School of Natural Resources, University of Nebraska, Lincoln, Lincoln, Nebraska, United States of America.
PLoS One. 2013 Sep 20;8(9):e75181. doi: 10.1371/journal.pone.0075181. eCollection 2013.
Plant demographic studies coupled with population modeling are crucial components of invasive plant management because they inform managers when in a plant's life cycle it is most susceptible to control efforts. Providing land managers with appropriate data can be especially challenging when there is limited data on potentially important transitions that occur belowground. For 2 years, we monitored 4 clonal Japanese knotweed (Polygonumcuspidatum) infestations for emergence, survival, shoot height until leaf senescence, dry shoot biomass after senescence, and rhizome connections for 424 shoots. We developed an integral projection model using both final autumn shoot height and shoot biomass as predictors of survival between years, growth from year to year, and number of rhizomes produced by a shoot (fecundity). Numbers of new shoots within an infestation (population growth rate λ) were projected to increase 13-233% in a year, with the greatest increase at the most frequently disturbed site. Elasticity analysis revealed population growth at 3 of the 4 sites was primarily due to ramet survival between years and to year-to-year growth in shoot height and shoot biomass. Population growth at the fourth site, the most disturbed, was due to the large production of new rhizomes and associated shoots. In contrast to previous studies, our excavation revealed that most of the shoots were not interconnected, suggesting rhizome production may be limited by the size or age of the plants, resource availability, disturbance frequency, or other factors. Future integration of plant population models with more data on belowground growth structures will clarify the critical stages in Japanese knotweed life cycle and support land managers in their management decisions.
植物种群研究与种群建模是入侵植物管理的重要组成部分，因为它们可以告知管理者在植物生命周期中何时最容易受到控制。当潜在重要的地下转变的相关数据有限时，为土地管理者提供适当的数据可能特别具有挑战性。在过去的两年中，我们监测了 4 个克隆日本虎杖（Polygonum cuspidatum）的入侵，监测内容包括出芽、存活率、出芽后至叶片衰老期间的茎高、衰老后茎干的干生物量以及 424 个出芽的根茎连接情况。我们使用最终秋季茎高和茎生物量作为预测因子，分别建立了综合投影模型，用于预测年际存活率、年增长率以及一个出芽产生的根茎数量（繁殖力）。在一年内，一个种群内新出芽的数量（种群增长率λ）预计将增加 13%至 233%，在最频繁受到干扰的地点，增长率最高。弹性分析表明，在 4 个地点中的 3 个地点，种群增长主要是由于年际间的营养体存活率以及茎高和茎生物量的年增长率。第四个地点（受干扰最严重的地点）的种群增长是由于新根茎和相关出芽的大量产生。与以前的研究不同，我们的挖掘表明，大多数出芽并没有相互连接，这表明根茎的产生可能受到植物的大小或年龄、资源可用性、干扰频率或其他因素的限制。未来将植物种群模型与更多关于地下生长结构的数据进行整合，将有助于阐明日本虎杖生命周期中的关键阶段，并为土地管理者的管理决策提供支持。
