Soil Fauna Feeding Activity Research Articles

Hydrological regime and forest development have indirect effects on soil fauna feeding activity in Central European hardwood floodplain forests

Soil fauna act as regulators of decomposition processes via their feeding activity, thereby playing an important role in regulating carbon cycling and sequestration. Hardwood floodplain forests are critically endangered habitats, but strongly contribute to carbon sequestration in Central Europe. In the present study, within a floodplain forest-development programme, we investigated the feeding activity of soil fauna via the Bait Lamina test in hardwood floodplain forests of the middle Elbe River in Germany in sites with different hydrological regimes and forest-development stages, with neighbouring grassland sites for comparison. While statistically significant differences in overall feeding activity between general hydrological regimes or forest development stages were not found, decreases in feeding activity with soil depth were strongly modulated by these factors, indicating more unfavourable conditions for soil fauna at increasing soil depth due to, e.g., anoxic conditions in floodplains of tributaries or low soil moisture content below the shallow rooting zone of grasslands. Registered effects of soil texture on soil fauna feeding activity were dependent on forest-tree density, and combined effects indicate that soil-fauna feeding activity varies with soil temperature during spring, but with soil moisture in early autumn. In conclusion, our results highlight the importance of the current abiotic conditions on soil-fauna feeding activities in floodplain forests, i.e. soil temperature, moisture and ground water level. Hydrological regime and forest development have a strong impact on the effect of these conditions, indirectly affecting soil fauna feeding activity and highlighting the multifactorial influence on soil fauna functional activity to be considered in floodplain-forest restoration programs.

Diversity and activity of soil biota at a post-mining site highly contaminated with Zn and Cd are enhanced by metallicolous compared to non-metallicolous Arabidopsis halleri ecotypes.

Hyperaccumulators' ability to take up large quantities of harmful heavy metals from contaminated soils and store them in their foliage makes them promising organisms for bioremediation. Here we demonstrate that some ecotypes of the zinc hyperaccumulator Arabidopsis halleri are more suitable for bioremediation than others, because of their distinct influence on soil biota. In a field experiment, populations originating from metal-polluted and unpolluted soils were transplanted to a highly contaminated metalliferous site in Southern Poland. Effects of plant ecotypes on soil biota were assessed by measurements of feeding activity of soil fauna (bait-lamina test) and catabolic activity and functional diversity of soil bacteria underneath A. halleri plants (Biolog® ECO plates). Chemical soil properties, plant morphological parameters, and zinc concentration in shoots and roots were additionally evaluated. Higher soil fauna feeding activity and higher bacterial community functional diversity were found in soils affected by A. halleri plants originating from metallicolous compared to non-metallicolous ecotypes. Differences in community-level physiological profiles further evidenced changes in microbial communities in response to plant ecotype. These soil characteristics were positively correlated with plant size. No differences in zinc content in shoots and roots, zinc translocation ratio, and plant morphology were observed between metallicolous and non-metallicolous plants. Our results indicate strong associations between A. halleri ecotype and soil microbial community properties. In particular, the improvement of soil biological properties by metallicolous accessions should be further explored to optimize hyperaccumulator-based bioremediation technologies.

Effects of organic fertilizer incorporation practices on crops yield, soil quality, and soil fauna feeding activity in the wheat-maize rotation system

The decline in soil quality is becoming a significant process of soil degradation. Optimizing organic fertilizer incorporation practices in cropland is essential to enhancing crop productivity and soil health. However, that requires a comprehensive understanding of crop yield and soil quality reaction across an application gradient of organic fertilizer. We investigated the effect of organic fertilizer incorporation practices on crop yield, soil quality, and fauna feeding activity from fluvo-aquic soils on wheat (Triticum aestivum)-maize (Zea mays) rotation field. The six treatments included were unfertilized N control (UC), traditional chemical fertilizer application (TF, 600 N kg ha−1 year−1), and recommended chemical fertilization (RF, 400 N kg ha−1 year−1) with no organic fertilizer application rate, low-level 15.0 (RFLO), medium-level 30.0 (RFMO), and high-level 45.0 t ha−1 year−1 (RFHO) application, respectively. The research findings show that the yield with organic fertilizer incorporation treatments increased 26.4%–44.6% for wheat and 12.5%–40.8% for maize compared to RF plots. The long-term organic fertilizer incorporation rate increased organic carbon from 54.7% to 110.6% versus UC plots and 27.9%–74.0% versus chemical fertilizer (TF and RF) treatments, and the total nitrogen content of soil increased from 41.8% to 59.2%, and 24.6%–39.2%. The long-term inorganic fertilizer combined with organic fertilizer incorporation practices significantly enhanced soil sucrose (30.1%–51.9%), urease (28.4%–38.3%), and β-1,4-glucosidase (34.6%–122.4%) activity. Still, nitrite reductase, polyphenol oxidase, and catalase significantly lower 27.3%–49.9%, 8.5%–26.3% and 23.3%–34.3% than single applications of inorganic N fertilizer groups. Meanwhile, the results showed that organic fertilizer incorporation practices improved soil fauna feeding activity by 35.2%–42.5%, and the excessive application of inorganic N fertilizer reduced the activity level of soil fauna.

