Departamento de Ciencias Ambientales, Universidad de Castilla-La Mancha, Toledo, 45071, Spain.
New Phytol. 2017 May;214(3):1118-1131. doi: 10.1111/nph.14454. Epub 2017 Feb 27.
Understanding how drought affects seeder and resprouter plants during post-fire regeneration is important for the anticipation of Mediterranean vegetation vulnerability in a context of increasing drought and fire caused by climate change. A Mediterranean shrubland was subjected to various drought treatments (including 45% rainfall reduction, 7 months drought yr ), before and after experimental burning, by means of a rainout-shelter system with an irrigation facility. Predawn shoot water potential (Ψ ), relative growth rate (RGR), specific leaf area (SLA) and bulk leaf carbon isotopic composition (δ C) were monitored in the main woody species during the first 3 yr after fire. Cistus ladanifer seedlings showed higher Ψ , RGR and SLA, and lower δ C, than unburned plants during the first two post-fire years. Seedlings under drought maintained relatively high Ψ , but suffered a decrease in Ψ and RGR, and an increase in δ C, relative to control treatments. Erica arborea, E. scoparia and Phillyrea angustifolia resprouts had higher Ψ and RGR than unburned plants during the first post-fire year. Resprouters were largely unaffected by drought. Overall, despite marked differences between the two functional groups, post-fire environments were favourable for plant functioning of both seeder and resprouter shrubs, even under the most severe drought conditions implemented.
了解干旱如何影响火后再生中的先锋植物和更新植物，对于预测气候变化引起的干旱和火灾增加背景下地中海植被的脆弱性很重要。在一个带有灌溉设施的避雨棚系统的作用下，在实验火烧前后，对一片地中海灌丛进行了各种干旱处理（包括减少 45%的降雨量，干旱 7 个月）。在火烧后的头 3 年里，监测了主要木本物种的黎明前枝条水势（Ψ）、相对生长率（RGR）、比叶面积（SLA）和叶片碳同位素组成（δ C）。与未燃烧的植物相比，火后前两年，乳香黄连木幼苗具有更高的 Ψ、RGR 和 SLA，以及更低的 δ C。在干旱条件下，幼苗保持相对较高的 Ψ，但与对照处理相比， Ψ和 RGR 下降， δ C 增加。火后第一年，Erica arborea、E. scoparia 和 Phillyrea angustifolia 的更新枝具有较高的 Ψ和 RGR。更新植物受干旱影响较小。总体而言，尽管这两个功能群之间存在明显差异，但即使在实施最严重的干旱条件下，火后环境也有利于先锋植物和更新植物的生长。
