Productivity–diversity patterns in arctic tundra vegetation
Productivity–diversity patterns in arctic tundra vegetation
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DOI：
10.1111/j.1600-0587.2012.07903.x
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发表时间：
2013-03
期刊：
影响因子：
5.9
通讯作者：
R. Virtanen;J. Grytnes;J. Lenoir;M. Luoto;J. Oksanen;L. Oksanen;Jens‐Christian Svenning
中科院分区：
文献类型：
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作者：
R. Virtanen;J. Grytnes;J. Lenoir;M. Luoto;J. Oksanen;L. Oksanen;Jens‐Christian Svenning
长期以来，生产力一直被认为是物种丰富度模式的主要驱动力。在本研究中，我们测试替代生产力多样性假说，从广阔的欧亚苔原植被数据。生产力物种池假说预测在细粒度和粗粒度的正相关关系，而生产力相互作用假说预测在细粒度的单峰模式，和单调的正模式在粗粒度。此外，我们希望找到平坦的积极（生产力物种池假说）或更强烈的负（生产力相互作用假说）的关系，地衣和brathtes比维管植物，因为作为一个群体，地衣和brathtes更好地适应极端的北极条件，更容易受到竞争的光比生长较高的维管植物。归一化植被指数（NDVI）被用来作为生产力的代理。一般单峰的生产力多样性模式是最符合生产力互动假说。有一个普遍的趋势，减少物种丰富度从中度到最高生产力的苔原，在协议的竞争性相互作用的重要性日益增加。维管植物和地衣的高度丰富性发生在生产力中等较低的苔原地区，而苔藓植物的高度丰富性发生在本研究覆盖的生产力最低的苔原栖息地。细颗粒和粗颗粒丰富度的趋势是令人惊讶的均匀和β多样性没有变化沿着生产力梯度被视为维管植物或branchites。然而，地衣β多样性变化沿着生产力梯度，可能反映了他们的栖息地条件和生物相互作用的敏感性。总体而言，结果表明，生产力多样性梯度存在于苔原，这些似乎在很大程度上是由竞争性的相互作用。我们的研究结果还表明，气候变暖驱动的生产力的增加将强烈影响北极植物多样性模式。
Productivity has long been argued to be a major driver of species richness patterns. In the present study we test alternative productivity–diversity hypotheses using vegetation data from the vast Eurasian tundra. The productivity–species pool hypothesis predicts positive relationships at both fine and coarse grain sizes, whereas the productivity–interaction hypothesis predicts unimodal patterns at fine grain size, and monotonic positive patterns at coarse grain size. We furthermore expect to find flatter positive (productivity–species pool hypothesis) or more strongly negative (productivity–interaction hypothesis) relationships for lichens and bryophytes than for vascular plants, because as a group, lichens and bryophytes are better adapted to extreme arctic conditions and more vulnerable to competition for light than the taller-growing vascular plants. The normalised difference vegetation index (NDVI) was used as a proxy of productivity. The generally unimodal productivity–diversity patterns were most consistent with the productivity–interaction hypothesis. There was a general trend of decreasing species richness from moderately to maximally productive tundra, in agreement with an increasing importance of competitive interactions. High richness of vascular plants and lichens occurred in moderately low productive tundra areas, whereas that of bryophytes occurred in the least productive tundra habitats covered by this study. The fine and coarse grain richness trends were surprisingly uniform and no variation in beta diversity along the productivity gradient was seen for vascular plants or bryophytes. However, lichen beta diversity varied along the productivity gradient, probably reflecting their sensitivity to habitat conditions and biotic interactions. Overall, the results show evidence that productivity–diversity gradients exist in tundra and that these appear to be largely driven by competitive interactions. Our results also imply that climate warming-driven increases in productivity will strongly affect arctic plant diversity patterns.