WHAT THE EVIDENCE SAYS
An Iowa experiment established prairie mixes across 11 grass-to-forb seed ratios and followed them for four years. Plant richness, flower production, volunteer biomass and pollinator and butterfly visitation showed nonlinear responses, with several outcomes strongest at intermediate grass-to-forb ratios. Net primary productivity did not show a significant relationship with the seed ratio.
WHY IT MATTERS / OUR READ
Seed-mix composition is a design variable, not just a species list. An intermediate functional balance may support multiple restoration objectives at once rather than forcing managers to choose between floral resources, resistance to unwanted colonists and standing productivity.
CAVEATS / UNCERTAINTY
The results come from one experimental restoration setting over four years. Optimal ratios will depend on species identities, soils, climate and management, and a null productivity response does not guarantee equal forage or habitat function.
SOURCE
Ecological Applications · Original evidence
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