Can we see the nitrate from the trees? Long-term linkages between tropical forest productivity and stream nitrogen concentrations
Can we see the nitrate from the trees? Long-term linkages between tropical forest productivity and stream nitrogen concentrations
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我们能从树上看到硝酸盐吗？
DOI：
10.1007/s10533-023-01030-1
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发表时间：
2023
期刊：
影响因子：
4
通讯作者：
Pringle, Catherine M.
中科院分区：
文献类型：
--
作者：
Ardón, Marcelo;Clark, Deborah A.;Marzolf, Nicholas S.;Ramirez, Alonso;Pringle, Catherine M.
热带森林中大量具有生物固氮能力的树木（以下简称“固氮者”）被假设与温带森林相比，能够驱动更高的溪流硝酸盐（NO3）浓度。然而，迄今为止还没有关于河流no3浓度与热带森林生产力之间的经验联系。在这里，我们结合了来自哥斯达黎加La Selva生物站的三个独特的长期数据集：21年来(1)同一流域内六个河流站点的年平均河流NO3-N浓度，(2)树木的年生长量，(3)年落叶量。我们假设固氮树种生长和落叶量增加的年份与较高的水体NO3-N浓度相关。我们还假设，景观位置介导了这些关系，在邻近斜坡上的固氮树木的生长与河流NO3-N的相关性比高原上的固氮树木的生长更强。我们发现年平均溪流NO3-N浓度一直很高（160-260µg L−1）。凋落叶（年际范围：5.4 ~ 8.1 Mg ha−1年−1）、固氮剂的生长（年际范围：1.2 ~ 2.2 Mg ha−1年−1）和所有其他树种的生长（年际范围：2.1 ~ 3.2 Mg ha−1年−1）均存在显著的年际变化。为了评估河流NO3-N与森林生产力的关系，我们使用水电导率来解释由可变排放引起的稀释。研究发现，NO3-N浓度与固定氮固氮物的年生长量呈正相关，与年凋落叶量呈负相关。河流NO3-N浓度与固氮剂或其他树种的生长无关。利用质量平衡，我们估计共生固氮可占no3出口的7-29%。邻近固氮物的生长和景观凋落物都是河流NO3-N浓度年际变化的重要驱动因素。我们的研究结果表明，气候变化导致的极端降水的预测变化将直接改变热带森林的氮动态，通过改变排放和出口，间接改变固定氮树的生产力。
High abundance of trees capable of biological N-fixation (henceforth “N-fixers”) in tropical forests has been hypothesized to drive higher stream nitrate (NO3) concentrations compared to temperate counterparts. However, to date there have been no empirical linkages of stream NO3concentrations with the productivity of tropical forests. Here, we combined three unique long-term datasets from La Selva Biological Station, Costa Rica: 21 years of (1) mean annual stream NO3-N concentrations in six stream sites within the same watershed, (2) annual growth of trees, and (3) annual leaf litterfall. We hypothesized that years of greater growth of N-fixer tree species and of greater leaf litterfall would be correlated with higher stream water NO3-N concentrations. We also hypothesized that landscape position mediates these relationships, with growth of N-fixer trees on adjacent slopes being more strongly correlated to stream NO3-N than the growth of such trees on upland plateau sites. We found that mean annual stream NO3-N concentrations were consistently high (160–260 µg L−1). There was substantial interannual variation in leaf litterfall (inter-year range: 5.4 to 8.1 Mg ha−1year−1), growth of N-fixers (inter-year range: 1.2 to 2.2 Mg ha−1year−1), and growth of all other tree species (inter-year range: 2.1 to 3.2 Mg ha−1year−1). To assess stream NO3-N relationships with forest productivity, we used water conductivity to account for dilution resulting from variable discharge. We found that NO3-N concentrations were positively related to the annual growth of the N-fixers on nearby slopes, and were negatively correlated with annual leaf litterfall. Stream NO3-N concentrations were not related to the growth of N-fixers or other tree species in the more removed plateau areas. Using a mass balance, we estimated that symbiotic N fixation can account for 7–29% of NO3export. Both the growth of adjacent N-fixers and landscape-wide leaf litterfall are important drivers of the inter-annual variability of stream NO3-N concentrations. Our results suggest that predicted changes in precipitation extremes due to climate change will alter N dynamics in tropical forests both directly, by altering discharge and export, and indirectly, by altering N-fixer tree productivity.
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影响因子：
6.1
作者：
Espeleta, J. F.;Clark, D. A.
通讯作者：
Clark, D. A.
DOI：
10.1111/nph.13734
发表时间：
2016-02
期刊：
The New phytologist
影响因子：
--
作者：
D. Menge;R. Chazdon
通讯作者：
D. Menge;R. Chazdon
影响因子：
4.8
作者：
B. Taylor;R. Chazdon;D. Menge
通讯作者：
B. Taylor;R. Chazdon;D. Menge
哥斯达黎加低地雨林中的固氮树和非固氮树在叶子化学和防御方面存在差异，但食草性则没有差异
影响因子：
1.4
作者：
B. Taylor;Laura R. Ostrowsky
通讯作者：
Laura R. Ostrowsky
拉塞尔瓦：新热带雨林的生态和自然历史。Lucinda A. McDade、Kamaljit S. Bawa、Henry A. Hespenheide、Gary S. Hartshorn
DOI：
--
发表时间：
1995
期刊：
影响因子：
--
作者：
M. Crawley
通讯作者：
M. Crawley