0000000000264481
AUTHOR
Jari Haimi
Does metal contamination affect clonal diversity of the parthenogenetic earthworm Dendrobaena octaedra?
Clonal diversity of the parthenogenetic earthworm Dendrobaena octaedra was studied in three metal contamination gradients in Finland. Metal concentrations in soils (both total and bioavailable fractions) and in earthworm tissues were analysed at each sampling site. Allozyme electrophoresis was used to determine clonal diversity and several genetic diversity measures were used to evaluate differences between populations at metal contaminated and uncontaminated sites. Cu and Zn in the soils and in the earthworms increased with decreasing distance from the emission sources in all areas. Metal contamination appeared to affect clonal diversity of D. octaedra only slightly, since clonal diversity…
Impact of genetic diversity of an earthworm on decomposition and ecosystem functioning
Abstract Ecosystem functioning is affected positively by increased biodiversity, through complementary functions of multiple species or because high-functioning species are more likely in a species-rich community. Genetic diversity is one level of biodiversity that has been shown to positively affect ecosystem functioning. Whether the genetic diversity of a key decomposer species affects decomposition processes, and ecosystem functioning in general, is still unknown. We compared low and high genetic diversity assemblages of the earthworm Dendrobaena octaedra in two different experiments: using microcosms containing a simple community of other decomposer animals (some nematodes and other mic…
Regulation of decomposer community structure and decomposition processes in herbicide stressed humus soil
Abstract Regulation of soil decomposer community structure and ecosystem processes, such as nutrient cycling, under herbicide stress was studied in a microcosm experiment. For the experiment, coniferous forest soil was defaunated and put into the microcosms. In the microcosms two different food webs including microbes, nematodes, tardigrades and oribatid mites, either with or without predatory mesostigmatid mites, were reconstructed. Half of the microcosms were stressed with a herbicide (active ingredient was terbuthylazine). During the 57 weeks incubation community structure of decomposers and nitrogen mineralisation were studied at five destructive samplings and two water irrigations. Soi…
Responses of decomposer community to root-isolation and addition of slash
Abstract We studied the causal relationships between forest harvesting and the soil decomposer community focusing on suppression of energy inputs from trees to the soil through root–mycorrhizal network and increased energy input to the soil in the form of slash left on site. We hypothesised that both of these factors would affect the decomposer community, since the soil food web has been regarded as a system in which the amount of resources controls the numbers of consumers. To study the importance of these factors without changes in microclimate, like in sunshine and shade, taking place in clear-felled areas, the experiment was performed in a mature spruce ( Picea abies (L.) Karst.) forest…
Effects of pentachlorophenol in forest soil: a microcosm experiment for testing ecosystem responses to anthropogenic stress
Changes in the structure and function of a soil decomposer community and growth of birch (Betula pendula) due to chemical contamination were studied in laboratory microcosms. Sodium pentachlorophenate (PCP) was added to the humus layer of a simulated forest soil at three nominal concentrations (0, 50 and 500 mg kg-1 dry mass). After two growing periods (48 weeks), there were more small soft-bodied mites, but less collembolans and microbial biomass, in the higher PCP concentration treatment than in the other treatments. Number of enchytraeids were significantly reduced and fungal-feeding nematodes became extinct in the soil with the higher PCP concentration. Soil respiration did not change d…
Aineenopettajankoulutus LUMA-aineissa Jyväskylän yliopistossa
Jyväskylän yliopistosta valmistuu aineenopettajia LUMA-aineissa kaikilta matemaattis-luonnontieteellisen tiedekunnan ainelaitoksilta, lisäksi tietotekniikan opettajia informaatioteknologian tiedekunnasta. Matemaattis-luonnontieteellisestä tiedekunnasta valmistuu vuosittain reilut 40 aineenopettajaa, kaikkiaan valmistuneista maistereista noin joka neljännellä on opettajan pätevyys. Tietotekniikan laitokselta valmistuu vuosittain noin 10 aineenopettajaa. Tulevan aineenopettajan opintopolku muodostuu opinnoista ainelaitoksilla, opettajankoulutuslaitoksella ja Normaalikoulussa. Opettajia kouluttavien yhteistyö on tärkeää opintojen kokonaisvaltaisessa suunnittelussa. Ainelaitosten, opettajankoul…
Responses of soil decomposer animals to wood-ash fertilisation and burning in a coniferous forest stand
Abstract Responses of soil decomposer animals (enchytraeids and microarthropods) to wood-ash fertilisation (1000 and 5000 kg ha−1) and a fire treatment mimicking prescribed burning were studied in a Scots pine stand in central Finland. The experiment was conducted on 30 × 30 m2 plots, each treatment being replicated four times. Soil animals were sampled throughout the growing season in the third year after the treatments. As a rule, numbers of soil animals increased during the study period. Numbers of the only enchytraeid worm species found at the study site, Cognettia sphagnetorum, were lower in the plots with higher ash level and plots which have been burned. In the plots having these tre…
Soil processes are constituents of planetary well-being
Soils play multiple roles in vital ecosystem processes, even though they form only a thin layer between Earth’s atmosphere and lithosphere. Soils are reservoirs of carbon, most nutrients and fresh water while acting as a substrate for plants, a site for decomposition processes, and a sink for harmful substances. The decomposition of dead organic matter and the associated recycling of nutrients are a prerequisite for photosynthesis by green plants and, therefore, for all life forms on Earth. Without healthy soils, the integrity of the Earth system cannot be maintained in the future. Soils are highly diverse habitats, inhabited by both structurally and functionally diversified organisms. Howe…
Community composition of soil microarthropods of acid forest soils as affected by wood ash application
Summary The responses of soil microarthropod communities of acid forest soils to wood ash-application was studied both in a sixty years old pine forest stand (wood ash dose: 3000kg ha —1 ) and in laboratory microcosms (wood ash dose: 5000kg ha —1 ). We also tested whether microarthropod communities stressed with wood ash were more sensitive to an additional disturbance, drought, than the microarthropod communities in the ash-free soil. Microarthropods were sampled five times during the field experiment and four times during the laboratory experiment. At each sampling the abundance and community structure of microarthropods were analysed. In the field the number of collembolans, and in the l…
Soil decomposer animal community in heavy-metal contaminated coniferous forest with and without liming
Abstract Responses of decomposer animals to heavy-metal contamination were studied near a Cu–Ni smelter in Finland. Samples were taken 0.5, 2 and 8 km from the smelter. In addition, plots fertilised with lime were sampled. Decomposer community in coniferous forest soil appeared to be quite resistant to heavy-metals. Only in the vicinity (0.5 km) of the smelter, were numbers of soil animals clearly decreased and their community structure strongly altered as compared to the control site (8 km). At the 2-km site, the community structure was only slightly changed. Most of the collembolan species were still found at the 0.5-km site. High metal sorption capacity of the humus, and heterogeneous di…
Does stump removal affect early growth and mycorrhizal infection of spruce (Picea abies) seedlings in clear-cuts?
