Range Science Program, North Dakota State University, USA.
Department of Animal and Range Sciences, New Mexico State University, USA.
J Environ Manage. 2018 Oct 1;223:908-916. doi: 10.1016/j.jenvman.2018.06.096. Epub 2018 Jul 10.
Global biodiversity is threatened by invasive plant species. Without a thorough understanding of effective management strategies, minimizing their impacts while improving native species diversity will be challenging. Burning in fire-prone landscapes has been successful for managing invasive species and increasing native biodiversity, but it is unclear how specific fire regimes improve restoration practices in novel ecosystems where invasive plants have a similar growth phenology to native plants. We investigated fire as a restoration practice in the Northern Great Plains to decrease the cover of Kentucky bluegrass Poa pratensis (bluegrass), a perennial cool-season invasive grass phenologically similar to dominant native cool-season grasses, by 1) evaluating season of burn (early-growing season, late-growing season, and dormant season) in a field experiment to test differences in plant community composition and 2) manipulating fine fuels (3000-5000 kg ha) in an experimental approach to determine the effects of fire on plant survivability of selected native grasses and bluegrass. Bluegrass cover decreased 27% on all field burned plots the first year post-fire. Three years post-fire, late-growing season and dormant season treatments had 35% less bluegrass, whereas the early-growing season treatment was not significantly different from the control. Overall, fire altered the native plant community, with native plants more associated with burned plots. However, native plant community changes were only evident three years post-fire in late-growing season and dormant season burn treatments. In the experimental approach, native grasses and bluegrass experienced high rates of mortality (40-50%) at fuel loads above 4000 kg ha and heat dosages above 30,000 °C·sec, features commonly associated with early-growing season burns. Therefore, early-growing season burns meant to reduce bluegrass may also impact native plants dominant in the region. Invasive species management is complicated in novel ecosystems when invasive plants have similar growth phenologies to native species. Control efforts should consider how different management strategies impact invasive and native plants alike. We found that late-growing season and dormant season burns, along with higher fuel loads, decreased bluegrass cover. Determining mechanisms of control in fire-prone landscapes is a crucial step to improving invasive plant control and increasing native biodiversity.
全球生物多样性受到入侵植物物种的威胁。如果没有深入了解有效的管理策略，那么在提高本地物种多样性的同时，最大限度地减少其影响将是具有挑战性的。在易发生火灾的景观中进行燃烧已成功用于管理入侵物种并增加本地生物多样性，但尚不清楚特定的火灾制度如何在新生态系统中改善恢复实践，在这些生态系统中，入侵植物与本地植物具有相似的生长物候。我们调查了北方大平原作为一种恢复实践的方法，以减少肯塔基蓝草（Poa pratensis）的覆盖范围，肯塔基蓝草是一种多年生冷季入侵草，在物候上与主要的本地冷季草相似，方法是 1）在田间试验中评估燃烧季节（生长早期、生长后期和休眠期），以测试植物群落组成的差异，2）通过实验方法操纵细可燃物（3000-5000 kg ha），以确定火对选定的本地草和蓝草植物存活率的影响。火后第一年，所有田间燃烧的斑块上的蓝草覆盖率降低了 27%。火后三年，生长后期和休眠期处理的蓝草减少了 35%，而生长早期处理与对照没有显著差异。总的来说，火改变了本地植物群落，与燃烧斑块相关的本地植物更多。然而，只有在生长后期和休眠期燃烧处理的火后三年，才会出现本地植物群落的变化。在实验方法中，在超过 4000 kg ha 的可燃物负荷和超过 30,000°C·sec 的热剂量下，本地草和蓝草的死亡率很高（40-50%），这些特征通常与生长早期的燃烧有关。因此，旨在减少蓝草的生长早期燃烧也可能影响该地区占优势的本地植物。在入侵植物与本地物种具有相似生长物候的新生态系统中，入侵物种管理变得复杂。控制措施应考虑不同的管理策略如何对入侵植物和本地植物产生相同的影响。我们发现，生长后期和休眠期燃烧以及更高的可燃物负荷降低了蓝草的覆盖范围。确定火灾多发地区的控制机制是提高入侵植物控制和增加本地生物多样性的关键步骤。
