Experimental Plant Ecology, Institute of Botany and Landscape Ecology, Greifswald University, Soldmannstrasse 15, Greifswald, 17487, Germany.
Disturbance Ecology, BayCEER, University of Bayreuth, Bayreuth, 95440, Germany.
Glob Chang Biol. 2016 Jan;22(1):449-64. doi: 10.1111/gcb.13114. Epub 2015 Nov 18.
Within-species and among-species differences in growth responses to a changing climate have been well documented, yet the relative magnitude of within-species vs. among-species variation has remained largely unexplored. This missing comparison impedes our ability to make general predictions of biodiversity change and to project future species distributions using models. We present a direct comparison of among- versus within-species variation in response to three of the main stresses anticipated with climate change: drought, warming, and frost. Two earlier experiments had experimentally induced (i) summer drought and (ii) spring frost for four common European grass species and their ecotypes from across Europe. To supplement existing data, a third experiment was carried out, to compare variation among species from different functional groups to within-species variation. Here, we simulated (iii) winter warming plus frost for four grasses, two nonleguminous, and two leguminous forbs, in addition to eleven European ecotypes of the widespread grass Arrhenatherum elatius. For each experiment, we measured: (i) C/N ratio and biomass, (ii) chlorophyll content and biomass, and (iii) plant greenness, root (15) N uptake, and live and dead tissue mass. Using coefficients of variation (CVs) for each experiment and response parameter, a total of 156 within- vs. among-species comparisons were conducted, comparing within-species variation in each of four species with among-species variation for each seed origin (five countries). Of the six significant differences, within-species CVs were higher than among-species CVs in four cases. Partitioning of variance within each treatment in two of the three experiments showed that within-species variability (ecotypes) could explain an additional 9% of response variation after accounting for the among-species variation. Our observation that within-species variation was generally as high as among-species variation emphasizes the importance of including both within- and among-species variability in ecological theory (e.g., the insurance hypothesis) and for practical applications (e.g., biodiversity conservation).
物种内和物种间对气候变化的生长反应差异已有大量记录，但物种内与物种间变异的相对幅度在很大程度上仍未得到探索。这种缺失的比较阻碍了我们对生物多样性变化做出一般预测的能力，并使用模型预测未来物种的分布。我们直接比较了三种主要预期气候变化压力（干旱、变暖、霜冻）下的物种间和物种内响应。之前的两个实验分别对四种常见的欧洲草本植物及其来自欧洲各地的生态型进行了（i）夏季干旱和（ii）春季霜冻的实验诱导。为了补充现有数据，进行了第三个实验，以比较不同功能群的物种间变异与物种内变异。在这里，我们模拟了（iii）四种草本植物、两种非豆科和两种豆科植物的冬季变暖加霜冻，以及广泛分布的蒿属 Arrhenatherum elatius 的十一种欧洲生态型。对于每个实验，我们测量了：（i）C/N 比和生物量，（ii）叶绿素含量和生物量，以及（iii）植物绿色度、根（15）N 吸收和活体和死组织质量。使用每个实验和响应参数的变异系数（CV），总共进行了 156 次种内与种间比较，比较了四个物种中每个物种的种内变异与每个种子起源（五个国家）的种间变异。在六个显著差异中，有四个案例中种内 CV 高于种间 CV。在三个实验中的两个实验中，对每个处理的方差进行划分表明，在考虑种间变异后，种内可变性（生态型）可以解释响应变异的另外 9%。我们观察到，种内变异通常与种间变异一样高，这强调了在生态理论（例如，保险假说）和实际应用（例如，生物多样性保护）中同时包含种内和种间变异性的重要性。