Abstract Stump removal procedure increases the extent of exposed mineral soil in the clear felled areas. In this study, our aim was to find out whether the early growth and mycorrhization of Norway spruce (Picea abies (L.) Karst.) seedlings differ between stump removal and mounding sites. Stumps were harvested from five one-hectare study sites and other five sites were mounded after clear felling. Twenty seedlings were planted on mounds at each study site. Although the height of spruce seedlings did not differ between the treatments after three growing periods, their mean growth was ca. 10% higher at the stump removal sites. The community of ectomycorrhizal (ECM) in the seedling roots did n…
History of land-use intensity can modify the relationship between functional complexity of the soil fauna and soil ecosystem services - A microcosm study
Abstract Agricultural intensification generally results in the loss of soil organic matter, a decline in soil biodiversity, and the reduced ability of soils to retain nutrients. Intensified land-use can bring about legacy effects in soil ecosystem services that may last for hundreds of years after the cessation of agricultural practises. We studied, in a laboratory pot experiment, whether legacy effects due to intensive land/soil management (intensively managed wheat field) can be alleviated by restoring the disturbed soil with soil fauna typical of less managed soils (grassland soil). We also compared the effects of functional complexity of the soil fauna (microfauna, microfauna + mesofaun…
Evolution education in natural history museums
During 2009, scientists around the world will celebrate the 200th anniversary of the birth of Charles Darwin, the father of the theory of evolution, and the 150th anniversary of the publication of his main thesis, On the Origin of Species by Means of Natural Selection. Today, the theory of evolution is considered to be one of the greatest milestones in the history of science. Despite its undisputed merit in science, there seems to be constant turmoil around the theory in the public, which might be related to the incomplete understanding of the basic principles of evolution [1,2].
Decomposer animals and bioremediation of soils
Abstract Although microorganisms are degrading the contaminants in bioremediation processes, soil animals can also have important — while usually an indirect — role in these processes. Soil animals are useful indicators of soil contamination, both before and after the bioremediation. Many toxicity and bioavailability assessment methods utilizing soil animals have been developed for hazard and risk-assessment procedures. Not only the survival of the animals, but also more sensitive parameters like growth, reproduction and community structure have often been taken into account in the assessment. The use of bioassays together with chemical analyses gives the most reliable results for risk anal…
Testing the usefulness of habitat corridors in mitigating the negative effects of fragmentation: the soil faunal community as a model system
Abstract 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 w…
Effects of Terbuthylazine on Soil Fauna and Decomposition Processes
Abstract Acute lethal and sublethal effects of terbuthylazine and the commercial herbicide preparation Gardoprim [terbuthylazine is the active ingredient (a.i.)] on soil organisms (microbes, oppioid mites, two gamasid mite species, enchytraeids, and nematodes) were studied. In the humus soil terbuthylazine had no toxic effects on soil animals tested. However, the herbicide preparation had acute toxic effects on enchytraeids [no-observed-effect level (NOEL) 1.0 g a.i./m 2 ] and both gamasid mites (NOEL 2.4 and 5.0 g a.i./m 2 ). According to filter paper test, the LC 50 value for oppioid mites was 14.5 g a.i./m 2 . In the humus soil the commercial preparation caused no dose-related mortality …
A microcosm study on the respiration and weight loss in birch litter and raw humus as influenced by soil fauna
The effect of diverse soil fauna (Collembola, Acari, Enchytraeidae, Nematoda) on decomposition of dead organic matter was studied in microcosms containing (1) birch leaf litter, (2) raw humus of coniferous forest and (3) litter on humus. Total respiration (CO2 evolution) was monitored weekly, and mass loss, length of fungal hyphae (total and metabolically active) and survival of animal populations were checked at the end of weeks 12 and 21–22 from the start of experiment. Animal populations established themselves well during the incubation. At the end of the experiment some replicates containing litter had microarthropod densities of up to 500 specimens per microcosm, corresponding to a fie…
Has long-term metal exposure induced changes in life history traits and genetic diversity of the enchytraeid worm Cognettia sphagnetorum (Vejd.)?
