Bartual A, Sutter L., Bocci G., Moonen A.-C., Cresswell J., Entling M., Giffard B., Jacot-Ammann K., Jeanneret P., Holland J., Pfister S., Pinter O., Veromann E., Winkler K., Albrecht M.
The potential of different semi-natural habitats to sustain pollinators and natural enemies in European agri-cultural landscapes.
Semi-natural habitats (SNH) are vital to sustain pollinators and natural enemies, and the ecosystem services they
provide in agroecosystems. However, little is known about the relative importance of different SNH types and
their vegetation traits for pollinators and natural enemies. Yet, such knowledge is essential for effective habitat
management to promote both functional arthropod groups and associated multiple ecosystem services. We
quantified vegetation traits and abundances of pollinators (bees) and natural enemies (predatory flies and
parasitic wasps) in 217 SNH differing in type (woody or herbaceous) and shape (linear or areal habitats), for
edge and interior locations within each SNH patch with respect to adjacent crops, across 62 agricultural landscapes
in four European countries. Pollinators and natural enemies responded distinctively to major SNH types
and within-habitat location of SNH: abundance of natural enemies (predatory flies and parasitic wasps) was
higher along woody habitat edges than herbaceous SNH or the interior of woody habitats. In contrast, bee
abundances, especially of honey bees, were generally higher in areal herbaceous compared to woody SNH.
Abundances of both wild bees and managed honey bees were lowest for the interior sampling location in areal
woody habitats. These findings reflected divergent key vegetation traits driving pollinator and natural enemy
abundances across SNH: bee pollinators increased with herbaceous plant cover and were well predicted by SNH
type and the floral abundance of identified key plant trait groups. In contrast, floral abundances of these plant
groups were poor predictors of the studied natural enemies, which were better predicted by SNH type and
sampling location within SNH. Our findings stress the need to move beyond the simplistic pooling of SNH types
and highlight the importance of considering their vegetation traits to more reliably predict pollinators and
natural enemies in agroecosystems. They suggest that the floral abundance of key groups of flowering plants is
crucial for habitat management to promote bee pollinators, while vegetation-structural traits appear more important
for predatory flies and parasitoids. The distinct importance of different SNH types and associated vegetation
traits for pollinators and natural enemies calls for agroecosystem management ensuring diverse SNH
with complementary vegetation traits to concomitantly foster pollination and pest control services.