Plasma-Treated Nitrogen-Enriched Manure Does Not Impose Adverse Effects on Soil Fauna Feeding Activity or Springtails and Earthworms Abundance

Plasma treatment of animal manure is a new technology, enriching the manure with plant-available nitrogen. Therefore, the product is termed nitrogen-enriched organic fertilizer (NEO). The producer (N2 Applied) claims that NEO can be a sustainable alternative to conventional fertilizers used in agriculture. However, the effect of this product on soil-dwelling organisms is unknown. This study investigates and compares the effects of NEO on changes in soil fauna feeding activity, the abundance of springtails, and the abundance and weight of earthworms to mineral fertilizer, organic fertilizer (cattle slurry), and no fertilizer in pot and field experiments with sandy clay loam soil. Early effect evaluation (week 7) indicated influences on soil fauna feeding activity; among treatments, higher amounts of fertilizers went along with lower feeding activity, regardless of fertilizer type. However, the initial fertilizer application stimulation was transient and stabilized with time after fertilization towards mid-term (week 14) and late effect evaluations (week 21). Accordingly, differences between feeding activities were less than five percent at late effect evaluation. Similarly, none of the fertilizers used imposed adverse effects on the abundance of springtails and the abundance and weight of earthworms; these parameters were almost identical among all fertilizing treatments. After two years of application in field trials and in a pot experiment, NEO and the other used fertilizers seem not to harm the selected soil-dwelling organisms.

Nitrogen Enriched Organic Fertilizer (NEO) and Its Effect on Ryegrass Yield and Soil Fauna Feeding Activity under Controlled Conditions

This study aimed to investigate the effects of a new nitrogen-enriched organic-based fertilizer (NEO) on Italian ryegrass (Lolium multiflorum Lam.) yield and soil fauna feeding activity. Nitrogen is transformed from the air to manure by a plasma process. At the farm level, NEO could improve self-sufficiency and sustainability. The work was carried out under controlled conditions in two pot trials. Five fertilization regimes were used: no fertilizer, different amounts of mineral fertilizer, three NEO types, organic fertilizer (untreated manure), and organic fertilizer + different amounts of N in mineral fertilizer, including 14 treatments in trial one and 11 treatments in trial two. Besides evaluating dry matter yields, we utilized the Bait-lamina test system to assess the feeding activity of soil fauna. The results indicated a clear positive impact of nitrogen (N) on ryegrass yield where all fertilizers increased the yield in correspondence with their N availability regardless of the fertilizer type; whereas the yield was highest with mineral fertilizer up to our maximum level of 235 kg N ha−1 in trial one and 175 kg N ha−1 in trial two. The NEO fertilizers yielded in the same range as mineral fertilizers. The same clear pattern was not observed for soil fauna feeding activity. Instead, a tendency was observed where no fertilization tends to give the highest feeding activity. We saw no correlation between the yield and the soil fauna feeding activity. The feeding activity was highest in depth below 5 cm from the soil surface. Feeding activity also increased over time after fertilization. The NEO fertilizers had no more adverse effects on soil fauna feeding activity than other fertilizers. Other factors than fertilization alone are determining the soil fauna feeding activity.