We studied whether long-term metal exposure has affected life history traits, population growth patterns and genetic diversity of the asexual enchytraeid worm Cognettia sphagnetorum (Vejd.). Enchytraeids from metal contaminated and uncontaminated forest soil were compared by growing them individually in the laboratory and by following their population development in patchily Cu contaminated microcosms. Genetic differences between the two native populations were studied using allozyme electrophoresis. Individuals from the contaminated site had slower growth rate and they produced fewer fragments of larger size when compared to individuals from the uncontaminated site. In patchily Cu contamin…
Effects of heavy metals on soil microflora
Elevated concentrations of heavy metals are known to cause disturbances in all living organisms. A reduction in the activity of forest microbes, expressed as decreased carbon and nitrogen mineralisation, may result in a slower rate of litter decomposition and slower nutrient cycling in the whole ecosystem (Baath 1989). In areas severely polluted by heavy metals, this can be seen as an accumulation of undecomposed litter on the forest floor. Thus, in addition to the direct toxicity of heavy metals, the trees may suffer from nutrient deficiency resulting from the decrease in the mineralisation of nutrients from the litter. Heavy metals can also retard litter decomposition processes in less po…
Assessment of Ecological Risks at Former Landfill Site Using TRIAD Procedure and Multicriteria Analysis
Old industrial landfills are important sources of environmental contamination in Europe, including Finland. In this study, we demonstrated the combination of TRIAD procedure, multicriteria decision analysis (MCDA), and statistical Monte Carlo analysis for assessing the risks to terrestrial biota in a former landfill site contaminated by petroleum hydrocarbons (PHCs) and metals. First, we generated hazard quotients by dividing the concentrations of metals and PHCs in soil by the corresponding risk-based ecological benchmarks. Then we conducted ecotoxicity tests using five plant species, earthworms, and potworms, and determined the abundance and diversity of soil invertebrates from additional…
Effects of small-scale habitat fragmentation, habitat corridors and mainland dispersal on soil decomposer organisms
Abstract Habitat corridors have been suggested to be one possible way to reduce the often negative effects of habitat fragmentation. In the present experiment, we focused on small habitat fragments (humus patches) inhabited by soil decomposer organisms. These fragments were either unconnected or connected with each other by habitat (humus) corridors. Moreover, these systems were either isolated from the mainland by a dispersal barrier (plastic “walls”) or were open to dispersal from the mainland. The fragments and corridors were embedded in a matrix of mineral soil that was expected to be uninhabitable or at least an unpreferred habitat for the organisms studied. Undisturbed forest soil fun…
Bioaccumulation of organochlorine compounds in earthworms
Abstract Bioaccumulation of chlorophenolic wood preservatives 2,3,4,6-tetrachlorophenol (2346-TeCP) and pentachlorophenol (PeCP) and their metabolites in earthworms were studied in the laboratory, and by taking worm samples from the contaminated soil of a sawmill which was abandoned 28 yr ago. In two laboratory experiments 2346-TeCP (containing PeCP as impurity) was added into the soil, and samples were taken at certain intervals both from the soil and the earthworms ( Lumbricus rubellus in experiment 1 and Aporrectodea caliginosa tuberculata in experiment 2). Considerable amounts of chlorophenols were found in field samples. Soil concentrations ranged from 157 to 338 μg 2346-TeCP g −1 dry …
Effects Of Combined Strength And Endurance Training On Physical Performance And Biomarkers Of Healthy Young Women
Kyröläinen, H, Hackney, AC, Salminen, R, Repola, J, Häkkinen, K, and Haimi, J. Effects of combined strength and endurance training on physical performance and biomarkers of healthy young women. J Strength Cond Res 32(6): 1554– 1561, 2018—Cardiovascular fitness has decreased and obesity has increased in young adults worldwide during the last 10 years. Therefore, there is an urgent need to find out optimal exercise training programs for improving physical performance and health outcomes, especially among sedentary women. Subjects were 25- to 30-year-old women with a very low physical activity, and 65% of them were overweight (body mass index . 25). They performed endurance and strength traini…
Growth increase of birch seedlings under the influence of earthworms—a laboratory study
The effects of the earthworm Lumbricus rubellus (Hoffm.) on net production and nitrogen content of birch seedlings were studied in laboratory microcosms. Coniferous forest floors with litter, humus and mineral horizons were simulated in transparent plastic cylinders. The materials were partially sterilized by microwaving, and re-inoculated with microflora and -fauna. A young (9 cm) birch seedling (Betula pendula Roth) was planted in each container. Earthworms were added to half of the replicates. The microcosms, through which a constant air flow was maintained, were incubated in a climate chamber. After two growth periods, leaf and stem biomasses of birch in treatments with earthworms incre…
Priorities for research in soil ecology
The ecological interactions that occur in and with soil are of consequence in many ecosystems on the planet. These interactions provide numerous essential ecosystem services, and the sustainable management of soils has attracted increasing scientific and public attention. Although soil ecology emerged as an independent field of research many decades ago, and we have gained important insights into the functioning of soils, there still are fundamental aspects that need to be better understood to ensure that the ecosystem services that soils provide are not lost and that soils can be used in a sustainable way. In this perspectives paper, we highlight some of the major knowledge gaps that shoul…
Soil decomposer community as a model system in studying the effects of habitat fragmentation and habitat corridors
Abstract Due to the practical difficulties of experimental study of habitat fragmentation and habitat corridors at the landscape scale, the use of smaller-scale model systems has been offered as a feasible alternative to uncover the ecological phenomena taking place in fragmented environments. In this mini-review, we consider the applicability of the soil decomposer community as such a model system. For the most part, this article is based on the few studies that have explicitly addressed this question by experimental manipulations of the natural habitat of soil decomposer community. However, to broaden the view, we also capitalize upon studies focusing on the effects of isolation and soil …
Polychlorinated phenols and their metabolites in soil and earthworms of sawmill environment
Abstract Topsoil and earthworm samples collected from three Finnish sawmill environments were analysed for polychlorinated phenols, 2,3,4,6-tetrachloro- and pentachlorophenol, and their metabolites. Analyses were carried out by gas chromatography/mass spectrometry using a selected ion monitoring technique and by dual-channel gas chromatography using quartz capillary columns and two electron capture detectors. The total chlorophenol concentrations ranged from ca. 260 to 480 μg/g (dry weight) in soil and from ca. 140 to 3500 μg/g fat in earthworms. The most important metabolites in soil were chlorinated dihydroxy-benzenes (also at ppm level); only traces of chlorinated anisoles were detected …
Aineenopettajankoulutus LUMA-aineissa Jyväskylän yliopistossa
Jyväskylän yliopistosta valmistuu aineenopettajia LUMA-aineissa kaikilta matemaattisluonnontieteellisen tiedekunnan ainelaitoksilta, lisäksi tietotekniikan opettajia informaatioteknologian tiedekunnasta. Matemaattis-luonnontieteellisestä tiedekunnasta valmistuu vuosittain reilut 40 aineenopettajaa, kaikkiaan valmistuneista maistereista noin joka neljännellä on opettajan pätevyys. Tietotekniikan laitokselta valmistuu vuosittain noin 10 aineenopettajaa. Tulevan aineenopettajan opintopolku muodostuu opinnoista ainelaitoksilla, opettajankoulutuslaitoksella ja Normaalikoulussa. Opettajia kouluttavien yhteistyö on tärkeää opintojen kokonaisvaltaisessa suunnittelussa. Ainelaitosten, opettajankoulu…
Effects of stump removal on soil decomposer communities in undisturbed patches of the forest floor
Abstract Soil preparation after clear-cutting leads to fragmentation of forest floor and, consequently, changes the habitat of decomposers. Stump removal for bioenergy is further increasing the disturbance in the soil. We studied responses of decomposers to stump removal in boreal spruce forests during the first 4 years after clear felling in relation to mounding. Samples for each decomposer organism group were taken from undisturbed forest floor patches that are the main habitat for decomposers after forest regeneration and whose amount and size obviously differ between the treatments. Microbial biomasses and community structure, and the abundance of enchytraeids, were not found to be affe…
Biomarker responses of the earthworm Aporrectodea tuberculata to copper and zinc exposure: differences between populations with and without earlier metal exposure.
