Abstract
Woody plant expansion and infilling into nonwooded rangeland ecosystems have been observed worldwide. Such expansion may lead to declines in herbaceous understory plant communities and increased fuel loads in rangelands. Under the US National Fire Plan, fuel-reduction treatments have been implemented over vast expanses of western forest types to reduce the risk of catastrophic wildfire and restore historical ecosystem structure, function, and diversity. The benefits of fuel-reduction may, however, also carry inherent ecological risk such as promoting non-native species colonization. Here, we compare understory plant community responses to three commonly used fuel-reduction treatments with seeding applications in an upland piñon (Pinus edulis Engelm.)- juniper (Juniperus osteosperma [Torr.] Little) woodland on the Colorado Plateau: 1) mechanical mastication, 2) lop and slash piled then burned (pile burn), and 3) lop and scatter followed by a broadcast burn (broadcast burn). Data were collected pretreatment (2009) and one (2010), two (2011), and six (2015) growing seasons post treatment. We found while understory perennial herbaceous plant cover remained low 1 and 2 yr post treatment, it increased by > 700% in all fuel-reduction treatment plots six growing seasons post treatment. Furthermore, while we observed minor increases in invasive annual grass, Bromus tectorum L. (cheatgrass), colonization in 2010 and 2011, there were substantial increases in B. tectorum cover by 2015. B. tectorum cover varied among treatments with the greatest cover in the unseeded mastication plot at nearly 30%. Seeding applications did not increase overall seed mix species cover but enhanced seed mix species richness and, thus, may have increased resistance to B. tectorum invasion in seeded treatment plots. Our findings offer valuable insights to the ecological consequences of fuel-reduction activities in piñon-juniper woodlands through comparison of common fuel-reduction treatments and seeding applications and highlight differences in understory plant community responses to treatments across short to longer time scales.
| Original language | English |
|---|---|
| Pages (from-to) | 609-620 |
| Number of pages | 12 |
| Journal | Rangeland Ecology and Management |
| Volume | 70 |
| Issue number | 5 |
| DOIs | |
| State | Published - Sep 2017 |
Funding
☆ This research was supported by a US Department of Agriculture National Research Initiative–Managed Ecosystems grant (Proposal 2008-00776) and a National Science Foundation Graduate Research Fellowship (Grant DGE 1144083). ⁎ Correspondence: Nichole N. Barger, Ecology & Evolutionary Biology Dept, University of Colorado, Campus Box 334, Boulder, CO 80309-0334, USA. Tel.: +1 303 483 8239; fax: +1 303 492 8699. E-mail address: [email protected] (N.N. Barger). We would like to thank Mark Miller and Jeff Herrick, who offered critical assistance with field methodologies in the early stages of this project, and Brian Keating, Gabe Bissonette, Paul Plemons, and Jason Kirks from the Canyon Country District of the Utah BLM for their support in the initial setup and maintenance of the experimental site. Additionally, Heidi Guenther assisted with this project as part of her master’s thesis, and Melinda Markin offered critical assistance with field plant identification. Other members of Barger lab field crews also helped greatly with project data collection and processing.
| Funders | Funder number |
|---|---|
| DGE 1144083 | |
| 1144083 | |
| 2008-00776 | |
| Utah Tech University | |
| University of Colorado Colorado Springs | 334, CO 80309-0334, +1 303 492 8699, +1 303 483 8239 |
| National Agriculture and Food Research Organization |
Keywords
- Bromus tectorum
- fuel-reduction
- mastication
- piñon-juniper
- prescribed fire
- seeding