Testate Amoeba (Arcellinida,Euglyphida) Ecology along a Poor‐Rich Gradient in Fens of Western Poland

We investigated the relationships between testate amoebae (Arcellinida, Euglyphida), vegetation and water chemistry along environmental gradients in minerotrophic peatlands (fens) in western Poland. We hypothesized that: a) hydrochemistry significantly influences structure of testate amoeba communities, and b) testate amoeba communities are more closely correlated with the hydrochemical variables (environment) than with the vegetation data. Testate amoeba communities and vegetation from 71 sample plots were investigated together with the hydro‐chemistry and hydrology based on 16 environmental variables and vegetation composition. Testate amoeba communities revealed a distinctive poor‐rich gradient in analysed fens. Mineral‐rich habitats, which were dominated by brown mosses, were preferred by a higher number of taxa than acidic habitats, which were dominated by Sphagnum. We recorded a total of 107 testate amoebae taxa. The average species richness of testate amoebae for brown mosses was higher (20) than for Sphagnum (13). We found that testate amoebae communities were similarly correlated with vascular plants, mosses and environmental parameters. Results of direct ordination demonstrate that hydrology, pH, Mg²⁺ and sodium remain the most important environmental control for the entire data set. CCA showed that in case of brown mosses hydrology, sodium and oxygen affect testate amoeba communities significantly whereas in Sphagnum only sodium emerge as most significant determining testate amoeba assemblages. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Potential Influence of Short-term Environmental Variability on the Composition of Testate Amoeba Communities in <Emphasis Type="Italic">Sphagnum</Emphasis> Peatlands

Testate amoebae are a group of moisture-sensitive, shell-producing protozoa that have been widely used as indicators of changes in mean water-table depth within oligotrophic peatlands. However, short-term environmental variability (i.e., sub-annual) also probably influences community composition. The objective of this study was to assess the potential influence of short-term environmental variability on the composition of testate amoeba communities in Sphagnum-dominated peatlands. Testate amoebae and environmental conditions, including hourly measurements of relative humidity within the upper centimeter of the peatland surface, were examined throughout the 2008 growing season at 72 microsites within 11 peatlands of Pennsylvania and Wisconsin, USA. Relationships among testate amoeba communities, vegetation, depth to water table, pH, and an index of short-term environmental variability (EVI), were examined using nonmetric multidimensional scaling and correlation analysis. Results suggest that EVI influences testate amoeba communities, with some taxa more abundant under highly variable conditions (e.g., Arcella discoides, Difflugia pulex, and Hyalosphenia subflava) and others more abundant when environmental conditions at the peatland surface were relatively stable (e.g., Archerella flavum and Bullinularia indica). The magnitude of environmental variability experienced at the peatland surface appears to be primarily controlled by vegetation composition and density. In particular, sites with dense Sphagnum cover had lower EVI values than sites with loose-growing Sphagnum or vegetation dominated by vascular plants and/or non-Sphagnum bryophytes. Our results suggest that more environmental information may be inferred from testate amoebae than previously recognized. Knowledge of relationships between testate amoebae and short-term environmental variability should lead to more detailed and refined environmental inferences.     

Palaeoecology of testate amoebae in a tropical peatland

We present the first detailed analysis of subfossil testate amoebae from a tropical peatland. Testate amoebae were analysed in a 4-m peat core from western Amazonia (Peru) and a transfer function developed from the site was applied to reconstruct changes in water table over the past ca. 8,000 years. Testate amoebae were in very low abundance in the core, especially in the lower 125 cm, due to a combination of poor preservation and obscuration by other organic matter. A modified preparation method enabled at least 50 testate amoebae to be counted in each core sample. The most abundant taxa preserved include Centropyxis aculeata, Hyalosphenia subflava, Phryganella acropodia and Trigonopyxis arcula. Centropyxis aculeata, an unambiguous wet indicator, is variably present and indicates several phases of near-surface water table. Our work shows that even degraded, low-abundance assemblages of testate amoebae can provide useful information regarding the long-term ecohydrological developmental history of tropical peatlands.     

