Mosaic grassland landscapes are the most beneficial in terms of ecosystem services, Swiss study finds

https://phys.org/news/2024-05-mosaic-grassland-landscapes-beneficial-terms.html#google_vignette

by Peter Rüegg, ETH Zurich, MAY 14, 2024

From intensively cultivated meadows to pastures and grassland: a mosaic of different farming practices increases the number of ecosystem services provided by grassland. Credit: Valentin Klaus / ETH Zurich

Grass, clover and herbs are the foundation of Swiss agriculture: Two-thirds of Switzerland’s agricultural land is grassland, much of which is barely suitable for arable farming. Vast areas of grassland are to be found primarily in the foothills of the Alps, in the Alps themselves and in the Jura Mountains. And grassland, in turn, is the basis for Swiss dairy and meat production.

However, in contrast to forests, whose ecosystem services such as timber production, water regulation, climate and recreation are firmly anchored in the public consciousness, grassland is rarely mentioned in terms of the diverse and numerous ecosystem services it provides for people. Yet it plays an even more important role in our food supply.

Grassland is an important carbon store and a haven for biodiversity. It protects against erosion and provides cultural services such as an attractive landscape with grazing animals that delights hikers and tourists. These are just a few examples of the many different benefits or functions that researchers attribute to grassland.

Services and farming practices are tightly connected

But which type of farming is especially well-suited to promoting the services that grassland provides? Researchers at ETH Zurich and the agricultural research institute Agroscope have tackled this question, and the resulting study was recently published in the journal Nature Communications.

In their study, the researchers took a close look at 90 permanent grassland areas on more than 30 farms in the canton of Solothurn in the north of Switzerland. In their study, they considered three grassland farming practices: fertilization (use of fertilizer or unfertilized extensive grassland, so-called biodiversity promotion areas), type of use (meadow or pasture) and farming system (conventional IP Suisse, or organic).

To understand how farming practices influence various ecosystem services, the researchers analyzed the soils and plant communities of all the permanent grassland involved. Because different stakeholder groups prefer different ecosystem services, the researchers split their analysis into three groups for analysis: provisioning services, regulating services and cultural services.

“We’ve observed that farming practices have a significant effect on many ecosystem services,” says Valentin Klaus, co-author of the study and senior scientist at ETH Zurich’s Institute of Agricultural Sciences. “However, there’s no one ‘Swiss army knife’ of farming practice that delivers all ecosystem services.”

More aesthetics, less feed in extensive grassland

The greatest effect on ecosystem services was achieved by extensive farming without fertilizer. This includes, for example, semi-natural pastures and meadows. Such areas greatly enhance the benefits of biodiversity, soil protection and landscape aesthetics. On the other hand, extensive grassland farming significantly reduces the quantity and quality of feed production for farmers.

“This trade-off between feed production and cultural or regulating services is well known. However, we were able to clearly show that extensive grassland farming produces not only biodiversity benefits but also many societally relevant ecosystem services,” Klaus says.

Meadows and pastures are very different

The researchers also found a pronounced effect on ecosystem services when grassland was used as pasture or meadow; in other words, depending on whether the area was predominantly grazed or mowed. But there were still trade-offs between services, Klaus says.

“Pastures are richer in plant species, have a higher quality of animal feed and are beautiful because of the livestock that enrich the landscape. Meadows, on the other hand, produce a higher amount of animal feed, which is important to farmers.”

In addition, the plant communities in meadows are more aesthetic, because unfertilized meadows in particular contain the most flowering herbs.

As for why meadows and pastures provide such different services, Klaus attributes that to how the frequent mowing of meadows favors certain plant species while suppressing others. Meadows are also fertilized more intensively on average than pastures, which has an additional impact on many ecosystem services.

Organic grassland with few benefits

To Klaus’s surprise, organic farming had only a slight positive effect on the grassland’s ecosystem services. “Although we found more symbiotic fungi and a lower risk of nitrogen leaching in such areas, conventionally and organically farmed grassland performs roughly equally well in terms of all ecosystem services,” Klaus says.

He assumes the reason for this weak effect of organic farming to be due to the high similarity in how conventionally and organically farmed grassland is managed. Both can be relatively intensively used with ample fertilizer.

As a result, it’s clear to Klaus that no one type of grassland management provides all ecosystem services at the same time. “To specifically increase and promote grassland ecosystem services in our landscapes, we need a mosaic of the farming practices mentioned; in other words, a combination of areas with and without fertilization as well as meadows and pastures next to each other,” Klaus says.

“As there’s no one ideal type of grassland, we always have to weigh up the pros and cons. We have to ask ourselves: Who’s benefiting the most from what kind of management and in what location?”

If a meadow is used mainly to produce feed, biodiversity and other important services suffer. In extensive unfertilized meadows, meanwhile, farmers must reckon with considerable production losses. “If we want to sustain and facilitate the provision of all ecosystem services, we need a combination of different grassland types at the farm and landscape level,” Klaus says.

The researchers will now use these findings to support farmers, land cooperatives and cantonal authorities. The study also helps to balance the various demands and interests and to achieve a high level of ecosystem service multifunctionality at the landscape level.