Howell Armin, Winkler Daniel E, Phillips Michala L, McNellis Brandon, Reed Sasha C
U.S. Geological Survey, Southwest Biological Science Center, Moab, UT, United States.
Department of Forest, Rangeland and Fire Sciences, University of Idaho, Moscow, ID, United States.
Front Plant Sci. 2020 Oct 15;11:570001. doi: 10.3389/fpls.2020.570001. eCollection 2020.
(cheatgrass) has successfully invaded and established throughout the western United States. grows early in the season and this early growth allows to outcompete native species, which has led to dramatic shifts in ecosystem function and plant community composition after invades. If the phenology of native species is unable to track changing climate as effectively as 's phenology then climate change may facilitate further invasion. To better understand how phenology will respond to future climate, we tracked the timing of germination, flowering, and senescence over a decade in three 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 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 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 phenology. Taken together, these results help elucidate how phenology may respond to future climate, increasing our predictive capacity for estimating when to time control efforts and how to more effectively manage this exotic annual grass.
（黑麦草）已成功入侵并在美国西部广泛分布。它在生长季节早期生长，这种早期生长使其能够胜过本地物种，这导致黑麦草入侵后生态系统功能和植物群落组成发生巨大变化。如果本地物种的物候不能像黑麦草的物候那样有效地跟踪气候变化，那么气候变化可能会促进其进一步入侵。为了更好地了解黑麦草物候将如何应对未来气候，我们在三个气候操纵实验中跟踪了黑麦草发芽、开花和衰老的时间，实验处理包括升高温度（比环境温度高2°C和4°C）、改变降水模式或两者结合。线性混合效应模型用于分析每个实验中处理对发芽、开花、衰老时间以及营养生长季节长度（从发芽到开花的时间）的影响。改变降水处理仅在研究的早期应用，降水处理及其遗留影响均未显著影响黑麦草物候。在任何升温处理及其各自的对照地块之间，发芽时间没有显著差异。然而，升温地块的黑麦草开花和衰老时间提前，营养生长季节也更短。升温导致的物候提前随着实验升温程度的增加而增加。升温地块和对照地块之间最大的差异出现在营养生长季节的长度上，在+4°C和+2°C升温水平下，营养生长季节分别缩短了约12天和7天。与年际气候变化的影响相比，实验升温的影响较小，这表明多种气候因素的相互作用控制和时间安排在决定黑麦草物候方面很重要。综上所述，这些结果有助于阐明黑麦草物候可能如何应对未来气候，提高我们预测何时进行控制措施以及如何更有效管理这种外来一年生草本植物的能力。
