Liepe Katharina J, Hamann Andreas, Smets Pia, Fitzpatrick Connor R, Aitken Sally N
Department of Renewable Resources University of Alberta Edmonton AB Canada.
Department of Forest and Conservation Sciences University of British Columbia Vancouver BC Canada.
Evol Appl. 2016 Jan 19;9(2):409-19. doi: 10.1111/eva.12345. eCollection 2016 Feb.
We investigated adaptation to climate in populations of two widespread tree species across a range of contrasting environments in western Canada. In a series of common garden experiments, bud phenology, cold hardiness, and seedling growth traits were assessed for 254 populations in the interior spruce complex (Picea glauca, P. engelmannii, and their hybrids) and for 281 populations of lodgepole pine (Pinus contorta). Complex multitrait adaptations to different ecological regions such as boreal, montane, coastal, and arid environments accounted for 15-20% of the total variance. This population differentiation could be directly linked to climate variables through multivariate regression tree analysis. Our results suggest that adaptation to climate does not always correspond linearly to temperature gradients. For example, opposite trait values (e.g., early versus late budbreak) may be found in response to apparently similar cold environments (e.g., boreal and montane). Climate change adaptation strategies may therefore not always be possible through a simple shift of seed sources along environmental gradients. For the two species in this study, we identified a relatively small number of uniquely adapted populations (11 for interior spruce and nine for lodgepole pine) that may be used to manage adaptive variation under current and expected future climates.
我们研究了加拿大西部一系列不同环境中两种广泛分布的树种种群对气候的适应性。在一系列的共同园试验中，对内陆云杉复合体（白云杉、恩氏云杉及其杂种）中的254个种群以及扭叶松的281个种群的芽物候、抗寒性和幼苗生长性状进行了评估。对不同生态区域（如北方、山地、沿海和干旱环境）的复杂多性状适应占总变异的15 - 20%。通过多元回归树分析，这种种群分化可以直接与气候变量联系起来。我们的结果表明，对气候的适应并不总是与温度梯度呈线性对应。例如，在明显相似的寒冷环境（如北方和山地）中可能会发现相反的性状值（如早芽萌动与晚芽萌动）。因此，气候变化适应策略可能并不总是能够通过沿着环境梯度简单地转移种子来源来实现。对于本研究中的这两个物种，我们确定了相对较少数量的具有独特适应性的种群（内陆云杉有11个，扭叶松有9个），这些种群可用于在当前和预期的未来气候条件下管理适应性变异。
