Gómez-González Susana, Paula Susana, Cavieres Lohengrin A, Pausas Juli G
Departamento de Biología-IVAGRO, Universidad de Cádiz, Puerto Real, España.
Centre for Science and Resilience Research [(CR)2], Universidad de Chile, Santiago, Chile.
PLoS One. 2017 Jul 12;12(7):e0180661. doi: 10.1371/journal.pone.0180661. eCollection 2017.
Fire is a selective agent shaping plant traits and community assembly in fire-prone ecosystems. However, in ecosystems with no fire history, it can be a cause of land degradation when it is suddenly introduced by humans, as plant species may not be able to respond to such novel disturbance. Unlike other Mediterranean-type ecosystems (MTE) of the world, natural fires have not been frequent during the Quaternary in the matorral of Central Chile, and thus, plant adaptive responses are expected to be uncommon. We evaluated the effect of heat shock on seed survival and germination of 21 native woody plants of the Chilean matorral and compiled information on smoke-stimulation and resprouting, to evaluate the importance of fire-adaptive responses in the context of the other MTE. We found that in the Chilean woody flora negative seed responses to fire cues were more frequent than positive responses. Although resprouting is a relatively widespread trait, fire-stimulated germination is not as common in the Chilean matorral as in other MTE. The seeds of seven endemic species were strongly damaged by fire cues and this should be considered in post-fire restoration planning. However, our results also showed that many species were resistant to elevated doses of heat shock and in some, germination was even stimulated. Thus, future research should focus on the evolutionary causes of these responses. These findings could help to develop strategies for fire management in the Chilean matorral. In addition, they will improve our understanding of the evolutionary forces that shaped this plant community and to better frame this region among the other MTE worldwide.
火是塑造易发生火灾生态系统中植物性状和群落组装的选择性因子。然而，在没有火灾历史的生态系统中，当人类突然引入火灾时，它可能成为土地退化的一个原因，因为植物物种可能无法应对这种新出现的干扰。与世界上其他地中海型生态系统（MTE）不同，智利中部马托拉尔地区在第四纪期间自然火灾并不频繁，因此，预计植物的适应性反应并不常见。我们评估了热激对智利马托拉尔地区21种本土木本植物种子存活和萌发的影响，并收集了有关烟雾刺激和再萌蘖的信息，以评估在其他MTE背景下火灾适应性反应的重要性。我们发现，在智利木本植物区系中，种子对火灾线索的负面反应比正面反应更频繁。尽管再萌蘖是一种相对普遍的性状，但火灾刺激萌发在智利马托拉尔地区并不像在其他MTE中那样常见。7种特有物种的种子受到火灾线索的严重损害，这在火灾后恢复规划中应予以考虑。然而，我们的结果还表明，许多物种对高剂量热激具有抗性，在某些情况下，萌发甚至受到刺激。因此，未来的研究应关注这些反应的进化原因。这些发现有助于制定智利马托拉尔地区的火灾管理策略。此外，它们将增进我们对塑造这个植物群落的进化力量的理解，并在全球其他MTE中更好地界定该地区。
