Functional diversity of decomposer organisms in relation to primary production

Abstract The term `biodiversity' is claimed to lack connections to a serious scientific background. In this work, we approached the concept of biodiversity from a functional point of view by asking: “At what level of the ecological organization (species, trophic species/feeding guilds, trophic levels etc.) should reduction in biodiversity matter to bring about visible changes in ecosystem performance?” We investigate the concepts of `functional diversity' and `ecosystem performance' in relation to feeding habits (such as fungivory, detritivory etc.) of soil fauna and plant growth. After analysing the results of a number of microcosm studies, we came into the following conclusions: (i) troph…

Global data on earthworm abundance, biomass, diversity and corresponding environmental properties

Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ec…

Responses of co-occurring populations of Dendrobaena octaedra (Lumbricidae) and Cognettia sphagnetorum (Enchytraeidae) to soil pH, moisture and resource addition

Summary Dendrobaena octaedra (Lumbricidae) and Cognettia sphagnetorum (Enchytraeidae) are the two most dominating soil invertebrates in terms of biomass in boreal coniferous forest soils. A microcosm experiment was set up in order to study the influence of pH, moisture and resource addition on D. octaedra and C. sphagnetorum when both species are simultaneously present. Two kinds of coniferous forest humus were used as substrate, pine stand humus (pH 4.2), and spruce stand humus (pH 4.6); in the third treatment the pine stand humus was adjusted with slaked lime (CaOH 2 ) to the same initial pH as the spruce stand humus. Each substrate was adjusted to water contents of 25%, 42.5% and 60% of …

Laboratory design to simulate complexity of forest floor for studying the role of fauna in the soil processes

We developed a technique for simulating the complexity of the soil system under controlled laboratory conditions. Removable microcosms were inserted in a homogeneous substrate soil in a large plastic box. This macrocosm was sealed, except for an inlet and outlet for air flow, and an aperture for collecting leachates. The system can be designed and manipulated in various ways according to the needs of a particular experiment. Respiration and nutrient fluxes can be measured either from the whole macrocosm or separately from the microcosms. We have performed three experiments in order to evaluate the role of animals in the soil processes. A set of macrocosms was constructed from components of …

Hämähäkkieläimet : Arachnida

<i>Amblyseius fennicus</i> sp. n. (Acarina, Gamasina: Phytoseiidae) from Finland, with a key to the <i>A. americanus</i> group

A new species is described belonging to the Amblyseius (s. str.) americanus group (Denmark & Muma, 1989). It was collected regularly from trunks of old trees in Finland. A key is given including the known species of the A. americanus group.

Soil Biology as Related to Land-Use Practices (Eighth International Colloquium on Soil Zoology), held in Syracuse, New York, USA, during 30 July-3 August 1979

Earthworms and pH affect communities of nematodes and enchytraeids in forest soil

In northern boreal forests the occurrence of endogeic and anecic earthworms is determined by soil pH. Increasing evidence suggests that large detritivorous soil animals such as earthworms can influence the other components of the decomposer community. To study the effects of earthworms and pH on soil nematode and enchytraeid communities, a factorially designed experiment was conducted with Lumbricus rubellus and/or Aporrectodea caliginosa. Earthworms were added to "mesocosms" containing unlimed (pH 4.8) or limed (pH 6.1) coniferous mor humus with their natural biota of micro-organisms. In the absence of earthworms, nematodes were significantly more abundant in limed than in unlimed humus. E…

Typhlodromips jurmoensis ; (Acari: Mesostigmata: Amblyseiinae), a new species from the archipelago of SW Finland

A new species belonging to the genus Typhloromips De Leon, 1965 is described. It was collected from Calluna moorland soil on Jurmo, a remote island in the SW archipelago of Finland. Typhlodromips herbarius (Wainstein, 1960) is considered a senior synonym of T.tenuis (Westerboer, 1963), syn.n. A key is given to related species with a similar spermathecal structure. peerReviewed

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…

Effects of hard frost and freeze-thaw cycles on decomposer communities and N mineralisation in boreal forest soil

Abstract Decomposition and mineralisation rates generally increase with increasing moisture and temperature. The expected global climate change may enhance precipitation and raise the temperatures at boreal latitudes, but absence of snow together with occasional low temperatures may cause disturbances in soil processes and faunal communities. To test the effects of disturbances such as hard frosts and freeze-thaw cycles on decomposer populations and N mineralisation, we performed two experiments. In the field experiment, carried out in a pine forest, we induced low soil temperatures by preventing snow covering the ground. In the laboratory test we established three “winter” temperature regi…

Interactions between enchytraeid (Cognettia sphagnetorum), microarthropod and nematode populations in forest soil at different moistures

Abstract Very little is known about the effects of microclimatic conditions on interactions within soil faunal communities. The aim of the experiment was to examine how the different functional components of the faunal community in coniferous forest soil affect each other at different moisture levels. Forest humus was defaunated by heating, adjusted to three water contents, distributed into glass jars and reinoculated with microflora and microfauna. Sets of 10 jars were inoculated with (1) Cognettia sphagnetorum, (2) Cognettia with Folsomia candida (Collembola), (3) Cognettia with a mixed community of microarthropods, (4) Folsomia alone, (5) mixed microarthropods alone, and (6) Cognettia wi…

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 …

Evaluation of different similarity indices as measures of succession in arthropod communities of the forest floor after clear-cutting.

