Intraspecific variation of a dominant grass and local adaptation in reciprocal garden communities along a US Great Plains’ precipitation gradient: implications for grassland restoration with climate change

Identifying suitable genetic stock for restoration often employs a ‘best guess’ approach. Without adaptive variation studies, restoration may be misguided. We test the extent to which climate in central US grasslands exerts selection pressure on a foundation grass big bluestem (Andropogon gerardii), widely used in restorations, and resulting in local adaptation. We seeded three regional ecotypes of A. gerardii in reciprocal transplant garden communities across 1150 km precipitation gradient. We measured ecological responses over several timescales (instantaneous gas exchange, medium-term chlorophyll absorbance, and long-term responses of establishment and cover) in response to climate and biotic factors and tested if ecotypes could expand range. The ecotype from the driest region exhibited greatest cover under low rainfall, suggesting local adaptation under abiotic stress. Unexpectedly, no evidence for cover differences between ecotypes exists at mesic sites where establishment and cove...

确定适宜的恢复用遗传材料通常采用“最佳猜测”方法。缺乏适应性变异研究时，恢复工作可能会偏离方向。我们测试了美国中部草原的气候对恢复工作中广泛使用的建群草种——大须芒草（Andropogon gerardii）施加选择压力的程度，以及由此产生的局部适应性。我们在横跨1150公里降水梯度的互惠移植园群落中，播种了大须芒草的三个区域生态型。我们测量了生态系统在不同时间尺度下对气候和生物因子的响应（瞬时气体交换、中期叶绿素吸光度，以及长期的建植和覆盖度响应），并测试了这些生态型是否能够扩展分布范围。最干旱地区的生态型在低降雨条件下表现出最高的覆盖度，这表明其在非生物胁迫下具有局部适应性。出乎意料的是，在中生境（mesic sites）中，生态型之间的覆盖度差异并无证据支持，而这些区域的建植和覆盖度...