Biogeography and comparative ecology of testate amoebae inhabiting Sphagnum-dominated peatlands in the Great Lakes and Rocky Mountain regions of North America

Testate amoebae (Protozoa: Rhizopoda) are common inhabitants of peatlands. Strong relationships between community composition and substrate moisture in Sphagnum‐dominated peatlands have made them particularly useful as hydrological proxies in environmental and palaeoenvironmental research. However, stability of these relationships in geographical space is important for widespread applicability. In this study, we compared testate amoeba communities inhabiting Sphagnum‐dominated peatlands of the Great Lakes and Rocky Mountain regions of North America. Our primary objectives were to describe patterns of community composition in the two regions, develop hypotheses to explain differences, and determine if taxa occupy similar ecological niches with respect to substrate moisture in both places. Our results indicated that testate amoeba communities are relatively different in the two regions, and these differences are probably caused by differences in climate and peatland trophic status, although other factors may also play a role. However, many taxa do occur in both regions and these taxa had comparable moisture preferences in each region, suggesting that the ecological niches of taxa with respect to substrate moisture are similar even within communities of relatively different composition.     

Testate amoebae response and vegetation composition after plantation removal on a former raised bog

Extensive drainage of peatlands in north-west Europe for the purposes of afforestation for timber production and harvesting has altered the carbon balance and biodiversity value. Large-scale restoration projects aim to reinstate hydrological conditions to keep carbon locked up in the peat and to restart active peat growth. Testate amoebae are an informal grouping of well-studied protists in peatland environments and as microbial consumers play an important role in nutrient and carbon cycling. Using a space for time substitution approach, this study investigated the response of testate amoebae assemblages and vegetation composition after tree removal on a drained raised bog. There was a clear difference in microbial assemblages between open and a chronosequence of restoration areas. Results suggest microbial recovery after rewetting is a slow process with plant composition showing a faster response than the microbial assemblage. Mixotrophic testate amoebae had not recovered seventeen years following plantation removal and the establishment of Sphagnum mosses in the wetter microforms. These results suggest that vegetation composition and Testate amoeba assemblages respond differently to environmental drivers at forest-to-bog restoration areas. Local physicochemical peat properties were a stronger driver of the testate assemblage compared with vegetation. Complete recovery of microbial assemblages may take place over decadal timescales.     

Fine-Scale Horizontal and Vertical Micro-distribution Patterns of Testate Amoebae Along a Narrow Fen/Bog Gradient

The ecology of peatland testate amoebae is well studied along broad gradient from very wet (pool) to dry (hummock) micro-sites where testate amoebae are often found to respond primarily to the depth to water table (DWT). Much less is known on their responses to finer-scale gradients, and nothing is known of their possible response to phenolic compounds, which play a key role in carbon storage in peatlands. We studied the vertical (0–3, 3–6, and 6–9 cm sampling depths) micro-distribution patterns of testate amoebae in the same microhabitat (Sphagnum fallax lawn) along a narrow ecological gradient between a poor fen with an almost flat and homogeneous Sphagnum carpet (fen) and a “young bog” (bog) with more marked micro-topography and mosaic of poor fen and bog vegetation. We analyzed the relationships between the testate amoeba data and three sets of variables (1) “chemical” (pH, Eh potential, and conductivity), (2) “physical” (water temperature, altitude, i.e., Sphagnum mat micro-topography, and DWT), and (3) phenolic compounds in/from Sphagnum (water-soluble and primarily bound phenolics) as well as the habitat (fen/bog) and the sampling depth. Testate amoeba Shannon H′ diversity, equitability J of communities, and total density peaked in lower parts of Sphagnum, but the patterns differed between the fen and bog micro-sites. Redundancy analyses revealed that testate amoeba communities differed significantly in relation to Eh, conductivity, water temperature, altitude, water-soluble phenolics, habitat, and sampling depth, but not to DWT, pH, or primarily bound phenolics. The sensitivity of testate amoebae to weak environmental gradients makes them particularly good integrators of micro-environmental variations and has implications for their use in paleoecology and environmental monitoring. The correlation between testate amoeba communities and the concentration of water-soluble phenolic suggests direct (e.g., physiological) and/or indirect (e.g., through impact on prey organisms) effects on testate amoebae, which requires further research.     

Comparative ecology of vascular plant,bryophyte and testate amoeba communities in four Sphagnum peatlands along an altitudinal gradient in Switzerland

