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1

The Past, Present and Future of Soil Protist Ecology

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Wilkinson D. M., Creevy A. L., Valentine J.

Acta Protozoologica

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2012

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vol. 51

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issue 3

PL

This essay introduces the special issue of this journal on the ecology of soil protists. This issue marks approximately the first 100 years of soil protistology as a discipline as some of the first studies to show that protozoa were an important part of soil ecology took place at Rothamsted, in southern England, towards the end of the first decade of the twentieth century. Much of the work on soil protists – and indeed the papers in this special issue – concentrate on traditional protozoa. In addition it is now realised that slime molds (Eumycetozoans) can potentially make an important contribution to the numbers and diversity of soil amoebae. We also argue that diatoms and other algae are likely important in soils and in need of more detailed study. By its nature microbiology (including soil protist ecology) is a science limited by technology – for example the subject could not really exist before the invention of the microscope. We suggest ways in which newer technologies (molecular methods, stable isotopes etc) may contribute to future studies on the ecology of soil protists.

2

The Use of Testate Amoebae in Monitoring Peatland Restoration Management: Case Studies from North West England and Ireland

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Valentine J., Davis S. R., Kirby a. R., Wilkinson D. M.

Acta Protozoologica

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2013

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vol. 52

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issue 3

PL

The nature conservation, and wider environmental importance of peatlands, particularly in relation to carbon management, has led to there being a growing interest in attempting to manage degraded peatlands in a way that will restore them to fully functioning peatland ecosystems. Much of this management is concerned with the rewetting of these sites therefore it has become important to monitor the surface wetness of these bogs and if possible compare current wetness with previous, pre-damage, conditions. We present previously unpublished case studies of the use of testate amoebae to monitor bog restoration schemes in N.W. England (Holcroft Moss, Cheshire) and Ireland (Ardagullion Bog, Co. Longford). In addition we summarise the key conservation related conclusions of our previously published work on two other sites in N.W England – Astley Moss (in the Chat Moss complex of Greater Manchester) and Danes Moss (Cheshire). At Holcroft the record of lead pollution from the peat core allows us to date recent changes in the testate community preserved in a peat core and relate these to both conservation management and other changes in the landscape around the bog in over the last 50 years. Ardagullion Bog provides an illustration of the utility of using multiple peat cores in the testate monitoring of peat bog restoration and illustrates that a bog that has only suffered limited ‘damage’ is able to be restored to something close to pre damage conditions on a decadal time scale. We also summarise what we see as the main lessons from testate studies of bog restoration – both from the case studies described in this paper and from the wider literature - and discuss the conditions under which testate amoebae may be of particular use in peatland restoration.

3

Latitudinal Diversity Gradients in Free-living Microorganisms – Hoogenraadia a Key Genus in Testate Amoebae Biogeography

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Bobrov A., Wilkinson D. M., QIN Y.

Acta Protozoologica

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2015

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vol. 54

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issue 1

PL

The extent to which free-living microorganisms show cosmopolitan distributions has been a contentious aspect of microbial ecology over the last few decades. Testate amoebae are a group of free living protists that can provide important evidence for the nature of the biogeography of microorganisms because there are relatively good data on the distribution of their morpho-species (compared to many other microbial groups). Many testate amoebae appear to exhibit ubiquitous distributions, while some taxa have proven to be endemic to limited regions. The genus Hoogenraadia (Gauthier-Lièvre and Thomas 1958) is of particular interest in this context as it appears to be restricted to relatively low latitudes. There are six described species of the genus: H. africana Gauthier-Lièvre and Thomas 1958, H. asiatica Wang and Min 1987, H. cryptostoma Gauthier-Lièvre and Thomas 1958, H. humicola Bonnet 1976, H. ovata Bonnet 1976, and H. sylvatica Vucetich 1974. However, information on these taxa is scattered through a number of different papers – here we provide a summary of what is known about the taxonomy and ecology of this genus. We also reinterpret recent new records of putative H. africana from China (suggesting this identification is not reliable). As an example of a protist taxon largely restricted to the tropics this genus is of particular interest in microbial biogeography and this paper discusses its morphology, ecology and distribution in this context.

4

Testate Amoebae Communities in the Rhizosphere of Rhododendron ponticum (Ericaceae) in an Evergreen Broadleaf Forest in Southern Spain

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Vohník M., Burdíková Z., Wilkinson D. M.

Acta Protozoologica

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2012

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vol. 51

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issue 3

PL

Testate amoebae (TA) are an important part of soil microbial communities and in certain ecosystems they may represent a substantial proportion of total microbial biomass. Their distribution and abundance is driven by various abiotic factors (e.g. pH, organic matter, soil moisture, soil/water chemistry) but comparatively less is known about the role of biotic interactions. TA often co-occur with Ericaceae, a ubiquitous plant family inhabiting acidic soils with poor nutrient status. Ericaceae can significantly change soil properties through production of recalcitrant litter and possibly also due to root exudates and activities of root-inhabiting fungi; this may result in profound modifications of microbial communities. A recent study from northwest England shows that the invasive ericaceous shrub Rhododendron ponticum may significantly modify communities of soil TA. Here, we investigate the effect of pH, organic matter, soil moisture and R. ponticum presence on TA communities within the native range of the ericaceous shrub at two sites in south Spain and compare our results with the previous study from NW England. At the Spanish sites, organic matter content, R. ponticum presence and pH affected occurrence and abundance of several TA species; R. ponticum presence and organic matter content were highly correlated and explained most of the observed variability in TA communities (= the effect of the R. ponticum rhizosphere). R. ponticum rhizosphere affected especially TA with relatively large tests, i.e. Cyclopyxis eurystoma, Phryganella acropodia and Trigonopyxis arcula. Interestingly, T. arcula was also positively associated with R. ponticum in the previously studied British sites. The rhizosphere of the ericaceous shrub appears to have a positive effect on testate amoebae taxon richness at the two studied autochthonous Spanish sites but may reduce taxon richness in the sites in Britain where R. ponticum is an introduced species. Such possible positive/negative effects of native/invasive species, as well as other plant guilds, on TA communities clearly deserve further investigation.

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The Past, Present and Future of Soil Protist Ecology

The Use of Testate Amoebae in Monitoring Peatland Restoration Management: Case Studies from North West England and Ireland

Latitudinal Diversity Gradients in Free-living Microorganisms – Hoogenraadia a Key Genus in Testate Amoebae Biogeography

Testate Amoebae Communities in the Rhizosphere of Rhododendron ponticum (Ericaceae) in an Evergreen Broadleaf Forest in Southern Spain