Species loss is due to mankind

Biodiversity more important for environmental services than assumed

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Biodiversity is not only a value in itself, it is also more important to us than previously thought. Because, as a study published in Nature now shows, even the loss of fewer species can impair the ecological processes on which humankind relies.

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Under ecosystem services, environmental researchers understand all the functions that an ecosystem uses to help us, such as food production, the provision of safe drinking water, or the binding of the greenhouse gas carbon dioxide from the atmosphere.

The impact of species loss on the various ecosystem services has already been undermined by scientists, but most have looked at just one single ecosystem service at a time. Whether these values ​​are representative of the full functionality of an ecosystem was not yet clear.

Even a small loss of species damages the system

Professor Andrew Hector of the Institute of Environmental Sciences of the University of Zurich and Robert Bagchi of the University of Oxford have therefore developed a new method that allows to consider several ecosystem processes at once. They applied this method as part of an analysis of European meadow communities, simultaneously covering seven ecosystem services. display

They noted that greater biodiversity is needed if all ecosystem services are included in the calculation than if only a single service is considered. Even the loss of just a few species can lead to the overall functioning of an ecosystem being affected. "Previous research has suggested that species important to an ecosystem service can provide all other services - but that does not seem to be the case, " explains Hector.

Species affect specific functions

The core result of the study is that different ecosystem services are affected by different groups of species. Robert Bagchi says: "Because different species are responsible for different ecosystem services, more species are needed to maintain a fully functioning system than just one kind of concentration." Researchers therefore recommend ecosystems manage multiple ecosystem services at the same time. Because the isolated consideration of a service such as the increase of the yield can lead to enormous problems. For example, excessive fertilization results in high nitrate levels in adjacent rivers, which in turn increases water pollution and weed growth and may have other negative impacts.

Practical test based on reforestation

For previous environmental efforts such as the afforestation of deforested rainforests, the study could have far-reaching consequences: According to Hector and Bagchi's findings, the previous practice - the replanting of a single tree species - falls short. As a next step, the two scientists are reviewing their findings on biodiversity using data from the tropics. Prof. Andrew Hector is one of the senior researchers of the Sabah biodiversity experiment in Malay Borneo, which investigates various re-integration issues of trees. The researchers want to find out which method is more successful in order to restore a fully functioning forest ecosystem: plantations with many different species or monocultures.

(University of Zurich, 12.07.2007 - NPO)