Monitoring tools are needed to assess changes in peatland biotic communities and ecosystem functions in response to on-going climate and other environmental changes. Although the responses of soil organisms and plants to ecological gradients and perturbations do not always correlate, peatland monitoring is mainly based on vegetation surveys. Testate amoebae, a group of protists, are important contributors to carbon and nitrogen cycling in organic soils and are useful bioindicators in peatland ecology and paleoecology. There is however little comparative data on the value of testate amoebae, vascular plants and bryophytes as bioindicators of micro-environmental gradients in peatlands.We compared the relationships of testate amoebae, bryophytes, and vascular plants with soil temperature, water table depth, micro-habitats and the carbon and nitrogen content of Sphagnum mosses in four peatlands along a 1300 m altitudinal gradient in Switzerland. We used the full diversity of vascular plants and bryophyte but only a selection of ten easily identifiable testate amoeba morpho-taxa (i.e. species or species-complexes).Indirect and direct gradient ordinations, multiple factor analysis (MFA) and transfer function models for inferring water table depth showed that a selection of ten testate amoeba taxa are more powerful (% variance explained in RDA) and accurate (discrimination among habitats) indicators of local conditions (micro-habitat type, water table depth and Sphagnum C/N ratio) than the vegetation (vascular plants and bryophytes either individually or combined and considering the full diversity).Our study showed that a limited list of ten easily identifiable testate amoeba taxa have higher bioindication value than the full bryophytes and vascular plants. Furthermore, testate amoebae can be analyzed on samples collected at any season (accessibility allowing and if precise sampling sites are well marked) – a clear advantage for biomonitoring and can be used to infer past changes from the peat record at the same taxonomic resolution. This simple approach could therefore be very useful for biomonitoring of peatlands.     

Seasonal changes in Sphagnum peatland testate amoeba communities along a hydrological gradient

Testate amoebae are an abundant and functionally important group of protists in peatlands, but little is known about the seasonal patterns of their communities. We investigated the relationships between testate amoeba diversity and community structure and water table depth and light conditions (shading vs. insolation) in a Sphagnum peatland in Northern Poland (Linje mire) in spring and summer 2010. We monitored the water table at five sites across the peatland and collected Sphagnum samples in lawn and hummock micro-sites around each piezometer, in spring (3 May) and mid-summer (6 August) 2010. Water table differed significantly between micro-sites and seasons (Kruskal–Wallis test, p = 0.001). The community structure of testate amoebae differed significantly between spring and summer in both hummock and lawn micro-sites. We recorded a small, but significant drop in Shannon diversity, between spring and summer (1.76 vs. 1.72). Strongest correlations were found between testate amoeba communities and water table lowering and light conditions. The relative abundance of mixotrophic species Hyalosphenia papilio, Archerella flavum and of Euglypha ciliata was higher in the summer.     

Contrasting Species—Environment Relationships in Communities of Testate Amoebae, Bryophytes and Vascular Plants Along the Fen–Bog Gradient

We studied the vegetation, testate amoebae and abiotic variables (depth of the water table, pH, electrical conductivity, Ca and Mg concentrations of water extracted from mosses) along the bog to extremely rich fen gradient in sub-alpine peatlands of the Upper Engadine (Swiss Alps). Testate amoeba diversity was correlated to that of mosses but not of vascular plants. Diversity peaked in rich fen for testate amoebae and in extremely rich fen for mosses, while for testate amoebae and mosses it was lowest in bog but for vascular plants in extremely rich fen. Multiple factor and redundancy analyses (RDA) revealed a stronger correlation of testate amoebae than of vegetation to water table and hydrochemical variables and relatively strong correlation between testate amoeba and moss community data. In RDA, hydrochemical variables explained a higher proportion of the testate amoeba and moss data than water table depth. Abiotic variables explained a higher percentage of the species data for testate amoebae (30.3% or 19.5% for binary data) than for mosses (13.4%) and vascular plants (10%). These results show that (1) vascular plant, moss and testate amoeba communities respond differently to ecological gradients in peatlands and (2) testate amoebae are more strongly related than vascular plants to the abiotic factors at the mire surface. These differences are related to vertical trophic gradients and associated niche differentiation.     

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

To study the relationships between groups of organisms and the degree to which these relationships are consistent across major climatic gradients, we analysed the testate amoeba ( Protozoa ) communities, vegetation and water chemistry of one peatland in five countries: Switzerland, The Netherlands, Great Britain, Sweden and Finland, as part of the BERI (Bog Ecosystem Research Initiative) project. The relationships between the different data sets and subsets were investigated by means of detrended correspondence analysis, canonical correspondence analysis and Mantel permutation tests. The comparison of data on vegetation and testate amoebae showed that inter-site differences are more pronounced for the vegetation than for the testate amoebae species assemblage. Testate amoebae are a useful tool in multi-site studies and in environmental monitoring of peatlands because: (1) the number of species in Sphagnum -dominated peatlands is much higher than for mosses or vascular plants; (2) most peatland species are cosmopolitan in their distributions and therefore less affected than plants by biogeographical distribution patterns, thus differences in testate amoeba assemblages can be interpreted primarily in terms of ecology; (3) they are closely related to the ecological characteristics of the exact spot where they live, therefore they can be used to analyse small-scale gradients that play a major role in the functioning of peatland ecosystems. This study revealed the existence of small-scale vertical gradients within the vegetation and life-form niche separation in response to water chemistry. The deep-rooted plants such as Carex spp. and Eriophorum spp. are related to the chemistry of water sampled at or near the ground water table, whereas the mosses are not. Testate amoebae were shown to be ecologically more closely related to the chemistry of water sampled at or near the water table level and to the mosses than to the deep-rooted plants.     

