Plant-plant interactions could limit recruitment and range expansion of tall shrubs into alpine and Arctic tundra
Plant-plant interactions could limit recruitment and range expansion of tall shrubs into alpine and Arctic tundra
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DOI：
10.1007/s00300-018-2355-9
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发表时间：
2018-11-01
期刊：
影响因子：
1.7
通讯作者：
Boudreau, Stephane
中科院分区：
文献类型：
--
作者：
Angers-Blondin, Sandra;Myers-Smith, Isla H.;Boudreau, Stephane
在气候变暖的影响下，限冷生物群落的物种将扩大其分布范围。对于植物来说，范围转移只能通过成功招募超过其当前分布限制而发生。然而，许多环境和生态过滤器可以在招募和建立时起作用，从而可能限制预期的气候驱动的变化。在这项研究中，我们研究了加拿大西部北极地区高山和北极苔原高灌丛植被对柳树物种成功建立的潜在机械和化学限制。我们收集了来自高山和北极灌丛的柳树种子，并进行了发芽试验，以测试(1)三种自然种子床和一种实验种子床对种子床的偏好，以及(2)对白垩矮灌木物种产生的化感化学物质的脆弱性。我们发现，在人工裸露的地面上，发芽率几乎是在完整的草本植被上的四倍。矮灌木四角木犀叶提取物对北极柳（Salix arctica）和pulchra柳（Salix pulchra）的种子没有影响，但四角木犀叶提取物对richardsonii柳（Salix richardsonii）的萌发率降低了24%。我们的研究结果表明，生物相互作用可能通过干扰萌发来限制高灌木在冻土带的预测扩张。看似物种特异性的反应强调了在更大范围的物种组合中进行重复研究的必要性。潜在的范围转移可能不会作为灌丛的统一易位而发生，但可能通过过滤掉某些物种而改变植物群落的组成。
Species in cold-limited biomes are expected to expand their distribution ranges in response to climate warming. For plants, range shifts can only occur via successful recruitment beyond their current distribution limit. However, many environmental and ecological filters can act upon recruitment and establishment, thereby potentially limiting the expected climate-driven shifts. In this study, we investigate potential mechanical and chemical constraints that vegetation above the tall shrubline in alpine and Arctic tundra could impose upon the successful establishment of willow species in the Canadian Western Arctic. We collected willow seeds from an alpine and an Arctic shrubline and conducted germination trials to test (1) for seedbed preferences among three natural and one experimentally scarified seedbeds, and (2) for vulnerability to allelopathic chemicals produced by ericaceous dwarf shrub species. We found that germination was almost four times higher on manually exposed bare ground than on intact, herbaceous vegetation. Seeds of two willow species, Salix arctica and Salix pulchra, were not affected by leaf extracts from dwarf shrubs, Cassiope tetragona and Vaccinum uliginosum, but the germination of Salix richardsonii was reduced by as much as 24% in the presence of chemicals from C. tetragona. Our results suggest that biotic interactions could limit the predicted expansion of tall shrubs in the tundra by interfering with germination. Seemingly species-specific responses highlight the need for replicated studies across a wider range of species combinations. Potential range shifts may not occur as a uniform translocation of the shrubline, but could change the composition of the plant community by filtering out certain species.