Just graze it! Biodiversity, nectar and forage resources in cultural landscapes grazed by different livestock species

The Nordhordland UNESCO Biosphere Reserve encompasses a heterogeneous landscape which provides numerous ecosystem services. Semi-natural grasslands provide forage for traditionally managed livestock and are important sources of nectar and pollen for pollinators. However, these services are not evenly distributed due to different biotic and abiotic constraints of the fjord landscape, which stretches from flat coastal areas to steep hills and mountains inland. We studied how geographic location and grazing livestock type affect the plant species richness, plant functional group composition, nectar and forage resources of these grasslands. We recorded plant species percentage cover in 30 fields in the Nordhordland Biosphere Reserve grazed by sheep, goats or cattle, and from these data we calculated indicator values for forage and nectar resource using species index values from existing trait databases. Sites grazed by cattle had significantly different plant functional group compositions than sites grazed by sheep or goats, independent of geographical location. Forage resource indicator values were lower at coastal sites grazed by sheep. We found a weak but significant positive correlation between nectar resource indicator value and plant species richness, as well as between nectar and forage resource indicator values. Type of livestock and geographical location are not the only factors influencing provisioning services in semi-natural grasslands. Nonetheless, traditional grazing maintains ecosystem service delivery even in low-productive coastal areas. Forage resource, nectar provision and plant species richness appear to be bundled, providing clear guidance for managing ecosystem services in Nordhordland UNESCO Biosphere Reserve's valuable cultural landscapes.