Testate amoeba as palaeohydrological indicators in the permafrost peatlands of north‐east European Russia and Finnish Lapland

Abstract

To explore the use of testate amoeba for investigating the impacts of climate change on permafrost peatland hydrology, we established a new modern training set from Arctic permafrost peatlands in north‐east European Russia and Finnish Lapland. Ordination analyses showed that water‐table depth (WTD) was the most important control on testate amoeba distribution. We developed a new testate amoeba‐based WTD transfer function and thoroughly tested it. We found that our transfer function had strong predictive power. The best‐performing model was based on tolerance‐downweighted weighted averaging with inverse deshrinking (R2 = 0.77, RMSEP = 5.62 cm with leave‐one‐out cross validation). The new transfer function was applied to a short peat core from Arctic Russia and revealed two major hydrological shifts, which could be validated against plant macrofossil data. We also compared our model to another two models from more temperate peatlands. Comparison of the different testate amoeba datasets suggests that testate amoeba ecohydrological relationships are similar for permafrost peatlands to those in more temperate regions, but there are some differences that suggest a need for training datasets that are fully representative of permafrost peatlands.

Ecology of peatland testate amoebae in the Alaskan continuous permafrost zone

“…This increases the global extent of testate amoebae as palaeohydrological indicators and opens opportunities to better understand how high-latitude ecosystems have responded to a changing climate throughout the Holocene. Individual taxa behave broadly as expected, comparing results to other studies in discontinuous permafrost (Amesbury et al, 2013;Swindles et al, 2015b;Zhang et al, 2017). Our largest anomaly was Archerella flavum, which we observe to be an intermediate indicator with an optimum WTD of around 19 cm.…”

“…Species-level associations with a limited range of environmental and hydrological conditions (Charman and Warner, 1992) (Zhang et al, 2017;Swindles et al, 2015b) and Canada (Lamarre et al, 2013), little is known about their ecology and effectiveness as ecological indicators in continuous permafrost. Previous studies have reported the presence of testate amoebae in both the contemporary and fossil record of continuous permafrost (e.g.…”

Decreased carbon accumulation feedback driven by climate‐induced drying of two southern boreal bogs over recent centuries

“…Further identification to species level was carried out using a high‐power light microscope at the magnification of 100–200. Plant‐based WTD reconstruction was carried out using the modern vegetation survey data from the Siikaneva and Lakkasuo sites based on a weighted average approach; transfer function development followed the methods described in Zhang et al ().…”

“…The lower resolution was sufficient where the proxy-based WTD reconstruction was used as an environmental variable in explaining carbon accumulation patterns, as carbon accumulation rate (CAR) calculations were completed at 4 cm resolution and were therefore comparable with the testate amoeba results. transfer function development followed the methods described in Zhang et al (2017).…”

The role of climate change in regulating Arctic permafrost peatland hydrological and vegetation change over the last millennium

“…In this study we investigated past hydrological changes and associated variations in vegetation composition during the last millennium in four permafrost peatlands. We used two different proxies; testate amoebae (Amesbury et al, 2016;Charman et al, 2007;Swindles et al, 2015b) and plant macrofossils (Väliranta et al, 2007; to reconstruct past moisture conditions and vegetation history, which enabled cross validation of results and therefore more dependable data interpretation (Loisel and Garneau, 2010;Väliranta et al, 2012). Using 14 C and 210 Pb dating, we linked detected changes to known climate periods.…”