USFWS Grant: Research on Grazing Effects on Applegate’s Milk-vetch at Collins Tract

Applegate’s milk-vetch (Astragalus applegatei) is one of Oregon’s rarest and most endangered plant species. Only a few sites remain, all confined to a very local area within or near Klamath Falls, Oregon. All but one of these appears to be declining due to significant habitat deterioration or fragmentation. The Collins Tract is one of the sites where this species occurs. The site is privately owned by the Collins Company and is currently leased for grazing. The owners have no future development plans for this site and are currently working with the Service to develop a conservation agreement for the management of the site.

In the 1993 final rule, the 1998 recovery plan and the 2008 draft 5-year status review for this species, herbivory is identified as a threat to this species. All of the information concerning herbivory on Applegate’s milk-vetch plants has been anecdotal to date. There have been no comprehensive studies to quantify the effects of herbivory on Applegate’s milk-vetch.

Cattle are grazed at the Collins Tract site and it has been documented that cattle do consume this species. At the Collins site, the species grows best under a cover of rabbitbrush (Ericameria nauseosus and E. viscidiflorus), where it appears that it is protected from grazing. However, older photographs of this site suggest that grazing was employed in the late 1920’s and grazing has been documented annually by horses and cattle at the site since the mid-1980’s. No information was provided on how many cows or horses currently or historically grazed this site. Although Applegate’s milk-vetch was not discovered on this site until 2002, it appears that Applegate’s milk-vetch has persisted regardless of the long-term use of this site for grazing. However, it is unknown if this species would benefit from a reduction in this activity.

The goal of this study would be to quantify the effects of cattle grazing at this site to determine the magnitude of this threat to the species. In order accomplish this study of this nature, multiple barbed wire fence exclosures will be built on the site to exclude cattle from areas where the plant occurs. A contractor would be hired to build these exclosures and the site manager form the Collins Company would help maintain the exclosures. The recepient would determine the study design, establish sample plots, conduct the research and produce a final report of the findings. This study would be a 5-year study beginning in 2008 and would be completed by 2012. The final report would be submitted to USFWS by December 31, 2012, however, the USFWS would receive annual progress reports.

Timeline (2008 – 2012):
Spring 2008 Project clearances, develop study design, build fence exclosures
Early summer, 2008 Establish sample plots and collect data
Summer 2009 – 2012 Collect data
December 31, 2012 Final report to USFWS