Stability in ecosystem functioning across a climatic threshold and contrasting forest regimes.
Stability in ecosystem functioning across a climatic threshold and contrasting forest regimes.
复制标题
DOI：
10.1371/journal.pone.0016134
复制
发表时间：
2011-01-18
期刊：
影响因子：
3.7
通讯作者：
Willis KJ
中科院分区：
文献类型：
--
作者：
Jeffers ES;Bonsall MB;Willis KJ
经典生态学理论预测，氮等基本资源的可利用性的变化应导致植物群落组成的变化，这是由于物种特定的营养需求的差异。然而，气候变化将在多大程度上改变植物群落与氮循环之间的关系，这一点仍然是未知的。在气候变化期间，氮循环的变化导致植被变化，还是群落组成的变化改变了氮的动态？我们使用长期的生态数据，以确定在全新世早期（16 K至8 K卡。年BP）的快速变化的气候下的森林物种组成的变化中的氮的可用性的作用。对8,000年来生态数据的统计计算分析表明，从针叶林到落叶林的次生演替与氮循环的变化无关。随着气候变暖，橡树取代松树，氮循环速率增加。有趣的是，物种与氮相互作用的机制在气候和优势树种的阈值变化中保持稳定。这表明，树木种群密度在演替时间尺度上的变化并不受氮素供应的影响。因此，目前的森林演替模型，包括有效氮的影响，可能会高估树木种群的变化，这可能会导致在气候变暖的未来森林动态的预测有偏见的资源。
Classical ecological theory predicts that changes in the availability of essential resources such as nitrogen should lead to changes in plant community composition due to differences in species-specific nutrient requirements. What remains unknown, however, is the extent to which climate change will alter the relationship between plant communities and the nitrogen cycle. During intervals of climate change, do changes in nitrogen cycling lead to vegetation change or do changes in community composition alter the nitrogen dynamics? We used long-term ecological data to determine the role of nitrogen availability in changes of forest species composition under a rapidly changing climate during the early Holocene (16k to 8k cal. yrs. BP). A statistical computational analysis of ecological data spanning 8,000 years showed that secondary succession from a coniferous to deciduous forest occurred independently of changes in the nitrogen cycle. As oak replaced pine under a warming climate, nitrogen cycling rates increased. Interestingly, the mechanism by which the species interacted with nitrogen remained stable across this threshold change in climate and in the dominant tree species. This suggests that changes in tree population density over successional time scales are not driven by nitrogen availability. Thus, current models of forest succession that incorporate the effects of available nitrogen may be over-estimating tree population responses to changes in this resource, which may result in biased predictions of future forest dynamics under climate warming.