Atividade alimentar da fauna do solo em sistemas de produção sob palhadas de plantas de cobertura

ABSTRACT To preserve a desirable level of soil quality, especially taking into consideration its health and sustainability, is not an easy task, due to the numerous factors that influence it. This study aimed to measure the feeding activity of soil fauna in production systems under cover crop straws sampled at the depth of 0-8.0 cm. A randomized blocks design, with four replicates and eight treatments, was used, corresponding to soybean cultivation under the following cover crop straws: maize monoculture; maize intercropped with Urochloa ruziziensis; U. ruziziensis monoculture; sorghum intercropped with U. ruziziensis; sorghum monoculture; sunflower intercropped with U. ruziziensis; mix (millet + Crotalaria spectabilis + U. ruziziensis); and a fallow treatment. At the depth of 1.0 cm, there was a variation of 63.59-37.06 % for consumption among the treatments, with the highest consumption for the mix, if compared to the fallow treatment. At the depth of 2.0-7.0 cm, the consumption did not vary among the treatments. For the depth of 8.0 cm, the fallow treatment presented the highest consumption (45.76 %; p < 0.05), when compared to sunflower intercropped with U. ruziziensis (20.51 %), sorghum (20.58 %) and sorghum intercropped with U. ruziziensis (18.96 %).

No apparent effect of invasive alien goldenrod on soil microbial communities or soil fauna feeding activity

Invasive alien species spreading in abandoned agricultural landscape may negatively affect native organisms, including plants and soil biota. This study assessed the effects of invasion by Solidago sp. (goldenrod) in southern Poland on soil fauna feeding activity and on soil microorganism activity, biomass, and functional and taxonomic diversity, in a comparisons of paired plots: goldenrod-invaded plots and nearby non-invaded plots of semi-natural grassland. Goldenrod-invaded plots had fewer vascular plant species (paired t-test) than non-invaded ones, and showed a distinct plant community composition (ANOSIM). Non-invaded and invaded plots did not differ in a range of measured soil physicochemical parameters. No differences were observed between non-invaded and invaded plots in soil fauna feeding activity (measured in the field using bait-lamina test), nor in soil microbial activity (basal respiration rate) and biomass (substrate-induced respiration rate). Goldenrod invasion also did not affect soil bacterial activity and functional diversity as assessed using Biolog® ECO plates, nor bacterial and eukaryotic taxonomic diversity as assessed using Illumina 16/18S rDNA gene fragment sequencing. Bacterial community functional structure (CLPP pattern) and the taxonomic structure of bacteria and eukaryotes (OTUbact and OTUeuk patterns) were not observed to differ between non-invaded and invaded plots. None of the measured soil microbial indices or soil fauna feeding activity were related to the number of vascular plant species (alpha diversity) as tested by simple regressions. The altered vegetation diversity and composition (beta diversity) was not reflected in the CLPP, OTUbact and OTUeuk patterns (Mantel tests). The reduced alpha and beta plant diversity resulting from goldenrod invasion was not reflected in soil microbial community parameters. Results of the effects of goldenrod invasion on soil organisms should be interpreted with caution, as the effects may not be so pronounced as the effects on aboveground organisms.

Impact of inorganic fertilizer to soil biological activity in an oil palm plantation

Oil palm can produce the highest quantity of vegetable oil per unit area. In order to reach this potential, as well as to maintain, and when necessary to improve the chemical fertility of soils, inorganic fertilizers are regularly applied in plantations. As it has been reported that the addition of inorganic fertilizers in agriculture, could negatively affect the biological characteristics of the soil, we have initiated a first research program to evaluate and confirm such possibility related to oil palm cultivation. This paper presents a study about the impact of inorganic fertilizer applications of soil biological activity in oil palm plantation located in the province of Riau in Sumatra, Indonesia. Observations have been conducted in a factorial NxPxK fertilizer trial, since 1995. For this study, our observations aimed to determine the short-term impact of these inorganic fertilizers, i.e. the impact during the following days after applications, as well as the long-term impact of similar fertilizers that have been applied repetitively, every six months since 1995. Bait lamina sticks were used to assess the biological soil activity (soil fauna feeding activity) from July to December 2017. Three types of fertilizer have been used for the study, Urea (as nitrogen source), Triple Super Phosphate (as phosphorus source) and Muriate of Potash (as potassium source) at various rates, and several combinations have been tested. The bait laminas were inserted in the palm circles, where fertilizers are commonly applied. The results show that in the short-term applications of inorganic fertilizers result in an increase of the soil fauna feeding activity: two days after urea applications, soil fauna feeding activity increased significantly compared the values before application. Phosphate and potassium fertilizer applications also increased the feeding activity, but this happened five days after the respective fertilizer applications. The intensity of the increase varied depending on the rate of applications. The long-term application of potassium fertilizer significantly increased the soil fauna feeding activity, while the application of phosphorus and nitrogen fertilizers did not show a significant increase.

