See below for some highlights from 2007

 Click here to download a summary paper on the project.

Year 4 (2008) Notes from the field

Field season began in mid-April for year 4 of this 5-year project.  So far, here are some patterns we are noticing at several of our sites:

• Seed addition has increased native diversity in our research plots, especially in treated plots.  We are seeing a successful second generation of the annual Plectritis congesta (Seablush), which is very exciting as this species is no longer found in many prairie remnants.  Other species sown in the fall of 2006, particularly Oregon sunshine, yarrow, buttercup, and Roemer's fescue are growing well.
• The combination of a burn in fall of 2006 followed by glyphosate dramatically reduced weedy forb abundance (particularly ox-eye daisy and hairy cat's-ear) the following spring (2007).  However, this spring the ox-eye daisy in particular seems to be making a comeback.  There are still fewer weedy forbs than the control plots, but this trend is something to keep an eye on.
• Plots that were burned in 2006 but not sprayed with Poast are seeing a resurgence of weedy grasses this spring.  In particular, sites with sweet vernal grass have seen large increases in this fire-tolerant weed.
  

Year 3 (2007) Project highlights

Our treatment combinations have already produced some large changes in the first 3 years of this long-term study.  Here's what we're finding:

• Poast (a grass specific herbicide), is very effective at reducing all the exotic grasses, both perennial and annual.
• Poast does not negatively impact the native Roemer's fescue and native grass like plants (Carex spp. and Luzula spp.).  Poast does negatively impact other native grasses (e.g. California oat-grass, California Brome, and wild-rye).
• Burning effectively reduces thatch and litter accumulation, and helps prepare a good seed bed for germination.  Thick moss layers were resistant to burning, and may take several burns to get to mineral soil.
• Applying glyphosate (a broad-spectrum herbicide) after the burn effectively targeted many broad-leaf weeds and some weedy grass species.  These weeds resprouted earlier than most native species after fire.
• Repeat spring and fall mowing has not yet produced noticable changes in exotic grass abundance.
• Spraying Poast in combination with a fall mow (rather than a fall burn) worked well at sites that do not have a problem with broad-leaved weeds.  At other sites, broad-leaf weeds such as ox-eye daisy and hairy cat's-ear increased as grass abundance declined.
• Seed limitation seems to be a problem at all sites.  Native seed addition added diversity to all experimental plots, even controls.  Seedling establishment was best in burned plots.
  

Here is a brief presentation on the project, with results of the most effective treatment combination (Treatment A: Spring Poast application, Fall burn, post-burn glyphosate application).