Institut de recherche pour l'ingénierie de l'agriculture et de l'environnement (Irstea/UR EMAX Écosystèmes méditerranéens et risques), 3275, route de Cézanne, CS 40061, 13182 Aix-en-Provence cedex 5, France.
C R Biol. 2012 Jun;335(6):424-34. doi: 10.1016/j.crvi.2012.04.006. Epub 2012 Jun 7.
The effects of fire recurrence on vegetation patterns in Quercus suber L. and Erica-Cistus communities in Mediterranean fire-prone ecosystems of south-eastern France were examined on stands belonging to 5 fire classes, corresponding to different numbers of fires (from 0 to 4) and time intervals between fires since 1959. A common pool of species was identified among the plots, which was typical of both open and closed maquis. Fire recurrence reduced the abundance of trees and herbs, whereas it increased the abundance of small shrubs. Richness differed significantly between the most contrasting classes of fire recurrence, with maximal values found in control plots and minimal values in plots that had burned recurrently and recently. Equitability indices did not vary significantly, in contrast to Shannon's diversity index which mostly correlated with richness. Forest ecosystems that have burnt once or twice in the last 50 years were resilient; that is to say they recovered a biomass and composition similar to that of the pre-fire state. However, after more than 3-4 fires, shrubland communities displayed lower species richness and diversity indices than unburned plots. The time since the last fire and the number of fires were the most explanatory fire variables, governing the structure of post-fire plant communities. However, environmental factors, such as slope or exposure, also made a significant contribution. Higher rates of fire recurrence can affect the persistence or expansion of shrublands in the future, as observed in other Mediterranean areas.
研究了法国东南部地中海火险生态系统中栓皮栎和石南-茜草灌丛中火灾复发对植被格局的影响。研究对象为属于 5 个火类别的林分，这些林分对应于 1959 年以来不同的火灾次数（从 0 到 4）和火灾之间的时间间隔。在各斑块之间确定了一个共同的物种库，该物种库是开阔灌丛和封闭灌丛的典型代表。火灾复发减少了树木和草本植物的丰度，而增加了小灌木的丰度。丰富度在火灾复发最显著的类群之间存在显著差异，控制样地的丰富度最高，最近反复燃烧的样地的丰富度最低。均匀度指数与香农多样性指数不同，其与丰富度大多呈正相关，而均匀度指数没有显著变化。在过去 50 年中只燃烧过一次或两次的森林生态系统具有弹性；也就是说，它们恢复了与火灾前状态相似的生物量和组成。然而，在经历了 3-4 次以上的火灾后，灌丛群落的物种丰富度和多样性指数低于未燃烧的斑块。最近一次火灾的时间和火灾次数是最能解释火灾变量，它们控制着火灾后植物群落的结构。然而，环境因素，如坡度或暴露，也做出了重大贡献。如在其他地中海地区所观察到的那样，较高的火灾复发率可能会影响未来灌丛的持续或扩张。