The role of oil palm biomass recycling on soil health in oil palm plantations

Oil palm cultivation produces a massive amount of biomass (e.g., empty fruit bunches (EFB), frond and trunk) which could be recycled directly in the plantation to maintain/improve the quality of soils. The impact of this biomass recycling, i.e., EFB and frond, - in term of chemical, physical and biological characteristics, will be analyzed. The fresh application of the EFB could alternate most of the soil parameters in line with the kinetics of the decomposition of the EFB and the release of nutrients. For example, the pH of the soil after the EFB application was higher during more than 18 months compared to the initial situation. Soil exchangeable potassium increased dramatically within a few days after EFB spreading. Frond recycling, at harvesting and pruning, modifies the chemical and physical characteristics of soils whether they were applied on heaps between palms in dedicated inter-rows, or spread on harvesting paths where they could reduce run-off and erosion. The systematic distribution of fronds in inter-rows reduced rainwater run-off by more than 30%, even on 5% gentle slopes. Subsequently, soil loss through erosion was reduced by 65% depending on the slope intensity of the terrain. Consequently, the loss of nutrients was considerably reduced, resulting in higher fertilizer efficiency. Similar measurements have been done when applying fresh EFB to the soil. The impact on soil physical fertility, i.e., rainwater infiltration rate and subsequently soil humidity are improved. We have also recorded a reduction of the soil resistance to penetration, as well as an improvement of the soil aggregate stability. Several representative parameters of soil biological activity, i.e., soil fauna feeding activity using bait-lamina test system and earthworm’ population showed the positive impact of EFB applications as well as frond spreading in inter-rows.

Nitrogen deposition slows down the litter decomposition induced by soil macrofauna in the soil of subtropical forests in China

AbstractAs atmospheric nitrogen (N) deposition elevates, extensive researches into the consequences of N deposition on litter decomposition process have been triggered; yet, responses of aboveground macro‐detritivores to atmospheric N deposition and their interactive effects on saprotrophic microorganisms and litter decomposition process are not thoroughly understood. By soil incubation, we assessed the influence of N deposition on the decomposition process of broad leaf (Quercus acutissima) and needle (Pinus massoniana) litter mediated by macro‐detritivore isopods (Armadillidium vulgare) and soil microorganisms. Changes in litter chemical composition (total carbohydrate and N), litter mass loss, soil pH values, soil microbial biomass and the activities of degradative enzymes were determined during a 6‐month laboratory incubation. Results showed that N addition enhanced Q. acutissima litter decomposition in the absence of A. vulgare, but decreased that when A. vulgare presence. N addition had no significant effect on P. massoniana litter decomposition regardless of A. vulgare presence or absence. However, N addition decreased isopod feeding contributions, with litter mass loss of 1.83–2.92 times lower than those of only isopod addition treatments in the two litter types. N addition inhibited soil microbial biomass and enzymatic activities related to N and phenolic metabolism of needle litter when isopods presence. Our findings suggest that N addition likely weakens the feeding activity of soil fauna and slows down the litter decomposition in broad‐leaved forests. This implies that a long‐term consequence of N deposition may induce the soil C accumulation and affect the balance of ecosystem nutrient flux in subtropical broad‐leaved forests.

Application of oil palm empty fruit bunch effects on soil biota and functions: A case study in Sumatra, Indonesia

Oil palm (Elaeis guineensis) is an important tropical crop which provides one-fifth of the world’s vegetable oil, yet its rapid expansion can negatively influence the soil ecosystem. Identifying suitable agronomic management such as crop residue application is important for the sustainable development of oil palm. We examined the effects of adding empty fruit bunches (EFB), a major oil palm residue, on multiple soil abiotic properties, soil biota, and indicators of soil functions. We compared treatments of EFB applications with three application rates, and a chemical fertilizer treatment in a 15–year trial in Central Sumatra, Indonesia. EFB application increased pH and aggregate stability in 0–10 cm soils and decreased the soil bulk density. EFB application increased the abundance of soil detritivore mites, soil fauna feeding activity, and soil microbial activity. EFB application decreased the biomass of a dominant invasive earthworm species, Pontoscolex corethrurus (Müller, 1857). Results from structural equation modelling suggested that EFB directly affected soil biota and functions, rather than through altering soil abiotic properties. The effects of EFB application on most soil abiotic properties, soil biota and function indicators were independent of the application rate. Our results revealed that EFB application has a high potential to enhance soil biota and functions in oil palm plantations.

