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Measurements of concentrations of easily extractable soil nitrogen (N) were carried out on samples collected at the Heron Wood Reserve, Scotland, concurrently with investigations of N associated with total microbial biomass and the abundances of bacteria, fungi, and invertebrates. Soil biota at the studied site appeared to be limited by N. There was a remarkable difference between the ambient (i.e., easily extractable N) and biomass nitrogen. The abundance data of bacteria, protozoa and nematodes significantly negatively correlated with ambient N but showed positive correlations with the total microbial N content. There were, however, remarkable differences between the correlation patterns exhibited by the fungal and the bacterial pathways, as fungi did not show any correlations with chemical variables. These differences should be taken into account whilst interpreting biological interactions both at this important site and elsewhere.

Abstract Microinvertebrate abundance was measured, together with forest soil properties and litter components in eight plots dominated by beech and birch during May to August 2001. The results were analysed using ANOVA, stepwise regression and correlation analysis. Both protozoa and nematodes were analysed according to their functional groups. The protozoa were flagellates, ciliates and naked amoebae, and the nematodes were microbial and plant feeding nematodes. Moisture levels were between 28% and 33% in soil, and 50% to 70% in litter. Population numbers were very variable between sites and dates, and showed variable levels between May and July followed by a significant increase in August.ANOVA showed significant site and date effects, mainly in the litter. Stepwise regression models and correlation analysis revealed a number of interactions among separate groups of protozoa and nematodes, as well as their interrelations with fungi and bacteria. In addition, statistical analysis of soil data revealed a number of microfaunal relationships with soil pH, moisture and organic content, whilst in the field layer a number of significant interactions with specific forest litter fractions were found.The results have revealed particularly high levels of microfaunal abundance in the litter fraction compared to the soil, with flagellates and microbial feeding nematodes showing the highest levels among the trophic groups studied. These data compare well with other studies in similar ecosystems. The invertebrates present appear to be concentrated in hotspots of biological activity. In soil, they may predominantly have been confined to the rhizosphere. In the litter, their numbers may have been enhanced by nutrient availability, which may have increased throughout the study period owing to the gradual progress of decomposition facilitated by the combination of faunal, bacterial and fungal activity.

Summary The composition of forest litter and understorey layer, and fungal biomass (in terms of ergosterol) were measured in eight subplots over a winter – spring period (January to April). The sampling site was positioned in a range of woodland habitats (variously dominated by beech, Fagus sylvatica ; birch, Betula pendula × pubescens , and oak Quercus petraea ) and a clear area covered with grass (dominated by Holcus lanatus ). The results were analysed together with data on bacteria and microinvertebrates available from parallel research. Levels of ergosterol in individual subplots ranged between 50 and 160 µ g g − 1 DW. Fungal biomass decreased in March, and then increased signifi cantly in April. Stepwise regression models for ergosterol indicated positive relationships with moisture content (February), bacteria (all but February and March), fl agellates (February) and plant-feeding nematodes and fl ies (January, overall). The relationships with roots, seeds, the collective variable ‘ other microinvertebrates ’ (all March), amoebae (February) and fragments (March, overall) were negative, while the relationship between fungi- and microbial-feeding nematodes changed sign between February ( − ) and March (+). Results of analysis of covariance for fungal ergosterol were signifi cant only for January and the combined dataset. In January, fungi were shown to be signifi cantly related to amoebae, bacteria and a collembolan Folsomia candida , while the only signifi cant predictor returned by the overall model was bacteria. Correlation analysis confi rmed some effects already noted, and revealed a number of further interactions. The results highlighted the complexity of factors infl uencing temporal dynamics and spatial variability of

Abstract The micro and meso-invertebrate abundance was measured, together with forest litter composition, in eight plots of differing vegetation (dominated by beech and birch) over a winter-spring period. The litter moisture content was a mean of 76% during the sampling period and the beech sites were the driest. The results were analysed using a suite of statistical techniques, together with data on protozoa, fungi and bacteria available from parallel research. Nematodes were analysed according to the trophic levels, which included microbial feeders, plant feeders and predators. The majority of arthropods found were the collembolan, Folsomia candida and cryptostigmatid mites, with very small quantities of other micro- and mesoarthropods (such as larvae and mesostigmatid mites). The microarthropod populations peaked in January and fell during subsequent months, while population numbers of nematodes showed a decrease between January and February, followed by an increase in March. ANOVA showed a significant date effect, but no site-date interactions for the population abundance of both nematodes and microarthropods. Ecological interactions of meiofauna were analysed by ANCOVA, stepwise regression, and correlation analysis. Examples of relationships revealed include positive relationships of plant-feeding nematodes (PFN) with microbial feeding nematodes (MFN), and of F. candida with cryptostigmatid mites. Other positive interactions were found for PFN, MFN, F. candida, cryptostigmatid and mesostigmatid mites with litter components, such as beech leaves and litter thickness, moisture and grass, and protozoa. Negative interactions were recorded for PFN, MFN, F. candida, cryptostigmatid and mesostigmatid mites with beech leaves, fungi, protozoa and bacteria. The results have highlighted a very complex structure of factors influencing the temporal and spatial dynamics of the forest litter community. It is suggested that temperature and moisture content particularly influence the invertebrates present. The invertebrates appear to be present in a range of microhabitats, which may have resulted in a reduced level of competition and a high level of positive interactions revealed.

