Department of Plant Ecology & Environmental Conservation, Institute of Botany, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland.
Ecosystem Management Research Group, Department of Biology, University of Antwerp, Antwerp, Belgium.
PLoS One. 2019 Apr 24;14(4):e0215645. doi: 10.1371/journal.pone.0215645. eCollection 2019.
In peatland restoration we often lack an information whether re-established ecosystems are functionally similar to non-degraded ones. We re-analysed the long-term outcomes of restoration on vegetation and plant functional traits in 38 European fens restored by rewetting (18 sites) and topsoil removal (20 sites). We used traits related to nutrient acquisition strategies, competitiveness, seed traits, and used single- and multi-trait metrics. A separate set of vegetation records from near-natural fens with diverse plant communities was used to generate reference values to aid the comparisons. We found that both restoration methods enhanced the similarity of species composition to non-degraded systems but trait analysis revealed differences between the two approaches. Traits linked to nutrient acquisition strategies indicated that topsoil removal was more effective than rewetting. After topsoil removal competitive species in plant communities had decreased, while stress-tolerant species had increased. A substantial reduction in nutrient availability ruled out the effect of initial disturbance. An ability to survive and grow in anoxic conditions was enhanced after restoration, but the reference values were not achieved. Rewetting was more effective than topsoil removal in restricting variation in traits values permitted in re-developing vegetation. We found no indication of a shift towards reference in seed traits, which suggested that dispersal constraint and colonization deficit can be a widespread phenomena. Two functional diversity indices: functional richness and functional dispersion showed response to restoration and shifted values towards reference mires and away from the degraded systems. We concluded that targeting only one type of environmental stressor does not lead to a recovery of fens, as it provides insufficient level of stress to restore a functional ecosystem. In general, restoration efforts do not ensure the re-establishment and long-term persistence of fens. Restoration efforts result in recovery of fen ecosystems, confirmed with our functional trait analysis, although more rigid actions are needed for restoring fully functional mires, by achieving high and constant levels of anoxia and nutrient stresses.
在泥炭地恢复中，我们经常缺乏关于重建生态系统是否在功能上与未退化系统相似的信息。我们重新分析了通过再湿地化（18 个地点）和表土去除（20 个地点）恢复的 38 个欧洲泥沼的植被和植物功能特征的长期结果。我们使用了与养分获取策略、竞争力、种子特征有关的特征，并使用了单一和多特征指标。还使用了具有不同植物群落的近自然泥沼的单独植被记录来生成参考值以辅助比较。我们发现，两种恢复方法都增强了物种组成与未退化系统的相似性，但特征分析显示了两种方法之间的差异。与养分获取策略相关的特征表明，表土去除比再湿地化更有效。在表土去除后，植物群落中的竞争物种减少，而耐胁迫物种增加。养分供应的大量减少排除了初始干扰的影响。在恢复后，在缺氧条件下生存和生长的能力得到了增强，但仍未达到参考值。与表土去除相比，再湿地化在限制重新发育植被中允许的特征值变化方面更为有效。我们没有发现种子特征向参考值转变的迹象，这表明扩散限制和定植不足可能是普遍现象。两个功能多样性指数：功能丰富度和功能分散度对恢复有反应，并且数值向参考沼泽转移，远离退化系统。我们得出的结论是，仅针对一种环境胁迫因子不会导致沼泽的恢复，因为它提供的压力水平不足以恢复功能生态系统。总的来说，恢复努力不能确保沼泽的重建和长期存在。通过我们的功能特征分析，恢复努力确实恢复了沼泽生态系统，尽管需要更严格的措施来恢复完全功能的沼泽，通过实现高且稳定的缺氧和养分胁迫水平。
