Context

Habitat loss and land use homogenization cause a decline in biodiversity in agricultural landscapes. Plant community in small landscape features which remain post-land use change (small natural or semi-natural habitats) may overlap with plant community in semi-natural grasslands and buffer species decline in landscapes where little or no grassland remains.

Objectives

We explored if small natural or semi-natural habitats buffer the decline of semi-natural grasslands when it comes to number of plant species with fleshy fruits and a variety of food resources for pollinators, throughout the vegetation season.

Methods

We surveyed plants in grasslands and small habitats in five agricultural landscapes; 13 semi-natural grasslands (area 7016–85547 m²), 50 forest edges (area 145–1850 m²) and 130 midfield islets (area 17–4788 m²). We than explored how the richness of plants and plant traits (fleshy fruits, flower morphology and flowering period) are related to habitat type, landscape and canopy cover in the focal habitats.

Results

Semi-natural grasslands and midfield islets had the highest richness of plant species and flower shapes compared to forest edges. In addition, midfield islets harboured more species with fleshy fruits. When comparing the plant community on midfield islets with the plant community in forest edges, midfield islets and semi-natural grasslands contributed equally with number of blooming plant species during the seasons. Landscapes that were less intensively used (less crop fields) provided food resources for a higher diversity of pollinators compares to less open landscapes, as there was a higher richness of plant species and flower morphologies. Forest edges were not as valuable to pollinators and frugivores as midfield islets.

Conclusions

Small natural or semi-natural habitats can provide food resources to pollinators and frugivores at the landscape scale in fragmented landscapes. More crop field in the landscape had a negative impact on the richness of plants and flower morphologies in the habitats. Forest borders may not be as species rich as midfield islets but are still a part of the green infrastructure in the landscape. Particularly, in intensively managed landscapes, small natural habitats can contribute to landscape plant diversity and have a complementary function to each other, but this does not fully compensate for the loss of semi-natural grasslands.