Mesofauna Community Research Articles

Comparison of soil meso-fauna community between spruce and larch stands

Comparison of soil meso-fauna community between spruce and larch stands

Starving the soil of plant inputs for 50 years reduces abundance but not diversity of soil bacterial communities

If soil communities rely on plant-derived carbon, is biodiversity lost when this primary source is removed? Soil microbial and mesofaunal communities at the Rothamsted Highfield site were compared under a mixed grass sward, arable rotation and a section maintained as a bare-fallow for the past 50 years by regular tillage. Organic matter reserves have been degraded and microbial and mesofaunal numbers and mite diversity have declined in this unique bare-fallow site, where fresh carbon inputs have been drastically reduced. However, it supports a species-rich metabolically active bacterial community of similar diversity to that in soil maintained as grass sward. Thus in contrast to soil mesofauna, bacterial diversity (but not abundance) is apparently independent of plant inputs.

Surveying soil faunal communities using a direct molecular approach

Soil faunal communities are often phylogenetically diverse and the accurate assessment of the taxonomic structure of these communities is both time-consuming and requires a high level of taxonomic expertise. Here we describe a DNA sequence-based methodology for characterizing soil micro- and mesofaunal communities that is similar to the molecular approaches commonly used to survey soil microbial diversity. The technique involves the direct extraction of faunal DNA from soil, PCR amplification of the extracted DNA with metazoan-specific primers, followed by the construction of clone libraries and direct sequencing of individual PCR products. We used this technique to characterize micro- and mesofaunal community composition from six individual soils representing two land-use types. The technique captured the more abundant faunal groups in the soils (nematodes, Collembola, Acari, tardigrades, enchytraeids) and provided sufficient taxonomic resolution to describe the overall structure of the communities. We compared the results obtained using this molecular approach to results obtained using a traditional, microscopy-based approach and found that the results were broadly similar. However, since biases are inherent in both methods it remains unclear which method provides a more accurate assessment of soil faunal community composition. Although this molecular approach has some distinct disadvantages over the more widely-used direct extraction methods, one advantage is that the taxonomic identification it can provide will be more accurate and consistent across research groups, facilitating effective comparisons of mesofaunal surveys.

EDAPHIC MESOFAUNA COMMUNITY STRUCTURE IN ORGANIC AND CONVENTIONAL MANAGEMENT OF CRANBERRY (Vaccinium sp.) PLANTATIONS: AN AGROECOLOGICAL APPROACH

The aim of the present study was to determine and compare taxa richness, abundance and diversity of the edaphic mesofauna community between plantations of cranberries (Vaccinium sp.) subjected to organic and conventional management in farms in central-south Chile (37°28'S), as also to evaluate changes produced in their diversity and abundance diversity and abundance, as result of the change from conventional to organic management. In July 2006 two farms were chosen, one with one year under organic management (OM1) and a second one under six years of certified organic management (OM6). Each farm was divided in four quadrants, each one with a surface of 2,500 m . In each quadrant was extracted one sample with six replicas of 188.5 cm3 each. Samples were processed in the laboratory using the Berlesse-Tullgren system for the extraction of mesofauna and the subsequent counting and identification of specimens. To compare the organic managed plantation, it was selected a farm under conventional management (CM) with similar climatic and edaphic conditions. On each parcel, taxa richness, abundance, alpha (a) diversity, dominance and beta (P) diversity were determined. Significant differences between diversity values were determined with Student's t test (a = 0.05). It is concluded that taxa richness is similar in all plantations, independent of agricultural management, whereas abundance of each taxon individually is different between both types of management. There are significant differences in diversity between the organic plantations (OM1 versus OM6) and between the conventional (CM) versus organic plantations (P<0.05). Qualitative (taxocenotic) and quantitative (biocenotic) similarity recorded in the edaphic communities from both types of plantation management may be explained by soil type and climate similarity, as well as by the homogeneity of the edaphic ecosystem.

