Background and aims

Nitrogen (N) and phosphorus (P) availabilities limit plant productivity, especially in primary succession; however, our understanding of species-specific strategies regarding their allocation and coordination with other functional traits remains limited.

Methods

Community-weighted mean traits were compared to decipher the ecophysiological mechanisms of forest succession in nine dominant species along 120-y successional stages across a glacier-retreating chronosequence.

Results

High foliar N and P concentrations in N₂-fixing plants on a 12-year-old surface did not result in high photosynthetic capacity due to the inefficient allocation, as indicated by their low photosynthetic N- and P-use efficiencies. On a 40-year-old surface, exploitative strategies, manifested in a higher specific leaf area and greater N allocation to Rubisco, as well as quick-return energy economics, helped deciduous forests dominate. When P availability decreased on a 120-year-old surface, evergreens maintained high photosynthetic P-use efficiency, by reducing overall P concentration and its allocation to structural fraction. Efficient P allocation and a higher ratio of leaf lifespan to payback time facilitated the dominance of evergreens in low P-sites.

Conclusions

Optimizing allocation of limiting N or P among foliar fractions and fast–slow economic strategies drive primary succession after glacier retreat. Integrating the above- and below-ground subsystems through food webs will provide further insights into ecosystem dynamics.

中文翻译：

---

优化限制营养元素的叶面分配和快速缓慢的经济策略，推动了青藏高原东部冰川退缩的时间序列的森林演替

背景和目标

氮（N）和磷（P）的利用率限制了植物的生产力，特别是在初次演替中；但是，我们对特定物种的策略在其分配和与其他功能性状的协调方面的理解仍然有限。

方法

比较了群落加权平均特征，以解释在冰川恢复的时间序列上，在120y演替阶段的9个优势种中，森林演替的生态生理机制。

结果

由于分配效率低，固定在N ₂上的N ₂植株中的叶面N和P浓度较高，并未导致较高的光合能力，这是由于其光合N和P利用率低所致。在具有40年历史的地表上，剥削策略表现为较高的比叶面积和对Rubisco的更大N分配，以及快速返回的能源经济学，这有助于落叶林占主导地位。当具有120年历史的地表上磷的有效性下降时，常绿植物通过降低总磷的浓度及其在结构部分的分配来保持高的光合磷利用效率。有效的磷分配和较高的叶片寿命与偿还时间的比率促进了低磷位点常绿植物的优势。

结论

优化限制叶面部分氮或磷的分配，以及快速而缓慢的经济策略，推动了冰川退缩后的主要演替。通过食物网整合地上和地下子系统将提供对生态系统动态的进一步见解。