Prieto Patricia, Peñuelas Josep, Ogaya Romà, Estiarte Marc
Unitat d'Ecofisiologia i Canvi Global CREAF-CEAB-CSIC (Centre for Ecological Research and Forestry Applications), Universitat Autònoma de Barcelona, Edifici C, 08193 Bellaterra, Spain.
Ann Bot. 2008 Aug;102(2):275-85. doi: 10.1093/aob/mcn090. Epub 2008 Jun 19.
Relationships between autumn flowering, precipitation and temperature of plant species of Mediterranean coastal shrublands have been described, but not analysed experimentally. These relationships were analysed for two species of co-occurring, dominant, autumn-flowering shrubs, Globularia alypum and Erica multiflora, over 4 years and in experimentally generated drought and warming conditions. The aim was to improve predictions about the responses and adaptations of flowering of Mediterranean vegetation to climate change.
Beginning of anthesis and date of maximum flowering intensity ('peak date') were monitored over 4 years (2001-2004) on a garrigue land type in the noth-east of the Iberian Peninsula. Two experimental treatments were applied, increased temperature (+0.73 degrees C) and reduced soil moisture (-17%) relative to untreated plots.
Flowering of Globularia alypum and Erica multiflora differed greatly between years depending on the precipitation of the previous months and the date of the last substantial rainfall (>10 mm). Globularia alypum flowered once or twice (unimodal or bimodal) as the result of differences in the distribution and magnitude of precipitation in late-spring and summer (when floral buds develop). The drought treatment delayed and decreased flowering of Globularia alypum in 2001 and delayed flowering in 2002. Warming extended the period between the beginning of flowering and the end of the second peak for autumn flowering in 2001 and also increased peak intensity in 2002. Flowering of Erica multiflora was unaffected by either treatment.
Autumn flowering of Globularia alypum and Erica multiflora is more dependent on water availability than on temperature. Considerable inter-annual plasticity in the beginning of anthesis and peak date and on unimodal or bimodal flowering constitutes a 'safe strategy' for both species in relation to varying precipitation and temperature. However, severe changes in precipitation in spring and summer may severely affect flowering of Globularia alypum but not Erica multiflora, thus affecting development/structure of the ecosystem if such conditions persist.
地中海沿岸灌木丛植物物种的秋季开花、降水和温度之间的关系已有描述，但尚未进行实验分析。对两种共生的优势秋季开花灌木——阿尔卑斯球花石南（Globularia alypum）和多花欧石南（Erica multiflora），在4年时间里以及在实验产生的干旱和变暖条件下，分析了这些关系。目的是改进对地中海植被开花对气候变化的响应和适应的预测。
在伊比利亚半岛东北部的一种灌木林地类型上，对花期开始时间和最大开花强度日期（“峰值日期”）进行了4年（2001 - 2004年）的监测。相对于未处理的地块，应用了两种实验处理，即温度升高（+0.73摄氏度）和土壤湿度降低（-17%）。
阿尔卑斯球花石南和多花欧石南的开花在不同年份差异很大，这取决于前几个月的降水量和最后一次大量降雨（>10毫米）的日期。由于春末和夏季（花芽发育时）降水分布和量级的差异，阿尔卑斯球花石南开花一次或两次（单峰或双峰）。干旱处理在2001年延迟并减少了阿尔卑斯球花石南的开花，在2002年延迟了开花。变暖延长了2001年秋季开花从开始到第二个峰值结束的时间，并且在2002年也增加了峰值强度。多花欧石南的开花不受任何一种处理的影响。
阿尔卑斯球花石南和多花欧石南的秋季开花更多地依赖于水分供应而非温度。花期开始时间、峰值日期以及单峰或双峰开花方面存在相当大的年际可塑性，这对两个物种而言，是应对降水和温度变化的一种“安全策略”。然而，春夏季降水的剧烈变化可能会严重影响阿尔卑斯球花石南的开花，但不会影响多花欧石南，如果这种情况持续下去，将会影响生态系统的发育/结构。
