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Wildfires and Invasive Plants . Carl E. Bell Regional Advisor – Invasive Plants University of California Cooperative Extension San Diego, CA. Fire Photo Project. Started in December 2003 32 continuing quarterly photo points through 2008
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Wildfires and Invasive Plants Carl E. Bell Regional Advisor – Invasive Plants University of California Cooperative Extension San Diego, CA
Fire Photo Project • Started in December 2003 • 32 continuing quarterly photo points through 2008 • Recovery slow in most cases, especially at lower elevations (CSS) • Winter 04, 06, 07 very dry • Winter 05 wet • Winter 08 winter rains were timely, but not heavy • Some points burned again in 2007 • Many carried by invasive annual grasses
Active Management of invasive plants. • Control of invasive annual grasses and forbs • Techniques could include; • Controlled burns • Mowing • Grazing • Herbicides • Combinations of any or all above (IVM)
Barnett Ranch: Sites B & C • Data collected • Plant and soil cover in fixed quadrats once per year • Time required to spray herbicide • Amount of herbicide used per treatment
Barnett Ranch: Sites B & C • Herbicide treatment responses 2007 (after replanting): • Site B: • Exotic forbs cover 5% vs 32% for UTC • Exotic grass cover 1% vs 13% for UTC • Native forb (17 species) cover 18% vs 2% for UTC • Site C: • Exotic forb cover 11% vs 4% for UTC • Exotic grass cover 21% vs 90% for UTC • Native forb cover 26% vs 2% for UTC
Barnett Ranch: Sites B & C: Herbicide application data: • Broadcast application to emerged weeds; before emergence of native annuals • 3/26/06; 2/15/07; 1/22/08 • 2 qts/A Roundup-Pro; 15 minutes/A to spray (4 acre/hr) • Spot spray application to weeds that emerged after the broadcast spray • 5/25/2006; 5/2/2007; 4/10/2008 • 3 to 9 hr/A • ca 0.6 qt of Roundup/A
Nassella pulchra tolerance to herbicides – San Diego and Los Angeles Counties • To evaluate purple needlegrass tolerance to postemergence herbicides • Cooperators and Co-PI’s; • Marti Witter, Jennifer Carlson, Joseph Algiers, NPS, Santa Monica Mountains NRA; John Ekhoff, CA DFG • Three sites: • Cheeseboro Canyon, SMMNRA (weed-free) • Rancho Jamul Ecological Reserve, CA-DFG (two sites; 2007 and 2008)
Nassella pulchra tolerance to herbicides – San Diego and Los Angeles Counties • Herbicides applied in spring to established purple needlegrass • Herbicide treatments include: • Fluazifop-butyl (Fusilade) • Clethodim (Envoy) • Glyphosate (Roundup) • Pelargonic acid (Scythe) • Imazapic (Plateau) • Trifluralin (Preen granules) • Aminopyralid (Milestone) • Triclopyr (Garlon)
Nassella pulchra tolerance to herbicides – San Diego and Los Angeles Counties • SMM site; • Herbicide applied 1/22/07 • Plots sampled on 5/23/07 for biomass, basal diameter, inflorescences per plant, and visual injury • No significant difference (p=0.19) between treatments and the UTC for biomass • No apparent injury related to treatment
Nassella pulchra tolerance to herbicides – San Diego and Los Angeles Counties • RJER site, 2007 trial: • Herbicides applied postemergence 2/9/07 • N. pulchra injury; • 6 WAT - 20-80% depending upon herbicide • 6 MAT – 10-60% • N. pulchra mean weight per plant – 6 MAT • Fluazifop – 47.3 g • Clethodim – 26.8 g • Glyphosate – 63.3 g • Aminopyralid – 53.9 g • UTC - 15.0 g
Nassella pulchra tolerance to herbicides – San Diego and Los Angeles Counties • RJER site, 2008 trials: • Both sites burned in 2003 and 2007 • Site One – reapplication 12/28/07 to 2007 experiment • Site two – new experiment – same treatments applied on 1/18, 2008 • N. pulchra injury; • Fluazifop – 10-20% • Clethodim – 20-60% • Glyphosate – 0-30% • Aminopyralid – 0-5% • UTC - 0%