The exploitation of farmland is being intensified with a focus to raising yields.
The exploitation of farmland is being intensified with a focus to raising yields. The degree to which yields actually increase as a result and the extent of the simultaneous loss of biological diversity have to date been under-researched factors. An international team of scientists led by the UFZ has now evaluated data from worldwide research in which both yield and biodiversity were examined before and after intensification measures. The findings of this meta-analysis have now been published in the journal Global Change Biology.
Around 80 percent of land area in Europe is used for settlement, agriculture and forestry. In order to increase yields even further than current levels, exploitation is being intensified. Areas are being consolidated in order to cultivate them more efficiently using larger machines. Pesticides and fertilisers are increasingly being used and a larger number of animals being kept on grazing land. "Such measures increase yield but, overall, they also have negative impacts on biodiversity," says UFZ biologist Dr. Michael Beckmann. "This is because even agricultural areas offer fauna and flora a valuable habitat - which is something that is frequently not sufficiently taken into consideration." In addition, previous studies have mostly examined the effects of intensified land use only from one perspective: either with regard to the increase in yield or the loss of biodiversity. "We unfortunately still know far too little about the relationship between the two and what price nature ultimately has to pay for increases in yield," says Beckmann. In the recent study, the team of scientists aimed to address this knowledge gap.
To this end, the researchers sifted through some 10,000 topically relevant studies looking for those that collected measurement data for yield and biodiversity both before and after intensification measures. "The majority of the studies fell through the net in this respect. A mere 115 studies actually measured both parameters for the same areas, making them relevant for our purposes," says Beckmann. The 449 agricultural areas examined in these studies are, however, distributed around the globe, are located in different climatic zones and the time they have been in use varies greatly. To be able to use these studies for their analysis, the researchers developed a mathematical model that takes account of these differences and renders the data comparable. They then summarised the respective yield increases and biodiversity losses. "We were able to demonstrate that, on average, intensification of land use gave rise to an increase in yield of 20 percent but this is, at the same time, associated with a nine percent loss of species," says Beckmann.
Read more at Helmholtz Centre for Environmental Research - UFZ
Image: To determine the responses of species richness and yield to conventional land-use intensification, we conducted a global meta-analysis. Across all production systems (food, fodder, wood), intensification increases yield (+20.3% / red arrow), but also leads to a loss of species (-8.9% / blue arrow). (Credit: UFZ)