Biomarkers in the earthworm Aporrectodea tuberculata (Eisen) were measured to find out their possible induction under Cu and Zn exposure and differences in the responses between two populations with different exposure history. The biomarkers applied were concentration of metallothioneins (MT), and cytochrome P4501A (CYP1A) monooxygenase and glutathione-S-transferase (GST) activities. These were measured from earthworms sampled at three distances from a steel smelter in Finland and from the individuals from two populations, one with and another without earlier metal exposure, exposed to three combined Cu/Zn concentrations in the laboratory. In the field, MT concentration, and cytochrome CYP1…
The asexual enchytraeid worm Cognettia sphagnetorum (Oligochaeta) has increased Cu resistance in polluted soil
We studied Cu resistance in the asexual (reproduction through fragmentation) enchytraeid worms (Cognettia sphagnetorum, Oligochaeta) originating from two sites: one uncontaminated, and another contaminated by heavy metals. Adult worms were smaller and population density was lower at the polluted site. However, adults from the contaminated site had better survival in Cu-contaminated soil, but lower survival as juveniles (fragments). As we do not know the genetic basis of Cu resistance of the worms, it may have been reached by acclimatization via induced Cu regulation. Because fragmentation is the only mode of reproduction, all phenotypic properties (including resistance) of a parental genera…
Responses of two earthworm populations with different exposure histories to chlorophenol contamination
Two populations of the earthworm Aporrectodea tuberculata (Eisen), one from a chlorophenol contaminated and another from an uncontaminated site in central Finland, were exposed to acute, toxic, and sublethal concentrations of pentachlorophenol (PCP). Exposure history seemed to have only slight effect on the responses of the earthworms. Values of a lethal concentration of 50% in the humus-rich soil were very high, 1,870 μg PCP per gram for the earthworms from the contaminated site and 1,520 μg/g for the earthworms from the uncontaminated site. No differences in the accumulation of PCP from the soil into the earthworms between the two populations were found. Earthworms from both populations s…
Effects of earthworms on decomposition and metal availability in contaminated soil: Microcosm studies of populations with different exposure histories
Abstract Population-specific differences in the responses of earthworms to simultaneous exposure to Cu and Zn were studied in microcosm experiments. Two populations of Aporrectodea caliginosa tuberculata (Eisen) with different metal exposure histories were chosen for the studies. Microcosms were prepared containing either uncontaminated soil or soils with low or high combined Cu/Zn -concentrations (79/139 or 178/311 mg kg −1 dry mass of soil, respectively). Earthworms from each population were introduced to the microcosm treatments with some microcosms serving as controls without earthworms. One series of microcosms was destructively sampled after 16 weeks incubation in a climate chamber. S…
Colonisation of newly established habitats by soil decomposer organisms: the effect of habitat corridors in relation to colonisation distance and habitat size
Abstract The aim of the present 2.5-year-long field experiment was to explore the ability of various members of the detrital food web to colonise newly established habitat patches in field conditions, either in the presence or absence of habitat corridors. Patch size and distance to the “mainland” (colonisation source) were manipulated to explore the scale dependency of the corridor effects. Sterilised humus patches, embedded in mineral soil regarded as uninhabitable (or non-preferred) matrix for the soil organisms, functioned as newly established habitats. Intact forest soil served as the source of colonisers. Three kinds of patches were established: large ones situated at relatively long …
Chloroanisoles in soils and earthworms
One important group of metabolites of chlorophenols in Finnish soils is their methylation products, i.e. chloroanisoles. Bioaccumulation of chloroanisoles into the biomass of earthworms was studied both in laboratory and by taking earthworm samples from contaminated soils. Concentrations of these compounds in the soils were also analysed. In the laboratory experiment, concentrations of 2,3,4,6-tetrachloroanisole (2346-TeCA) and pentachloroanisole (PeCA) were high in earthworms 1 week after introduction (approx. 50 μ/g fat). Later on, the concentrations decreased to a low level at a considerable rate, bcth in soil and in earthworms. The higher the concentration of chloroanisoles in the soil …
Sensitivity of soil processes in northern forest soils: are management practices a threat?
Abstract There is evidence that forest management practices influence soil-decomposer communities. It is also established that changes in the trophic structure and composition of these communities can induce changes in soil-nutrient dynamics, thereby affecting plant growth. Whether forest productivity is affected by management-induced changes in, e.g. soil faunal structure, is, however, yet to be shown. The aim of this study was (1) to determine the resolution of the ecological hierarchy (e.g. species, functional groups, trophic levels) at which a change in soil fauna would alter biotically-controlled processes in soils, and (2) to examine the sensitivity of soil fauna of the boreal forest …
Changes in soil fauna 10 years after forest harvestings: Comparison between clear felling and green-tree retention methods
Abstract We studied the responses of soil decomposer animals to clear felling and alternative, green-tree retention harvesting methods (GRT) in Norway spruce forests in Finland. The study plots which were sampled for immediate treatment effects (up to three years) were resampled after 10 years. We hypothesized that responses of decomposers still depends on the level of GTR. The treatments, in addition to untreated controls (100% retained), were: (1) selection felling (70% dispersed tree retention), (2) and (3) gap felling with and without site preparation, respectively (three small gaps were felled in a 1-ha area and 50% of the stand volume was retained), (4) retention felling (10% of the s…
Influence of resource quality on the composition of soil decomposer community in fragmented and continuous habitat
Abstract The aim of this field experiment was to explore the combined effects of two factors potentially affecting the local composition of soil decomposer community: resource quality and habitat fragmentation. We created humus (habitat) patches with three different resource quality: (1) pure homogenised humus; (2) humus enriched with needle litter; and (3) humus enriched with needle and leaf litter. These patches were embedded either in a mineral soil matrix, thus representing fragmented habitat, or in natural forest soil, representing continuous (non-fragmented) habitat. The development of faunal (colonisations/extinctions of soil animal populations) and microbial communities in the patch…
Do testate amoebae communities recover in concordance with vegetation after restoration of drained peatlands?
