PARENT SESSION
Oral Session #73: Restoration Using Fire.
Presiding: D. Falk
Thursday, August 8. 9:00 AM to 11:30 AM. Mohave Meeting Room, TCC.
Monitoring understory response to ecological restoration treatments in southwestern forests requires multiple years of data.
DANIELS, MARK*,1, SPRINGER, JUDITH1, KORB, JULIE1, FULE, PETER1, COVINGTON, W.1, 1 Northern Arizona University, Flagstaff, Arizona
ABSTRACT- The Ecological Restoration Institute has conducted large-scale experimental restoration treatments involving thinning small-diameter trees and instituting controlled burns at several sites in the ponderosa pine forests of northern Arizona since 1998. At each site permanent monitoring plots were installed prior to restoration treatments in treated and control units, and understory vegetation data were collected annually following treatment utilizing point line-intercept transects and 500 m2 presence/absence plots to measure species frequency and richness. In early 2002 we assessed the initial response of understory vegetation by comparing the trajectories of vegetation community change in treated vs. control units. Non-metric multi-dimensional scaling (NMDS) was utilized to ordinate and graphically display the state of the understory communities at each site, using successional vectors to show change in permanent plots over time. With the two or three years of post-treatment data available at these sites, little or no differentiation was seen in trajectory paths between treated and control units. Instead, year-to-year variation (presumably due to climatic factors) accounted for most of the observed change, with treated and control units following more-or-less parallel paths through ordination space over time. From these data, we recommend that researchers working in semi-arid ecosystems not make assumptions prematurely about the success or failure of restoration treatments on understory vegetation communities. Many years of monitoring may be required to show the response of understory vegetation communities to intensive restoration treatments.
KEY WORDS: restoration, monitoring, vegetation, ordination