Restoring habitat degraded by invasive species is often a primary focus of conservation strategies, yet few studies investigate the effects of invasive species control on multiple at‐risk taxa. Selective herbicides are increasingly used because they can selectively reduce aggressive invasive plant species with the aim of minimizing effects on other taxa within the habitat. We conducted a four‐year experiment to test how annual application of grass‐specific herbicide affected the demography on Fender's blue butterfly (Icaricia icarioides fenderi) and Kincaid's lupine (Lupinus oreganus), two federally protected species which persist in highly degraded prairie remnants in western Oregon, USA. Effects of herbicide application were transitory for the butterfly; reduction of invasive grasses increased fecundity and led to higher annual population growth (λ) at one of two conservation areas in the first season. There were no detectable differences in λ in subsequent seasons—suggesting that treatments caused neither extensive harm nor extensive benefit to the butterfly population. For the lupine, there were no detectable differences in leaf and flower abundance between control and herbicide treatments. However, greater seed production in herbicide plots in the first and third seasons suggests that lupines in herbicide‐treated plots have greater potential reproductive success. While treatments do not have a long‐term benefit to annual population growth for the butterfly, increasing reproductive success of the threatened plant may justify integrating this strategy into restoration plans. Considering the impact of restoration practices on the demography of multiple at‐risk taxa within a community is critical to effective recovery strategies.

中文翻译：

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基于除草剂的恢复的人口成本和收益，以改善濒临灭绝的蝴蝶和受威胁植物的栖息地

恢复入侵物种退化的栖息地通常是保护策略的主要重点，但很少有研究调查入侵物种控制对多种高危生物分类的影响。选择性除草剂的使用日益广泛，因为它们可以选择性地减少侵略性入侵植物，目的是将对生境中其他类群的影响降至最低。我们进行了为期四年的实验，以测试每年使用草类专用除草剂如何影响Fender的蓝蝴蝶（Icaricia icarioides fenderi）和Kincaid的羽扇豆（Lupinus oreganus）的人口统计学。），这两个受联邦政府保护的物种在美国俄勒冈州西部的高残留草原中仍然存在。除草剂的施用对蝴蝶而言是短暂的。减少侵袭性草的提高繁殖力，并导致更高的年人口增长率（λ）在第一季的保护区之一。λ中没有可检测的差异在随后的几个季节中，这表明治疗对蝴蝶种群既没有造成广泛的危害，也没有带来广泛的利益。对于羽扇豆，对照和除草剂处理之间的叶和花丰度没有可检测到的差异。但是，在第一个和第三个季节，除草剂地块的种子产量更高，这表明在除草剂处理过的地块中羽扇豆具有更大的潜在繁殖成功率。尽管治疗对蝴蝶的年种群增长没有长期好处，但受威胁植物繁殖成功的增加可能证明将该策略纳入恢复计划是合理的。考虑到恢复实践对社区内多个处于危险中的分类单元的人口统计学的影响，对于有效的恢复策略至关重要。