Relationships among testate amoebae (Protozoa), vegetation and water chemistry in five <i>Sphagnum</i>‐dominated peatlands in Europe

Mitchell, Edward A. D.; Buttler, Alexandre; Grosvernier, Philippe; Rydin, Håkan; Albinsson, Crister; Greenup, A.; Heijmans, M.M.P.D.; Hoosbeek, Marcel R.; Saarinen, Timo

doi:10.1046/j.1469-8137.2000.00550.x

Cited by 91 publications

(83 citation statements)

References 31 publications

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“…Sites variables are more important to the vegetation than amoebae data. A similar result from a study on a broader scale had been interpreted as evidence that the vegetation is controlled by both the local environment and broader biogeographic patterns, while the generally cosmopolitan testate amoebae responded only to the micro-environmental conditions (Mitchell et al 2000). Given the proximity of Figure 7.…”

Section: Testate Amoebae Ecologymentioning

confidence: 54%

Ecology of Testate Amoebae from Mires in the Central Rhodope Mountains, Greece and Development of a Transfer Function for Palaeohydrological Reconstruction

Payne

Mitchell

2007

Protist

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Testate amoebae are useful environmental indicators in ecological and palaeoecological studies from peatlands. Previous quantitative studies have focused on the peatlands of Northern and Central Europe, North America, and New Zealand and have considered a relatively restricted variety of peatland types, mostly ombrotrophic or Sphagnum-dominated while more minerotrophic fens have been less studied. Here we present the first quantitative ecological study of testate amoebae from four small mesotrophic fens (pH 5.5-8.1) in the Elatia Forest, northern Macedonia province, Greece. Relationships with the environmental data were investigated using redundancy analysis and mantel tests. Transfer function models were derived using a variety of techniques. Results demonstrate that as for Sphagnumdominated mires hydrology is the most important control on amoebae community composition. Transfer function models should enable water tables to be predicted within 2.5 cm, when data selection is used this is reduced to less than 2 cm. pH is also an important environmental control on testate amoebae communities, a transfer function model enables pH prediction within 0.4 pH units. The hydrological transfer function is the best performing such model yet produced in terms of prediction error. This study provides new data on the ecology of testate amoebae in fens, and the transfer function models should allow quantitative palaeohydrological reconstruction.Key words: protists; transfer functions; palaeoclimate; peatlands; mire surface wetness.Abbreviations: Boot, results assessed by bootstrap cross validation e.g. RMSEP boot denotes RMSEP assessed by bootstrapping; DWT, depth to water table; Jack, results assessed by jack-knife (also termed 'leave-one-out') cross validation e.g. RMSEP jack denotes RMSEP assessed by jack-knifing; LOI, loss on ignition; MaxBias; maximum bias; ML, maximum likelihood; PLS, partial least squares; RMSEP, root mean square error of prediction; WA, weighted average; WA-PLS, weighted average partial least squares.

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Section: Testate Amoebae Ecologymentioning

confidence: 54%

Ecology of Testate Amoebae from Mires in the Central Rhodope Mountains, Greece and Development of a Transfer Function for Palaeohydrological Reconstruction

Payne

Mitchell

2007

Protist

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“…The symbols following the species and sample names indicate for the species the percentage of variance of each species explained by the model (no indication: <15%, *: 15-25%, **: 25-45%, ***: 45-60%), and for the samples the percentage fit of the model (no indication: <25%, *: 25-50%, **: 50-75%, ***: 75-100%). For readability, the scores of species and explanatory variables were multiplied by 3. diversity of testate amoebae as compared to bryophytes or plants in Sphagnum-dominated peatlands in general and the apparent cosmopolitan distribution of most species [48].…”

Section: Resultsmentioning

confidence: 99%

“…Sampling methods were based on previous studies [15,22,48,49,80]. In Jelenia Wyspa mire a transect approach was chosen to span the hydrological and nutrient gradient from fen to Sphagnum peatland.…”

Section: Study Sitesmentioning

confidence: 99%

The Ecology of Testate Amoebae (Protists) in Sphagnum in North-western Poland in Relation to Peatland Ecology

