Completed evidence syntheses
Here you can read more about the systematic evidence syntheses that Formas has carried out so far. The most recently completed synthesis is at the top of the list.
Effects of converting cropland to grassland on greenhouse gas emissions from peat and organic-rich soils
Organic soils accumulate a high proportion of organic matter during the soil formation process. Farmlands with such soils have often been created by draining peatlands or by lake subsidence. Unfortunately, after draining, these soils start leaking carbon dioxide and nitrous oxide, which are potent greenhouse gases. We have investigated what research says about the effects of converting cropland to grassland on greenhouse gas emissions from organic soils.
What is the effect on biodiversity in semi-natural pastures of giving the grazers access to additional nutrient sources?
Semi-natural pastures are among the most species-rich habitats in the world. This is partly because these lands are relatively nutrient-poor. To qualify for environmental subsidies for semi-natural pastures, their management must fulfil certain conditions. For example, on semi-natural pastures judged to be particularly valuable, supplementary feeding is not permitted. The aim is to protect biodiversity. However, farmers report that bans on supplementary feeding can create problems, in terms of productivity as well as animal welfare. We have investigated what research says about the effect on biodiversity in semi-natural pastures of giving the grazers access to additional nutrient sources.
Effects of mosquito control with Bti on aquatic and terrestrial ecosystems
In some places in Sweden, mass outbreaks of mosquitoes are controlled with the biological control agent Bti, a bacterium. Compared to many chemical insecticides, Bti has limited or no direct impacts on organisms other than the insects it is intended to control. But this does not mean that spreading Bti in the environment is completely risk-free, and its use can be particularly problematic in conservation areas. We have investigated what research says about the effects of mosquito control with Bti on ecosystems.
Soil retention of phosphorus from on-site wastewater treatment systems
There are about one million on-site wastewater treatment systems in Sweden. Most of them are soil-based. This means that the wastewater is discharged into the ground after the sludge has been removed. The phosphorus in wastewater may cause eutrophication of lakes, rivers and seas. Hence, in certain cases, a high phosphorus removal rate of the facilities is required by Swedish authorities, and property owners may have to take costly measures to meet these requirements. However, as wastewater flows from the on-site wastewater treatment system to the recipient surface water, various natural processes cause phosphorus transport to be inhibited. This is called soil retention. The effectiveness of soil retention is important while determining what requirement that should be placed on individual on-site wastewater treatment systems in terms of phosphorus removal. We have mapped the existing evidence on soil retention of phosphorus from on-site wastewater treatment systems.
Effects on groundwater storage of restoring, constructing or draining wetlands
Many wetlands were previously drained for agricultural or forestry purposes. Today, some wetlands are being restored to bring back the benefits that they can provide. Restoration is usually done by filling in the ditches, which causes the groundwater level to rise. However, the magnitude of the effects has been unclear, as well as whether also the groundwater outside the wetland itself is affected. We have investigated what research says about the effects on groundwater storage of restoring, constructing or draining wetlands.
Swedish municipal wastewater and its impact on aquatic organisms
Treated municipal wastewater is discharged into nearby lakes, rivers and seas. Despite treatment, potentially harmful substances remain in the wastewater. The question is how these substances affect the organisms living in the recipient surface waters, and whether more advanced wastewater treatment is necessary. We have investigated what research says about the impact of Swedish wastewater on aquatic organisms.
Effects of crop rotations on organic carbon in agricultural fields
Long-term and repeated cultivation of the same crop can, in many cases, deplete the soil of organic carbon, leading to reduced fertility. In addition, some of the carbon can be converted into carbon dioxide and contribute to global warming. Rotating specific crops on the same field can reduce soil carbon losses and may in some cases even increase soil carbon stocks. We have investigated what research says about the impact of selected crop rotations on soil organic carbon.