Record conversion of native ecosystems to intensive agriculture has prompted parallel calls for increased forest restoration and regenerative agriculture. Hybrid approaches to restoration that include provisioning services can achieve both goals; however, the evidence base for effective hybrid restoration interventions is limited. Therefore, we established a long-term experiment with a community-based, non-profit farm in He‘eia, Hawai‘i to better understand the social-ecological outcomes of agroforestry restoration. We asked, how do species mixes designed for erosion control and early successional facilitation, through a co-design, functional trait approach, affect 1) plant survival, plant growth, and understory cover and 2) sediment retention? 3) How do cultural services, yields, and costs vary between species mixes? We started the experiment using before-after-control-impact design on fallow agricultural land with 100% non-native plant cover. We selectively thinned the canopy, cleared the understory, and then planted, tagged, and monitored over 1000 individuals of 20 species in five 12m x 15m plots and thirty 2m x 2m subplots per restoration scenario. We monitored the plots pre-clearing, at planting, and at six-months and one-year post-planting. We will measure soil root length density in subplots as a proxy for erosion control services at two years post-planting.
Results/Conclusions
Plots planted with a species mix selected for early successional facilitation had significantly faster growth rates than plots with a species mix selected for erosion control services at six-months and one-year post-planting. Cover of non-native species was significantly higher in the erosion control plots and composition of non-native species varied across the two species mixes. However, survival of trees and shrubs was the same in both erosion control and early succession treatments. Both scenarios produced plant material for harvest within the first year of planting. Over 700 community members and students volunteered at the experimental restoration in the first year, which also produced intangible benefits including enhanced connection to place.