Abstract

Fossorial rodents are recognized as diversity drivers in grassland ecosystems and are therefore considered ecosystem engineers and keystone species. However, there is a lack of evidence regarding this function for species in temperate grasslands, especially one of the most threatened, the European ground squirrel. We examined the effect of the European ground squirrel on plant species composition and diversity along the disturbance gradient mediated by their different population density and subsequently different disturbance intensity. We evaluated the effect of ground squirrel disturbance on plant diversity patterns in two plant communities with different species richness to determine whether the same pattern exists in contrasting habitats. In each plant community, we established transect of 25 × 250 m composed of 10 quadrats with different disturbance intensities of the ground squirrels. Vascular plant species were recorded in 320 plots of 1 m². The distribution of individual species along the ground squirrel-mediated disturbance gradient was analysed using redundancy analysis. Diversity measures were calculated and modelled as a function of disturbances using generalized additive models. We observed significant compositional changes in plant communities accompanied by a reduction in dominant graminoid cover and a non-decreasing trend in forb cover along the disturbance gradient in both types of communities. We found that increasing disturbance activity leads to an increase in diversity at coarse spatial scale (625 m²) and spatial heterogeneity in species composition of both species-poor and species-rich plant community. The fine-scale (1 m²) diversity increased significantly only in species-poor community. Our results demonstrate that the European ground squirrel can be deservedly labelled as an important ecosystem engineer and keystone species promoting the diversity and heterogeneity of European temperate grasslands.

中文翻译：

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欧洲地松鼠的干扰增加了温带草原植物群落的多样性和空间异质性

摘要

啮齿类啮齿动物被认为是草原生态系统中的多样性驱动因素，因此被认为是生态系统工程师和重点物种。但是，在温带草原，特别是最受威胁的欧洲地松鼠之一中，缺乏有关这种功能的证据。我们研究了欧洲地松鼠对植物种类组成和多样性的影响，这些松鼠沿着不同的种群密度和随后不同的干扰强度介导的干扰梯度。我们评估了地松鼠干扰对物种丰富度不同的两个植物群落中植物多样性模式的影响，以确定在相对的生境中是否存在相同的模式。在每个植物群落中 我们建立了25×250 m的样条，该样条由10个四边形组成，它们具有不同的地松鼠干扰强度。在1 m的320个样地中记录了维管束植物物种²。使用冗余分析分析了沿地鼠介导的干扰梯度的单个物种的分布。计算了多样性测度，并使用广义加性模型将其作为干扰的函数建模。我们观察到植物群落中的显着成分变化，伴随着两种类型群落的扰动梯度，主要的类蠕虫类动物的覆盖减少，而福布的覆盖率却没有下降。我们发现，增加干扰活动会导致在粗糙的空间尺度（625 m ²）上多样性的增加以及物种贫乏和物种丰富的植物群落物种组成的空间异质性。精细规模（1 m ²仅在物种贫乏的社区中多样性才显着增加。我们的结果表明，应将欧洲地松鼠标记为促进欧洲温带草原多样性和异质性的重要生态系统工程师和重点物种。