Soil microbial and faunal responses to herbicide tolerant maize and herbicide in two soils

A glasshouse experiment was set up to compare processes and organisms in two soils planted with genetically modified (GM) herbicide tolerant (HT) maize treated with appropriate herbicides. This was part of a wider project (ECOGEN) looking at the consequences of GM cropping systems on soil biology using a tiered approach at laboratory, glasshouse and field scales. Soil for the experiment was taken from field sites where the same maize cultivars were grown to allow comparison between results under glasshouse and field conditions. The maize cultivars T25 (GM HT glufosinate-ammonium tolerant), Orient (non HT near isogenic control for T25) and Monumental (a conventional, non HT variety) were grown in contrasting sandy loam and clay loam soils, half were sprayed with the appropriate herbicide as used in the field and soil samples were taken at the five-leaf and flowering plant growth stage. The main effects on all measured parameters were those of soil type and plant growth stage, with four categories of subsequent interaction: (1) there were no effects of herbicide on plant growth or soil microarthropods: (2) the maize cultivar (but not the GM HT trait) had effects on the decomposition of cotton strips and the nematode community; (3) herbicide application in general altered the community level physiological profile of the microbial community and reduced both soil basal respiration and the abundance of protozoa; and (4) the specific application of glufosinate-ammonium to T25 maize altered soil microbial community structure measured by ester linked fatty acids. The results from this glasshouse experiment support the findings from the field that there are effects of herbicide application on the soil microbial and meso-faunal community but that, compared to other standard agricultural practices, the differences are relatively small.

Impact of elevated carbon dioxide on the rhizosphere communities of Carex arenaria and Festuca rubra

AbstractThe increase in atmospheric carbon dioxide (CO2) levels is predicted to stimulate plant carbon (C) fixation, potentially influencing the size, structure and function of micro‐ and mesofaunal communities inhabiting the rhizosphere. To assess the effects of increased atmospheric CO2 on bacterial, fungal and nematode communities in the rhizosphere, Carex arenaria (a nonmycorrhizal plant species) and Festuca rubra (a mycorrhizal plant species) were grown in three dune soils under controlled soil temperature and moisture conditions, while subjecting the aboveground compartment to defined atmospheric conditions differing in CO2 concentrations (350 and 700 μL L−1). Real‐time polymerase chain reaction (PCR) and PCR‐denaturing gradient gel electrophoresis methods were used to examine effects on the size and structure of rhizosphere communities. Multivariate analysis of community profiles showed that bacteria were most affected by elevated CO2, and fungi and nematodes to a lesser extent. The influence of elevated CO2 was plant dependent, with the mycorrhizal plant (F. rubra) exerting a greater influence on bacterial and fungal communities. Biomarker data indicated that arbuscular mycorrhizal fungi (AMF) may play an important role in the observed soil community responses. Effects of elevated CO2 were also soil dependent, with greater influence observed in the more organic‐rich soils, which also supported higher levels of AMF colonization. These results indicate that responses of soil‐borne communities to elevated CO2 are different for bacteria, fungi and nematodes and dependent on the plant type and soil nutrient availability.

Responses of soil mesofauna communities and oribatid mite species to site preparation treatments in high-elevation cutblocks in southern British Columbia

Summary Five years after operational preparation of planting sites in high-elevation clearcuts, we studied the densities of soil Acari and Collembola to determine whether their response was related to the level of disturbance. In the forest floor (the organic horizon overlying the mineral soil), Acari and Collembola densities were lower in the burned sites than in the untreated sites. In the upper mineral soil, there were no differences in Acari density among untreated, burned, and scalped planting sites, but Acari density was lower in mounded sites which were the most severely disturbed at the micro-site level. For Collembola, density was lower in burned and mounded sites than untreated sites. Treated sites all had generally reduced soil nutrient levels compared to untreated sites. In the forest floor, 23 species of oribatid mites were identified. Oppiella nova and Platynothrus septentrionalis dominated the forest floor in untreated sites while Liochthonius brevis and Quadroppia quadricarinata dominated the forest floor in burned planting sites. Twenty-four oribatid mite species were collected from the upper mineral soil. There were significantly more species in the upper mineral soil of untreated than of mounded, burned or scalped sites. Five species ( L. brevis , Platynothrus sibiricus , Q. quadricarinata , Suctobelbella sp. nr. acutidens , and Synchthonius crenulatus ) dominated the upper mineral soil in untreated sites, Synchthonius crenulatus and L. brevis in burned sites, Neoliochthonius occultus and Suctobelbella sp. nr. sarekensis in scalped sites and O. nova , Cultrobates sp., and Suctobelbella palustris in the mounds. The results suggest that disturbance effects on mites and collembola persist into the 5th year after site preparation in these forest types.

