School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK; Joint Research Unit CTFC - AGROTECNIO, Av. Alcalde Rovira Roure 191, E25198 Lleida, Spain; Department of Crop and Forest Sciences, University of Lleida, Av. Alcalde Rovira Roure 191, E25198 Lleida, Spain.
Ptyxis Ecology, Railway Cottages, Lambley, Northumberland CA8 7LL, UK.
Sci Total Environ. 2021 Mar 10;759:143508. doi: 10.1016/j.scitotenv.2020.143508. Epub 2020 Nov 12.
Environmental and management pressures are considered a threat for preserving plant communities worldwide. Identification of long-term impacts of changing management practices on plant community composition must, therefore, be a major priority to ensure improvement in conservation value. Land abandonment/wilding is one topical area where there is little available information on long-term impacts. To address this, here, we describe plant species compositional change over relatively long-time scales in a range of four British upland communities (high-level grasslands, intermediate grasslands, blanket bogs and high-level bogs) and its relationships with a series of life-history and plant trait variables. Our aims were to determine whether the business-as-usual sheep grazing practice was maintaining these communities, and if grazing was to be removed as part of abandonment/wilding strategies, would there be a conservation benefit. We used a series of long-term experimental grazing-exclosure studies at twelve sites (>40 years) on the Moor House National Nature Reserve in northern England. Each site consisted of paired plots; i.e. sheep-grazed versus ungrazed. Our results showed that there was relatively little change in dominant plant species with most change occurring within sub-dominant species. Similarly, different temporal responses in plant species richness were detected between the experiments (richness was reduced in three experiments, only one increased). In any case, the vegetation temporal trajectories were moving in similar direction in grazed and ungrazed plots at most sites. Interestingly, blanket bog experiments showed a clear compositional convergence for both grazed and ungrazed plots, although, the between-site differences related to a combination of elevation and past burning testament. Finally, the bryophytes (especially liverworts) and lichens were the groups that contributed most to the reductions in species richness. Moreover, implementation of a no-stock grazing strategy under a land abandonment/wilding approach will not bring about much plant change in the short-term in the plant communities studied here.
环境和管理压力被认为是全球范围内保护植物群落的威胁。因此，确定不断变化的管理实践对植物群落组成的长期影响必须成为首要任务，以确保保护价值的提高。土地废弃/野生化是一个很少有关于长期影响信息的热门领域。为了解决这个问题，在这里，我们描述了在一系列英国高地群落（高级草地、中级草地、毯子沼泽和高级沼泽）中相对长时间段内的植物物种组成变化及其与一系列生活史和植物特征变量的关系。我们的目的是确定常规绵羊放牧实践是否在维持这些群落，如果放牧作为废弃/野生化策略的一部分被移除，是否会有保护效益。我们在英格兰北部摩尔豪斯国家自然保护区的 12 个地点（>40 年）使用了一系列长期的实验性放牧围栏研究。每个地点都由一对样地组成；即绵羊放牧和未放牧。我们的结果表明，主要植物物种的变化相对较少，大多数变化发生在亚优势物种中。同样，在不同的实验中，植物物种丰富度的时间响应也不同（三个实验中丰富度降低，只有一个增加）。在任何情况下，大多数情况下，放牧和未放牧样地的植被时间轨迹都朝着相似的方向移动。有趣的是，毯子沼泽实验表明，无论是放牧还是未放牧的样地，其组成都明显趋同，尽管站点之间的差异与海拔和过去燃烧的结合有关。最后，苔藓植物（特别是地钱）和藻类是导致物种丰富度降低的主要类群。此外，在土地废弃/野生化方法下实施无放牧策略，在短期内不会导致研究中的植物群落发生太多的植物变化。
