Hellenic Centre for Marine Research, Institute of Marine Biological Resources and Inland Waters, 46.7 km of Athens-Sounio Ave., 19013, Anavyssos, Attiki, Greece; Department of Biology, University of Patras, University Campus Rio, GR 26500, Patras, Greece.
Hellenic Centre for Marine Research, Institute of Marine Biological Resources and Inland Waters, 46.7 km of Athens-Sounio Ave., 19013, Anavyssos, Attiki, Greece.
J Environ Manage. 2021 Oct 15;296:113307. doi: 10.1016/j.jenvman.2021.113307. Epub 2021 Jul 26.
Aquatic and riparian plants play a crucial role in the functioning of riverine ecosystems. Hence, analyzing multiple facets of plant diversity could be extremely useful for assessing the ecological integrity of lotic ecosystems. The main objective of this study was to investigate the response of multiple facets of aquatic plant diversity, such as species richness, taxonomic distinctness and compositional dissimilarity, to environmental factors (i.e. nutrient pollution and hydromorphological alteration) in 72 stream reaches of mainland Greece. We employed Generalized Additive Models to identify the variables with the highest influence and examine the response of species richness and taxonomic distinctness to environmental gradients. The relationship between compositional dissimilarity and the environment was examined with Generalized Dissimilarity Modelling. Our results supported our hypothesis that human disturbances play a considerable role in shaping macrophyte assemblages. In particular, phosphates and hydromorphological modification were significant predictors of species richness, whereas taxonomic distinctness was unaffected by indicators of anthropogenic stress but it was influenced mostly by elevation, water temperature and pH. Concerning the compositional dissimilarity, geographic distance, elevation, temperature and total inorganic nitrogen were the most important environmental parameters. Our findings suggest that human stressors, such as hydromorphological modification and nutrient enrichment, affect the plant species richness at stream reach scale, but when considering community composition or taxonomic distinctness, environmental factors associated with the natural variability (e.g. elevation, temperature and geographic distance) are of higher importance. Overall, our results emphasize the advantage of examining multiple aspects of diversity when designing conservation schemes and management plans for riparian areas.
水生植物和河岸植物在河流生态系统的功能中起着至关重要的作用。因此，分析植物多样性的多个方面对于评估流水生态系统的生态完整性可能非常有用。本研究的主要目的是调查水生植物多样性的多个方面（如物种丰富度、分类学独特性和组成差异）对希腊大陆 72 个溪流地段环境因素（即营养污染和水力学形态变化）的响应。我们采用广义加性模型来确定具有最大影响的变量，并检查物种丰富度和分类学独特性对环境梯度的响应。使用广义差异模型来检验组成差异与环境之间的关系。我们的结果支持了这样的假设，即人为干扰在塑造大型植物组合方面起着相当大的作用。特别是磷酸盐和水力学形态变化是物种丰富度的重要预测因子，而分类学独特性不受人为压力指标的影响，但主要受海拔、水温、pH 值的影响。关于组成差异，地理距离、海拔、温度和总无机氮是最重要的环境参数。我们的研究结果表明，水力学形态变化和营养富化等人为压力会影响溪流地段的植物物种丰富度，但在考虑群落组成或分类学独特性时，与自然变异性相关的环境因素（如海拔、温度和地理距离）更为重要。总的来说，我们的研究结果强调了在设计河岸地区保护计划和管理计划时，检查多样性的多个方面的优势。
