Purpose of the Review

The escalating impacts of human activities and climate change, particularly increased nutrient leaching and deposition, could significantly alter the productivity, structure, and function of tropical vegetation. To better understand how nutrient deposition affects regeneration in tropical ecosystems, we synthesised studies that added N, P, NP, or NPK to the seedlings of tropical tree and shrub species.

Recent Findings

In the tropics, nutrient limitation leads to multiple resource constraints. Our systematic review and hierarchical meta-analyses aimed to: (1) test the effect of nutrient addition on the growth rate and biomass allocation of seedlings of tropical species; (2) examine seedling responses across climate-defined groups; (3) quantify the effects of experimental methods and wood density on species’ responses to experimental fertilisation.

Summary

Overall, nutrient addition increased seedling shoot biomass by 26% and growth rates by 14%. Pot and transplantation experiments demonstrated stronger positive effects than in-situ observational studies. Nutrient combinations yielded the highest growth rates (NPK: 27%, and NP: 18%), and N was critical for shoot biomass (N: 38%, and NP: 48%). The responses of shoot biomass indicated co-limitation of N and P, but also high variability in seedling responses to individual nutrients. Temperature and precipitation had indirect regulating effects, while seasonality showed the strongest impact in seasonally dry sites (38% growth rate and 70% shoot biomass). Species showed individual responses to nutrients, influenced by biotic and abiotic interactions. Finally, we suggest tracking additional parameters, like forest successional status, that may intensify nutrient deposition effects on tropical soils due to climate change.

中文翻译：

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热带树苗对养分添加的响应：了解热带森林动态未来变化的荟萃分析

 审查目的

人类活动和气候变化的影响不断升级，特别是养分浸出和沉积的增加，可能会显着改变热带植被的生产力、结构和功能。为了更好地了解养分沉积如何影响热带生态系统的再生，我们综合了在热带乔木和灌木物种的幼苗中添加 N、P、NP 或 NPK 的研究。

 最新发现

在热带地区，养分限制导致多种资源限制。我们的系统评价和分层荟萃分析旨在：（1） 测试养分添加对热带物种幼苗生长速率和生物量分配的影响;（2） 检查气候定义组的幼苗响应;（3） 量化实验方法和木材密度对物种对实验施肥反应的影响。

 总结

总体而言，养分添加使幼苗芽生物量增加了 26%，生长速率增加了 14%。盆栽和移植实验显示出比原位观察研究更强的积极影响。养分组合产生的生长速率最高（NPK：27% 和 NP：18%），N 对芽生物量至关重要（N：38% 和 NP：48%）。地上部生物量的响应表明 N 和 P 的共限制性，但幼苗对单个养分的响应也具有高度可变性。温度和降水具有间接调节作用，而季节性在季节性干燥地点表现出最强的影响 （38% 的生长速率和 70% 的芽生物量）。物种对营养物质表现出个体反应，受生物和非生物相互作用的影响。最后，我们建议跟踪其他参数，例如森林演替状态，这些参数可能会因气候变化而加剧对热带土壤的养分沉积效应。