Dwindling rainforests also harm the peasants

Occurrence of useful insects for pollination and pest control is threatened

Rainforest in Ecuador © University of Göttingen
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The transformation of tropical rainforests into intensively used agricultural areas does not just change the habitat. It also provokes dramatic changes in the food webs of ecosystems. This also threatens the presence of beneficial insects that provide important ecosystem services for agriculture, including pollination of crops and pest control. Scientists now report this in the journal "Nature".

Agro-ecologist Jason Tylianakis from the University of Göttingen, together with colleagues from the University of Oxford in Ecuador, studied several thousand bee and wasp nests. He was able to show for the first time how the interactions between these organisms and their natural counterparts change due to land use.

Farmers dependent on ecological "services"

As Tylianakis explains, food webs result from the interactions of different species with each other and with their environment. They form the basis for the structure and function of ecosystems. How agro-food webs can change along different land-use systems has been extensively described by agro-ecologists.

Thus, their research shows that in unswept landscapes such as grazed grassland or rice acreage dominated by a parasitic wasp. It is an "enemy" of bees and wasps, whose existence here is far more endangered than in the shady coffee agroforestry or rainforest. "Many poor farmers in Ecuador are dependent on the bees and wasps 'free' services for pollination and pest control, and the destruction of rainforests and the extinction of beneficial insects are also threatening agricultural production, " says Tscharntke.

The mix does it

The Göttingen scientist therefore demands a sustainable agriculture, which takes into account the central processes of the food webs: "The coffee cultivation in agroforestry systems shows that a connection of agricultural production and nature protection is possible." In the words of Owen Lewis, however, this must not become a nationwide land management instrument. display

"Although food webs in the coffee agroforestry resemble those of a rainforest, the conservation value of such land use systems should not be overstated." Like other tropical countries, Ecuador is characterized by a colorful mix of rainforest remains and other forms of land use Converting coffee growing can have a dramatic environmental impact, "warns the British researcher.

(University of Gttingen, 12.01.2007 - NPO)