Sewage Sludge Effects on Mesofauna and Cork Oak (Quercus suberL.) Leaves Decomposition in a Mediterranean Forest Firebreak

Effects of sewage sludge on litter mesofauna communities (Collembola and Acari) and cork oak (Quercus suber L.) leaf litter decomposition have been studied during 18 mo using litterbags in an in situ experimental forest firebreak in southeastern France. The sludge (2.74 t DM ha(-1) yr(-1)) was applied to fertilize and maintain a pasture created on the firebreak. Litterbag colonization had similar dynamics on both the control and fertilized plots and followed a typical Mediterranean pattern showing a greater abundance in spring and autumn and a lower abundance in summer. After 9 mo of litter colonization, Collembola and Acari, but mainly Oribatida, were more abundant on the sludge-fertilized plot. Leaf litter decomposition showed a similar pattern on both plots, but it was faster on the control plot. Furthermore, leaves from the fertilized plot were characterized by greater nitrogen content. Both chemical composition of leaves and sludges and the decomposition state of leaves have significantly affected the mesofauna community composition from each plot.

Some rules of soil invertebrate community organization (by the example of Amur Basin mesofauna)

Some rules of organization of soil communities in the zone of mixed, Jeddo spruce, and larch taiga as well as forest-steppe in the Amur Basin have been formulated on the basis of the factual data. Abundant resources in the soil layer proved to decrease the competition in favor of neutralism, which allows sister species to occupy the same ecological niche. The stability of soil conditions allows considerable contraction of the realized niche volume, which increases species richness in soil. The biocenotic significance of soil organisms is determined by their biomass, productivity, and functional interchangeability. Ecological redundancy makes the mesofauna community much more resistant to environmental factors. The interaction type can change with environmental conditions. Competition prevails in soil communities outside their ecological optimum. Under these conditions, the community demonstrates the concentration of domination and decreased species richness due to the disappearance of closely related invertebrate species largely in biologically regressing groups.

Interspecific relationships among soil invertebrates influence pollutant effects of phenanthrene

Five mesofauna communities varying in both structure and composition were exposed to phenanthrene in mesocosms for up to four months. Effects of phenanthrene were assessed on mesofauna population dynamics, fungal biomass (ergosterol concentrations), and litter decomposition (litter mass loss, nitrogen concentration). The effects of each community on the fate of phenanthrene were also assessed. We hypothesize that phenanthrene affects the population dynamics of mesofauna and soil biological functioning depending on exposure duration, type of community, or both. Results show that phenanthrene exerted an effect on mesofauna and that the effects on some species, like Folsomia fimetaria, were influenced by the species composition in the mesocosms, the soil layer, and the sampling date. However, the effects of phenanthrene on ergosterol content and organic matter decomposition were not significantly influenced by community composition. These results demonstrate that interspecific relationships are needed to assess the toxicity of pollutants and should be taken into account in ecotoxicological risk assessment. Furthermore, this work does not support the hypothesis of a direct link between toxic effects of organic pollutants on mesofauna species and soil biological functioning.

