The more it swarms, crawls and flies, the better for people who benefit from the varied services provided by nature, according to the finding of a study by more than 60 researchers from a number of universities, including the Institute of Plant Sciences at the University of Bern, Switzerland, and the Senckenberg Biodiversity & Climate Research Centre in Germany.

A meadow in Thuringia — one of the 150 grasslands where research was carried out. Alongside grass for silage and hay these grasslands provide us with many other important ecosystem services. A high diversity of plants and many other organisms helps to sustain these services. Credit: WWU/Klaus Vakentin.

A diverse ecosystem populated by many species from all levels of the food chain provides higher levels of ecosystem services, the team reported Aug. 17 in Nature. Even rather unpopular insects and invisible soil-dwelling organisms are important in maintaining a wide range of ecosystem services. The results underline the necessity of maintaining species-rich ecosystems for the good of humanity.

Grasslands provide many important services for people, including food production, alongside supporting services such as soil development, regulating services such as pest control and climate regulation and cultural services such as the use of the grassland for recreation.

Grasslands are also a complex ecosystem containing many species belonging to different levels in the food chain — so-called "trophic levels."

People are causing declines in biodiversity for many of these groups, and evidence from experiments on plants suggests that this might threaten ecosystem services. However, studies had not looked at diversity at many trophic levels at the same time, according to the announcement.

Therefore, the research team, led by Dr. Santiago Soliveres from the University of Bern, studied all groups in a grassland food chain for the first time. They collected data on a total of 4,600 species of animal and plant from nine trophic groups, including often-neglected ones such as microorganisms in the soil and insects that live in the soil or on the plants. The data were collected as part of a program supported by Deutsche Forschungsgemeinschaft in 150 grasslands across Germany. This "Biodiversity Exploratories" program constitutes the most extensive ecological sampling in Europe.

Biodiversity required

“Working out how different groups affect ecosystem services is like trying to solve a very complicated puzzle, but with our extensive data, we are able to put together a coherent picture of how important individual groups are for 14 ecosystem services,” Soliveres said. "Each ecosystem service is dependent on at least three groups, and the higher the number of species within the group, the more reliably the ecosystem service is provided. In addition, each individual group influences at least one ecosystem service."

Dr. Eric Allan from the University of Bern added, “Many different groups are important for providing essential ecosystem services. In order for nature to continue ‘working’ reliably for us, we, therefore, need to protect biodiversity at all levels in the food chain, including in often-overlooked groups such as microbes or insects. This is especially important for regulating processes and cultural services.”

Microbes and insects are overlooked and are not generally considered in conservation. However, this study found that it's time for such a view to change, because many insects and soil organisms play a central role, alongside plants, in supplying the services people depend on.

“Plants supply biomass, which forms the beginning of the food chain, but insects act as pollinators, and soil organisms increase soil fertility through the breakdown and retention of chemical elements such as phosphorus. The more different species there are, particularly within these three groups, the more positive the effect on all services,” Soliveres explained.

Often, fertilizer is applied to the soil in order to increase soil fertility and, thus, increase plant growth. Fertilizers help in the short term, but if biodiversity is reduced, then the downsides outweigh this. Maintaining high levels of biodiversity throughout the food chain is more economical and wiser in the long term than destroying it for short-term gains.

Importance underestimated

Markus Fischer from the Institute of Plant Science at the University of Bern and head of the Biodiversity Exploratories project, explained, “If biodiversity is rapidly destroyed, what consequences does this have for humans? What courses of action are available? Thus far, there has been insufficient research into this, which is one of the reasons why the IPBES (Intergovernmental Science-Policy Platform on Biodiversity & Ecosystem Services) was founded."

This study also shows that the importance of biological diversity has been underestimated because previous research focused only on individual trophic groups. “Our extensive research program demonstrates how important it is to study the broader context and that there is a need for action to protect ecosystems,” Fischer said.