Quantifying immediate and delayed effects of anthelmintic exposure on ecosystem functioning supported by a common dung beetle species.

Dung beetles (Coleoptera: Scarabaeoidea) support numerous ecosystem functions in livestock-grazed pastures. Exposure to veterinary anthelmintic residues in livestock dung can have lethal and sublethal effects on dung beetles, and can reduce rates of dung removal, but the immediate and longer-term consequences for other dung beetle mediated functions have rarely been studied. We investigated the consequences of anthelmintic exposure on survival of the dung beetle Aphodius fossor and its delivery of four ecosystems functions that underpin pasture production: dung removal, soil fauna feeding activity, primary productivity, and reduction of soil compaction. We tested whether anthelmintic exposure had immediate or delayed effects on these functions individually and simultaneously (i.e., ecosystem multifunctionality). We found no evidence that ivermectin residues had a lethal effect on adult beetles. For dung removal, we found a significant interaction between the timing of exposure and functioning: while dung removal was impaired by concurrent exposure to high levels of ivermectin, functioning was unaffected when beetles that had been exposed previously to the same concentration of anthelmintic later interacted with untreated dung. Other ecosystem functions were not affected significantly by anthelmintic exposure, and there was no evidence to suggest any persistent impact of anthelmintic exposure on ecosystem multifunctionality. While anthelmintic residues remain a significant threat to dung beetle populations, for adult beetles, we found no evidence that residues have detrimental consequences for ecosystem functioning beyond the immediate point of exposure.

Effect of N addition on home-field advantage of litter decomposition in subtropical forests

The ‘home-field advantage’ (HFA) postulates that litter decompose faster in its home habitat than in other habitats. However, the HFA of litter decomposition appears to be highly variable, and the effects of environmental conditions on HFA have rarely been investigated. Thus, in this study, we performed a reciprocal litter transplant experiment using coarse and fine mesh litterbags under nitrogen (N) addition treatments in a subtropical coniferous forest dominated by Pinus massoniana and a broad-leaved forest dominated by Quercus variabilis. Results showed no significant difference in decomposition between the two dominant litters in the fine-mesh litterbags at home and away habitats under control and N addition plots. P. massoniana litter in the coarse-mesh litterbags decomposed twice as fast at home than in away habitats under N addition. The result suggests a positive HFA effect in the coniferous forest under N addition, but no significant HFA effect was observed in the control plots. N addition did not enhance Q. variabilis litter decomposition in the home habitat. The positive HFA effect of P. massoniana litter in the coarse-mesh litterbags in N addition plots was associated with more abundant soil fauna than in the control plots. However, N addition had no significant effect on the activity of most soil enzyme during litter decomposition. Moreover, soil microbial biomass showed no relationship with the HFA of litter decomposition. Our findings suggest that N addition likely enhances the feeding activity of soil fauna by increasing fauna abundance. This further reinforces the habitat specificity of soil mesofauna in coniferous forests, resulting in a positive HFA of P. massoniana litter decomposition. C and N cycling in coniferous forest may be enhanced by N addition, and coniferous forest management should be suitable for this change.

Biosolids applied to agricultural land: Influence on structural and functional endpoints of soil fauna on a short- and long-term scale

Biosolids have well-documented crop and soil benefits similar to other sources of organic amendment, but there is environmental concern due to biosolids-associated pollutants. The present study investigated two field sites that had received biosolids at commercial-scale rates in parallel to associated field sections which were managed similarly but without receiving biosolids (controls). The investigated endpoints were abundance and diversity of soil organisms (nematodes, enchytraeids and earthworms) and soil fauna feeding activity as measured by the bait lamina assay. Repeated sampling of one of the field sites following the only biosolids application demonstrated an enrichment effect typical for organic amendments, which was mostly exhausted after 44months. After an initial suppression, the proportion of free-living plant-parasitic nematodes tended to increase in the biosolids-amended soil over time. Yet, none of the endpoints at this site indicated significant negative effects resulting from the biosolids until 44months post application. In contrast to the repeatedly tilled first field site, the second one was left fallow after three biosolids applications, and was sampled 96months post last application. It was only at this field site that potential evidence for a long-term impact of biosolids was detected with regard to two endpoints: earthworm abundance and structure of the nematode assemblage. Agricultural management and correlation with abiotic soil parameters explained the observed difference in earthworm abundance. Yet, the development of a highly structured and mature nematode assemblage at the control but not at the biosolids-amended section of this fallow field could not be explained by such correlations nor by soil metal concentrations. Overall, the present study found only weak evidence for negative long-term impacts of biosolids applied at commercial rates on soil fauna. High-level community parameters such as the nematode structure index (SI) appeared more suitable to detect deleterious effects on soil fauna than simple abundance measurements.

