Abstract
Aerial seed broadcast by aircraft is a promising approach to ecosystem restoration and land rehabilitation over large, remote, and inaccessible areas. Aerial seeding has been used internationally for forest and grassland restoration since the 1930s but is not commonly applied to ecosystem restoration in New Zealand. Advances in unmanned aerial vehicle (UAV) technologies have created opportunities to test inexpensive aerial seed broadcast at small spatial scales (< 20ha), and a small number of UAV aerial seeding trials are underway in New Zealand. However, successful aerial seeding depends on cost-effective methods for collecting, processing and storing New Zealand native plant seeds. Seed encapsulation methods are also needed to help disperse and convey aerially broadcast seed to the ground, provide a controlled microenvironment to increase seed resilience to environmental stressors, and enhance early growth and establishment success. In this study, we trialled simple seed collection, processing, and storage methods, and measured the germinability of seed encapsulated in seed balls comprising clay, humate, vermiculite, and/or sphagnum moss. We focused on 11 common New Zealand native plant species that play pivotal roles in the early stages of native vegetation succession and produce large volumes of readily harvestable seed. Seed collection, cleaning, and storage methods were efficient and mean seed viability was high (> 85%). Seed encapsulation in seed balls generally reduced germinability and damaged large soft seeds, but ∼20% of seed balls produced seedlings suggesting that with refinement aerial seed ball broadcast could be used to establish native plants at large spatial scales. Further research is needed to: optimise seed storage methods for a wider range of ecologically significant native plants, identify factors that induce or reverse seed dormancy, ARTICLE HISTORY