Loss of small glaciers will diminish beta diversity in Pyrenean streams at two levels of biological organization
Loss of small glaciers will diminish beta diversity in Pyrenean streams at two levels of biological organization
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DOI：
10.1111/j.1466-8238.2012.00766.x
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发表时间：
2013-01-01
影响因子：
6.4
通讯作者：
Milner, Alexander M.
中科院分区：
文献类型：
--
作者：
Finn, Debra S.;Khamis, Kieran;Milner, Alexander M.
目标 小型（< 1 平方公里）高山冰川可能在本世纪消失，导致相关溪流的区域栖息地异质性降低。受冰川影响的溪流内部的异质性和空间隔离都可以增强溪流生物的β多样性。我们测量了目前受小比利牛斯冰川影响的溪流内部和之间的群落和种群遗传水平的贝塔值。我们的目的是评估这两个层面之间的模式是否相似，应用各种方法来表征贝塔，并推断未来冰川消失对区域生物多样性的影响。位置 法国比利牛斯国家公园的四个冰川盆地。方法 根据四种物理化学特征，我们将流域内 18 条河段分别分为高冰川期、中冰川期或低冰川期（冰川影响）组。在每个河段，我们收集了大型无脊椎动物群落，并评估了 1113 个 Baetis alpinus Pictet 个体的线粒体 DNA 单倍型。使用类群/单倍型作为基本单位，我们同时评估了群落和群体遗传β多样性。我们通过三种主要方式测量β多样性：作为多变量（索伦森相异性，Jost D）和经典（伽玛/阿尔法）变异来比较冰川活动组之间的差异，以及沿每个盆地内冰川活动梯度的周转。结果对于两个组织层面的大多数方法，β在高冰川河段中最大，高冰川河段中β变化的绝对值在不同级别之间惊人地相似，盆地内最陡的周转发生在高冰川河段和中冰川河段之间。因此，高冰川河段所包含的组合和种群在该河流类型（流域之间）内以及与流域内的其他河流类型相比都是独一无二的。主要结论 种群遗传和群落水平上的平行 β 多样性模式表明，环境驱动因素对这些水平的影响类似。高冰川活动流中的极端条件（例如低温、高度不稳定、孤立）可能会增强两个层面的贝塔值。随着该系统冰川的持续减少，溪流贝塔多样性可能会大幅减少。
Aim Small (< 1 km2) alpine glaciers are likely to disappear in this century, resulting in decreased regional habitat heterogeneity in associated streams. Both heterogeneity within and spatial isolation among glacier-influenced streams can enhance beta diversity of stream-dwelling organisms. We measured beta at both community and population-genetic levels within and among streams currently influenced by small Pyrenean glaciers. We aimed to evaluate whether patterns are analogous between the two levels, to apply various approaches for characterizing beta, and to infer the outcome of future glacier loss on regional biodiversity. Location Four glacier-fed basins in the Parc National des Pyrenees, France. Methods We classified each of 18 stream reaches across the basins into either high-, mid- or low-glaciality (glacial influence) groups according to four physicochemical characteristics. At each reach, we collected macroinvertebrate communities and evaluated mitochondrial DNA haplotypes for 1113 individuals of Baetis alpinus Pictet. Using taxa/haplotypes as basic units, we evaluated community and population-genetic beta diversity simultaneously. We measured beta diversity in three major ways: as multivariate (Sorensen's dissimilarity, Jost D) and classical (gamma/alpha) variation to compare among glaciality groups, and as turnover along the glaciality gradient within each basin. Results For most approaches at both organizational levels, beta was greatest among high-glaciality reaches, absolute values of variation of beta in high-glaciality streams were strikingly similar between levels, and the steepest turnover within basins occurred between high- and mid-glaciality reaches. Therefore, high-glaciality reaches contained assemblages and populations that were unique both within that stream type (among basins) and compared with other stream types within basins. Main conclusions Parallel beta diversity patterns at population-genetic and community levels suggested that environmental drivers influence these levels analogously. Extreme conditions (e.g. low temperature, high instability, isolation) in high-glaciality streams probably enhance beta at both levels. Stream beta diversity is likely to decrease substantially with continued glacial reduction in this system.