| Popis: |
Nematode communities showed possibilities to be good indicators of different kind of disturbances in ecosystems. Some groups of nematodes can survive under disturbed environmental conditions, while others cannot. The objective of this investigation was to determine if the nematode communities in the soil could serve as bioindicators of anthropogenic activities in agroecosystems. Research was conducted in 2000, in Kneževo near Osijek. The nematode communities were investigated on three different soil treatments: Poplar forest, Arable land with standard tillage regimes – wheat, Arable land with standard tillage regimes – corn. Sampling was done using a corer Ø ; 2 cm, to a depth of 20 cm. There were 4 replicate plots of each treatment. Nematodes were extracted from 100 g subsamples of soil by the Seinhorst method (Seinhorst, 1956). Identification was done by using keys of Bongers (1994), Mai & Lyon (1975) and Andrassy (1984). Total number of nematodes and number of genera were determined and compared between treatments, as well as Maturity index (MI), Plant parasitic index (PPI) and PPI/MI (Bongers, 1990). Trophic structure was determined according to Yeates et al. 1993. Abundance of nematodes was higher in agricultural treatments in compare to treatment without human intervention (poplar). In opposite, number of genera in treatments was highest in poplar, while in agricultural soil, number of genera that survive was lower. Trophic structure analyses showed similar patterns in all treatments investigated. Five trophic groups occurred (bacterivorous, fungivorous, plant-feeding nematodes, omnivorous and predators). Plant - feeding nematodes were dominant in poplar treatment while in agricultural treatments dominated bacterial feeding nematodes followed by plant feeding nematodes. Although MI and PPI do not show statistically significant differences among treatments the trends in them do represent an effective tool as distinguishing parameters of anthropogenic influence in agro ecosystem. The obtained results provide us information that nematode communities in the soil could serve as reliable bioindicator of anthropogenic activities in agro ecosystems. |