Landscape-Scale Implications of the Edge Effect on Soil Fauna Activity in a Temperate Forest

Although studies on edge effects on species richness and abundance are numerous, the responses of ecosystem processes to these effects have received considerably less attention. How ecosystem processes respond to edge effects is particularly important in temperate forests, where small fragments and edge habitats form a considerable proportion of the total forest area. Soil fauna are key contributors to decomposition and soil biogeochemical cycling processes. Using the bait lamina technique, we quantified soil fauna feeding activity, and its dependence on soil moisture and distance to the edge in a broad-leaved forest in Southern England. Feeding activity was 40% lower at the forest edge than in the interior, and the depth of edge influence was approximately 75 m. A watering treatment showed that moisture limitation was the main driver of the reduced feeding activity at the edge. In England, only 33% of the forest area is greater than 75 m from the edge. Therefore, assuming that the results from this single-site study are representative for the landscape, it implies that only one- third of the forest area in England supports activity levels typical for the forest core, and that edge effects reduce the mean feeding activity across the landscape by 17% (with lower and upper 90% confidence intervals of 1.3 and 23%, respectively). Changing climatic conditions, such as summer droughts may exacerbate such effects as edges lose water faster than the forest interior. The results highlight the importance of taking edge effects into account in ecological studies and forest management planning in highly fragmented landscapes.

Effects of soil management practices on soil fauna feeding activity in an Indonesian oil palm plantation

Optimizing the use of available soil management practices in oil palm plantations is crucial to enhance long-term soil fertility and productivity. However, this needs a thorough understanding of the functional responses of soil biota to these management practices. To address this knowledge gap, we used the bait lamina method to investigate the effects of different soil management practices on soil fauna feeding activity, and whether feeding activity was associated with management-mediated changes in soil chemical properties, in a 15-year-old oil palm plantation. We examined the four management zones: (1) empty fruit bunch (EFB) application along the sides of harvesting paths; (2) chemical fertilization within palm circles; (3) understory vegetation with pruned fronds in inter-row areas; (4) no input in the cleared part of the harvesting paths. Our results showed significantly higher soil fauna feeding activity under the EFB application compared to other management practices, and this was associated with improved soil chemical properties and soil moisture conditions. Principal component analysis on soil properties indicated that 71.2% of variance was explained by the first two principal components (PCs). Soil pH, base saturation and soil moisture contributed positively to PC1, while exchangeable aluminum and hydrogen contributed negatively to PC1. The results demonstrate that different soil management practices at the tree-scale have the ability to create spatial complexity in soil fauna feeding activity and soil chemical properties. This suggests that the practice of EFB application plays an important role in enhancing soil ecosystem functioning in oil palm plantations, which may ultimately contribute to sustainable palm oil production.

Application of the Bait-Lamina Method to Measure the Feeding Activity of Soil Fauna in Temperate Forests

The aim of the study was to compare the feeding activity of soil fauna in seven temperate forests with the application of the bait-lamina method. Seven types of temperate forests located throughout Poland (East-Central Europe) were tested, ranging from dry pine forest with a typical poor quality soil to eutrophic riparian fresh deciduous forest. Each forest type was represented by five stands and all stands altogether represented natural gradient of soil fertility, texture and vegetation diversity. Despite clear diversification between the studied forest types according to a range of soil physicochemical properties and vegetation characteristics in addition to applying recommended measurement conditions for the method, we determined that the feeding activity of soil fauna did not differ between forest types. The activity of soil fauna did not depend on site botanical characteristics or any soil physical or chemical features, indicating that the bait lamina method was useless in measuring the feeding activity of soil fauna in temperate forest soils. Differences in the feeding activity of soil fauna might result from other environmental factors that influence soil fauna feeding activity in forest stands that were not measured here, i.e., soil temperature and humidity. The differences could also be attributable to the attractiveness of the bait substrate to soil fauna, which may be different in various soil conditions.

