Negative effects of long-term phosphorus additions on understory plants in a primary tropical forest
Negative effects of long-term phosphorus additions on understory plants in a primary tropical forest
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长期添加磷对热带原始森林林下植物的负面影响
DOI：
10.1016/j.scitotenv.2021.149306
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发表时间：
2021
影响因子：
9.8
通讯作者：
Lu Xiankai
中科院分区：
文献类型：
--
作者：
Mao Qinggong;Chen Hao;Gurmesa Geshere Abdisa;Gundersen Per;Ellsworth David Scott;Gilliam Frank S.;Wang Cong;Zhu Fiefei;Ye Qing;Mo Jiangming;Lu Xiankai
人类活动通过向自然生态系统中引入大量的磷，干扰了全球磷循环。虽然自然磷梯度和施肥研究发现，植物群落特征与磷的有效性密切相关，目前还不清楚如何增加磷供应影响植物生长和多样性在磷缺乏的热带森林。采用10年期（2007-2017年）的磷添加试验，研究了增加磷输入对热带森林林下植物生长和物种多样性的影响。我们监测幼苗生长的动态，存活率，和林下植物的多样性在整个施肥期间控制和磷添加在15 g P m-2 yr-1。为了确定响应的驱动因素，分析了P浓度、光合速率和非结构碳。结果表明，长期施磷显著增加了土壤库和植物组织中的磷含量。然而，磷添加并没有增加林下植物的光饱和光合速率或生长速率。此外，磷的添加显著降低了幼苗的存活率，降低了林下植物的物种丰富度和密度。磷添加的负面影响可能是由于增加碳成本，由于组织的维持与较高的磷浓度的植物。这些研究结果表明，单独增加磷供应是没有必要的，有利于植物生长的生态系统中的低磷可用性，和P输入可以抑制林下植物，并可能改变社区组成。因此，我们呼吁在向热带森林生态系统输入P时需要谨慎。
Human activities have disturbed global phosphorus (P) cycling by introducing substantial amounts of P to natural ecosystems. Although natural P gradients and fertilization studies have found that plant community traits are closely related to P availability, it remains unclear how increased P supply affects plant growth and diversity in P-deficient tropical forests. We used a decadal P-addition experiment (2007–2017) to study the effects of increased P input on plant growth and diversity in understory layer in tropical forests. We monitored the dynamics of seedling growth, survival rate, and diversity of understory plants throughout the fertilization period under control and P addition at 15 g P m−2yr−1. To identify the drivers of responses, P concentration, photosynthesis rate and nonstructural carbon were analyzed. Results showed that long-term P addition significantly increased P concentrations both in soil pools and plant tissues. However, P addition did not increase the light-saturated photosynthesis rate or growth rate of the understory plants. Furthermore, P addition significantly decreased the survival rate of seedlings and reduced the species richness and density of understory plants. The negative effects of P addition may be attributed to an increased carbon cost due to the tissue maintenance of plants with higher P concentrations. These findings indicate that increased P supply alone is not necessary to benefit the growth of plants in ecosystems with low P availability, and P inputs can inhibit understory plants and may alter community composition. Therefore, we appeal to a need for caution when inputting P to tropical forests ecosystems.