Background invertebrate herbivory on dwarf birch (Betula glandulosa-nana complex) increases with temperature and precipitation across the tundra biome
Background invertebrate herbivory on dwarf birch (Betula glandulosa-nana complex) increases with temperature and precipitation across the tundra biome
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DOI：
10.1007/s00300-017-2139-7
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发表时间：
2017-11-01
期刊：
影响因子：
1.7
通讯作者：
Kozlov, Mikhail V.
中科院分区：
文献类型：
--
作者：
Barrio, Isabel C.;Linden, Elin;Kozlov, Mikhail V.
无脊椎动物慢性的、低强度的食草性，被称为背景食草性，在冻土带已经得到了充分的研究，但其影响可能会在变暖的北极地区增加。然而，这些变化的幅度很难预测，因为我们对苔原目前无脊椎食草动物水平的驱动因素知之甚少。我们评估了一种常见的冻土带植物矮桦树（Betula glandulosa-nana complex）的无脊椎草食强度，并研究了其与整个冻土带生物群系纬度和气候的关系。研究人员从56个地点的192个地点采集样本，测量了无脊椎动物的落叶、采伐和胆囊形成对叶片的损害。我们的研究结果表明，无脊椎食草动物在整个冻土带生物群系中几乎无处不在，但发生的强度很低。平均而言，无脊椎动物破坏了11.2%的叶片，并使总叶面积减少了1.4%。主要由外源取食者造成，大部分受损叶片仅受轻微影响（叶面积损失12%）。在收集数据的年份，无论纬度如何，叶片损害与仲夏（7月）温度始终呈正相关，与降水呈较小程度的正相关。我们的模型预测，平均而言，夏季气温每升高1摄氏度，矮桦树无脊椎动物的叶面损失可能会比目前的水平增加6-7%。研究结果表明，矮桦树的无脊椎食草性规模较小，但考虑到其普遍性和对气候变量的依赖性，应将背景无脊椎食草性纳入气候变化对冻土带生态系统的影响预测。
Chronic, low intensity herbivory by invertebrates, termed background herbivory, has been understudied in tundra, yet its impacts are likely to increase in a warmer Arctic. The magnitude of these changes is however hard to predict as we know little about the drivers of current levels of invertebrate herbivory in tundra. We assessed the intensity of invertebrate herbivory on a common tundra plant, the dwarf birch (Betula glandulosa-nana complex), and investigated its relationship to latitude and climate across the tundra biome. Leaf damage by defoliating, mining and gall-forming invertebrates was measured in samples collected from 192 sites at 56 locations. Our results indicate that invertebrate herbivory is nearly ubiquitous across the tundra biome but occurs at low intensity. On average, invertebrates damaged 11.2% of the leaves and removed 1.4% of total leaf area. The damage was mainly caused by external leaf feeders, and most damaged leaves were only slightly affected (12% leaf area lost). Foliar damage was consistently positively correlated with mid-summer (July) temperature and, to a lesser extent, precipitation in the year of data collection, irrespective of latitude. Our models predict that, on average, foliar losses to invertebrates on dwarf birch are likely to increase by 6-7% over the current levels with a 1 degrees C increase in summer temperatures. Our results show that invertebrate herbivory on dwarf birch is small in magnitude but given its prevalence and dependence on climatic variables, background invertebrate herbivory should be included in predictions of climate change impacts on tundra ecosystems.