The integration of a comprehensive monitoring programme conducted in a temperate woodland through statistical analysis and simulation modelling is presented here. The Heron Wood Reserve in Peebleshire, Scotland is a 7.5-ha wood, left untended to facilitate investigation into a natural Scottish Woodland Ecosystem. Data on fungal fruiting have been collected since 1994, and since November 2000 physico-chemical and biotic experiments on soil and woodland litter have also been conducted with the aim to construct and integrate a number of simulation submodels of the various ecological systems present in an untended Scottish woodland. Important systems for modelling include patterns of fungal succession, habitat characteristics and fungal biochemical patterns. A large volume of data has been collected so computer software is used for the storage and handling of data. Microsoft Access was the database used for storage; integration of functions available in Microsoft Excel with a customised software written in Microsoft Visual Basic and Microsoft VBA allowed various statistical modelling tests (e.g. Scheffe analysis of contrast) to be carried out, and the quick display of data in a suitable manner. Model Maker software is used to construct and test simulation models formulated from the data and ultimately to facilitate the running of various simulations. Integration of the separate lines of investigation is demonstrated on the example of a case study describing differences in the dynamics of decomposers in beech- and birch-dominated habitats. Integration of the information obtained allowed us to put forward the following hypothesis. The leaf litter produced by beech trees is of lower quality compared to birch, and decomposition in beech-dominated habitats is delayed (i.e. in comparison to birch-dominated) because of the differences in the extent to which these plants create and maintain a litter and humus layer ( sensu Wardle, Communities and Ecosystems. Linking the Aboveground and Belowground Components, Princeton University Press, Princeton, 2002). Hence, the decomposition in beech-dominated habitats mainly occurs somewhat deeper in the soil profile, and may be carried out with some considerable involvement of ectomycorrhizal fungi. The correct understanding of the site-specific peculiarities of the ecological patterns is important for the improvement of biodiversity of woodland and forest ecosystems both in Scotland and worldwide.

A sufficiently large body of knowledge on British ground beetle (Carabidae) communities now exists to allow investigation of whether habitats may be classified or described on the basis of their ground beetle communities, in the same way that the National Vegetation Classification (NVC) describes British plant communities. A data set of ground beetle abundances from pitfall traps at 481 sites in a range of natural, semi-natural and agricultural habitats throughout Scotland was available for analysis. Multivariate analysis (detrended correspondence analysis and fuzzy cluster analysis) was carried out on proportional catch data of 156 species of ground beetle from 444 of these sites and the results related to the NVC of the sites. Initial analysis classified the sites into five broad categories: 1) peatlands, 2) calcifugous, 3) mesotrophic, 4) dry river sediments and 5) damp river sediments. Further analysis identified 15 ground beetle assemblages, each corresponding to a relatively well defined vegetation type within one of these broad categories. The major environmental factors appearing to determine the distribution of ground beetle assemblages were substratum type, disturbance and soil moisture, all of which are also important determinants of the distribution of plant communities. The presence and absence of relatively stenotopic species were important discriminants of certain habitats such as wetlands and river sediments but the relative abundances within assemblages of more eurytopic species provided good indications of a relationship between ground beetle assemblages and NVC categories.

The abundance of heterotrophic flagellates, ciliates and naked amoebae was measured in 8 sites covered with different vegetation (beech, birch, beech-birch, birch-oak-beech, grass) from January to April 2001. The results were analysed by a suite of mathematical techniques, together with data on bacteria, fungi, nematodes, microarthropods, and the composition of forest litter and field layer, available from parallel research. The population levels ranged between 4.02 and 795 × 103, 28 and 1010, 35 and 1170 g–1 litter dry wt for flagellates, ciliates and amoebae, respectively. Temporal changes in the microbiota appeared to be affected by progressive winter cooling followed by a spring increase in temperature, and influenced by habitat characteristics and a complex multivariate interplay among ecosystem components. The population abundance in winter (January-mid March) was higher than in spring (late March–April) for all protozoa. Amoebae showed minimum values in March, followed by considerable recovery in April. However, ciliate values dropped slightly between March and April, whilst flagellate values steadily decreased throughout the whole research period, suggesting that the spring growth of ciliates and flagellates might have been arrested by increased predation and/or competition. Statistical analysis revealed a number of significant relationships between the protozoa studied and other ecosystem components. These relationships were indicative of the conditions studied and may, therefore, be useful for future reference. The results highlighted the complexity of transient multivariate interactions of protobiota in forest litter, suggesting that any interpretations of the population dynamics must take account of a full range of both temporal and spatial factors.

Interrelations of fungal mycelium with other soil biota are of paramount importance in forestry and soil ecology. Here we present the results of statistical analysis of a comprehensive data set collected in the first (and the only) British fungus sanctuary over a period of four months. The variables studied included a number of soil properties, bacteria, protozoan flagellates, ciliates and amoebae, microbial and plant feeding nematodes, various microarthropods, and two fungal biomarkers--glomalin and ergosterol. One way ANOVA showed that the dynamics of the microbiota studied was influenced by seasonal changes. Superimposed on these changes, however, was variability due to biological interactions and habitat characteristics. Two fungal biomarkers, ergosterol and glomalin, were differently influenced by other biota and abiotic variables. The results indicate that the dynamics of soil fungi is influenced not only by soil microarthropods, but also by those found in forest litter. The overall outcome, therefore, is likely to be very complex and will depend upon specific conditions of any particular ecosystem.