Search results for "Microfauna"
showing 10 items of 14 documents
Climate, environment and human behaviour in the Middle Palaeolithic of Abrigo de la Quebrada (Valencia, Spain): The evidence from charred plant and m…
2019
Abstract The Abrigo de la Quebrada rock shelter was occupied by Neanderthal groups during the early Upper Pleistocene, yielding evidence for their subsistence practices and local resource exploitation. This paper focuses on the plant macroremains and the micromammals, which provide information about occupation patterns, the surrounding landscape, the use of resources, and the environment. Mountain pine forests and permanent grass formations containing humid zones and open spaces that would have harboured an eurythermal microfauna were the dominant landscape type. Cold-climate pines provided most of the firewood. The data are consistent with a recurrent, seasonal occupation pattern, in which…
Impact of genetic diversity of an earthworm on decomposition and ecosystem functioning
2020
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…
Soil processes are not influenced by the functional complexity of soil decomposer food webs under disturbance
2002
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…
Short-term effects of different tillage in a sustainable farming system on nematode community structure
2000
This study investigated the effects of different tillage practices on the nematode community structure. The different tillage systems were: untilled control, conventional deep plough, two-layer plough and cultivator. Sampling was carried out in a field experiment at Worrstadt-Rommersheim (Rhineland-Palatinate, Germany) in order to study the effects of these tillage systems in a sustainable farming system. Soil samples were taken every 3 months from June 1994 to March 1995 and divided into two depths of 0–10 and 10–20 cm in order to study the vertical distribution of nematode density and community structure. Nematode density was significantly reduced after the first tillage. The second tilla…
Responses of decomposer community to root-isolation and addition of slash
2001
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…
Interactions between enchytraeid (Cognettia sphagnetorum), microarthropod and nematode populations in forest soil at different moistures
1998
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…
Distribution of soil animals in patchily contaminated soil
1996
Abstract Distribution of soil animals with respect to patchy chemical contamination was studied in microcosms containing reconstituted coniferous forest floor. Soil materials were defaunated and soil organisms were reinoculated into a mesh basket in the centre of each microcosm. Part of the humus layer was contaminated with three concentrations of sodiumpentachlorophenate (0, 50 or 500 mg PCP kg −1 of dry humus) and put into mesh baskets (two per concentration) around the central patch. No differences in dispersion ability from the reinoculated patch were found between microarthropod species. PCP decreased microbial biomass in the humus. Numbers of collembolans were significantly lower in t…
Laboratory design to simulate complexity of forest floor for studying the role of fauna in the soil processes
1990
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 …
The ESR age of Portlandia arctica shells from glacial deposits of Central Latviaan answer to a controversy on the age and genesis of their enclosing …
1998
Abstract The occurrence of Portlandia arctica shells in glacigenic sediments of Central Latvia had created a controversy in many publications about (1) their age ranging from the Holsteinian to the Late Weichselian and (2) the genesis of their enclosing sediments: glacial, glaciomarine or marine. Our reinvestigation of the main object of controversy, the Licupe site, leads to a conclusion that the sedimentary package of diamictons, clays and sands containing Portlandia arctica shells and marine microfossils is a large glacial raft that had been transported and deposited by the Riga lobe during the Weichselian. The electron spin resonance (ESR) ages on five sets of Portlandia arctica shells …
Understanding the Impact of Trampling on Rodent Bones
2022
Experiments based on the premise of uniformitarism are an effective tool to establish patterns of taphonomic processes acting either before, or after, burial. One process that has been extensively investigated experimentally is the impact of trampling to large mammal bones. Since trampling marks caused by sedimentary friction strongly mimic cut marks made by humans using stone tools during butchery, distinguishing the origin of such modifications is especially relevant to the study of human evolution. In contrast, damage resulting from trampling on small mammal fossil bones has received less attention, despite the fact that it may solve interesting problems relating to site formation proces…