Factors Affecting Soil Fauna Feeding Activity in a Fragmented Lowland Temperate Deciduous Woodland

British temperate broadleaf woodlands have been widely fragmented since the advent of modern agriculture and development. As a result, a higher proportion of woodland area is now subject to edge effects which can alter the efficiency of ecosystem functions. These areas are particularly sensitive to drought. Decomposition of detritus and nutrient cycling are driven by soil microbe and fauna coactivity. The bait lamina assay was used to assess soil fauna trophic activity in the upper soil horizons at five sites in Wytham Woods, Oxfordshire: two edge, two intermediate and one core site. Faunal trophic activity was highest in the core of the woodland, and lowest at the edge, which was correlated with a decreasing soil moisture gradient. The efficiency of the assay was tested using four different bait flavours: standardised, ash (Fraxinus excelsior L.), oak (Quercus robur L.), and sycamore (Acer pseudoplatanus L.). The standardised bait proved the most efficient flavour in terms of feeding activity. This study suggests that decomposition and nutrient cycling may be compromised in many of the UK's small, fragmented woodlands in the event of drought or climate change.

Soil fauna feeding activity in temperate grassland soils increases with legume and grass species richness

Edaphic fauna contributes to important ecosystem functions in grassland soils such as decomposition and nutrient mineralization. Since this functional role is likely to be altered by global change and associated shifts in plant communities, a thorough understanding of large scale drivers on below-ground processes independent of regional differences in soil type or climate is essential. We investigated the relationship between abiotic (soil properties, management practices) and biotic (plant functional group composition, vegetation characteristics, soil fauna abundance) predictors and feeding activity of soil fauna after accounting for sample year and study region. Our study was carried out over a period of two consecutive years in 92 agricultural grasslands in three regions of Germany, spanning a latitudinal gradient of more than 500 km. A structural equation model suggests that feeding activity of soil fauna as measured by the bait-lamina test was positively related to legume and grass species richness in both years. Most probably, a diverse vegetation promotes feeding activity of soil fauna via alterations of both microclimate and resource availability. Feeding activity of soil fauna also increased with earthworm biomass via a pathway over Collembola abundance. The effect of earthworms on the feeding activity in soil may be attributed to their important role as ecosystem engineers. As no additional effects of agricultural management such as fertilization, livestock density or number of cuts on bait consumption were observed, our results suggest that the positive effect of legume and grass species richness on the feeding activity in soil fauna is a general one that will not be overruled by regional differences in management or environmental conditions. We thus suggest that agri-environment schemes aiming at the protection of belowground activity and associated ecosystem functions in temperate grasslands may generally focus on maintaining plant diversity, especially with regard to the potential effects of climate change on future vegetation structure.

Effects of soil temperature and moisture on the feeding activity of soil animals as determined by the bait-lamina test

The aim of the study was to determine the effect of soil temperature and moisture on the feeding activity of soil fauna. To measure this activity, we conducted two short-term (14 days) experiments using the bait-lamina method. In experiment 1, the enchytraeid Cognettia sphagnetorum was added to defaunated mor humus. The experiment included incubations at four temperatures (−4, 5, 14, and 24 °C) and three moisture regimes (220, 260, and 300% of dry weight). No feeding activity was detected at −4 °C, but at other temperatures the bait-laminae were perforated, and the number of baits consumed increased with time. Because of variable animal survival and because of the rather low bait consumption, the effect of temperature and moisture on the feeding activity was unclear. In experiment 2, intact soil cores were either pre-treated at −21 °C or were not treated until being placed at −4, 5, 14 and 24 °C and two moisture regimes. The pre-treatment at −21 °C killed all meso- and macrofauna except collembolans and mites. Despite high densities of collembolans and moderate densities of mites at 24 °C in the pre-treated cores, there was no bait perforation. In the non-frozen cores, there was no feeding activity at −4 °C, but the activity increased with temperature up to 24 °C. The study showed that the bait-laminae were perforated by the activity of soil-living animals. Bait perforation seemed to be dependent on animals like enchytraeids and lumbricids and to a lesser degree collembolans and mites. The feeding activity measured by the bait-laminae increased with temperature, whereas the effect of soil moisture was less evident.