Bromus tectorum (cheatgrass) has successfully invaded and established throughout the western United States. Bromus tectorum grows early in the season and this early growth allows B. tectorum to outcompete native species, which has led to dramatic shifts in ecosystem function and plant community composition after B. tectorum invades. If the phenology of native species is unable to track changing climate as effectively as B. tectorum’s phenology then climate change may facilitate further invasion. To better understand how B. tectorum phenology will respond to future climate, we tracked the timing of B. tectorum germination, flowering, and senescence over a decade in three in situ climate manipulation experiments with treatments that increased temperatures (2°C and 4°C above ambient), altered precipitation regimes, or applied a combination of each. Linear mixed-effects models were used to analyze treatment effects on the timing of germination, flowering, senescence, and on the length of the vegetative growing season (time from germination to flowering) in each experiment. Altered precipitation treatments were only applied in early years of the study and neither precipitation treatments nor the treatments’ legacies significantly affected B. tectorum phenology. The timing of germination did not significantly vary between any warming treatments and their respective ambient plots. However, plots that were warmed had advances in the timing of B. tectorum flowering and senescence, as well as shorter vegetative growing seasons. The phenological advances caused by warming increased with increasing degrees of experimental warming. The greatest differences between warmed and ambient plots were seen in the length of the vegetative growing season, which was shortened by approximately 12 and 7 days in the +4°C and +2°C warming levels, respectively. The effects of experimental warming were small compared to the effects of interannual climate variation, suggesting that interactive controls and the timing of multiple climatic factors are important in determining B. tectorum phenology. Taken together, these results help elucidate how B. tectorum phenology may respond to future climate, increasing our predictive capacity for estimating when to time B. tectorum control efforts and how to more effectively manage this exotic annual grass.

雀麦(cheatgrass) 已成功入侵并在整个美国西部建立。雀麦在季节早期生长，这种早期生长允许B. 顶盖与本地物种竞争，导致生态系统功能和植物群落组成发生巨大变化B. 顶盖入侵。如果本地物种的物候学无法像B. 顶盖的物候学，那么气候变化可能会促进进一步的入侵。为了更好地理解如何B. 顶盖物候将对未来的气候做出反应，我们跟踪了时间B. 顶盖发芽、开花、衰老，历经十多年，分三期就地气候操纵实验，包括提高温度（比环境温度高 2°C 和 4°C）、改变降水状况或将这几种方法相结合的处理。在每个实验中，使用线性混合效应模型来分析处理对发芽、开花、衰老时间和营养生长季节长度（从发芽到开花的时间）的影响。改变的降水处理仅在研究的早期应用，降水处理和处理的遗产都没有受到显着影响B. 顶盖物候学。任何变暖处理及其各自的环境地块之间的发芽时间没有显着差异。然而，变暖的地块在时间上有所提前。B. 顶盖开花和衰老，以及较短的营养生长期。随着实验变暖程度的增加，变暖引起的物候变化也随之增加。变暖地块和环境地块之间的最大差异在于营养生长季节的长度，在+4°C和+2°C变暖水平下，营养生长季节分别缩短约12天和7天。与年际气候变化的影响相比，实验性变暖的影响较小，这表明交互控制和多种气候因素的时间安排对于确定B. 顶盖物候学。总而言之，这些结果有助于阐明如何B. 顶盖物候学可能会对未来的气候做出反应，从而提高我们估计何时发生的预测能力B. 顶盖控制工作以及如何更有效地管理这种奇异的一年生草。