Effects of sewage sludge and copper enrichment on both soil mesofauna community and decomposition of oak leaves (Quercus suber) in a mesocosm

A laboratory mesocosm experiment was performed to study the effects of copper-enriched sewage sludge application on a mesofauna community. For 12 weeks, characteristics and changes in this defined and artificial mesofauna community structure were monitored as well as the dynamics of leaf litter decomposition. The mesofauna community comprised six species of Collembola (Folsomia fimetaria, Isotomurus prasinus, Lepidocyrtus cyaneus, Mesaphorura macrochaeta, Parisotoma notabilis, Protaphorura armata), two species of acari Oribatida (Achipteria coleoptrata, Adoristes sp.), one species of acari Gamasida (Hypoaspis aculeifer) and one species of enchytraeid (Enchytraeus crypticus). Three treatments included the addition of 22 g dry weight (DW) sludge spiked with 0, 200 and 1,000 mg Cu kg−1 DW sludge in each mesocosm, and one treatment had 66 g DW sludge spiked with 1,000 mg Cu kg−1 DW sludge added in each mesocosm. Copper, complexed with sludge due to a favourable pH, had no effect on community and litter parameters when added to low amount of sludge. In contrast, tripling the sludge dose in addition to a high dose of Cu changed in time the sludge and leaf chemical composition as well as mesofauna community structure. Responses of the mesofauna to this treatment differed between species. The abundance of species such as I. prasinus, L. cyaneus, M. macrochaeta and P. notabilis decreased, whereas the abundance of H. aculeifer increased and became dominant.

Testing the usefulness of habitat corridors in mitigating the negative effects of fragmentation: the soil faunal community as a model system

The corridor hypothesis predicts that habitat corridors should attenuate the negative effects of fragmentation on populations or communities by enhancing the dispersal of organisms between the habitat fragments (the ‘rescue effect’). In the present 12-month mesocosm experiment, this hypothesis was tested using the soil micro- and mesofaunal community in humus patches—either connected or unconnected with humus corridors to each other—as a model system. Of particular interest was to explore whether faunal groups with differing life strategies (e.g. in trophic position and dispersal capacity) would differ in their responses to the corridors. The results showed that enchytraeid worms were the only faunal group affected by the corridors: population growth of the worms was promoted by the presence of the corridors. The lack of corridor effects on other soil fauna, such as microarthropods, is likely to be due to unexpected increases in the populations and species richness of this fauna in the humus patches, thus providing no grounds for the rescue effect to operate. The results of the experiment indicate that the faunal groups studied are not sensitive to fragmentation-induced changes in their landscape. It is suggested that the high heterogeneity and availability of resources (including space) even in a small volume of soil render the use of corridors by this soil fauna ineffective.

Increasing species and trophic diversity of mesofauna affects fungal biomass, mesofauna community structure and organic matter decomposition processes

A laboratory mesocosm experiment was set up to study the effects of five mesofauna model communities on litter fungal biomass (ergosterol content) and litter decomposition parameters (litter mass remaining, N concentration) for 4 months. The five treatments were: (1) no soil mesofauna, (2) the collembolan Folsomia fimetaria, (3) an assemblage of the collembolan species Isotomurus prasinus, Hypogastrura assimilis, F. fimetaria, Mesaphorura macrochaeta and Protaphorura armata, (4) the same collembolan assemblage plus the enchytraeid Enchytraeus crypticus, and (5) the six species plus the predaceous mite Hypoaspis aculeifer. After 30, 60, 90 and 120 days of incubation, six mesocosms of each treatment were sacrificed and biomass, species richness and dominance were measured. Changes occurred during the study with an increase in total detritivore biomass and a decrease in species richness with strong dominance by a few species in multispecies mesocosms. A vertical stratification of species was also observed in the mesocosms. Litter mass loss and N mineralisation were reduced with the introduction of fauna and showed the largest effects in the multispecies detritivore treatments. Ergosterol production was only temporary reduced in the multispecies treatments reflecting an effect of mesofauna on fungal biomass related to diversity rather than the biomass of mesofauna. An inhibitory predator effect was observed on functional decomposition parameters and indicated top-down control of decomposition via detritivorous mesofauna.

