Document Type

Report

Publication Date

12-31-2010

First page number:

1

Last page number:

82

Abstract

Species selection can make the difference between successful revegetation projects and costly failures. Candidate native species for revegetating burned arid lands in the southwestern United States must meet at least two criteria. These species must: (1) be competitive in postfire environments typically dominated by exotic grasses, and (2) be able to become established reliably by seeding or planting. In response to Manager’s Request Task 3 (reestablishment of native vegetation after fires on arid lands) in the 2006 JFS announcement for proposals, this research tackled the problem of selecting native species with the greatest chance of revegetation success by conducting synergistic experiments and studies in the Mojave Desert. In the first part of the project, we established experimental native plant communities and monocultures of 12 native species ranging from native early successional forbs to late-successional shrubs. We introduced seeds of the invasive, exotic annual grasses Bromus rubens (red brome) and Schismus spp. (Mediterranean grass) and also manipulated soil nitrogen. We found that an early successional forb community reduced biomass of the exotic grasses by 8- to 33-fold compared to controls (no native vegetation) and below the biomass fire threshold for Mojave Desert ecosystems. Some of these early successional forbs, such as Sphaeralcea ambigua (desert globemallow) also performed best in planting trials in the second part of the project, and are recommended species for revegetating desert wildfires. Further work is needed, however, to increase seeding success. In a mensurational field study as the third part of the project, we found that cover of exotic grasses was generally lowest below native perennial species that do not readily form fertile islands, consistent with parts 1 and 2 of the project. In three-value added supplemental parts to the project, we (1) conducted a greenhouse competition experiment of target native species with Bromus rubens, (2) conducted a seed fate study with the native species of the project to determine post-seeding seed fates since establishment through seeding on the burn was poor, and (3) a literature synthesis of post-fire responses of native species in the Mojave-Sonoran Deserts, which included the species of this experiment. Collectively, this project’s findings have helped identify which native species (e.g., Sphaeralcea ambigua) are expected to be most successful for post-fire revegetation efforts and suggest that there is high potential for identifying native species that compete with, and reduce, the exotic annual grasses that fuel fires. These findings are unique, as previous research has focused on the effects of the exotic grasses on native species, and not vice versa.

Keywords

Bromus rubens; Endemic plants; Fire ecology; Grasses; Invasive plants; Mediterranean grass; Nevada – Goodsprings; Nurseries (Horticulture); Plant communities; Plant competition; Red brome; Revegetation; Schismus; United States – Lake Mead National Recreation Area

Disciplines

Environmental Indicators and Impact Assessment | Environmental Monitoring | Natural Resources and Conservation | Natural Resources Management and Policy | Plant Biology | Plant Sciences | Systems Biology | Weed Science

Language

English

Comments

This research was sponsored by the Joint Fire Science Program, executed through a cooperative agreement between the National Park Service (Lake Mead National Recreation Area) and the University of Nevada Las Vegas.

JFSP Project Number 07-1-3-24

Journal articles have been redacted due to copyright concerns.