RestoreNet: An emerging restoration network to promote dryland plant and ecosystem recovery

Seth M. Munson, Hannah L. Farrell, Katherine M. Laushman and Molly L. McCormick, Southwest Biological Science Center, U.S. Geological Survey, Flagstaff, AZ, Caroline A. Havrilla, Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, Kathleen R. Balazs and Bradley J. Butterfield, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, Elise S. Gornish, School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, Akasha M. Faist, Department of Animal and Range Sciences, New Mexico State University, Las Cruces, NM, Loralee Larios, Department of Botany and Plant Sciences, University of California-Riverside, Riverside, CA, Helen Rowe, School of Earth Sustainability, Northern Arizona University, Flagstaff, AZ, Michael C. Duniway and Sasha C. Reed, Southwest Biological Science Center, U.S. Geological Survey, Moab, UT

Background/Question/Methods:
Despite widespread demand for dryland restoration, there is often sparse information available to help reestablish native vegetation and stabilize soils at degraded sites. Restoration treatments that help overcome barriers of suitable plant material, low and variable rainfall, high temperatures, infertile soils, and invasive species can enhance plant and ecosystem recovery. RestoreNet is a restoration field trial network that systematically tests restoration treatments across environmental gradients in the southwestern US. Our objectives were to determine: 1) how different seeded and greenhouse-grown plant species (warm- and cool-adapted) performed in combination with treatments to increase water retention (pits - depressions, wood mulch, artificial nurse plants), and 2) how this performance was shaped by spatial and temporal environmental variation.

Results/Conclusions:
Digging pits and applying wood mulch treatments increased total seedling density, with pits promoting the highest seeded species recruitment while limiting unseeded non-native species establishment. Seeding increased total seedling density regardless of seed mix type, but seed mixes with cooler-adapted species promoted greater seeded species density relative to warmer adapted mixes. Seedling recruitment was tied to site, time, and environmental context. The positive effect of high precipitation was greatest in the weeks immediately following seeding and in the first-year treatments were implemented. Outplanting greenhouse grown plants led to higher survival than seeding, and survival of these plants was driven by traits that allowed for rapid water acquisition during favorable periods at warmer sites. RestoreNet represents a growing opportunity to compare restoration effectiveness across sites and infer appropriate treatments at new sites along environmental gradients before suitable methods are needed following large-scale disturbance.