RSPB Centre for Conservation Science, The Lodge, Sandy, Bedfordshire, SG19 2DL, UK.
RSPB Centre for Conservation Science, The Lodge, Sandy, Bedfordshire, SG19 2DL, UK.
J Environ Manage. 2022 Aug 15;316:115221. doi: 10.1016/j.jenvman.2022.115221. Epub 2022 May 12.
Agri-environment incentives form a central mechanism supporting changes to land management to provide public benefits. This study assesses the medium-term effects of woodland management on 13 target, specialist woodland bird species, as well as other woodland birds in a single region of the UK. The abundance of breeding birds (using two methods: point counts and territory mapping) and metrics of woodland structure were recorded on sites with Woodland Improvement Grants (improvement sites) and nearby comparison sites (control sites). Initial measurements were made prior to management and repeated 7-9 years later. A separate comparison of changes in bird abundance was made between the managed woodland sites and woodland from similar landscapes surveyed as part of the national Breeding Bird Survey (BBS). There was an increase in abundance of target species on improvement sites compared to a decrease on both control sites and BBS sites, although this was only evident from point count data. The effects on target species were stronger than for other woodland specialists and there was no apparent effect on woodland generalists, suggesting that the management interventions were appropriate for the target species. Changes in woodland structure were generally consistent with the expected effect of management, with lower tree density and greater Bramble (Rubus sp.) cover. However, contrary to the aim of increasing understorey cover, a reduction was recorded within the 2-10 m height category in improvement sites. This contrast is due to the removal of young trees during thinning affecting this height band and the short time period since management to allow regrowth. Our findings show that bespoke management supported through government agri-environment incentives can have a positive impact on target woodland birds. For managed forests, identifying species requirements and how management can be adapted to improve their habitats can be an effective way of delivering biodiversity gains when financial incentives are provided to achieve policy goals.
农业环境激励措施是支持土地管理变革以提供公共利益的核心机制。本研究评估了林地管理对英国单一地区 13 种目标、专业林地鸟类以及其他林地鸟类的中期影响。在有林地改善补助金（改善地）和附近对照地（对照地）的地点，使用两种方法（点计数和领地测绘）记录繁殖鸟类的丰度和林地结构指标。在管理之前进行初始测量，并在 7-9 年后重复测量。还对管理林地地点和作为全国繁殖鸟类调查（BBS）一部分调查的类似景观中的林地鸟类丰度变化进行了单独比较。与对照地和 BBS 地相比，改善地的目标物种丰度增加，尽管这仅从点计数数据中明显看出。目标物种的影响强于其他林地专家，对林地普通物种没有明显影响，表明管理干预措施适合目标物种。林地结构的变化通常与管理的预期效果一致，树木密度降低，荆棘（Rubus sp.）覆盖增加。然而，与增加林下植被覆盖的目标相反，在改善地的 2-10 米高度范围内记录到减少。这种对比是由于间伐过程中去除幼树影响了这个高度带，并且自管理以来时间很短，无法重新生长。我们的研究结果表明，通过政府农业环境激励措施支持的定制管理可以对目标林地鸟类产生积极影响。对于管理森林，确定物种需求以及如何调整管理以改善其栖息地，可以在提供财政激励以实现政策目标时，有效地实现生物多样性的增加。
