Andean grasslands are as productive as tropical cloud forests
Andean grasslands are as productive as tropical cloud forests
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DOI：
10.1088/1748-9326/9/11/115011
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发表时间：
2014-11
影响因子：
6.7
通讯作者：
I. Oliveras;C. Girardin;C. Doughty;N. Cahuana;C. Arenas;V. Oliver;W. H. Huasco;Y. Malhi
中科院分区：
文献类型：
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作者：
I. Oliveras;C. Girardin;C. Doughty;N. Cahuana;C. Arenas;V. Oliver;W. H. Huasco;Y. Malhi
我们的目标是评估安第斯热带高山草原（普纳）的净初级生产力（NPP）和碳循环，并将其与热带山地云林的NPP进行比较。我们提出以下问题：（1）草地的NPP和土壤呼吸在季节周期中如何变化？ (2) 烧荒和放牧如何影响普纳生产力？ （3）如果山地森林扩展到普纳，生产力会发生什么变化？研究地点位于秘鲁安第斯山脉东南部；一个草原点和森林点位于Wayqecha生物站，另一个草原点位于马努国家公园。在每个草原地点，我们选择了一个烧毁和未烧毁的区域，在每个区域安装了无围栏和围栏样线，并监测了地上生产力（NPPAG）、地下生产力（NPPBG）和土壤呼吸（Rs）2年。在森林中，我们对 NPPAG、NPPBG 和 Rs 进行了 2-4 年的监测。草地 NPP 在 4.6 ± 0.25（受干扰区域）至 15.3 ± 0.9 Mg C ha−1 yr−1（未受干扰区域）之间变化，云林 NPP 在 7.05 ± 0.39 至 8.0 ± 0.47 Mg C ha−1 yr−1 之间变化，而土壤碳储量在 126 ± 22 至 285 ± 范围内。 31 Mg C ha−1。普纳和森林点之间的NPP没有显着差异。最不受干扰的地点的 NPP 明显高于其他草地地点，但在其他地点的放牧和火灾方面没有发现差异。与地下生物量相比，地上生物量的停留时间较短。草原 NPPAG 和 NPPBG 存在强烈的季节性信号，分配在南半球夏季初发生变化。高海拔热带草原的生产力与邻近的云雾林相同，但其碳循环和保留特性与云雾林截然不同。
We aim to assess net primary productivity (NPP) and carbon cycling in Andean tropical alpine grasslands (puna) and compare it with NPP of tropical montane cloud forests. We ask the following questions: (1) how do NPP and soil respiration of grasslands vary over the seasonal cycle? (2) how do burning and grazing affect puna productivity? (3) if the montane forest expands into the puna, what will be the resulting change in productivity? The study sites are located at the South-eastern Peruvian Andes; one grassland site and the forest sites are in Wayqecha biological station, and another grassland site in Manu National Park. At each grassland site, we selected a burnt and an unburnt area, installed unfenced and fenced transects in each area, and monitored above-ground productivity (NPPAG), below-ground productivity (NPPBG) and soil respiration (Rs) for 2 yr. In the forest, we monitored NPPAG, NPPBG and Rs for 2–4 yr. Grassland NPP varied between 4.6 ± 0.25 (disturbed areas) to 15.3 ± 0.9 Mg C ha−1 yr−1 (undisturbed areas) and cloud forest NPP was between 7.05 ± 0.39 and 8.0 ± 0.47 Mg C ha−1 yr−1, while soil carbon stocks were in the range of 126 ± 22 to 285 ± 31 Mg C ha−1. There were no significant differences on NPP between the puna and forest sites. The most undisturbed site had significantly higher NPP than other grassland sites, but no differences were found when relating grazing and fire at other sites. There were lower residence times of above-ground biomass compared to below-ground biomass. There was a strong seasonal signal on grassland NPPAG and NPPBG, with a shift on allocation at the beginning of the austral summer. High elevation tropical grasslands can be as productive as adjacent cloud forests, but have very different carbon cycling and retention properties than cloud forests.