Unraveling the ecosystem functions in the Amazonia–Cerrado transition: evidence of hyperdynamic nutrient cycling
Unraveling the ecosystem functions in the Amazonia–Cerrado transition: evidence of hyperdynamic nutrient cycling
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DOI：
10.1007/s11258-016-0681-y
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发表时间：
2017-02
期刊：
影响因子：
1.7
通讯作者：
B. Oliveira;Ben Hur Marimon Júnior;H. A. Mews;M. B. X. Valadão;B. Marimon
中科院分区：
文献类型：
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作者：
B. Oliveira;Ben Hur Marimon Júnior;H. A. Mews;M. B. X. Valadão;B. Marimon
亚马逊-塞拉多过渡地带稀树草原与森林之间的接触以植被的超动态(补充与死亡)为特征。然而，在这些条件下相关的营养动态还没有被很好地理解。我们首次确定了过渡区植被的生物地球化学循环，估计了Cerradão和Cerrado样地的凋落物、养分输入、分解速率和养分释放。我们检验了营养循环与植被动态密切相关的假设。在2年的时间里，在1公顷的植被地块内放置了30个陷阱，对凋落物进行了采样。在这两个地区，也使用分解袋估计了从凋落物中释放回土壤的养分。分解速率在不同地区之间没有差异，尽管在塞拉多地区，总生物量(9.27亿mg/ha−1年−1)和总养分(219.17 mg/ha−1年−1)的输入、总生物量的分解以及大部分养分通过凋落物和分解的循环至少是塞拉多地区的两倍。这些结果证实了关于不同植被类型在养分循环中的差异的假设，首次表明在两种植被中观察到的超动态也反映在生物地球化学循环中，特别是在Cerradão。因此，在Cerradão观察到的养分的快速和有效循环可能是保证Cerradão有能力在以前典型的Cerrado占据的新区域定居的关键条件。
The contact between savanna and forest in the Amazonia–Cerrado transition zone is characterized by the hyperdynamics of the vegetation (recruitment vs. mortality). However, the related nutrient dynamics under these conditions are not well understood. We determined for the first time the biogeochemical cycles of the vegetation in the zone of transition estimating the litterfall, nutrient input, decomposition rates, and nutrient release in cerradão and cerrado plots. We examine the hypothesis that nutrient cycling is strongly associated with the vegetation dynamics. The litterfall was sampled in 30 traps placed within 1-ha vegetation plots for 2 years. The release of nutrients from the litterfall back to the soil was also estimated using decomposition bags in the two areas. The decomposition rates did not vary between areas, although in the cerradão the input of total biomass (9.27 Mg ha−1year−1) and total nutrients (219.17 kg ha−1year−1), the decomposition of the total biomass, and the cycling of most nutrients through litterfall and decomposition were at least twice higher than in the cerrado. These results confirmed the hypothesis concerning the differences between vegetation types in nutrient cycling, suggesting for the first time that the hyperdynamics observed in both vegetations were also reflected in the biogeochemical cycle, particularly in the cerradão. Thus, it is likely that the rapid and effective cycling of nutrients observed in the cerradão might be a key condition guaranteeing the ability of the cerradão to colonize new areas previously occupied by the typical cerrado.