Lepš Jan, Lisner Aleš
Department of Botany, Faculty of Science University of South Bohemia České Budějovice Czech Republic.
Biology Center of the Czech Academy of Sciences Institute of Entomology České Budějovice Czech Republic.
Ecol Evol. 2025 Jan 29;15(2):e70923. doi: 10.1002/ece3.70923. eCollection 2025 Feb.
Traditionally managed grasslands are among the most species-rich communities, which are threatened by land use changes-management intensification or abandonment. The resistance of their species composition to mismanagement and ability to recover after re-establishment of traditional management is of prime conservational interest. In a manipulative experiment in a wet meadow, we simulated mismanagement by a factorial combination of abandonment of mowing and fertilization. The dominant species was removed in half of the plots to assess its role in community dynamics. The 21 years' mismanagement period was followed by the re-establishment of the traditional management. The plots were sampled yearly from 1994 (the baseline data, before the introduction of the experimental treatments), until 2023. Estimates of cover of all vascular plant species provided the species richness and effective number of species. For each year, the chord distances to baseline species composition and to corresponding control plot were calculated. The compositional data were analyzed by constrained ordination methods, and the univariate characteristics by Repeated Measures ANOVA. All the plots, including those with traditional management throughout the whole experiment, underwent directional changes, probably caused by a decrease in groundwater level due to global warming. Both fertilization and abandonment led to a loss of competitively weak, usually low-statured species, due to increased asymmetric competition for light. The effect of fertilization was faster and stronger than that of abandonment demonstrating weaker resistance to fertilization. The removal of dominant species partially mitigated negative effects only in unmown, non-fertilized plots. The recovery following mismanagement cessation was faster (signifying higher resilience) in unmown than in fertilized plots, where it was slowed by a legacy of fertilization. In a changing world, two reference plot types are recommended for assessment of resistance and resilience, one original state and one reflecting compositional changes independent of treatments.
传统管理的草原是物种最为丰富的群落之一，却受到土地利用变化（管理强度增加或弃管）的威胁。其物种组成对管理不善的抵抗力以及在恢复传统管理后恢复的能力是保护工作的首要关注点。在一个湿地草甸进行的操控实验中，我们通过割草和施肥弃管的因子组合来模拟管理不善的情况。在一半的样地中移除优势物种，以评估其在群落动态中的作用。在21年的管理不善期之后，恢复传统管理。从1994年（引入实验处理之前的基线数据）到2023年，每年对样地进行采样。对所有维管植物物种的盖度估计提供了物种丰富度和有效物种数。每年计算与基线物种组成以及相应对照样地的弦距离。通过受限排序方法分析组成数据，通过重复测量方差分析分析单变量特征。所有样地，包括在整个实验中采用传统管理的样地，都经历了方向性变化，这可能是由于全球变暖导致地下水位下降所致。施肥和弃管都导致了竞争力较弱、通常植株较矮的物种的丧失，这是由于对光照的不对称竞争加剧。施肥的影响比弃管更快、更强，表明对施肥的抵抗力较弱。仅在未割草、未施肥的样地中，移除优势物种部分减轻了负面影响。管理不善停止后的恢复在未割草的样地中更快（意味着恢复力更高），而在施肥的样地中则较慢，施肥的遗留影响减缓了恢复。在不断变化的世界中，建议使用两种参考样地类型来评估抵抗力和恢复力，一种是原始状态，另一种反映独立于处理的组成变化。
