing peatland degradation, monitoring methods have been developed in order to evaluate their ecological state. Here, the usefulness of testate amoebae (TA) as biological indicators of peatland disturbance and restoration actions success, their use as surrogates of plant community responses to peatland restoration, as well as indicators of disturbances caused by peat extraction in surrounding lakes was assessed. To better understand the response of TA to human-induced changes in peatlands, environmental variables broadly known to affect TA such as temperature, water chemistry, and water table depth were also analysed. TA appeared to be an excellent tool to evaluate disturbance in Finnish peatlands as their responses to human-induced changes overrode natural variation caused by spatiality and seasonality. On the other hand, TA showed to respond faster to peatland restoration actions than plant communities. Also, lake TA communities from sediments did not reflect effects of peat extraction in lakes. Overall, the study showed promising results when considering terrestrial TA as indicators of peatland land use changes, including the evaluation of restoration success. However, more studies are required to evaluate the usefulness of TA lake sediment communities as indicators of the effects of peat extraction on receiving lakes. The results also highlighted the need for future research on TA combining molecular tools and morphological analysis to fully understand their potential use as indicators of peatland changes and to further comprehend their complexity and biodiversity. Keywords: Bioindicators, boreal catchments, community concordance, peatland hydrology, restoration, seasonal variation, spatial variation