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EN
The effect of mid-field shelterbelts on litter decomposition and the numbers and biomass of litter inhabiting invertebrate macrofauna was evaluated. The question was how far into the fields such an effect could reach. To answer this question an experiment was set up, in which a uniform substratum (sand and loam) was laid out inside the metal frames dug in the earth. Litter of cocksfoot (Dactylis glomerata) was laid out on these substrates. Samples were taken from the middle of a seven years old wood strip (S) and along the transect i.e. in the ecotone from its wooded side (Es), from its field side (E[F]) and in the field 10 (F10) and 50 (F50) meters far from the shelterbelt. Decomposition rate of litter was retarded with increasing distance from the shelterbelt. Biomass of the litter dwelling macrofauna was lower in the field as compared to the shelterbelt and ecotones. Input of dead invertebrate mass to the soil under litter decreased also from the shelterbelt towards the field center. At the end of the experiment dead invertebrate biomass contributed to 24% of the total (dead and alive) of animal biomass in the transect. Average contribution of predators to the total animal biomass was the highest in the field ecotone (E[F] - 79%) and the lowest in the field site F50 (56%). A significant negative relationship was found between the density and biomass of predators (Carabidae) and the density and biomass of their potential prey (larvae of Diptera and Collembola) along the whole transect.
EN
The rate of grass decomposition was analysed in three field experiments (I, II, and III) in mesocosms where patrolling of area by large epigean invertebrates was unlimited (O - open) or restricted (C - closed). The mesocosm contained soil cores (100 cm^2, 15 cm deep) or were filled with poor substrate (sand with clay) and placed in a meadow soil profile. In Experiment III an additional treatment was applied, i.e. litter manuring with insect faeces (of cockhafer larvae Osmoderma eremita (Scarabeidae) and of locust Locusta migratoria (Oeolipodidae). The last treatment aimed at determining the effect of macrofauna faeces on litter decomposition rate. To exclude influence of roots' ingrowth into the substrate on the rate of litter decay the mesocosms with restricted ingrowth were applied. The litter exposed on the soil surface decayed faster than when exposed on sand. Patrolling of the area by large soil invertebrates had no effect on the litter decay rate during the first 8-13 months from the exposure (Exp. I and II). In the experiment, where litter remained longer in the field, i.e. 24 months (Exp. III), in 13-months after grass exposure it was found that the amount of remaining matter was significantly higher and the daily decay rate was lower in the closed mesocosms than in the open ones. These differences were maintained in the second year up to the end of the experiment. Litter manuring with insects' faeces was clear only in the treatment without root' ingrowth into the substrate.
EN
Changes of environmental conditions in mesocosms differentiated in the accessibility for epigean arthropods (closed and open for animals) were compared on a meadow of the Arrhenatheretalia order. In general, moisture of the exposed litter and of the underlying substrate did not differ between the open and closed treatments. Plant biomass, considered as an index of the environmental conditions, did not differentiate the two mesocosm types, either aboveground (total and subdivided into dead and living) or belowground. The open mesocosms were characterised by higher weight of fragmented plant material and of invertebrate faeces than the closed treatment.
EN
The effect of mid-field shelterbelts on litter decomposition and the numbers and biomass of litter inhabiting invertebrate macrofauna was evaluated. The question was how far into the fields such an effect could reach. To answer this question an experiment was set up, in which a uniform substratum (sand and loam) was laid out inside the metal frames dug in the earth. Litter of cocksfoot (Dactylis glomerata) was laid out on these substrates. Samples were taken from the middle of a seven years old wood strip (S) and along the transect i.e. in the ecotone from its wooded side (Es), from its field side (EF) and in the field 10 (F10) and 50 (F50) meters far from the shelterbelt. Decomposition rate of litter was retarded with increasing distance from the shelterbelt. Biomass of the litter dwelling macrofauna was lower in the field as compared to the shelterbelt and ecotones. Input of dead invertebrate mass to the soil under litter decreased also from the shelterbelt towards the field center. At the end of the experiment dead invertebrate biomass contributed to 24% of the total (dead and alive) of animal biomass in the transect. Average contribution of predators to the total animal biomass was the highest in the field ecotone (EF - 79%) and the lowest in the field site F50 (56%). A significant negative relationship was found between the density and biomass of predators (Carabidae) and the density and biomass of their potential prey (larvae of Diptera and Collembola) along the whole transect.
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38%
EN
A field exclusion experiment in Arrhenatherrethalia mown meadow was carried out in mesocosms to analyse the role of epigeic, mobile macroarthropods in decomposition processes. A mineral bag technique allowed assessment of annual organic matter accumulation in the sandy substrate of mesocosms. Higher total organic C content was recorded in the top substrate layer (0-3 cm) in mesocosms accessible for macroarthropods, than in closed, inaccessible ones (17 and 23% more, respectively, in the two years), as well as higher amount of C in humus acids (6 and 36% more in two years). Possible reasons for these differences were considered. The total plant biomass, the litter disappearenc3 rate and water content in litter did not differ significantly between the types of mesocosms. In the top layer of mesocosms accessible for macroarthropods higher content of comminuted plant material (38,9 g m^-2) and arthropods feces (12.3 g^-2) were found compared to the amount in closed mesocosms (17,1 and 2,1 g m^-2 respectively). But the particulate organic matter derived from comminuted plant remnants and from fecal pellets accounted, in the period of the highest content, for about a half of the total carbon accumulated in the top substrate layer. In the litter of the open mesocosms reduced number of fungivorous mites and aphids was found, coupled with higher density of bacterivorous nematodes and higher abundance of fungi. The density of fungivorous mites was negatively correlated with the intensity of area patrolling by Araneae (tau = -0.79, P=0,0028) and Staphylinidae (tau = -0.58, P = 0.03). The elimination of aphids was positively correlated with area patrolling by the last group (tau = 0.81, P = 0.005). These results suggest that predation by macroarthropods changed proportions between fungi- and bacteriovorous invertebrates and as a consequence proportions between fungi and bacteria.
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