The worldwide decrease of amphibians is well documented. Currently, every third amphibian species is assumed to be endangered at the global level, one of them being the red belly toad (Bombina bombina), which is short listed in several red lists across Europe. Among other reasons, such as climate change, agriculture is seen as the main cause of endangerment.
To complete their life cycle amphibians need two types of habitats: aquatic habitats like small water bodies and lakes, where the reproduction takes place, and terrestrial habitats like scrub areas or hedges etc. for hibernation. To change between the habitat types the amphibians usually have to cross agricultural areas. Two main migration periods are observed: one in spring and one in late summer. Within these time periods the amphibians are at risk to get harmed or killed by the different agricultural operations taking place on the plots, such as ploughing, fertilisation, spraying, cutting and harvesting.

To assess different crop production practices regarding their impacts on amphibians, respectively, the red belly toad, the following assessment parameters were taken into account:

1. the time- and operation-related risk potential of single operations to disturb, harm or kill animals during their migration periods,
2. the risk associated to the application of mineral nitrogen fertilisers (especially calcium ammonium nitrate) due to toxicity and
3. the number of pesticide sprayings which are linked to direct toxic effects, particularly in regard to the aquatic life stadiums that show a high sensitivity to pesticides, as well as indirect effects, such as the diminishment of food resources like insects.

All alternative production practices of all crops defined for the model were assessed by their goal achievement levels using a fuzzy logic tool with the optimum being a zero risk for the amphibian species to get harmed or negatively affected by agricultural activities.

Best results were calculated for permanent and rotational set aside. Grassland, alfalfa and grass clover mixtures for forage use scored well, too. The worst ratings were given to sugar beets.