The environmental importance of peatlands has stimulated efforts to restore their specific ecosystem structure and functions. Monitoring and assessment of the ecological state of the peatland is fundamental in restoration programmes. Most studies have focused on the responses of vegetation and, to a lesser extent, on testate amoebae (TA). To our knowledge, none have investigated whether these two groups show concordance in the context of restoration of drained peatland. Here we assess community concordance between TA and vegetation in boreal peatlands belonging to four different land use management classes (natural, drained, restored 3–7 years ago, and restored 9–12 years ago). TA and veget…
Properties of food loads delivered to nestlings in the pied flycatcher: effects of clutch size manipulation, year, and sex.
Experimental manipulation of the number of altricial offspring is supposed to modify parental expenditure in birds. In addition to the observed increase in parental feeding rate, it is also possible that the choice of prey or the size of load may change with the changing demand for food. Sexual differences in the provisioning response are also expected, on the basis of earlier studies. We examined the effect of brood size manipulation on choice of prey brought to nestlings and load size in the pied flycatcher. The composition and size of loads differed between years, possibly depending on varying availability of different prey types. Males responded to brood size enlargement by gathering he…
Effects of Pentachlorophenol and Biotic Interactions on Soil Fauna and Decomposition in Humus Soil
In a laboratory experiment, effects of chemical stress (pentachlorophenol, PCP, at concentrations of 0, 50, and 500 mg/kg) and biotic interactions (nematodes in the presence or absence of collembolas and enchytraeids) on the community structure of soil animals and decomposition processes were studied. PCP was strongly adsorbed to humus that contained 65% organic matter. Numbers of fungal-feeding nematodes decreased significantly at the highest PCP concentration, while no effects were found in bacterial feeders. There were differences in the numbers of nematodes between different animal combinations, but at the highest PCP concentration, collembolas and enchytraeids had no effect on them. Nu…
Capacity of various organic residues to support adequate earthworm biomass for vermicomposting
We tested the potential of different kinds and combinations of wastes to support the biomass ofEisenia fetida (Sav.) capable of processing a given amount of waste in a period of ca. 1 month. Mixed miscellaneous wastes and activated sewage sludge mixed with or embedded in sieved pine bark showed capacity to maintain the required biomass for a long period. Wastes were converted into odourless castings of good physical structure, provided that a sufficient population was present from the beginning and fresh waste was added regularly. A horizontally working “worm bed compost” was designed instead of the “load-on-top” principle.
Responses of soil carbon and nitrogen transformations to stump removal
We studied in central Finland whether stump harvesting after clear felling of coniferous forest poses further short-term changes in soil carbon and nitrogen dynamics when compared to the traditional site preparation method, mounding. Exposed mineral soil patches in Norway spruce (Picea abies) dominated clear-cut stands were sampled 1â5 years after the treatments. The extent of the exposed mineral soil surface was significantly larger at the stump removal sites when compared to the mounding sites. No differences were found in soil pH, organic matter content or total concentration of soil C between the treatments or treatment years. Total concentration of soil N was consistently higher and …
Soil processes are not influenced by the functional complexity of soil decomposer food webs under disturbance
Abstract A 3 yr experiment, using field lysimeters with seedlings of Scots pine (Pinus sylvestris) growing in raw humus, was established to study how functional complexity of the soil decomposer food web affects ecosystem functioning. The functional complexity of decomposer system was manipulated by (1) allowing either microfauna (fine mesh) or microfauna+mesofauna (coarse mesh) to enter the initially defaunated systems, and (2) treating half of the lysimeters with wood ash. To test whether altering functional complexity of the decomposer community is related to the system's ability to resist disturbance, the lysimeters were later on disturbed with drought. Ecosystem function, measured as l…
Impacts of elevated CO2 and temperature on the soil fauna of boreal forests
Abstract Responses of dominant soil decomposer animals in northern coniferous forests, enchytraeids and microarthropods, to elevated CO 2 concentration and temperature were studied by sampling an experiment consisting of closed field chambers with a ground area of 5.9 m 2 . Six species of enchytraieds were found in the study, with Cognettia sphagnetorum comprising 87% of all individuals. The treatments did not significantly affect the numbers of C. sphagnetorum . No treatment induced changes were found in oribatid mites, but numbers of acaridid mites were lowest in the chambers with elevated CO 2 concentration and in those with elevated temperature. The chambers had lower densities of actin…
Responses of microbial activity and decomposer organisms to contamination in microcosms containing coniferous forest soil.
