Local and regional drivers of taxonomic homogenization in stream communities along a land use gradient
Local and regional drivers of taxonomic homogenization in stream communities along a land use gradient
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DOI：
10.1111/geb.12976
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发表时间：
2019-07
影响因子：
6.4
通讯作者：
William R. Budnick;T. Leboucher;J. Belliard;J. Soininen;I. Lavoie;Katrina L. Pound;A. Jamoneau;J. Tison‐Rosebery;É. Tales;V. Pajunen;Stéphane Campeau;S. Passy
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作者：
William R. Budnick;T. Leboucher;J. Belliard;J. Soininen;I. Lavoie;Katrina L. Pound;A. Jamoneau;J. Tison‐Rosebery;É. Tales;V. Pajunen;Stéphane Campeau;S. Passy
目的土地利用与推动生物同质化(β多样性丧失)的局部和区域过程的相互作用还知之甚少。我们探讨了：(A)溪流β多样性对土地覆盖(森林与农业)的物理化学和物理化学异质性的响应；(B)这些响应是否受到区域物种池，即γ多样性，或通过局部(α)多样性的局部组装过程的限制；(C)局部组装是通过区域物种丰度分布运行，还是通过种内空间聚集；以及(D)对个体大小、扩散能力和营养水平(生产者与消费者)的依赖。位置：美国、加拿大和法国。时间段为1993-2012年。主要分类群研究溪流硅藻、昆虫和鱼类。方法我们分析了6个数据集，共计1225个溪流样本。我们用回归方法比较了森林和农业溪流对富营养化和物理化学异质性的多样性响应。零模型量化了两种类型土地覆盖的局部集聚对β多样性(β-dev，β)的贡献，并将其划分为由区域SAD(βSAD)与聚集度(βAGG)解释的部分。结果富营养化解释了种群间的同质化和更不均匀的区域SADS，但不同类群的局部和区域生物多样性反应是不同的。β开发环境对土地利用不敏感。βSAD值在很大程度上超过了βAGG，农业的SAD值更高。主要结论农业水体的富营养化而不是物理化学的异质性是硅藻、昆虫和鱼类β多样性丧失的基础。农业不限制地方和地区对β多样性的影响的大小，但控制了当地的组装机制。虽然SAD在两种土地覆盖中占主导地位，但在农业中进一步增加，但损害了聚集性。值得注意的是，区域SADS在农业上更不均衡，表现出过多的常见物种或更强的优势度。硅藻和昆虫在生物多样性、SAD形状和βDEV模式方面与鱼类不同，表明与营养位置相比，身体大小和/或扩散能力具有压倒一切的作用。
Aim The interaction of land use with local versus regional processes driving biological homogenization (β‐diversity loss) is poorly understood. We explored: (a) stream β‐diversity responses to land cover (forest versus agriculture) in terms of physicochemistry and physicochemical heterogeneity; (b) whether these responses were constrained by the regional species pool, i.e. γ‐diversity, or local assembly processes through local (α) diversity; (c) whether local assembly operated through the regional species abundance distribution (SAD) or intraspecific spatial aggregation; and (d) the dependence on body size, dispersal capacity and trophic level (producer versus consumer). Location USA, Canada and France. Time period 1993–2012. Major taxa studied Stream diatoms, insects and fish. Methods We analysed six datasets totalling 1,225 stream samples. We compared diversity responses to eutrophication and physicochemical heterogeneity in forested versus agricultural streams with regression methods. Null models quantified the contribution of local assembly to β‐diversity (β‐deviance, βDEV) for both types of land covers and partitioned it into fractions explained by the regional SAD (βSAD) versus aggregation (βAGG). Results Eutrophication explained homogenization and more uneven regional SADs across groups, but local and regional biodiversity responses differed across taxa. The βDEV was insensitive to land use. The βSAD largely exceeded βAGG and was higher in agriculture. Main conclusions Eutrophication but not physicochemical heterogeneity of agricultural streams underlay β‐diversity loss in diatoms, insects and fish. Agriculture did not constrain the magnitude of local versus regional effects on β‐diversity but controlled the local assembly mechanisms. Although the SAD fraction dominated in both land covers, it increased further in agriculture at the expense of aggregation. Notably, the regional SADs were more uneven in agriculture, exhibiting excess common species or stronger dominance. Diatoms and insects diverged from fish in terms of biodiversity, SAD shape and βDEV patterns, suggesting an overriding role of body size and/or dispersal capacity compared with trophic position.