Restorationists generally assume that by definition a novel ecosystem cannot reasonably be restored to historic site condition. Inclusion of culturally significant resources in the plant pallet is not part of project goals on highly disturbed sites. At the Bushy Lake Project on the American River, restoration is occurring in a highly disturbed riparian habitat prone to frequent human-caused wildfires. Restoration project goals are to create a fire-resilient understory combining modern restoration techniques with the traditional ecological knowledge of local Native American tribes. White root (Carex barbarae) and creeping wild rye (Leymus triticoides) are being tested in the restoration effort as these plant species are fire resilient, drought tolerant, and valuable cultural resources. We concluded three experiments to determine whether: 1) planting density made a difference in species survival or biomass production; 2) 2) whether planting monotypic stands of creeping wildrye (Leymus triticoides), Santa Barbara sedge (Carex barbarae) or a mixture of the two species was most effective; and 3) whether plant survival increased within an herbicide treated plots or companion plantings facilitated through inter-planting within plots of native species. Student high impact learning, citizen science and community service were intrinsic to the restoration planning, implementation, monitoring and adaptive management.
Results/Conclusions
Our results suggest that using fire resilient understory species adapted to fire management provides both ecological and cultural services at the restoration site. Experimental data indicated that density experiments at 1’ and 0.5’ spacing resulted in no significant difference between survival and relative cover. Therefore, low-density plantings were more cost-effective and less time-intensive than high-density plantings. Second, in a species composition treatment of monotypic Elymus triticoides, monotypic Carex barbarae, and mixed plots we determined that Elymus triticoides had higher above-ground absolute cover in both homogenous and mixed planting treatments than Carex barbarae (p ≤ 0.032, α=0.05). In 2016, we planted monotypic stands at low density designed to evaluate differences between herbicide treatment and companion planting within stands of native species. Facilitated planting within plots of native species Artemisia douglasiana, Euthamia occidentalis and Rubus ursinus had significantly higher survival rates than the Roundup herbicide treatment ( p ≤ 0 .002, α = .05). Our results suggest that to restore understory species in a riparian setting, lower densities and monotypic planting optimize restoration efforts. In addition, survival is optimized by facilitated planting within remnant native understory, which provide shade and cooler temperatures, reducing stress on plants and potentially increased available soil moisture.