Title: MEDUSAHEAD DISPERSAL AND ESTABLISHMENT IN SAGEBRUSH PLANT COMMUNITIES Author
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 22, 2007
Publication Date: January 26, 2008
Citation: Davies, K.W. 2008. Medusahead dispersal and establishment in sagebrush plant communities. Society for Range Management Meeting Abstracts. Range & Pasture Management Poster #24. Technical Abstract: Medusahead (Taeniatherum caput-medusae (L.) Nevski) is an invasive annual grass that that is rapidly invading sagebrush plant communities. To prevent medusahead invasion land managers need to know 1) when and how far medusahead seeds disperse and 2) its establishment rates and interactions with the plant communities being invaded. Medusahead seed dispersal was measured using seed traps along 23, 35-m transects. Medusahead establishment was evaluated by introducing medusahead at 1, 10, 100, 1000, 10 000 seeds*m-2 at 12 sites. Most medusahead seeds dispersed less than 0.5 m from the infestation (P < 0.01) and no medusahead seeds were captured in the traps beyond 2 m from the infestations. Medusahead seeds dispersed from the parent plants from early July to the end of October with peek dispersal occurring in August (P < 0.01). Medusahead establishment increased with higher seeding rates (P < 0.01). Medusahead density was negatively correlated to tall tussock perennial grass density and positively correlated to annual grass density of the preexisting plant communities (P = 0.02 and 0.02, respectively). Medusahead cover was also negatively correlated with the tall tussock perennial grass density (P = 0.03). Our results suggest that containment barriers around medusahead infestations would only have to be a few meters wide to be effective. This study also suggests promoting tall tussock perennial grass in areas at risk of invasion can reduce the establishment success of medusahead.