Does urbanization lead to taxonomic and functional homogenization in riparian forests?
Does urbanization lead to taxonomic and functional homogenization in riparian forests?
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DOI：
10.1111/ddi.12565
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发表时间：
2017-07-01
影响因子：
4.6
通讯作者：
Poulin, Monique
中科院分区：
文献类型：
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作者：
Brice, Marie-Helene;Pellerin, Stephanie;Poulin, Monique
目的：在城市化地区，外来入侵、本土排斥、栖息地的改变和自然过程推动了同质化，这是生物灭绝的一种形式。本研究探讨城市化和洪水是否会导致同质化的草本群落在河岸森林和量化的分类和功能β-diversity.Location之间的关系：蒙特利尔，魁北克，加拿大。分类和功能β-多样性的计算为三个层次的城市化和洪水的物种或性状组成的网站之间的相似性。干扰水平之间的差异进行了比较，使用多元分散体的同质性测试。我们量化了当地物种丰富度，外来比例，分类和功能β多样性之间的相关性。我们还划分分类β多样性为物种周转和丰富度difference.Results：城市化导致分类和功能分化，而增加洪水导致分类和功能同质化。我们发现分类和功能β多样性之间存在显著相关性。β-多样性的变化与城市化和洪水水位之间的物种和性状周转，并与物种丰富度的变化。分化与低物种丰富度，和高物种丰富度的同质化。外来入侵倾向于促进物种分化，但仅在较低的城市化水平下。主要结论：城市化对河岸林植物多样性的影响是双重的：第一，它通过对物种损失和周转的影响直接诱导分类和功能分化（高城市化水平下的β多样性较高）;第二，通过减少洪水（在低洪水水位时更高的β多样性）间接有利于分化。分类学和功能β多样性遵循类似的模式，可能是因为物种入侵和灭绝不是随机的，而是与物种特征有关。我们的研究结果强调，需要把我们的重点从外来物种的生物多样性丧失和同质化，特别是土地利用的变化和人类干扰的真正的根本因素。
Aim: In urbanized areas, exotic invasions, native extinctions, and the alteration of habitats and natural processes drive homogenization, which is a form of biotic impoverishment. This study examines whether urbanization and flooding induce homogenization of herbaceous communities in riparian forests and quantifies the relationships between taxonomic and functional beta-diversity.Location: Montreal, Quebec, Canada.Methods: Inventories were conducted in 56 riparian forests. Taxonomic and functional beta-diversity were calculated as between-site similarities in species or trait composition for three levels of urbanization and flooding. Differences among the disturbance levels were compared using tests for homogeneity in multivariate dispersions. We quantified the correlation between local species richness, exotic proportion, taxonomic and functional beta-diversity. We also partitioned taxonomic beta-diversity into species turnover and richness difference.Results: Urbanization led to taxonomic and functional differentiation, while increased flooding led to taxonomic and functional homogenization. We found a significant correlation between taxonomic and functional beta-diversity. Changes in beta-diversity were associated with species and trait turnover among both urbanization and flood levels, and with changes in species richness. Differentiation was associated with low species richness, and homogenization with high species richness. Exotic invasions tended to favour differentiation, but only at a low urbanization level.Main Conclusions: The effect of urbanization on plant diversity in riparian forests was twofold: first, it directly induced taxonomic and functional differentiation through its effect on species loss and turnover (higher beta-diversity at high urbanization level); second, differentiation was indirectly favoured through the reduction in flooding (higher beta-diversity at low flood level). Taxonomic and functional beta-diversity followed similar patterns, likely because species invasions and extinctions are not random, but are related to species traits. Our results underline the need to move our focus from exotic species to the true underlying factors of biodiversity loss and homogenization, notably land use changes and human disturbances.