Effects of extreme drought manipulation on free-living nematode densities
Abstract
Free living nematodes are a very numerous and diverse component of soil biota with a broad range of sensibility and generation time. Therefore, this group is widely used for environmental indication. During the first year of an experiment called ExDRain (Extreme Drought and Chronic Rain Manipulation Experiment), performed in the Hungarian Great Plain, we studied the effects of an extreme drought treatment (achieved by the complete exclosure of precipitation from the plots) on nematode density. The effects of presence or absence of vegetation on the nematode density were also examined. Our questions: (1) Are there any effects of the precipitation exclosure on the nematode densities? (2) Are there any effects of the vegetation on the nematode densities? At all of the four sampling times there were positive effects of the vegetation cover (March p < 0,001; May p < 0,001; July ; p < 0,01; September p < 0,01). The effect of the extreme drought was significant only twice: one and five months after the start of the precipitation exclosure treatment (May; p < 0,01; September ; p < 0,01). In conclusion, even density, this less sensitive nematological parameter may be suitable for monitoring the effects of robust changes in climate, but just supplemented with other indexes, like the distribution of the feeding groups.
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