Low-Tech Seed Enhancement Technology Could Improve Seedling Establishment of Longleaf Pine Understory Perennial Forbs

Reintroducing native plants into restoration and revegetation projects could increase plant species diversity, increase floral resources for pollinators, and positively affect trophic-level interactions in the community. Direct seeding in restoration projects has generally had poor success rates due to biotic and abiotic factors, leading to significant seed wastage of the already insufficient native seed supply. Seed balls (aka seed aggregates, seed bombs, and seed pellets) are a low-cost, low-tech seed enhancement technology. The seeds are encased in a soil and clay matrix, providing good seed-soil contact, controlling seed planting depth, nutrients, and protection from seed predators. We conducted a greenhouse and field experiment testing 5.0 g seed ball shape (round vs disk) and cayenne pepper (+/-) on seed germination and seedling establishment of native perennial understory species of the longleaf pine ecosystem. Repeated measures two-way ANOVA of seedling counts indicate significant species-specific seed ball shape, cayenne pepper, and interactions for the greenhouse and field experiments. Significantly more seedlings were established from disk vs. round seed balls, and considerably fewer seedlings were found in seed balls with cayenne pepper under greenhouse conditions. The field experiments showed significant shape, cayenne pepper, or interactions for seven seed sources, which often differed from greenhouse results. While greenhouse studies are useful for experimentation, field study results likely represent a better estimate of seed enhancement methods on seedling recruitment in the longleaf pine ecosystem. These findings suggest that seed ball enhancement methods could be a viable tool for improving seedling establishment to restore longleaf pine ecosystems.