Agriculture is transforming entire ecosystems

A research team has investigated the effects of agricultural grassland use on biological communities. Their study, recently published In the journal Nature Communicationsshows for the first time that actions such as fertilization and cutting affect organisms at all levels of ecosystems and throughout food chains, thereby accelerating the entire system.

Everywhere in nature, organisms adapt to their habitat conditions. Depending on the environment, they rely on fast or slow growth, large or small body size strategies, and they reproduce at different rates. Two factors are decisive in this regard: the availability of nutrients, and the extent of “disturbing” external influences.

“You can think of it as the fable of the hare and the tortoise—except that depending on the environment, the ‘race’ is sometimes ‘won’ by organisms with one strategy and sometimes by those following another,” Prof. The doctor explains. Peter Manning from the Senckenberg Biodiversity and Climate Research Center in Frankfurt, who led the research team with Dr. Margot Neret from the University of Grenoble-Alpes.

“In undisturbed, nutrient-poor ecosystems, slow organisms—’turtles’—predominate. They use their resources more sparingly, grow more leisurely, and reproduce less frequently, but they usually But grow larger and live longer. Under high nutrient-rich conditions, on the other hand, the faster ‘rabbits’ rise to the top—these organisms are smaller and have a higher turnover of nutrients, less With long life expectancy and high reproductive rate.

“In our study, we were able to demonstrate for the first time that intensive agricultural use of grasslands leads to the presence of ‘rabbits’ at all levels of the ecosystem.”

In their study, the researchers analyzed a wealth of data collected as part of a biodiversity exploration project for the Swabian Alb, the Heinach region of central Germany, and the Brandenburg-Schwarzweiss Biosphere Reserve.

“We examined organisms from all sectors of the sampled ecosystem – from microorganisms in the soil to plants, butterflies and other arthropods, birds and bats,” reports Neret, formerly a research assistant at SBiK-F.

“We were able to determine the effects of agricultural management in terms of fertilization, mowing and grazing for almost all organisms. Compared to unmanaged, Natural areasOrganisms that follow a ‘grow fast, die young’ strategy dominate here – in these cases the entire ecosystem was ‘fast’.

“This is due in part to a direct effect of altered resources and environmental conditions and in part to indirect, cascading effects within food chains. Depending on the intensity of use, the ecosystems studied are ‘slow’. distributed along an axis from to ‘fast’. ‘Only in a few large animals and soil organisms were we unable to observe this effect.’

As the study shows, agricultural use also affects a variety of ecosystem functions performed by organisms, which are “intensified” by the intensity of cultivation. “In fast ecosystems, processes such as decomposition, biomass production, or Nutrient cyclingFor example, also happens more quickly,” explains Manning.

“From a human perspective, such systems are initially more agriculturally productive and provide higher yields. However, this can reduce their capacity to store carbon. At the same time, food Additions lead to higher levels of pollution. Undisturbed, natural ecosystems, on the other hand, tend to have higher levels of biodiversity and are more resilient. They are also more prone to climate-related increases in extreme weather events. plays a role.”

“Because of more and more intensive agriculture, we’re probably accelerating ecosystems around the world,” Neret added. It takes a lot of time to return to the original ‘slow’ state. Thus we are losing more and more slow systems with their specific organisms and functions.