Toward Cost-Effective Restoration: Scaling up Restoration in Ecosystems Degraded by Nonnative Invasive Grass and Ungulates

Table 3.

Baseline Parameters for Labor Time Rates, Labor Costs, and Material Costs Used to Estimate the 3 Yr Cost of Conducting the 0.13 ha Experimental Field Trial within the Wai'anae Kai Forest Reserve, O'ahu, Hawai'i, with the Following Site Conditions: Fully Accessible by Road, ~10 m Elevation Gradient, Fairly Rough and Rocky Terrain, Dominated by an Invasive Grass with Few Scattered Invasive Trees, and Requiring Exclusion of Ungulates via Fence Construction

^a Fence maintenance is assumed to take place twice per year during the second and third years to ensure the integrity of the fence; this is a key consideration in areas with ungulates where ingress can rapidly degrade ecosystems.

^b Clearing maintenance includes clearing of invasive trees and application of herbicide to cut stumps and is assumed to occur in year 2.

^c See Supplemental Table S2 for the calculated herbicide amounts per ha and unit costs for each herbicide used.

^d Plants that died within 1 month of outplanting were replaced (D. viscosa, 29% mortality; T. populnea, 13% mortality; M. sandwicense, 6% mortality; C. subcordata, 38% mortality; P. zeylanica, 15% mortality).

^e Water delivery occurs four times, with 1 liter per plant each time; assumes first watering included at initial planting time, followed by watering once per week for 3 subsequent weeks, then discontinuing thereafter; water is transported to site in work vehicles via plastic tanks.