Schnoor Tim, Bruun Hans Henrik, Olsson Pål Axel
Biodiversity, Department of Biology, Lund University. The Ecology Building, SE-223 62 Lund, Sweden.
Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark.
PLoS One. 2015 Apr 13;10(4):e0123698. doi: 10.1371/journal.pone.0123698. eCollection 2015.
Soil disturbance is recognized as an important driver of biodiversity in dry grasslands, and can therefore be implemented as a restoration measure. However, because community re-assembly following disturbance includes stochastic processes, a focus only on species richness or establishment success of particular species will not inform on how plant communities respond ecologically to disturbance. We therefore evaluated vegetation development following disturbance by quantifying species richness, species composition and functional trait composition. Degraded calcareous sandy grassland was subjected to experimental disturbance treatments (ploughing or rotavation), and the vegetation was surveyed during four subsequent years of succession. Treated plots were compared with control plots representing untreated grassland, as well as nearby plots characterized by plant communities representing the restoration target. Species richness and functional diversity both increased in response to soil disturbance, and rotavation, but not ploughing, had a persistent positive effect on the occurrence of specialist species of calcareous sandy grassland. However, no type of soil disturbance caused the plant species composition to develop towards the target vegetation. The disturbance had an immediate and large impact on the vegetation, but the vegetation developed rapidly back towards the control sites. Plant functional composition analysis indicated that the treatments created habitats different both from control sites and target sites. Community-weighted mean Ellenberg indicator values suggested that the observed plant community response was at least partially due to an increase in nitrogen and water availability following disturbance. This study shows that a mild type of disturbance, such as rotavation, may be most successful in promoting specialist species in calcareous sandy grassland, but that further treatments are needed to reduce nutrient availability. We conclude that a functional trait based analysis provides additional information of the vegetation response and the abiotic conditions created, complementing the information from the species composition.
土壤扰动被认为是干旱草原生物多样性的一个重要驱动因素，因此可作为一种恢复措施来实施。然而，由于扰动后的群落重新组装包括随机过程，仅关注物种丰富度或特定物种的建立成功率并不能说明植物群落如何对扰动做出生态响应。因此，我们通过量化物种丰富度、物种组成和功能性状组成来评估扰动后的植被发育情况。对退化的钙质沙质草原进行了实验性扰动处理（耕作或旋耕），并在随后的四年演替过程中对植被进行了调查。将处理过的样地与代表未处理草原的对照样地以及以代表恢复目标的植物群落为特征的附近样地进行比较。物种丰富度和功能多样性均因土壤扰动而增加，旋耕而非耕作对钙质沙质草原特有物种的出现具有持续的积极影响。然而，没有一种土壤扰动类型能使植物物种组成朝着目标植被发展。扰动对植被产生了即时且巨大的影响，但植被迅速恢复到对照样地的状态。植物功能组成分析表明，这些处理创造了与对照样地和目标样地都不同的栖息地。群落加权平均埃伦贝格指示值表明，观察到的植物群落响应至少部分归因于扰动后氮和水有效性的增加。这项研究表明，轻度扰动类型，如旋耕，可能在促进钙质沙质草原特有物种方面最为成功，但需要进一步处理以降低养分有效性。我们得出结论，基于功能性状的分析提供了植被响应和所创造的非生物条件的额外信息，补充了来自物种组成的信息。
