Responses of tundra plants to experimental warming:: Meta-analysis of the international tundra experiment
Responses of tundra plants to experimental warming:: Meta-analysis of the international tundra experiment
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DOI：
10.1890/0012-9615(1999)069
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发表时间：
1999-11-01
影响因子：
6.1
通讯作者：
Wookey, PA
中科院分区：
文献类型：
--
作者：
Arft, AM;Walker, MD;Wookey, PA
国际冻土带实验（ITEX）是一项合作的多地点实验，使用一种常见的温度操纵来检查冻土带生态系统在气候和地理梯度上物种反应的可变性。ITEX是专门为研究北极和高山物种对温度升高的反应而设计的。我们收集了来自13个不同ITEX站点的1 - 4年的实验数据，并使用元分析方法分析了植物物候、生长和繁殖对实验变暖的响应。结果表明：在整个研究期间，暖样地的叶芽萌发和开花等关键物候事件发生时间均较早；然而，在赛季结束时，对生长停止的影响很小。在试验的前几年，温热地块的营养生长的定量测量是最大的，而繁殖的努力和成功在随后的几年增加。在第四个治疗年从营养生长转向生殖努力和成功表明从初始反应到二次反应的转变。营养反应的变化可能是由于植物储备的消耗，而生殖反应的滞后可能是由于花蕾在开花前一到几个季节形成。不同的生命形式对营养和生殖的反应各不相同；草本植物比木本植物有更强和更一致的营养生长反应。草本植物的响应性更强可能是由于它们的形态更灵活，以及它们相对较大的植物储备比例。最后，温暖的低北极地区产生了最强的生长反应，但寒冷的地区产生了更大的繁殖反应。在低北极地区，更多的资源投资于营养生长可能是一种保守的策略，在那里，光、养分或水的竞争更激烈，成功发芽或幼苗发育的机会可能很少。相比之下，在高北极地区，在更高温度的情况下生产种子的大量投资可能为物种提供了在无植被的土地上定居的机会。观测到的对变暖的不同响应表明，驱动响应的主要力量因气候带、功能群和时间而异。
The International Tundra Experiment (ITEX) is a collaborative, multisite experiment using a common temperature manipulation to examine variability in species response across climatic and geographic gradients of tundra ecosystems. ITEX was designed specifically to examine variability in arctic and alpine species response to increased temperature. We compiled from one to four years of experimental data from 13 different ITEX sites and used meta-analysis to analyze responses of plant phenology, growth, and reproduction to experimental warming. Results indicate that key phenological events such as leaf bud burst and flowering occurred earlier in warmed plots throughout the study period; however, there was little impact on growth cessation at the end of the season. Quantitative measures of vegetative growth were greatest in warmed plots in the early years of the experiment, whereas reproductive effort and success increased in later years. A shift away from vegetative growth and toward reproductive effort and success in the fourth treatment year suggests a shift from the initial response to a secondary response. The change in vegetative response may be due to depletion of stored plant reserves, whereas the lag in reproductive response may be due to the formation of flower buds one to several seasons prior to flowering. Both vegetative and reproductive responses varied among life-forms; herbaceous forms had stronger and more consistent vegetative growth responses than did woody forms. The greater responsiveness of the herbaceous forms may be attributed to their more flexible morphology and to their relatively greater proportion of stored plant reserves. Finally, warmer, low arctic sites produced the strongest growth responses, but colder sites produced a greater reproductive response. Greater resource investment in vegetative growth may be a conservative strategy in the Low Arctic, where there is more competition for light, nutrients, or water, and there may be little opportunity for successful germination or seedling development. In contrast, in the High Arctic, heavy investment in producing seed under a higher temperature scenario may provide an opportunity for species to colonize patches of unvegetated ground. The observed differential response to warming suggests that the primary forces driving the response vary across climatic zones, functional groups, and through time.