Soil respiration from microcosms contaminated with pentachlorophenol, 2-ethanolhexanoate, creosote, CuSO4, and benomyl was measured in order to evaluate usefulness of soil microcosms and microbial respiration rate monitoring as a toxicity test in soils with high organic matter content. Coniferous forest soil and its organisms were used as test objects. In addition, how a short-term low temperature period including frost affects respiration dynamics in stressed soils was studied, i.e., whether contaminants reduce resistance of the community to other (also natural) stresses. In addition, at the end of the experiment, effects of contaminants on faunal and microbial community structures were an…
Effects of endogeic earthworms on soil processes and plant growth in coniferous forest soil
The effects of the endogeic earthworm, Aporrectodea caliginosa tuberculata (Eisen) on decomposition processes in moist coniferous forest soil were studied in the laboratory. The pH preference of this species and its effects on microbial activity, N and P mineralization, and the growth of birch seedlings were determined in separate pot experiments. Homogenized humus from a spruce stand was shown to be too acid for A. c. tuberculata. After liming, the earthworms thrived in the humus and their biomass increased (at pH above 4.8). In later experiments in which the humus was limed, the earthworms positively influenced the biological activity in humus and also increased the rate of N mineralizati…
Spot mounding and granulated wood ash increase inorganic N availability and alter key components of the soil food web in clear-cut Norway spruce forests
Abstract The interactive effects of site preparation (spot mounding) and fertilization (granulated wood ash) on soil properties, soil micro- and mesofauna and ground vegetation were studied in two Norway spruce plantations established in clear-cut forests in Central Finland. Half of the seedlings were planted on mounds created by the planting machine, and the rest on intact forest floor. Half of the seedlings on mounded and intact forest floor were fertilized by adding granulated wood ash to circular plots surrounding the seedlings. Initial samples were taken from mounded and intact soil immediately after planting in June. Samples were taken from all treated plots in the autumn in the first…
Dead-wood effects on enchytraeids and nematodes in thinned and unmanaged Norway spruce forests
Abstract The effects of dead wood on enchytraeids and nematodes were studied in thinned and uncut Norway spruce forests in two experiments. Fifteen pairs of small spruce logs (one enclosed in polyethylene sheet and another untreated control) were returned to the forest floor in a complete randomized block design after thinning. Soil under the logs and at distances of 0–6 cm and 6–12 cm from each log was sampled after one growing season, and enchytraeids and nematodes were extracted and forest floor properties measured. Log enclosure increased enchytraeid length irrespective of the distance from the log. Soil moisture or pH were not affected by enclosure, but organic matter content was reduc…
Short-term responses of soil decomposer and vegetation communities to stump harvesting in boreal forests
Recently, in addition to logging residues, stumps have become an important component in energy production since there is growing global interest in the use of renewable energy sources in order to decrease anthropogenic carbon emissions. Harvesting of stumps influences the forest floor by changing vegetation and soil organic layers and exposing mineral soil across large areas. We studied whether stump harvesting after clear felling poses further short-term changes in boreal forest soil decomposer community (microbes and mesofauna) and vegetation when compared to the traditional site preparation practice (mounding). In general, stump harvesting caused decline in enchytraeid abundance but did …
Horizontal distribution of copper, nickel and enchytraeid worms in polluted soil
We studied the horizontal distribution of Cu, Ni and enchytraeid worms (Cognettia sphagnetorum, Vejdovsky, Oligochaeta, Enchytraeidae) in forest soil near a Cu–Ni smelter in SW Finland. Soil samples were taken from a polluted site (2 km from the smelter) and a reference area (8 km from the smelter). We used a hierarchical sampling design in the polluted area for studying possible scale-dependent variability in parameters measured, distance between the samples (different scales) being 5, 50 and 500 cm. Distribution of metals was moderately heterogeneous in the polluted soil; coefficient of variances (CV), 26% for Cu and 32% for Ni. Instead, distribution of enchytraeids in the area was highly…
Short-term responses of soil macroarthropod community to clear felling and alternative forest regeneration methods
Abstract We studied the influence of clear felling and new alternative forest regeneration methods on soil macroarthropods during the first 3 years after the harvesting. We focused on changes in the abundances of functional groups, and community structure at the levels of species (Coleoptera) or higher taxa. The experiment was carried out in central Finland in spruce (Picea abies (L.) Karst.) stands on 1 ha study plots. The following five treatments were used in addition to the untreated controls: (1) selection felling (70% of the stand volume retained), (2) gap felling (0.1–0.2 ha gaps felled), (3) gap felling with site preparation, (4) retention felling (small groups of trees retained on …
Do enchytraeid worms and habitat corridors facilitate the colonisation of habitat patches by soil microbes?
Due to their high abundance and ubiquitous existence, microbes are considered to be efficient colonisers of newly established habitats. To shed light on the dispersal mechanisms of soil microbes, a controlled microcosm experiment was established. In these microcosms, the dispersal of microbes from a source humus patch to originally sterile humus patches (embedded in a mineral soil matrix) was followed for 16 months, applying 16S and 18S ribosomal DNA-based PCR-DGGE molecular methods. Specifically, the role of enchytraeid worms and habitat (humus) corridors as possible facilitators of microbe dispersal was studied. The results showed that enchytraeid worms function efficiently as vectors for…
Global monitoring of soil animal communities using a common methodology.
Here we introduce the Soil BON Foodweb Team, a cross-continental collaborative network that aims to monitor soil animal communities and food webs using consistent methodology at a global scale. Soil animals support vital soil processes via soil structure modification, consumption of dead organic matter, and interactions with microbial and plant communities. Soil animal effects on ecosystem functions have been demonstrated by correlative analyses as well as in laboratory and field experiments, but these studies typically focus on selected animal groups or species at one or few sites with limited variation in environmental conditions. The lack of comprehensive harmonised large-scale soil anim…
Relationship between soil microarthropod species diversity and plant growth does not change when the system is disturbed
Soil microarthropods influence vital ecosystem processes, such as decomposition and nutrient mineralisation. There is evidence, however, that proper functioning of ecosystems does not require the presence of all its constituent species, and therefore some species can be regarded as functionally redundant. It has been proposed that species redundancy can act as an insurance against unfavourable conditions, and that functionally redundant species may become important when a system has faced a disturbance (the “insurance hypothesis”). We conducted a laboratory microcosm experiment with coniferous forest soil and a seedling of silver birch (Betula pendula). A gradient of microarthropod diversit…
Effects of heavy metals on earthworms along contamination gradients in organic rich soils.