Communities of spiders (Araneae) and beetles (Coleoptera) living in the soil and litter of clear-cut areas were compared with those of intact forest stands. Sixteen different indices of similarity were tested on three sets of material: spiders and beetles examined during one year in three clear-cut areas felled 3, 6 and 9 years earlier, and spiders in one clear-cut area examined during 7 successive years after felling. Other sources of evidence showed that succession in the spider community was divergent for at least 7 years after felling. The indices that seemed to express the changes best were: (1) Kendall's rank correlation test, (2) the Bray-Curtis measure, (3) Renkonen's percentage sim…

Microfungal community structure in anthropogenic birch stands in central Finland

We describe the soil microfungal communities in 30-year-old birch (Betula pendula Roth) stands planted either on former spruce forest soil (BS) or on former arable soil (BF) and compare these with the soil microfungal communities in spruce forests (S), arable fields (F) and old deciduous forests (D). Fungi were isolated from 0- to 3-cm and 3- to 6-cm samples collected in September 1997 and May 1998. Principal components analysis differentiated fungal communities in the S and BS sites from those in the other site types. The Morisita-Horn index of similarity indicated that fungal communities in the F and BF sites were less similar to those in the other site types. Fungal communities of the BS…

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…

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 …

Habitat patchiness affects decomposition and faunal diversity: a microcosm experiment on forest floor.

Environmental heterogeneity has been intensively studied, but little is known about relationships between habitat patchiness and soil processes. The aim of this study was to investigate (1) the impact of patchiness of the litter layer on the decomposer community and litter decomposition rate, and (2) whether the impact of soil fauna on the rates of processes differs in relation to patchiness. An experiment was carried out in microcosms with coniferous forest humus and four kinds of litter with different C:N ratios or stages of decomposition, either separately (i.e. in patches) or mixed with each other. Microarthropod species diversity was better maintained in the patchy systems. In the abse…

Evaluation of the soil fauna impact on decomposition in a simulated coniferous forest soil

Long-term experiments (ca. 2 years) were carried out in laboratory systems that simulated the complexity of a coniferous forest floor. The test materials were partially sterilized by freezing and thawing, and reinoculated with (1) microbes alone or (2) microbes with fauna. Removable microcosms containing birch litter, spruce litter, or humus were inserted into a humus substrate. Two experiments used organic matter only, and another included a layer of mineral soil below the humus. Both were incubated in climate chambers that simulated both summer and winter conditions. The evolution of CO2 was measured at regular intervals. In order to determine the C content of the leachates, the macrocosm…

Plant effects on the soil community: A microcosm experiment

Abstract An experiment was carried out in microcosms for testing the hypothesis that a higher level of primary production should maintain a decomposer community with higher biomass and activity. Microcosms with coniferous forest humus and a diverse microbial and faunal community were divided into three sets: (1) control without plants, (2) with birch seedlings in full illumination, and (3) with birch seedlings, shaded to reduce the net primary production. During 16 weeks of incubation at +16 °C, no treatment effects were found in numbers or biomass of taxonomic or functional groups of soil organisms, nor in the system respiration in darkness. The community structure of the shaded systems di…

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 …

Oribatid mites (Acari: Oribatida) in boreal forest floor and decaying wood

Summary We studied the oribatid mite communities in forest floor and in decaying wood in pine (Pinus sylvestris), spruce (Picea abies) and deciduous (mainly Betula pendula and B. pubescens) forests at different latitudes in Finland. The study sites were either in mature managed forests or in old-growth forests in nature reserves. Altogether 78 sites were sampled in 2004 and 2005, yielding a total of 38,145 oribatid mites belonging to 133 species, of which four were new to Finland. Oribatid mite communities differed in terms of total number and community structure between forest types and latitudes within the boreal forest zone. The most abundant and diverse communities were in spruce forest…

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.

