Climate adaption and post-fire restoration of a foundational perennial in cold desert: insights from intraspecific variation in response to weather
Climate adaption and post-fire restoration of a foundational perennial in cold desert: insights from intraspecific variation in response to weather
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DOI：
10.1111/1365-2664.12679
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发表时间：
2017-02-01
影响因子：
5.7
通讯作者：
Richardson, Bryce A.
中科院分区：
文献类型：
--
作者：
Brabec, Martha M.;Germino, Matthew J.;Richardson, Bryce A.
在半干旱地区，由于火灾规模和频率的增加，山艾树等基础但不耐火的多年生植物的损失促使人们努力恢复它们，但往往是成败参半，甚至没有成功。蒿属植物tridentata及其相关物种的种子必须从种子源转移到种植地很远的地方，但这种转移并没有受到对当地气候适应的理解的指导。最初的幼苗建立及其对天气的反应是一个关键的人口瓶颈，可能在不同亚种和种群中有所不同。在外植18个月的时间里，我们评估了11种不同亚种、细胞型和原产地气候的山艾树种子源对天气的生存、生长和生理反应的差异。山地、怀俄明和盆地大山艾属植物的二倍体或多倍体种群。vaseyana， A.tridentata s.p。怀俄明和三叉戟。结果表明，在5个正常生长的地点种植三叉戟，三叉戟的生长和存活率最高，四倍体种群的存活率和高度均高于二倍体种群。不同亚种/细胞型死亡的季节时间不同，与最低温度的关系比与水分亏缺的关系更密切。诱导冰形成所需的温度在4n- a - t高达6摄氏度。tridentata和a.t.w owomingensis比其他亚种/细胞型更强，表明它们更能避免冷冻。相比之下，亚种/细胞型间光合作用的抗冻性仅变化1℃，其中a.t.w owomingensis的抗冻性最大，而通常被认为最冷的亚种a.t.w aseyana的抗冻性最小。在亚种/细胞型中，观察到对避冻和耐冻的广泛依赖，并对应于火灾后存活的差异。亚种/细胞型之间水分亏缺反应的差异不那么强，与生存模式无关。合成与应用。低温响应是确定山艾树幼苗气候适应的关键轴，与亚种相比，细胞型的变化更大，这与传统的强调(i)水分限制来解释在这些沙漠中的建立，以及（ii）亚种选择恢复种子形成对比。这些关于气候适应的重要和新颖的见解对于种子选择和参数化种子转移区至关重要，并且通过将天气数据与生存统计相结合而成为可能。这里使用的生存/天气统计数据可以应用于任何恢复种植或播种，以帮助阐明促成成功的因素，并实现适应性管理。
The loss of foundational but fire-intolerant perennials such as sagebrush due to increases in fire size and frequency in semi-arid regions has motivated efforts to restore them, often with mixed or even no success. Seeds of sagebrush Artemisia tridentata and related species must be moved considerable distances from seed source to planting sites, but such transfers have not been guided by an understanding of local climate adaptation. Initial seedling establishment and its response to weather are a key demographic bottleneck that likely varies among subspecies and populations of sagebrush. We assessed differences in survival, growth and physiological responses of sagebrush seedlings to weather among eleven seed sources that varied in subspecies, cytotype and climates-of-origin over 18months following outplanting. Diploid or polyploid populations of mountain, Wyoming and basin big sagebrush (A.tridentata ssp. vaseyana, A.tridentata ssp. wyomingensis and A.tridentata ssp. tridentata, respectively) were planted onto five burned sites that normally support A.t.wyomingensis with some A.t.tridentata.A.t.wyomingensis had the most growth and survival, and tetraploid populations had greater survival and height than diploids. Seasonal timing of mortality varied among the subspecies/cytotypes and was more closely related to minimum temperatures than water deficit. Temperatures required to induce ice formation were up to 6 degrees C more negative in 4n-A.t.tridentata and A.t.wyomingensis than in other subspecies/cytotypes, indicating greater freezing avoidance. In contrast, freezing resistance of photosynthesis varied only 1 degrees C among subspecies/cytotypes, being greatest in A.t.wyomingensis and least in the subspecies normally considered most cold-adapted, A.t.vaseyana. A large spectrum of reliance on freezing avoidance vs. freezing tolerance was observed and corresponded to differences in post-fire survivorship among subspecies/cytotypes. Differences in water deficit responses among subspecies/cytotypes were not as strong and did not relate to survival patterns.Synthesis and applications. Low-temperature responses are a key axis defining climate adaptation in young sagebrush seedlings and vary more with cytotype than with subspecies, which contrasts with the traditional emphases on (i) water limitations to explain establishment in these deserts, and (ii) subspecies in selecting restoration seedings. These important and novel insights on climate adaptation are critical for seed selection and parameterizing seed transfer zones, and were made possible by incorporating weather data with survival statistics. The survival/weather statistics used here could be applied to any restoration planting or seeding to help elucidate factors contributing to success and enable adaptive management.