Nebela jiuhuensis nov. sp. (Amoebozoa; Arcellinida; Hyalospheniidae): A New Member of the Nebela saccifera ‐ equicalceus ‐ ansata Group Described from Sphagnum Peatlands in South‐Central China

Hyalospheniids are among the most common and conspicuous testate amoebae in high‐latitude peatlands and forest humus. These testate amoebae were widely studied as bioindicators and are increasingly used as models in microbial biogeography. However, data on their diversity and ecology are still very unevenly distributed geographically: notably, data are lacking for low‐latitude peatlands. We describe here a new species, Nebela jiuhuensis, from peatlands near the Middle Yangtze River reach of south‐central China with characteristic morphology. The test (shell) has hollow horn‐like lateral extensions also found in N. saccifera, N. equicalceus (=N. hippocrepis), and N. ansata, three large species restricted mostly to Sphagnum peatlands of Eastern North America. Mitochondrial cytochrome oxidase (COI) data confirm that N. jiuhuensis is closely related to the morphologically very similar North American species N. saccifera and more distantly to N. ansata within the N. penardiana group. These species are all found in wet mosses growing in poor fens. Earlier reports of morphologically similar specimens found in South Korea peatlands suggest that N. jiuhuensis may be distributed in comparable peatlands in Eastern Asia (China and Korea). The discovery of such a conspicuous new species in Chinese peatlands suggests that many new testate amoebae species are yet to be discovered, including potential regional endemics. Furthermore, human activities (e.g., drainage, agriculture, and pollution) have reduced the known habitat of N. jiuhuensis, which can thus be considered as locally endangered. We, therefore, suggest that this very conspicuous micro‐organism with a probably limited geographical distribution and specific habitat requirement should be considered as a flagship species for microbial biogeography as well as local environmental conservation and management.     

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

Northern boreal peatlands are important ecosystems in modulating global biogeochemical cycles, yet their biological communities and related carbon dynamics are highly sensitive to changes in climate. Despite this, the strength and recent direction of these feedbacks are still unclear. The response of boreal peatlands to climate warming has received relatively little attention compared with other northern peatland types, despite forming a large northern hemisphere‐wide ecosystem. Here, we studied the response of two ombrotrophic boreal peatlands to climate variability over the last c. 200 years for which local meteorological data are available. We used remains from plants and testate amoebae to study historical changes in peatland biological communities. These data were supplemented by peat property (bulk density, carbon and nitrogen content), ¹⁴C, ²¹⁰Pb and ¹³⁷Cs analyses and were used to infer changes in peatland hydrology and carbon dynamics. In total, six peat cores, three per study site, were studied that represent different microhabitats: low hummock (LH), high lawn and low lawn. The data show a consistent drying trend over recent centuries, represented mainly as a change from wet habitat Sphagnum spp. to dry habitat S. fuscum. Summer temperature and precipitation appeared to be important drivers shaping peatland community and surface moisture conditions. Data from the driest microhabitat studied, LH, revealed a clear and strong negative linear correlation (R² = .5031; p < .001) between carbon accumulation rate and peat surface moisture conditions: under dry conditions, less carbon was accumulated. This suggests that at the dry end of the moisture gradient, availability of water regulates carbon accumulation. It can be further linked to the decreased abundance of mixotrophic testate amoebae under drier conditions (R² = .4207; p < .001). Our study implies that if effective precipitation decreases in the future, the carbon uptake capacity of boreal bogs may be threatened.     

