Ventenata (Ventenata dubia L.) is an invasive annual grass that has rapidly expanded its range across temperate grassland and shrub-steppe ecosystems in western North America. However, there is little published regarding its ecology, especially its relationship with fire on rangelands. The objective of this study was to examine the effect of fire on ventenata invasion in the Pacific Northwest Bunchgrass (PNB) Prairie. Given the influence of fire on the invasion of other annual grasses such as cheatgrass (Bromus tectorum L.), we expected that fire would facilitate the spread and increase in abundance of ventenata. In addition, we considered that annual variation in precipitation might mask the effect of fire and drive the year-to-year variation in production of ventenata. Therefore, we resampled 56 plots in 2015 and 2016 where frequency and foliar cover of ventenata had been recorded in 2008 and where 12 of these plots had burned in the past 15 yr. We then compared ventenata abundance (frequency and foliar cover) between burned and unburned plots within each sampling yr (2008, 2015, and 2016), as well as the change in abundance over time. Our data revealed that ventenata frequency and cover increased on all plots. However, there was not significantly higher abundance in burned plots in any of the sampling years. In addition, ventenata abundance did not increase more in burned plots over time. Our findings suggest that, unlike cheatgrass, fire may not be a driving factor in the spread and increase of ventenata across the PNB Prairie. This finding has important implications for the management and control of ventenata, as well as the conservation of the PNB Prairie.

Ventenata （Ventenata dubia L.）是一种侵入性的一年生草，已经在北美西部的温带草原和灌木草原生态系统中迅速扩展了其范围。但是，关于其生态学，尤其是与牧场火灾之间关系的报道很少。这项研究的目的是研究大火对太平洋西北邦奇格拉斯（PNB）草原的气仙菌入侵的影响。鉴于大火对其他一年生草入侵的影响，例如象草（Bromus tectorumL.），我们预计大火将有助于气仙草的扩散和增加。此外，我们认为降水的年度变化可能掩盖了火的影响，并驱动了每年的气仙产量变化。因此，我们在2015年和2016年对56个样地进行了重新采样，这些样地在2008年记录了文氏菌的发生频率和叶面覆盖，其中有12个样地在过去15年中燃烧过。然后，我们比较了每个采样年（2008年，2015年和2016年）内燃烧和未燃烧土地之间的气孔丰度（频率和叶面覆盖度），以及随时间变化的丰度变化。我们的数据显示，在所有地块上，弧菌的发生频率和覆盖率都有所增加。但是，在任何采样年中，烧成的土地上的丰度都没有显着更高。此外，随着时间的推移，在烧成的土地上，气孔菌的丰度并没有增加更多。我们的发现表明，与虎杖不同，火可能不是推动整个PNB草原气室扩散和增加的驱动因素。这一发现对风疹的管理和控制以及PNB草原的保护具有重要意义。