Search results for "decomposer"
showing 10 items of 44 documents
Decomposer communities in contaminated soil: Is altered community regulation a proper tool in ecological risk assessment of toxicants?
1997
Abstract Effects of patchy soil contamination on decomposer organisms, their community regulation and nutrient mineralization were studied in a microcosm experiment. Coniferous forest soil was patchily contaminated with three concentrations of sodiumpentachlorophenate PCP (0, 50 and 500 mg PCP kg−1 of dry soil). Abundance of microbes, enchytraeids, nematodes, small oribatids and predatory mites were reduced by the PCP. Direct toxicity of PCP and lowered microbial biomass seemed to affect animal community composition in the most contaminated patches. Some large oribatids which seemed to be tolerant to PCP increased their numbers in the most contaminated patches. Although predatory mites suff…
The effect of forest fuel harvesting on the fungal diversity of clear-cuts
2012
Abstract The removal of logging residues and stumps from clear-cuts has become a common forestry practice. Forest fuel harvesting decreases the initially low volume of dead wood in managed forests, but the biodiversity effects are poorly known. We studied the effects of forest fuel harvesting on decomposer fungi on clear-cut Norway spruce stands in central Finland. The number of occurrences and taxa of polypores, saprotrophic agarics and pleurotoid agarics were determined on 10 forest fuel harvested and 10 control clear-cuts 4–5 years after logging. In total, we recorded 148 fungal taxa. The total number of taxa, the number of polypore occurrences, and the number of polypore species within …
Root-induced decomposer growth and plant N uptake are not positively associated among a set of grassland plants
2007
Abstract It is known that plant species can induce development of different soil decomposer communities and that they differ in their influence on organic matter decomposition and N mineralization in soil. However, no study has so far assessed whether these two observations are related to each other. Based on the hypothesis that root-induced growth of soil decomposers leads to accelerated decomposition of SOM and increased plant N availability in soil, we predicted that (1) among a set of grassland plants the abundance of soil decomposers in the plant rhizosphere is positively associated with plant N uptake from soil organic matter. To test this, we established grassland microcosms consisti…
Do interactions with soil organisms mediate grass responses to defoliation?
2008
Abstract Defoliation-induced changes in grass growth and C allocation are known to affect soil organisms, but how much these effects in turn mediate grass responses to defoliation is not fully understood. Here, we present results from a microcosm study that assessed the role of arbuscular mycorrhizal (AM) fungi and soil decomposers in the response of a common forage grass, Phleum pratense L., to defoliation at two nutrient availabilities (added inorganic nutrients or no added nutrients). We measured the growth and C and N allocations of P. pratense plants as well as the abundance of soil organisms in the plant rhizosphere 5 and 19 d after defoliation. To examine whether defoliation affected…
The role of loquat to maintain entomological diversity in the Conca d'Oro orchards
2014
The loquat [Eriobotryo japonica (Thumb.) Lindl.] is an allochthonous species long cultivated in Sicily. In some parts of Sicily such as the Siracusa province, the loquat is cultivated in mono-specific orchards. In other sites, like Conca d'Oro and other places near the town of Palermo, loquat is intercropped with other tree species such as citrus, apricot, peach, mulberry, walnut, Mediterranean hackberry. The loquat plays an important role in order to increase biodiversity within these orchards. The old or dead loquat trees host a variety of xylophagous insects and more in particular Coleoptera: Cerambycidae beetles Dynastidae, and Cetoniidae. Longhorn beetles, rhinoceros beetles and flower…
Earthworms and pH affect communities of nematodes and enchytraeids in forest soil
2003
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…
Composition and Trophic Structure of Detrital Food Web in Ant Nest Mounds of Formica aquilonia and in the Surrounding Forest Soil
1998
Community composition and food web structure of soil decomposer biota in relation to various habitat properties were compared between upper parts of red wood ant (Formica aquilonia) nest mounds and the adjacent forest soil. For a description of trophic structure of the decomposer community in the two habitats, soil decomposers were classified into 14 trophic groups. Classification of the taxa into three habitat preference categories resulted in a clear division of the fauna into either soil or nest specialists, relatively few taxa falling between these two groups. A large majority of the nest specialists belonged to a non-myrmecophilous soil decomposer fauna so far largely overlooked in stu…
Responses of soil decomposer animals to wood-ash fertilisation and burning in a coniferous forest stand
2000
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…
Vertical stratification and trophic interactions among organisms of a soil decomposer food web – a field experiment using 15N as a tool
2002
Abstract In this field study, we explored the spatial segregation between the litter- and humus-inhabiting organisms of the detrital food web using 15 N-isotope technique. The study was established in 11 × 11 m plots fertilized with 15 N-labelled urea. Ten years after urea application, soil samples were taken, both from the litter layer and the combined F+H layer. The samples were analysed for N content and the proportion of 15 N in (i) the residual organic matter in the litter and F+H layer (excluding microbes), (ii) microbial biomass, and (iii) various feeding guilds of soil fauna. The basal resource, soil microbes, and the fauna were more enriched with 15 N in the F+H layer than in the l…
Decomposer animal communities in forest soil along heavy metal pollution gradient
1996
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…