ARS | Publication request: Practical Use of Intermountain Native Annuals in Assisted Succession

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2011
Publication Date: February 12, 2011
Citation: Harmon, D.N., Clements, D.D. 2011. Practical Use of Intermountain Native Annuals in Assisted Succession [abstract]. Intermountain Native Plant Summit VI. 6:24.

Technical Abstract: Assisted succession is a sensible management practice that recognizes the value of introduced perennial grasses as a tool to improve the establishment of native species and allow progression along a successional gradient. We examine the role that native annual species have in succession with regards to establishment, persistence, perennial facilitation and cheatgrass suppression. Since 2007 we have experimented with over 20 native annual species at numerous field sites in northwestern Nevada and northeastern California. We have found it difficult to overcome the limitations of native annuals in management practices to suppress such invasive exotic weeds as cheatgrass. In order for an annual to maintain a population, they first have to compete with cheatgrass every year at the seedling stage, a stage when cheatgrass dominates. Native annuals also have a heavy seed rain that is difficult to mimic with artificial seeding. Facilitation is limited in an arid ecosystem with an immense cheatgrass presence. We found no evidence of perennial grass facilitation by the native annuals we tested. Of the native annual species we tested, those that performed the best at establishment, persistence and competing with cheatgrass for resources were Fiddleneck (Amsinkia tessellate) Baily’s buckwheat (Eriogonum baileyi) and cushion cryptantha (Cryptantha circumsciss). However, for succession to take place the native annuals must significantly decrease cheatgrass densities and seed banks. Cheatgrass suppression only occurs after the establishment of a mature perennial grass not during the seedling stage of the perennial grass. Because of this it is very difficult to determine the long term affects of native annuals on cheatgrass seed banks and fire frequency. We continue to research the top performing native annual species with “on the ground” research and long term monitoring to determine effects on assisted succession management practices.