Earthworm communities and metal (bio)availability to earthworms along contamination gradients was studied in order to support chemical analyses in risk assessment of metal contaminated soils. Earthworms were sampled in three metal contaminated areas with different habitat and soil properties in Finland. Earthworm and soil samples were collected at three distances (1, 2, and 4 km) from the emission sources. Earthworms were identified as to species and analyzed for heavy metals. Total soil metal concentrations were analyzed using an ultrasound-assisted extraction method and bioavailable metal fraction was estimated by acetic acid extraction. In two of the three areas studied, heavy metal conc…
Effect of earthworms on decomposition processes in raw humus forest soil: A microcosm study
The earthworms Lumbricus rubellus (Hoffmeister) and Dendrobaena octaedra (Savigny) were studied in the laboratory to determine their effects on decomposition and nutrient cycling in coniferous forest soil. CO2 evolution was monitored, and pH, PO 4 3− −P, NH 4 + −N, NO 3 − −N, total N, and total C in the leaching waters were measured. After three destructive samplings, numbers of animals, mass loss, pH, and KCl-extractable nutrients were analysed. The earthworms clearly enhanced the mass loss of the substrate, especially that of litter. L. rubellus stimulated microbial respiration by 15–18%, whereas D. octaedra stimulated it only slightly. The worms significantly raised the pH of the leachin…
Species richness and food web structure of soil decomposer community as affected by the size of habitat fragment and habitat corridors
While most ecologists agree that the effects of fragmentation on diversity of organisms are predominantly negative and that the scale of fragmentation defines their severity, the role of habitat corridors in mitigating those effects still remains controversial. This ambiguousness rests largely on various difficulties in experimentation, a problem partially solved in the present paper by the use of easily manipulated soil communities. In this 2.5-year-long field experiment, we investigated the responses of soil decomposer organisms (from microbes to mesofaunal predators) to habitat fragment size, in the presence or absence of habitat corridors connecting the fragments. The habitat fragments …
Variation in gene expression within clones of the earthworm Dendrobaena octaedra
Gene expression is highly plastic, which can help organisms to both acclimate and adapt to changing environments. Possible variation in gene expression among individuals with the same genotype (among clones) is not widely considered, even though it could impact the results of studies that focus on gene expression phenotypes, for example studies using clonal lines. We examined the extent of within and between clone variation in gene expression in the earthworm Dendrobaena octaedra, which reproduces through apomictic parthenogenesis. Five microsatellite markers were developed and used to confirm that offspring are genetic clones of their parent. After that, expression of 12 genes was measured…
Methylation products of chlorophenols, catechols and hydroquinones in soil and earthworms of sawmill environments
Abstract Soil samples and earthworms collected from one noncleaned and two cleaned sawmill environments were analysed for their content of chlorinated anisoles (methoxybenzenes), veratroles (1,2-dimethoxybenzenes) and 1,4-dimethoxybenzenes. 2,3,4,6-tetrachloroanisole and pentachloroanisole were observed in all soil samples studied, in maximum combined amount about 1.5 μg/g dry soil. Small amounts (ca. 1–110 ng/g dry mass) of 3,4,5-trichloroveratrole, tetrachloroveratrole and tetrachloro-1,4-dimethoxybenzene were found in the most polluted soil samples. Only 2,3,4,6-tetrachloroanisole and pentachloroanisole were found in earthworms, where concentrations of each were ca. 0.1–20 μg/g fat. In g…
Avoidance of Cu- and Zn-contaminated soil by three ecologically different earthworm species
Earthworm avoidance response to soils contaminated with harmful substances has been proposed as a potential tool for assessing soil toxicity with low test effort. In the present study, the objective was to find out whether three ecologically different earthworm species, Aporrectodea tuberculata (Eisen), Lumbricus rubellus (Hoffmeister), and Dendrobaena octaedra (Savigny), avoid soils simultaneously spiked with Cu and Zn. In addition, metal-contaminated field soil taken close to a Cu-Ni smelter was tested with A. tuberculata using a two-section avoidance lest procedure. All three earthworm species clearly avoided Cu/Zn contaminated soil but differently: D. octaedra was the most sensitive spe…
The arthropod community of boreal Norway spruce forests responds variably to stump harvesting
Forest fuel harvesting increases the need to collect not just logging residues but also tree stumps from harvested stands. This biomass removal has raised concern over forest biodiversity. Here, the effects of stump harvesting on spiders, ants, harvestmen, ground beetles and epiedaphic springtails occupying boreal Norway spruce (Picea abies) forest floor were studied two and five years after harvesting by comparing pitfall trap samples from clear-cut sites with and without subsequent stump harvesting and from unharvested mature forests in central Finland. At harvested sites, traps were placed both on intact and exposed mineral soil surface. Open-habitat and generalist ground beetles benefit…
Toxicity of copper and zinc assessed with three different earthworm tests
Abstract At present, standardised earthworm acute toxicity and reproduction tests are used to assess the toxicity of heavy metal contaminated soils. These tests are, however, time-consuming, laborious and costly, and in addition, some sublethal responses may remain overlooked. Avoidance of metal contaminated soils by earthworms may be a useful parameter when assessing ecological risks with a low test effort. The objective of the present study was to find out whether the earthworm Aporrectodea tuberculata avoids soils simultaneously contaminated with Cu and Zn, and whether earlier exposure to metal-polluted soil affects its avoidance response. The aim was also to compare the sensitivity of t…
Body size and population dynamics of enchytraeids with different disturbance histories and nutrient dynamics
The population dynamics of the enchytraeid Cognettia sphagnetorum originating from an unmanaged forest (FP), a clear-cut area (CCP) or a plot treated with birch ash (APP) and the effects of population origin on labile C and N dynamics were investigated. Twenty individuals of C. sphagnetorum were introduced in microcosms containing humus from the unmanaged forest devoid of enchytraeids and amended with sucrose, and incubated for 14 weeks. Triplicate microcosms from FP, CCP and APP treatments were destructively sampled every second week and enchytraeid population density, individual length, nematode abundance and trophic structure, humus properties and dissolved organic C (DOC) and N (DON), a…
Effects of dimethoate and benomyl on soil organisms and soil processes – a microcosm study
Abstract Effects of two pesticides, dimethoate, an insecticide, and benomyl, a fungicide, applied singly or together, on soil organisms and plant growth were studied in microcosms containing agricultural soil and indigenous soil fauna together with introduced invertebrates and barley. Dimethoate reduced soil microarthropod populations and the reduction was stronger in the upper than in the lower soil layer. The collembolan community structure was affected by both pesticides. Populations of microarthropods in pesticide-treated microcosms recovered during the experiment but the community structures remained differentiated. Total numbers of enchytraeids and nematodes were not affected by eithe…
Leaching of n and c from birch leaf litter and raw humus with special emphasis on the influence of soil fauna
Abstract To examine the role of a community of soil animals in N-mineralization and C fluxes in dead organic matter, we established a microcosm system with substrates composed of: (a) birch leaf litter; (b) raw coniferous humus; and (c) litter on humus. Every 3–4 wks the substrates were irrigated with distilled water, and the amounts of NO5-N, NH4-N, total-N and total-C (as well as humic substances at one recording) in the leachates were analyzed. At the end of the experiment, water-soluble and exchangeable forms of N were measured in the test materials. The differences in the release of N were clear both between the replicates with and without soil animals and between the different forms o…
Role of the fauna in soil processes: techniques using simulated forest floor
Abstract Laboratory experiments were conducted to test the influence of soil animals on processes such as decomposition, nutrient cycling, and plant growth in northern coniferous forests. The techniques included simulation of a complex pattern of forest floor, controlled air flow through the systems, and automatic measurement of carbon flows. The soil fauna generally enhanced evolution of CO2 and mineralization of N and P from soil and litter, and increased considerably the biomass production and N content of birch seedlings. Significant results were also obtained on interactions between different faunal components.
