December 17, 2014

Horse Rock Ridge habitat assessment: Second year report

Andrea S. Thorpe | 2007

This report describes the first year of a three-year project at Horse Rock Ridge Area of Critical Environmental Concern/Research Natural Area (ACEC/RNA). The purpose of this project is to assess

This report describes the first year of a three-year project at Horse Rock Ridge Area of Critical Environmental Concern/Research Natural Area (ACEC/RNA). The purpose of this project is to assess the current condition of high-priority ecosystems in the Horse Rock Ridge and prioritize native plant communities and invasive species for management action.

High levels of invasive species were found including Leucanthemum vulgare, Hypericum perforatum, Cynosurus echinatus, Aira caryophylla, Bromus hordeaceus,  Rubus laciniatus, and Rubus armeniacus. 

The majority of the grassland at Horse Rock Ridge is dominated by the exotic grass, Cynosurus cristata. Several native forbs commonly co-occur with C. cristata, including Eriophyllum lanatum and Allium amplectans. In general, native grasses, particularly Elymus glaucus and Festuca roemeri were more abundant in wetter areas and areas that fell under the canopy of trees. Rocky outcrops and other areas with low soil depth tended to be dominated by the Stipa lemmonii/Racomitrium canescens (Lemmon’s needlegrass/moss) associations. Both Danthonia californica and Koeleria cristata commonly co-occured with E. glaucus and F. roemeri.

SUMMARY OF FUTURE ACTIONS

In 2008, we will

  • finish mapping by ground-truthing the areas mapped in 2006-2007 and mappingareas that were not covered during previous efforts;
  • establish 30 plots to test methods to remove Leucanthemum vulgare andHypericum perforatum;
  • remove the aboveground biomass of Rubus spp. in spring, summer, and fall;
  • remove all small patches of invasive species,
  • collect native seed and distribute in areas treated for invasive weeds; and
  • utilize the information from the mapping procedure and experimental weedtreatment plots to write a Restoration Plan for Horse Rock Ridge.