Climate change and evolution of plant phenology

全球变暖将极大地改变加拿大的植被景观，从而给森林管理、自然遗址保护、杂草控制和提供生态系统服务带来挑战。气候变化可以说是加拿大最普遍的环境威胁，因为所有其他此类问题都有气候因素。全球变暖的短时间尺度导致许多人从生态学的角度思考其生物学后果。许多人预测，来自南方的适应更热的种群会向极地迁徙。其他人预计常住人口的生理和发育会发生表型上的可塑性变化。这样的反应可以改善对自然种群的影响，但只能在他们目前的基因谱系允许的程度上。重要的是，气候变化强加了不同的选择制度，因此对全球变暖的整体生物反应将具有进化层面。一小部分研究，包括我的团队的一项，已经表明了对气候变化的进化反应。在十年时间框架内的进化变化可能在具有短到中等生命周期的物种中广泛存在。我提出了一个研究计划，以了解进化变化的速度--特别是对延长生长季节的遗传适应--以及自然选择、基因流动和非随机交配可能如何影响它。项目将检验具体的假设，包括：1.虽然极地迁徙可能带来耐热基因，但这些适应基因的导入将受到以下因素的抑制：a)在北纬的光周期下，与导致生殖物候不适应的基因座的配子(连锁)不平衡，以及b)由这种不适应物候引起的分类交配；2.生长季节延长将选择居民种群延迟的开花时间；3.物候分类交配加速了开花时间的进化转变；4.进化对气候变化的反应速度随着纬度的增加而增加。该计划将利用几种一年生和短命的多年生植物，并将在小丑山的科夫勒科学保护区使用人工变暖的地块来执行。

Global warming will drastically alter Canada's vegetation landscape, thereby presenting challenges for forest management, preservation of natural sites, weed control and delivery of ecosystem services. Climate change is arguably Canada's most pervasive environmental threat since all other such problems have a climatic element. The short time scale of global warming leads many to think about its biological consequences in ecological terms. Many predict pole-ward migration from more thermally adapted populations from the south. Others anticipate phenotypicaly plastic shifts in physiology and development in resident populations. Such responses can ameliorate the impact on natural populations, but only to the degree allowed by their current genetic repertoire. Importantly, altered climate imposes altered selection regimes and hence the total biological response to global warming will have evolutionary dimensions. A small number of studies, including one form my group, already indicate evolutionary responses climate change. Evolutionary change on a decadal time frame could be widespread among species with short to medium life cycles. I propose a research program to understand the rate of evolutionary change-particularly genetic adaptation to extended growing seasons-and how natural selection, gene flow, and non-random mating might affect it. Projects will test specific hypotheses, including: 1. Although pole-ward migrants may bring thermal tolerance genes, introgression of these adaptive loci will be inhibited by a) gametic (linkage) disequilibrium with loci causing maladaptive reproductive phenology under the photoperiodic cycle of northern latitudes, and b) assortative mating caused by this maladaptive phenology; 2. Extended growing seasons will select for delayed flowering times in resident populations; 3. Evolutionary shifts in flowering time are accelerated by phenolgical assortative mating; and 4. The rate of evolutionary response to climate change increases with latitude. The program will employ several species of annual and short-lived perennial plants, and will be executed with the use of artificial warming plots at the Koffler Scientific Reserve at Jokers Hill.