Indicators for evaluating soil quality

Interactions between the diversity of primary producers (plants) and of decomposers (microbes and mesofaunal communities), the two key functional groups that form the basis of all ecosystems have major consequences on the functioning of agricultural ecosystems. Soil microorganisms control the transformation and mineralization of natural compounds and xenobiotics. The soil microbiota, existing in extremely high density and diversity, rapidly modify the energetic performance and activity rates to changing environmental conditions. Thus, the microbial consortium possesses the ability to accommodate environmental constraints by adjusting (i) activity rates, (ii) biomass, and (iii) community structure. These parameters are particularly important to take into consideration when evaluating soil quality. The present paper gives an overview about the possibilities to use bacterial and fungal populations as an indicator for soil quality. Furthermore also the applicability of nematodes for the determination of soil health will be discussed.

Effects of water level and nutrients on spatial distribution of soil mesofauna in peatlands drained for forestry in Finland

We investigated the within-site distribution of Enchytraeidae, Collembola, Oribatida, Mesostigmata and Prostigmata relative to varying water level and substrate quality on pine mire sites forming a drainage succession continuum. Collembolans were most intolerant of wetness, favoring drier locations at all stages of the drainage succession. In general, the effect of water level variation on the within-site distribution of the soil fauna was strongest when the site was at an early stage of either progressive or regressive water level change. When the average water level was below 20 cm, it no longer had a significant effect on the distribution of mites, but still affected that of Enchytraeidae and Collembola. Boron was positively correlated with faunal density in several cases, and thus may be the growth limiting nutrient affecting substrate quality for decomposers in these sites. The overall changes in the soil mesofauna in drained peatlands depicted here show that these peatland forests are converging ecologically on upland forests where decomposition in general is much faster than in pristine peatlands. The change caused by restoration shows how labile these ecosystems are also with respect to the mesofaunal community.

Reciprocal interactions between Scots pine and soil food web structure in the presence and absence of ectomycorrhiza.

Mycorrhizal plants are commonly believed to direct much more of their photosynthates into the soil than non-mycorrhizal plants. As the growth of most organisms of the detrital food web is limited by energy, the flow of C through mycorrhizal plants into the below-ground milieu is widely assumed to nourish a variety of decomposer organisms in soils. In the current experiment, I explored whether some representatives of soil mesofauna, either fungivores or microbi-detritivores, derive benefit from the presence of ectomycorrhizal (EM) fungi growing on the roots of Scots pine (Pinus sylvestris). I also investigated whether the role of soil mesofauna in affecting pine growth depends on the presence of EM fungi in the pine rhizosphere. The study was established in microcosms with a mixture of raw humus and sand. The soil was defaunated, reinoculated with 10 species of soil bacteria and 11 species of saprophytic soil fungi, and pine seedlings, either infected or non-infected with four taxa of EM fungi, were planted in the microcosms. Five treatments with different food web configurations were established: (1) saprophytic microbes alone, (2) as (1) but with the omnivorous enchytraeid species Cognettia sphagnetorum present, (3) as (1) but with Collembola (Hypogastrura assimilis), (4) as (1) but with four species of oribatid mites (Acari) involved, and (5) as 1) but with C. sphagnetorum, H. assimilis and the Acari. The microcosms were incubated in a climate chamber with varying temperature and illumination regimes for two growing periods for the pine. After 60 weeks, pine biomass production was significantly greater in the mycorrhizal systems, the total biomass being 1.43 times higher in the presence than absence of EM fungi. Similarly, almost ten times more fungal biomass was detected on pine roots growing in the mycorrhizal than in the non-mycorrhizal systems. The presence of EM fungi was also associated with significantly lowered pH and percent organic matter of the soil. Despite the clearly larger biomass of both the pines and the fungi on the pine roots, neither the numbers nor biomasses of the mesofauna differed significantly between the EM and non-EM systems. The presence of Collembola and C. sphagnetorum had a positive influence on pine growth, particularly in the absence of EM fungi, whereas oribatid mites had no effects on pine growth. The complexity of the mesofaunal community was not related to the biomass production of the pines in a straightforward manner; for example, the complex systems with each faunal group present did not produce more pine biomass than the simple systems where C. sphagnetorum existed alone. The results of this experiment suggest that the short-term role of EM fungi in fuelling the detrital food web is less significant than generally considered, but that their role as active decomposers and/or stimulators of the activity of saprophytic microbes can be more important than is often believed.

