Search results for "decomposer"

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

2003

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…

Soil decomposer animal community in heavy-metal contaminated coniferous forest with and without liming

2002

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…

Regulation of decomposer community structure and decomposition processes in herbicide stressed humus soil

1997

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…

Decomposer animals and bioremediation of soils

1998

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…

Impacts of elevated CO2 and temperature on the soil fauna of boreal forests

2005

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…

Effects of stump removal on soil decomposer communities in undisturbed patches of the forest floor

2011

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…

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

1998

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…

Short-term responses of soil decomposer and vegetation communities to stump harvesting in boreal forests

2011

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 …

Local forest continuity – important for species-rich Micarea lichen communities, but less so for decomposers

2018

THE ROLE OF THE LOQUAT IN MAINTAINING ENTOMOLOGICAL DIVERSITY IN THE CONCA D'ORO ORCHARDS OF SICILY

2015

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…