2005

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We studied the relationship between testate amoebae (Protozoa) communities and the depth to the water table (DWT), pH, conductivity, and microhabitat type in Sphagnum dominated peatlands of north-western Poland and built predictive (transfer function) models for inferring DWT and pH based on the testate amoebae community structure. Such models can be used for peatland monitoring and paleoecology. A total of 52 testate amoebae taxa were recorded. In a redundancy analysis, DWT and pH explained 20.1% of the variation in the species data and allowed us to identify three groups of taxa: species that are associated with (1) high DWT and low pH, (2) low DWT and low pH, and (3) high pH and mid-range DWT. Our transfer function models allow DWT and pH to be estimated with mean errors of 9.89 cm and 0.71 pH units. The prediction error of the DWT model and the tolerance of the species both increase with increasing dryness. This pattern mirrors the ecology of Sphagnum mosses: Species growing in wet habitats are more sensitive to change in water table depth than the species growing in drier microhabitats. Our results are consistent with studies of testate amoeba ecology in other regions, and they provide additional support for the use of these organisms in paleoecological and biomonitoring contexts. IntroductionTestate amoebae are unicellular organisms living in a variety of habitats including lakes and mires [3,32,65]. Sphagnum peatlands are characterized by a high diversity of microhabitats in which many testate amoebae species occur. Testate amoebae produce shells (tests) that can be proteinaceous, pseudochitinous, or agglutinated with one or two pseudostome(s) and are diagnostic for identification [70,77]. Testate amoebae are an important component in the soil microbial food web. Together with other protozoans, testate amoebae are believed to regulate bacterial populations [31] and to play a role in nutrient mineralization and plant growth [29]. Some species are mixotrophic and contain endosymbiotic algae [63].Many species have well-defined ecological preferences, and this stenotopy makes them very useful bioindicators [30,47]. Previous studies have shown that the abundance of each taxon and hence the structure of communities are controlled by a set of environmental variables. Water availability (moisture or water table depth) was often identified as being the single most important factor controlling testate amoebae community composition on peatlands, the second most important variable usually being pH [4-6, 10-12, 15, 21, 45, 46, 48, 49, 71, 76]. The correlation between testate amoebae communities and moisture conditions is increasingly used to infer palaeohydrological changes in peatlands and, in the case of ombrotrophic peatlands, these data are ultimately used to infer past climate changes [13, 16-19, 35, 44, 79]. In addition to paleoecology, testate amoebae research can be applied to environmental monitoring of natural ecosystems and those affected by human activities. Examples include the monitoring of lak...

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“…Whilst the environmental preferences of these organisms are generally consistent between regions, their sensitivity to microsite variations and localised idiosyncrasies (Mitchell et al, 2000b) suggest it would be unreasonable to make palaeoecological inferences for one region using contemporary data from another (Charman et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Comparing regional and supra-regional transfer functions for palaeohydrological reconstruction from Holocene peatlands

Turner

Swindles

Charman

et al. 2013

Palaeogeography, Palaeoclimatology, Palaeoecology

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Testate amoebae-based transfer functions are commonly used in peatland palaeoclimate studies. These models have been developed in several regions of the world and are sometimes used for palaeohydrological reconstruction from fossil data in locations where no transfer functions exist. Limitations of this approach may include missing modern analogues and problems associated with site-specific or regional factors in testate amoebae ecology and biogeography. This study presents new testate amoebae-hydrology transfer functions based on data from six peatlands in Northern England. Transfer functions were generated for water table depth and moisture content using weighted averaging tolerance downweighted regression with inverse deshrinking and model performance was assessed using leave-one-out (jacknifing) cross-validation.To examine the robustness of applying transfer functions extra-regionally, we performed a number of spatially independent cross-validation (SICV) tests using contemporary testate amoebae and environmental data from established Northern Ireland and European transfer functions. Inferred water table depths were consistent with observed values in terms of position along the hydrological gradient, however magnitudes varied. We then applied the three independent transfer functions to fossil data from a peatland in Northern England to compare the reconstructions. The results show that the direction of the reconstructions is consistent in terms of wet/dry shifts.However, variation in the magnitudes of the reconstructed water tables is apparent.This probably reflects the sampling regime, including temporal/seasonal effects, and differences in testate amoebae ecology between regions and individual sites.

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Relationships among testate amoebae (Protozoa), vegetation and water chemistry in five Sphagnum‐dominated peatlands in Europe

Cited by 91 publications

References 31 publications

Ecology of Testate Amoebae from Mires in the Central Rhodope Mountains, Greece and Development of a Transfer Function for Palaeohydrological Reconstruction

Ecology of Testate Amoebae from Mires in the Central Rhodope Mountains, Greece and Development of a Transfer Function for Palaeohydrological Reconstruction

The Ecology of Testate Amoebae (Protists) in Sphagnum in North-western Poland in Relation to Peatland Ecology

Comparing regional and supra-regional transfer functions for palaeohydrological reconstruction from Holocene peatlands

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