Wet grassland populations of wading birds in the United Kingdom have declined severely since 1990. To help mitigate these declines, the Royal Society for the Protection of Birds has restored and managed lowland wet grassland nature reserves to benefit these and other species. However, the impact of these reserves on bird population trends has not been evaluated experimentally due to a lack of control populations. We compared population trends from 1994 to 2018 among 5 bird species of conservation concern that breed on these nature reserves with counterfactual trends created from matched breeding bird survey observations. We compared reserve trends with 3 different counterfactuals based on different scenarios of how reserve populations could have developed in the absence of conservation. Effects of conservation interventions were positive for all 4 targeted wading bird species: Lapwing (Vanellus vanellus), Redshank (Tringa totanus), Curlew (Numenius arquata), and Snipe (Gallinago gallinago). There was no positive effect of conservation interventions on reserves for the passerine, Yellow Wagtail (Motacilla flava). Our approach using monitoring data to produce valid counterfactual controls is a broadly applicable method allowing large-scale evaluation of conservation impact.

中文翻译：

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衡量湿草地保护对英国繁殖鸟类种群影响的反事实方法

自 1990 年以来，英国涉水鸟类的湿草原种群数量急剧下降。为了帮助缓解这些下降，皇家鸟类保护协会已经恢复和管理低地湿草原自然保护区，以使这些物种和其他物种受益。然而，由于缺乏控制种群，这些保护区对鸟类种群趋势的影响尚未通过实验评估。我们将 1994 年至 2018 年在这些自然保护区繁殖的 5 种受保护鸟类的种群趋势与匹配的繁殖鸟类调查观察得出的反事实趋势进行了比较。我们根据保护区种群在没有保护的情况下如何发展的不同情景，将保护区趋势与 3 种不同的反事实进行了比较。Vanellus vanellus )、Redshank ( Tringa totanus )、Curlew ( Numenius arquata ) 和 Snipe ( Gallinago gallinago )。保护干预措施对雀形目黄鹡鸰 ( Motacilla flava )的保护区没有积极影响。我们使用监测数据来产生有效的反事实控制的方法是一种广泛适用的方法，允许对保护影响进行大规模评估。