Floral trait functional diversity is related to soil characteristics and positively influences pollination function in semi-natural grasslands

•We analysed relations between grassland variables and floral functional diversity.•We studied consequences of these relations on plant-pollinator interaction frequency.•Floral functional diversity was negatively related to total soil phosphorus content.•Interaction frequency was positively related to total floral functional diversity.•Interaction frequency was positively related to diversity of nectar sugar production.