Scholarship & Research
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/1
Browse
2 results
Search Results
Item Bromus tectorum Response to Fire Varies with Climate Conditions(2014-09) Taylor, Kimberley T.; Brummer, Tyler J.; Rew, Lisa J.; Maxwell, Bruce D.The invasive annual grass Bromus tectorum (cheatgrass) forms a positive feedback with fire in some areas of western North America’s sagebrush biome by increasing fire frequency and size, which then increases B. tectorum abundance post-fire and dramatically alters ecosystem structure and processes. However, this positive response to fire is not consistent across the sagebrush steppe. Here, we ask whether different climate conditions across the sagebrush biome can explain B. tectorum’s variable response to fire. We found that climate variables differed significantly between 18 sites where B. tectorum does and does not respond positively to fire. A positive response was most likely in areas with higher annual temperatures and lower summer precipitation. We then chose a climatically intermediate site, with intact sage-brush vegetation, to evaluate whether a positive feedback had formed between B. tectorum and fire. A chronosequence of recent fires (1–15 years) at the site created a natural replicated experiment to assess abundance of B. tectorum and native plants. B. tectorum cover did not differ between burned and unburned plots but native grass cover was higher in recently burned plots. Therefore, we found no evidence for a positive feedback between B. tectorum and fire at the study site. Our results suggest that formation of a positive B. tectorum-fire feedback depends on climate; however, other drivers such as disturbance and native plant cover are likely to further influence local responses of B. tectorum. The dependence of B. tectorum’s response to fire on climate suggests that climate change may expand B. tectorum’s role as a transformative invasive species within the sage-brush biome.Item Impact of growing conditions on the competitive ability of Camelina sativa (L.) Crantz (Camelina)(2013-03) Davis, Phillip B.; Maxwell, Bruce D.; Menalled, Fabian D.It has been claimed that Camelina sativa, a recently introduced crop in the northern Great Plains, is a highly competitive species. However, this issue has not been formally tested. Utilizing replacement series diagrams, we assessed the importance of growing conditions in the competitive ability of C. sativa. Results indicated that canola and Bromus tectorum were superior competitors in both loam and sandy soils, thus providing evidence that C. sativa may not be as competitive as previously indicated.