Response of testate amoeba assemblages to peatland drain blocking

Abstract

Peatlands represent globally important habitats and carbon stores. However, human impacts and climate change leave peatlands with a substantial management challenge. Degradation of peatland habitats and their hydrological integrity is increasingly counteracted through the rehabilitation of peatlands including re-wetting and drain blocking. Research into how such management interventions affect peatland microbial assemblages is limited. Here, we investigate the response of testate amoebae (established unicellular amoeboid protist indicators of hydrological conditions in peatlands) to drain blocking on three small lowland raised bogs in Northern Ireland, UK. We sampled Sphagnum adjacent to areas of focused flow near sites of damming in addition to control sites away from dam blocking. These restoration measures show complex but meaningful results after restoration. We observe several key developments following dam blocking: (i) species diversity increases; (ii) unambiguous wet indicator taxa appear in increasing abundance at dammed sites; (iii) and transfer-function reconstructed water-table depths show wetter conditions in the dammed sites. These findings imply wetter conditions after restoration, where routine monitoring presented no clear trend in water-table depths. We found no statistically significant assemblage-level response to experimental or environmental variables, which may be related to antecedent conditions and significant periods of drought during the study period. Thus, caution is advised when utilising testate amoebae for bioindication until their assemblage-level response to restoration is better understood. Nevertheless, this study emphasises the potential of an indicator-taxa based approach to applying testate amoebae as contemporary bioindicators of peatland restoration—particularly on short-term timescales immediately following restoration.

Biodiversity of testate amoebae in Sphagnum bogs: the dataset from forest-steppe ecotone (Middle Volga Territory, Russia)

“…Testate amoebae are widely used in bioindication ( Payne 2007 ) of water table depth and surface moisture in mires ( Zheng et al 2019 , Krashevska et al 2020 , Swindles et al 2020 , Qin et al 2021b , Šímová et al 2022 ), organic matter content ( Laggoun‐Défarge et al 2007 , Escobar et al 2008 , Daza et al 2020 ), macronutrients ( Wilkinson and Mitchell 2010 , Patterson et al 2012a ), acidity ( Payne 2009 , Lamentowicz et al 2011 , Patterson et al 2012b , Siver et al 2020 , Sim et al 2021 ), metal ions concentration ( Nguyen-Viet et al 2006 , Asada and Warner 2009 , Cockburn et al 2020 ) in aquatic environments, ecosystem restoration ( Carballeira and Pontevedra-Pombal 2021 , Qin et al 2021a , Evans et al 2023 , Creevy et al 2023 ) etc. Testate amoebae are successfully applied in quantitative reconstructions of hydrological regimes ( Lamentowicz et al 2017 , Tsyganov et al 2017 , Swindles et al 2019 , Zhang et al 2022 ), serving as a valuable proxy.…”