Seed mix design and floral resources drive multi-trophic interactions in prairie restoration

Ecological restoration often targets plant community recovery, but
restoration success may depend on the recovery of a complex web of biotic
interactions to maintain biodiversity and promote ecosystem services.
Specifically, management that drives resource availability, such as
seeding richness and provenance, may alter species interactions across
multiple trophic levels. Using experimentally seeded prairies, we examine
three key groups – plants, pollinators, and goldenrod crab spiders
(Misumena vatia, predators of pollinators) – to understand the effects of
species richness and admixture seed sourcing of restoration seed mixtures
on multi-trophic interactions. Working with prairie plants, we
experimentally manipulated seed mix richness and the number of seed source
regions (single-source region or admixture seed sourcing). In each
experimental prairie, we surveyed floral abundance and richness,
pollinator visitation, and plant-M. vatia interactions. A high-richness
seed mix increased floral abundance when seeds were sourced from a single
geographic region, and floral abundance strongly increased pollinator
visitation, M. vatia abundance, and prey capture. Seeding richness and
admixture seed sourcing of the seed mixture did not affect floral species
richness, but floral species richness increased pollinator visitation.
Pollinators interacted with different floral communities across seeding
treatments, indicating a shift in visited floral species with restoration
practices. Synthesis and applications. Long-term success in prairie
restoration requires the restoration of plant-arthropod interactions. We
provide evidence that seed mix richness and admixture seed sourcing affect
arthropod floral associations, but effective restoration of
plant-arthropod interactions should consider total floral resource
availability. Incorporating a food web perspective in restoration will
strengthen approaches to whole ecosystem restoration.