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CHARACTERIZATION OF AGROSTIS SPP. HABITAT IN CENTRAL OREGON
Citation:
WATRUD, L. S., G. KING, M. A. BOLLMAN, AND M. STORM. CHARACTERIZATION OF AGROSTIS SPP. HABITAT IN CENTRAL OREGON. Presented at Botany 2007 (BSA/ASPB) Meeting, Chicago, IL, July 07 - 11, 2007.
Description:
Creeping bentgrass, Agrostis stolonifera L., is a non-native grass commonly found at mesic sites in central Oregon. Interest in A. stolonifera plant communities and the factors that may control its distribution has increased since field trials of A. stolonifera engineered to be resistant to glyphosate herbicide were conducted in Central Oregon in 2003. Our earlier studies documented long-distance (multi-km) movement of viable pollen from transgenic bentgrass fields to compatible naturalized Agrostis spp. (Watrud et al. 2004) and the establishment of transgenic A. stolonifera plants in non-agronomic habitats (Reichman et al. 2006). Herein, we report the results of autecological studies of Agrostis spp. in central Oregon. We employed a stratified sample design to collect vegetation and soil chemistry data in four plot types (Agrostis gigantea, Agrostis stolonifera, non-Agrostis and transgenic Agrostis) in six habitat types where Agrostis typically occurs in the study area. Four quadrats (50 x 100 cm) were placed along each of 3 linear 15m transects located 3 m apart and parallel to the long axis of the most proximal water course or topographic low point (e.g., irrigation canal, creek, roadside ditch). Surveys of sixty-two plots indicated that Agrostis spp. often occur in wetland plant communities that have a high proportion of alien species (56-67%) e.g., Bromus tectorum, Phalaris arundinacea, and Lolium arundinaceum. Canonical Correspondence Analysis (CCA) indicates that plant community composition is most strongly related to soil moisture and iron concentration along axis 1 (cumulative % variance = 17%), and copper and total carbon along axis 2 (cumulative % variance = 15%). Agrostis stolonifera cover is strongly related to soil moisture; the competitive ruderal species occurs over a wide range of soil conditions (e.g., pH 6.1-8.7, Fe 17-258 ppm).