longer, researchers observed a drastic insects shrinkage in Germany and the whole of Europe. In the autumn 20178 published long-term study found that the biomass has insects flying in the German nature conservation in 27 years to 76 percent removed. The number of butterflies has fallen from meadows field to middle to two-thirds, as of 2019 resulted in a further study.
insect survey in Eco – and normal farming
Now, researchers complement to Axel Hausmann of the Zoological state collection of Munich, these findings another interesting aspect. Because they have examined whether and how the insect population of fields adjacent to conventional or organic fields. In contrast to the previous studies, they used not only a Parameter – biomass, number of animals or species diversity as an indicator of insect diversity and abundance, but recorded all of these parameters. This was made possible by a combination of two methods of fishing: the classic Malaise-Traps for daytime flying insects and light-active arthropods traps for night. All catches were weighed for biomass determination, counted and by means of DNA Barcoding is of a type associated with it. The Traps were from April to October, 2018 active.
The analysis showed clear differences between the insect populations in the environment in ecologically and conventionally managed fields. “Our data reveal a higher biomass and greater species richness in Organic farming, and double the amount of endangered nocturnal butterflies in comparison to conventional locations,” reports Hausmann and his colleagues. The total biomass of insects was in the Organic farming 2.6-Fold higher than in the environment of the conventionally managed fields. The number of species was according to the case site in order to ten to 30 percent higher.
especially butterflies and endangered species benefit
the differences are Particularly important in the case of the butterflies were With the light, the scientists fall began, a total of 256 moths species on the ecological sites and 222 on the locations in the vicinity of conventional Fields. Also the incidence was higher In Organic farming as many moths were one and a half times in the case. Even more pronounced are the differences in the Malaise were to Fall: “The organic agricultural field environment brought about 4.3 Times more butterflies than the Fall in the vicinity of the conventional fields,” say the researchers.
the Clear advantages the analysis also showed for rare and threatened butterfly species On the organically farmed areas, the scientists found 30 species double the amount of endangered species from the Red list than on the conventionally farmed land. “Our data show that Red list species are found mainly near organic fields,” says Hausmann and his Team. “This is consistent with studies showing that more specialized species, which are often included in the Red list, are particularly affected by the intensification of agriculture.”
Yet these results come only from a small pilot study with a few areas. Therefore, the researchers want to lead now as a next sampling in the framework of a five-year research program to continue and expand. Nevertheless, their study provides now evidence that organic farming contributes to reducing the loss of biodiversity in agricultural areas.
source: the state scientific collections of Bavaria; journal article: Ecology and Evolution, doi: 10.1002/ece3.6166
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