Data from: Quercus suber dieback alters soil respiration and nutrient availability in Mediterranean forests

An increase in tree mortality rates has been recently detected in forests
world-wide. However, few works have focused on the potential consequences
of forest dieback for ecosystem functioning. Here we assessed the effect
of Quercus suber dieback on carbon, nitrogen and phosphorus cycles in two
types of Mediterranean forests (woodlands and closed forests) affected by
the aggressive pathogen Phytophthora cinnamomi. We used a spatially
explicit neighbourhood approach to analyse the direct effects of Q. suber
dieback on soil variables, comparing the impact of Q. suber trees with
different health status, as well as its potential long-term indirect
effects, comparing the impact of non-declining coexistent species. Quercus
suber dieback translated into lower soil respiration rates and phosphorus
availability, whereas its effects on nitrogen varied depending on forest
type. Coexistent species differed strongly from Q. suber in their effects
on nutrient availability, but not on soil respiration rates. Our models
showed low interannual but high intra-annual variation in the ecosystem
impacts of tree dieback. Synthesis. Our results support that tree dieback
might have important short- and long-term impacts on ecosystem processes
in Mediterranean forests. With this work, we provide valuable insights to
fill the existent gap in knowledge on the ecosystem-level impacts of
forest dieback in general and P. cinnamomi-driven mortality in particular.
Because the activity and range of this pathogen is predicted to increase
due to climate warming, these impacts could also increase in the near
future altering ecosystem functioning world-wide.

近年来，全球森林的树木死亡率均已被监测到呈上升趋势。然而，目前针对森林衰退对生态系统功能潜在影响的相关研究仍较为稀缺。本研究针对受破坏性病原菌樟疫霉（Phytophthora cinnamomi）侵染的两类地中海森林（疏林与密闭林），评估了栓皮栎（Quercus suber）衰退对碳、氮、磷循环的影响。我们采用空间显式邻域分析法（spatially explicit neighbourhood approach），通过对比不同健康状态下栓皮栎的影响，分析其衰退对土壤变量的直接效应；同时通过对比共存的未衰退树种的影响，探究其潜在的长期间接效应。研究结果显示，栓皮栎衰退会导致土壤呼吸速率与磷有效性降低，但其对氮循环的影响则因森林类型而异。共存树种与栓皮栎在养分有效性的影响上差异显著，但对土壤呼吸速率的影响并无明显区别。我们的模型表明，树木衰退对生态系统的影响存在较低的年际变异性，但年内变异性较高。综上，本研究结果证实，树木衰退可能对地中海森林的生态系统过程产生重要的短期与长期影响。本研究填补了当前森林衰退（尤其是由樟疫霉介导的树木死亡）的生态系统层面影响相关研究的空白，为该领域提供了具有价值的认知。鉴于气候变暖将导致该病原菌的活动范围与侵染活性进一步扩张，未来其对全球森林生态系统功能的负面影响或将进一步加剧。