Activity and role of the enchytraeid worm Cognettia sphagnetorum (Vejd.) (Oligochaeta: Enchytraeidae) in organic and mineral forest soil
Summary Site preparation following clear felling of coniferous forest creates a mosaic of different kinds of habitats for soil decomposers, ranging from bare mineral soil to thick layers of organic soil and felling residues. To study whether the impact of enchytraeids on nutrient mineralisation processes is different in residues, organic layer, and mineral soil, a microcosm experiment was conducted in the laboratory. Microcosms contained mineral soil (sand) alone or with soil organic layer (humus and F-layer materials) and spruce needles, either separately or together. Enchytraeids (Cognettia sphagnetorum) were introduced to the half of the microcosms. Numbers of enchytraeids, their gut con…
Decomposer animal communities in forest soil along heavy metal pollution gradient
Responses of soil decomposer animals to heavy metal contamination and to concomitant changes in organic matter quality and quantity and in soil microbial biomasses have been studied along a pollution gradient from a Cu-Ni smelter. Samples have been taken separately for nematodes, enchytraeids and microarthropods 0.5, 2 and 8 km from the smelter. Special attention has been paid to the changes in the collembolan fauna. The sampling sites have been located in homogeneous Scots pine ( Pinus sylvestris) forests with podsolic soil profiles. In addition, an experiment has been carried out in which intact soil cores have been transferred in mesh baskets between the sites 2 and 8 km from the smelter…
Life history and spatial distribution of the enchytraeid wormCognettia sphagnetorum(Oligochaeta) in metal-polluted soil: Below-ground sink-source population dynamics?
We studied the life history, metal-avoidance behavior, spatial distribution, and population growth of enchytraeid worms (Cognettia sphagnetorum [Oligochaeta]) originating from two sites: one uncontaminated, and another patchily polluted by heavy metals. Effects of patchy soil contamination on populations were studied in microcosms. In uncontaminated soil, worms from the polluted site had lower viability and reduced growth rate as juveniles but higher growth rate as adults compared to worms from the unpolluted site. They were also smaller in size at fragmentation (reproduction). Worms from the polluted site reached a larger population size than worms from the unpolluted site. Hence, worms fr…
Testate amoebae as a potential tracer of organic matter dislodged from peat extraction areas
In the boreal zone, surface waters mostly receive external organic matter (OM) from surrounding peatlands. The lake’s biological communities may respond to changes in OM inputs caused by anthropogenic activities in the catchment. Testate amoebae (TA) possess an outer shell that preserves well in lake sediments and are commonly used in paleo-environmental studies. Additionally, they fall into the size range of particles transported from peatlands to lakes, making them potential particle tracers. Here, we compared TA communities of current and pre-peat extraction sediments from lakes receiving OM only from peat extraction areas (impact lakes) with lakes receiving OM from peatlands under other…
Testate amoebae community analysis as a tool to assess biological impacts of peatland use
As most ecosystems, peatlands have been heavily exploited for different human purposes. For example, in Finland the majority is under forestry, agriculture or peat mining use. Peatlands play an important role in carbon storage, water cycle, and are a unique habitat for rare organisms. Such properties highlight their environmental importance and the need for their restoration. To monitor the success of peatland restoration sensitive indicators are needed. Here we test whether testate amoebae can be used as a reliable bioindicator for assessing peatland condition. To qualify as reliable indicators, responses in testate amoebae community structure to ecological changes must be stronger than ra…
Effect of Cd-containing wood ash on the microflora of coniferous forest humus
The use of wood ash in forestry has been questioned because the cadmium (Cd) concentration of ash, which varies between 1 and 20 mg kg(-1) ash, exceeds the level allowed for fertilizers (3 mg kg(-1)) used in agriculture. To investigate the combined and separated effects of Cd and ash on the forest humus microflora, pumice or wood ash, spiked with a water-soluble (CdCl(2)) or -insoluble (CdO) form of Cd at three levels (0, 400 and 1000 mg kg(-1)), were applied at a fertilization level of 5000 kg ha(-1) in a laboratory microcosm study. The trial consisted of 60 microcosms (five replications per treatment), which were incubated in darkness at +20 degrees C and a constant relative air humidity …
Influence of Cognettia sphagnetorum (Enchytraeidae) on birch growth and microbial activity, composition and biomass in soil with or without wood ash
In this laboratory study using microcosms with seedlings of silver birch (Betula pendula), we explored whether Cognettia sphagnetorum (Enchytraeidae) can retain its important role of accelerating decomposition processes in soils and stimulating primary production under disturbance. We established systems with or without wood ash amendment (first-order disturbance) in the soil, either in the presence or absence of C. sphagnetorum. To test whether the systems treated with wood ash are more sensitive to an additional disturbance than the ash-free systems, the microcosms were later on disturbed by drought. To determine the influence of two disturbances on the enchytraeids and populations of oth…