Soil macroarthropod communities in planted birch stands in comparison with natural forests in central Finland

The aim of the study was to compare the soil macroarthropod communities in anthropogenous birch stands of different origin with each other and with natural forests at the same latitude in Finland. A total of nine forest sites was investigated: three birch stands (Betula pendula) planted ca. 30 years prior to the study after clear-cutting of spruce stands (“Birch after Spruce”, BS), three birch stands planted ca. 30 years earlier on arable soil that had been under normal cultivation until reforestation (“Birch after Field”, BF), and three “Natural Deciduous” (D) forests. These were sampled three times in 1998, animals were extracted with large Tullgren funnels, counted per square metre, and …

A new species of Arctoseius Thor, 1930 (Acari: Ascidae) from taiga regions of the Palaearctic, with a key to Arctoseius species of Fennoscandia, NW Europe

A new mesostigmatid mite species belonging to the genus Arctoseius Thor, 1930, is described based on material from subarctic coniferous forests, Finland, and Altai highlands, Russia. Arctoseius ambiguus sp. nov. is similar to Arctoseius venustulus (Berlese, 1916), but can be distinguished from the latter by its larger size, wider dorsal shield, weakly sclerotized presternal platelets, pronounced differences in the length of opisthonotal setae, and distinct punctation of the anal shield. A key for 15 Arctoseius species recorded in continental North-Western Europe (Fennoscandia) is given. The Fennoscandian fauna of Arctoseius species is rather specialised. It includes four European temperate …

Temporal and spatial fluctuations in moisture affect humus microfungal community structure in microcosms

The effects of temporal and spatial fluctuations in moisture on the microfungal community were studied in birch litter plus pine humus microcosms over 6 months. Two treatments were used: a uniform treatment in which moisture was maintained at the original moisture content throughout the profile over the course of the experiment; and a fluctuating moisture treatment in which the moisture content of the whole microcosm fluctuated weekly around the original moisture content. At 6 months, fungal species richness was higher and diversity was lower under moisture fluctuations than under uniform moisture. The number of fungal isolates and proportional diversity was significantly higher in the bott…

Catalogue of the Mesostigmata mites in Finland

This catalogue of Mesostigmata found in Finland is based on published records, material deposited in the Zoological Museum of Turku University, and collections by the author, deposited in the Zoological Museum of Helsinki University. The total number of recorded species is 451, including 15 unidentified or undescribed species. 121 of the identified species were not previously reported from Finland. General distribution in Finland and preferred habitats of the species are given, or of rare species the details of the records. peerReviewed

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…

Dispersal of microarthropods in forest soil

Summary This experiment was a part of a research on the soil community in anthropogenous birch stands in Finland. In that study it was found that communities of Collembola are similar in birch stands of different origin (cultivated field or spruce forest), while the communities of Oribatida are essentially different. When compared to original spruce forest, the communities of both groups are different. Cultivation eliminates the populations of most microarthropod species, that have to disperse after reforestation from the surrounding areas. The aim of the experiment was to study the ambulatory dispersal of soil microarthropods. It was carried out in plastic boxes filled with an intact block…

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…

Effects of soil fauna on leaching of nitrogen and phosphorus from experimental systems simulating coniferous forest floor

Long-term experiments (97–98 weeks) were carried out in macrocosm systems simulating the complexity of coniferous forest soil. The macrocosms were partially sterilized by freezing, thawing and drying, then re-inoculated with microbes alone or microbes + soil fauna. Removable microcosms containing birch litter, spruce litter, or humus were inserted into the substrate humus in the macrocosms. Two experiments used organic matter only, and in the third there was mineral soil below the humus. The macrocosms were incubated in climate chambers that simulated both summer and winter conditions. At 4- to 6-week intervals the substrates were irrigated for analyses of pH, total N, NH 4 + −N, NO 3 − −N,…

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.

Collembolan communities in deciduous forests of different origin in Finland

The aim of the study was to compare the collembolan communities in anthropogenous birch stands of different origin with each other and with natural forests at the same latitude. Nine sites were investigated: three birch stands (Betula pendula) planted ca. 30 years prior to the study after clear-cutting of spruce stands, three birch stands planted ca. 30 years earlier on arable soil that had been under cultivation until reforestation, and three natural deciduous forests. These were sampled in August and October 1998, and microarthropods were extracted, counted and identified. Thirty years after reforestation, the collembolan communities of “Birch after Spruce” and “Birch after Field” differe…

Effects of temperature and moisture fluctuations on an experimental soil microarthropod community

Summary We established an experiment in microcosms with coniferous forest humus and birch leaf litter for testing the effects of constant vs. diurnally fluctuating temperature and uniform vs. varying moisture, on the population densities and species richness of Collembola and Mestostigmata. These parameters and the vertical distribution of populations were analysed by layers (top, centre, bottom) at two samplings (weeks 10 and 27). The hypotheses were that populations of at least some species benefit from fluctuating microclimate, and that varying conditions permit more species to coexist than uniform conditions. At fluctuating temperature regime, four species and total Collembola were more…