In places where humans use grasslands more intensively, the landscape also becomes more monotonous, ultimately leading to colonisation by the same few species. Ironically enough, this process of homogenisation results in nature no longer being able to provide the ‘services' on which farmers rely, such as soil formation, pollination and pest control.

These findings are the result of a major study, involving over 300 scientists and led by the Technical University of Munich, who published their research in the journal Nature this week. The researchers looked at 4,000 species in 150 grassland habitats over a period of several years, including some of “the most comprehensive ecological field research sites in Europe.” They said theirs is a particularly valuable study, as it looks at the full range of life in a given area, rather than one type of species like birds or wildflowers. The researchers looked at lifeforms along the food chain ranging from single-celled soil organisms to birds.

The Munich study is the first to provide statistical evidence that intensified use led to all grasslands becoming homogeneous and only being able to provide habitats for a few species. This was the case over different geographical regions.

Normally, every meadow is different, and different species are able to find a suitable habitat somewhere. Intensified human land use leads to a smaller number of distinct plant communities on grasslands, which the researchers said is what leads the number of other species to dwindle.

Even moderate land use results in species decline

The study showed declines were associated with even moderate use of habitats. For example, a distinction was made between areas where grass was cut twice or four times a year. "According to our observations, the homogenization of species does not progress proportionally to the intensity of use. Instead, even a moderate management of grassland results in cross-regional communities being reduced to the same, less demanding all-rounders," said Dr Martin M. Gossner, who led the research. "a further increase in the intensity of use simply doesn't have a comparably large effect."

The process of cultivating some species (like certain common grass species with higher fodder value) makes it difficult for others to survive, particularly specialised species, which have complex relationships with other plants or creatures. This effect is called 'biotic homogenization'. "More intensive mowing is the main cause of biotic homogenization," according Professor Eric Allan from the University of Bern, who was senior author of the study.

"What is new here is the finding that the homogenization of species takes place across landscapes, thereby reducing the diversity of species at a regional and national level," said Prof Gossner. "Which is probably a more significant consequence of the intensification of land use than the local loss of species alone."

Less interaction between species changes the ecosystem

The researchers said a decline in species diversity also results in fewer interactions between individual species: "Interactions between plants and their consumers are increasingly weakened by more intensive agricultural usage," Prof Gossner added. "which ultimately causes processes in the ecosystem to shift and change."

According to Gossner, it is only when as many species as possible are able to find the unique habitats they require across large areas that 'ecosystem services', which improve human well-being, can remain intact.