The curse of taxonomic uncertainty in biogeographical studies of free-living terrestrial protists: a case study of testate amoebae from Amsterdam Island

Aim A current debate in microbial biogeography contrasts two views concerning the distribution of free‐living microorganisms. The first view assumes a ubiquitous distribution, while the second assumes that at least some species have limited geographical distributions. We tested for limited geographical distributions by identifying testate amoebae morphospecies from an extremely remote oceanic island where the potential for endemism is high. Location Amsterdam Island, Indian Ocean. Methods Sixty moss and water samples collected from the top of the volcano to the lowland were investigated for their testate amoeba content. Due to taxonomic uncertainties among the Argynnia (Nebela) dentistoma species complex (including A. antarctica), we also performed light and scanning electron microscopy investigations on the shell ultrastructure and biometric analyses on several specimens of this taxon. Results We identified a total of 43 testate amoeba taxa belonging to 15 genera. Only four testate amoeba taxa had previously been recorded on this island. Testate amoeba communities of Amsterdam Island are dominated by cosmopolitan ubiquitous euglyphid taxa such as Trinema lineare, Assulina muscorum and Corythion dubium. The length and width ranges for Argynnia dentistoma on Amsterdam Island overlap with other records of this species and of A. antarctica, suggesting that A. antarctica is not a distinct taxon. Main conclusions Although Amsterdam Island is among the most remote islands in the world, an extensive inventory of testate amoeba morphospecies provided no clear evidence for endemism. On the one hand, our detailed morphometric analysis of the A. dentistoma complex revealed that A. antarctica, a morphospecies previously suggested to display endemism, cannot be confidently distinguished from the cosmopolitan morphospecies A. dentistoma. On the other hand, five morphotaxa could not be identified with certainty and might represent new species, potentially with limited distribution. These examples illustrate how taxonomic uncertainties undermine biogeographical studies of testate amoebae. In order to allow better interpretation of morphology‐based testate amoeba distribution data, an assessment of genetic diversity among and within morphotaxa in relation to geographical distance for some common testate amoebae should be given high priority.     

Seasonal dynamics in the community structure and trophic structure of testate amoebae inhabiting the Sanjiang peatlands,Northeast China

Peatlands cover 3% of the earth’s land surface but contain 30% of the world’s soil carbon pool. Microbial communities constitute a crucial detrital food web for nutrient and carbon cycling in peatlands. Heterotrophic protozoans are considered top predators in the microbial food web; however, they are not yet well understood. In this study, we investigated seasonal dynamics in the community and the trophic structure of testate amoebae in four peatlands. Testate amoebae density and biomass in August were significantly higher than those in May and October. The highest density, 6.7 × 10⁴ individual g⁻¹ dry moss, was recorded in August 2014. The highest biomass, 7.7 × 10² μg C g⁻¹ dry moss, was recorded in August 2013. Redundancy analyses showed that water-table depth was the most important factor, explaining over one third of the variance in fauna communities in all sampled seasons. High trophic position taxa dominated testate amoebae communities. The Shannon diversity index and community size structure index declined from August to October in 2013 and from May to October in 2014. These seasonal patterns of testate amoebae indicated the seasonal variations of the peatlands’ microbial food web and are possibly related to the seasonal carbon dynamics in Northeast Chinese peatlands.     

Seasonal Influences on the Ecology of Testate Amoebae (Protozoa) in a Small <Emphasis Type="Italic">Sphagnum</Emphasis> peatland in Southern Ontario,Canada

Testate amoebae (Protozoa) were studied in spring, summer, and fall from the same microhabitats in a small Sphagnum-dominated peatland in southern Ontario, Canada. A total of 32 sampling stations were established in two wetland plant communities, 19 in an open Ericaceae low-shrub community and 13 in a closed Picea mariana and Larix laricina swamp community. Sphagnum was collected in each station for analysis of testate amoebae and measurement of soil water content parameters and water table depth in May, August, and October 2001. pH and dissolved oxygen of the groundwater under the Sphagnum were measured also. A total of 52 taxa including the rotifer, Habrotrocha angusticollis, were identified. Soil water content and water table variables emerged as the primary factors separating testate amoebae between the open bog/fen community and swamp community. Testate amoebae in the open bog/fen community showed a clear separation between the May sampling period and the August and October sampling periods. Sampling stations in May had much higher water table and were wetter than those in August and October. Conversely, testate amoebae in the swamp community did not show a clear difference between sampling periods. Soil moisture and water tables appear to be more constant in the swamp communities. Biological factors or other microscale environmental factors may need to be considered to explain seasonal changes in testate amoebae. A greater understanding of relationships between testate amoebae and microenvironmental factors is necessary to track seasonality in testate amoebae distributions.     

