Mechanisms Controlling the Distribution of Two Invasive Bromus Species

摘要: In order to predict future range shifts for invasive species it is important explore their ability acclimate the new environment and understand physiological reproductive constraints controlling distribution. My dissertation studied mechanisms by which temperature may affect distribution of two aggressive plant invaders in North America, Bromus tectorum rubens. I first evaluated winter freezing tolerance demonstrated that mechanism explaining distinct northern limits different acquisition time tolerance. While B. rubens has a slower rate acclimation leads intolerance sudden, late-autumn drops below -12°C, rapidly hardens so not impacted sudden onset severe cold. addition, analysis male development seed production showed neither produces at or above 36°C, due complete pollen sterility, might trigger climate-mediated contractions southern margins. Finally, detailed gas-exchange combined with biochemical modelling both broad temperatures photosynthetic response does explain current separation.