Changes in mesofauna abundance in peat soils drained for forestry

Soil mesofauna community structure was studied in a drainage-succession continuum of peatland sites supporting Scots pine ( Pinus sylvestris L.) dominated stands in southern Finland. The numbers of Enchytraeidae, Collembola, Oribatida, Mesostigmata and Prostigmata in an 8-cm-deep surface peat layer were compared among a pristine undrained pine mire site, comparable sites drained for forestry 12, 26 and 60 years earlier, and a 42-year-old drained site re-wetted two years earlier. Drainage and the consequent water-level draw-down clearly increased the numbers of all soil animals studied, the numbers showing highly significant correlation with the water-table level of the sites. On the older drained sites, the populations were generally about ten times higher than on the undrained site; for Collembola, almost 100 times higher. After re-wetting, the numbers dropped abruptly, falling between those of the undrained and the youngest drained site. Oribatida were the most frequently found animals on the sites studied: on the undrained site almost 60% of the total number were these mites, the relative proportion somewhat decreasing along the drainage succession. The proportion of Enchytraeidae also decreased slightly after drainage, whereas that of Collembola clearly increased. Most of the soil fauna was found close to the soil surface. In general, >80% of Collembola, Oribatida, Mesostigmata and Prostigmata, and >60% of Enchytraeidae were found in the topmost 4-cm layer. In the course of the drainage succession, the soil fauna community structure became more similar to that of upland sites with similar tree-stand growth potential.

Influence of compaction of a forest soil on the soil fauna in a subtropical region: I. Oribatei (Acari, Cryptostigmata) and Collembola (Insecta)

An experiment to observe some changes of composition and population of Oribatei and Collembola was carried out on a Cambicsoil covered with Pinus taeda L. (Pinaceae). This study area is located on the Canguiri Experimental Station Center, Universidade Federal do Parana, 20km north to Curitiba city, Brazil. The climate of the area is subtropical. The observations resulted in a conclusion that the compaction strongly changes the structure of edaphic mesofauna community as the consequence of the modification of physical properties of soils.

Invertébrés de la litière dans des érablières saines et dépéries du sud-est du Québec

A study was carried out during the summers of 1987 and 1988 in healthy and declining maple forests in southeastern Quebec to estimate the impact of forest decline on the litter's invertebrate mesofauna communities. Insects, arachnids (opilions and spiders), gastropods, and myriapods were the four major groups sampled. The class Insecta represented 50% of all organisms collected. The mean abundance of insects and, for the most part, arachnids and gastropods tended to be lower in declining sites. However, myriapods were always more abundant in these sites. The variability observed in the litter pH and thickness can not alone account for the changes observed in the litter fauna communities. We suggest that temperature and moisture modifications resulting from canopy opening may be responsible for such a variation in abundance.

Relationship of Mesofauna Bioiversity and Undergrowth Vegetations in Jobolarangan Forest

Soil mesofauna is one group of soil biodiversity, which take main role of decomposition processes of organic matter. The objective of this research was to investigate the composition and diversity of soil mesofauna at Jobolarangan forest. Soil samples were collected from 8 sampling points which different vegetation types. Soil mesofaunas extracted by modified Barless-Tullgren extractor apparatus for 4 days. The results showed that in the north side of Jobolarangan forest were identified 6 groups of microarthropods, i.e.: Mesostigma and Astigma (Ordo: Acarina), Isotomidae (Ordo: Collembola), Rhinotermitidae (Ordo: Hymenoptera), Staphyllinidae and Carabidae (Ordo: Coleoptera). The group with highest density and wide distribution was Astigma. There were high diversities of soil mesofauna community structure at Jobolarangan forest.© 2001 Jurusan Biologi FMIPA UNS SurakartaKey words: soil mesofauna, biodiversity, Jobolarangan forest.