Abrupt ecological changes in the last 800 years inferred from a mountainous bog using testate amoebae traits and multi-proxy data

Mountainous peatlands of Western Sudetes are considered a unique habitat in Central Europe. The region contains one of the largest raised bog complexes in temperate Europe and is thus of great importance for biodiversity conservation. In this first high-resolution study from this region we use long-term ecological data to assess how these mountain wetland ecosystems responded to anthropogenic impacts and climate change. We used testate amoebae morphological traits, micro- and macroscopic charcoal, pollen and plant macrofossils to reconstruct the history of peatland development over 800 years, illustrating shifts in its development and fire dynamics. Five hydrological stages of peatland development were recognized. Testate amoebae morphological traits reflected several abrupt ecological changes linked to anthropogenic modifications of landscape openness. A shift towards mixotrophic taxa, linked to hydrological change or shrubs expansion and shading, preceded aperture position change, which was associated to dust input through surrounding deforestation and simultaneous water-table increase. Fire reconstruction revealed increasing burning together with intensifying human activity, including the expansion of a nearby settlement. This study confirms the potential of testate amoeba communities and the use of morpho-functional traits as indicators of ecological effects of land-use change over long-temporal scales.     

Flourish or Flush: Effects of Simulated Extreme Rainfall Events on Sphagnum-dwelling Testate Amoebae in a Subarctic Bog (Abisko, Sweden)

Extreme precipitation events are recognised as important drivers of ecosystem responses to climate change and can considerably affect high-latitude ombrotrophic bogs. Therefore, understanding the relationships between increased rainfall and the biotic components of these ecosystems is necessary for an estimation of climate change impacts. We studied overall effects of increased magnitude, intensity and frequency of rainfall on assemblages of Sphagnum-dwelling testate amoebae in a field climate manipulation experiment located in a relatively dry subarctic bog (Abisko, Sweden). The effects of the treatment were estimated using abundance, species diversity and structure of living and empty shell assemblages of testate amoebae in living and decaying layers of Sphagnum. Our results show that increased rainfall reduced the mean abundance and species richness of living testate amoebae. Besides, the treatment affected species structure of both living and empty shell assemblages, reducing proportions of hydrophilous species. The effects are counterintuitive as increased precipitation-related substrate moisture was expected to have opposite effects on testate amoeba assemblages in relatively dry biotopes. Therefore, we conclude that other rainfall-related factors such as increased infiltration rates and frequency of environmental disturbances can also affect testate amoeba assemblages in Sphagnum and that hydrophilous species are particularly sensitive to variation in these environmental variables.     

Quantifying the effect of testate amoeba decomposition on peat-based water-table reconstructions

Testate amoebae are a widely-used tool for palaeohydrological reconstruction from peatlands. However, it has been observed that weak idiosomic siliceous tests (WISTs) are common in uppermost peats, but very rarely found as subfossils deeper in the peat profile. This taphonomic problem has been noted widely and it has been established that WISTs disaggregate and/or dissolve in the low pH condition of ombrotrophic peatlands. Here we investigate the effect of this taphonomic problem on water-table reconstructions from thirty European peatlands through the comparison of reconstructions based on all taxa and those with WISTs removed. In almost all cases the decomposition of WISTs does not introduce discernible bias to peatland water-table reconstructions. However, some discrepancy is apparent when large abundances of Corythion-Trinema type are present (9−12 cm deviation with 50–60% abundance of this particular taxon). We recommend that WISTs should be removed before carrying out water-table reconstructions, and that the minimum count of testate amoebae per sample should exclude WISTs to ensure the development of robust reconstructions.     

Ecology of testate amoebae in moorland with a complex fire history: implications for ecosystem monitoring and sustainable land management

Testate amoebae represent a crucial component of soil microfauna and have been studied extensively in ombrotrophic peatlands. However, little is known about their ecology in moorlands which are important habitats in terms of biodiversity and carbon storage potential. Moorlands are under threat from a range of factors such as drainage, burning, over grazing, pollution and climate change. In this study we investigate testate amoebae communities within three zones of a UK moorland characterised by contrasting fire histories, and use these data to examine the potential of testate amoebae as environmental bioindicators in moorlands. Although several factors control testate amoebae communities in moorlands, it is clear that there are marked differences in testate amoebae communities between the zones which primarily relate to hydrological status, influenced by fire regime. The taxon Hyalosphenia subflava is a clear indicator of severe disturbance as it was found to be abundant in mosses which colonised a hydrophobic peat surface following a severe wild-fire event. Testate amoebae have much potential for ecosystem monitoring of moorlands which can inform sustainable land management practices.