Seasonal climate manipulations result in species-specific changes in leaf nutrient levels and isotopic composition in a sub-arctic bog
Seasonal climate manipulations result in species-specific changes in leaf nutrient levels and isotopic composition in a sub-arctic bog
复制标题
DOI：
10.1111/j.1365-2435.2009.01566.x
复制
发表时间：
2009-08-01
影响因子：
5.2
通讯作者：
Cornelissen, Johannes H. C.
中科院分区：
文献类型：
--
作者：
Aerts, Rien;Callaghan, Terry V.;Cornelissen, Johannes H. C.
寒冷生物群落的气候变化不仅涉及夏季气温升高，而且还涉及春季变暖和冬季降水增多。到目前为止，鲜为人知的是，物种对这些季节性气候变化的组成部分的反应。我们实验操纵春季和夏季的温度和冬季积雪和温度独立在亚北极瑞典泥炭地。这产生了六个气候情景，我们研究了泥炭藓泥炭藓，万年青矮灌木Empetrum hermaphroditum和仙女座polifolia，落叶矮灌木白桦和笃斯越橘，草拂子茅和杂类乌藨子chamaemorus.We发现大量种间差异的叶营养和碳交换变量，反映了苔原植物对气候变化的响应。S.从万年青矮灌木到草本、落叶矮灌木和杂类草，N和P浓度逐渐升高（C/N和C/P比值逐渐降低），褐叶草的N和P浓度最低。叶片N/P比值在10 ~ 14之间，表明植物生长受N限制，N-15的自然丰度在不同物种和生长类型之间差异很大。这些差异对应的存在和类型的菌根协会在植物根系。叶碳同位素辨别力在不同物种和生长型之间也有很大差异，但绝对差异相对较小（< 5 ppm）。排名顺序是：4年后，实际气候变化对叶片养分和碳交换变量的影响因物种而异，与物种和生长形式之间的差异相比，其影响一般较小。在表型水平上，春季增暖或冬季降雪效应与夏季增暖效应一样频繁地发生，这意味着在寒冷生物群落中期变暖研究中观察到的植物群落物种组成和结构的变化对植物介导的养分和碳循环途径和速率的影响要比气候变化引起的表型响应大得多。不管这些气候变化的季节性时间。
P>Climate change in cold biomes not only involves higher summer temperatures, but also warmer springs and more winter precipitation. So far, little is known about species responses to these seasonal components of climate change.We experimentally manipulated spring and summer temperatures and winter snow accumulation and temperatures independently in a peatland in sub-arctic Sweden. This yielded six climate scenarios and we studied the responses of the peat moss Sphagnum fuscum, the evergreen dwarf shrubs Empetrum hermaphroditum and Andromeda polifolia, the deciduous dwarf shrubs Betula nana and Vaccinium uliginosum, the grass Calamagrostis lapponica and the forb Rubus chamaemorus.We found substantial interspecific differences in leaf nutrient and carbon exchange variables that reflect the response of tundra plants to climate change. S. fuscum had the lowest N and P concentrations, with increasing N and P concentrations (and decreasing C/N and C/P ratios) going from evergreen dwarf shrubs, to the grass, deciduous dwarf shrubs and the forb. Leaf N/P ratios varied between 10 and 14 which points to N-limited plant growth.The natural abundance of N-15 varied very strongly among species and growth forms. These differences corresponded with the presence and type of mycorrhizal association in the plant roots. Leaf carbon isotope discrimination also differed strongly among species and growth forms, but the absolute differences were relatively small (< 5 parts per thousand). The rank order was: forb and graminoid < moss and evergreen shrubs < deciduous shrubs.After 4 years, the effects of realistic climate change manipulations on leaf nutrient and carbon exchange variables were idiosyncratic with respect to species and generally small compared to the differences among species and growth forms. At the phenotypic level, spring warming or winter snow addition effects occurred as frequently as summer warming effects.This implies that the changes in the species composition and structure of plant communities that have been observed in medium-term warming studies in cold biomes will have much more impact on plant-mediated nutrient and carbon cycling pathways and rates than climate-change induced phenotypic responses, irrespective of the seasonal timing of these climate changes.