Fuels and fires influence vegetation via above- and belowground pathways in a high-diversity plant community
Fuels and fires influence vegetation via above- and belowground pathways in a high-diversity plant community
复制标题
DOI：
10.1111/1365-2745.12421
复制
发表时间：
2015-07-01
影响因子：
5.5
通讯作者：
Paine, C. E. Timothy
中科院分区：
文献类型：
--
作者：
Gagnon, Paul R.;Passmore, Heather A.;Paine, C. E. Timothy
火强烈地影响着世界各地的植物种群和群落，使其成为植物进化的重要因素。火通过多种途径影响植被，包括地上和地下。很少有研究试图通过土壤加热以机械的方式将这些途径联系在一起，尽管土壤加热对易发生火灾的生态系统中的植物的重要性越来越被认识到。在这里，我们结合联合收割机的实验方法与结构方程模型（SEM），同时检查多个途径，通过火可能会影响草本植被。在美国路易斯安那州的一个高多样性的长叶松地被植物群落中，我们操纵了细燃料生物量，并使用高分辨率的热电偶监测了由此产生的火灾，热电偶放置在地上和地下的垂直剖面中。我们预测，植被对燃烧的反应将呈负相关的燃料负荷，由于燃料，火灾温度，持续时间和土壤加热之间的关系。我们发现，燃料操纵改变了火属性和植被的反应，其中土壤加热被证明是一个高度准确的预测。火持续时间通过土壤加热作用是重要的植被响应在我们的SEM，而火温度不是。我们的研究结果表明，在这个草本植物群落，火灾持续时间是一个很好的预测土壤加热，因此植被对火灾的反应。土壤加热可能是生态系统中植被对火灾反应的关键决定因素，其中植物通过从土壤储存的繁殖体中重新发芽或重新播种而持续存在。我们的SEM展示了如何同时研究火灾影响植物群落结构和动态的复杂途径。不同社区对这些途径的比较研究将为易发生火灾的生态系统的生态、进化和保护提供重要的见解。
Fire strongly influences plant populations and communities around the world, making it an important agent of plant evolution. Fire influences vegetation through multiple pathways, both above- and belowground. Few studies have yet attempted to tie these pathways together in a mechanistic way through soil heating even though the importance of soil heating for plants in fire-prone ecosystems is increasingly recognized. Here we combine an experimental approach with structural equation modelling (SEM) to simultaneously examine multiple pathways through which fire might influence herbaceous vegetation. In a high-diversity longleaf pine groundcover community in Louisiana, USA, we manipulated fine-fuel biomass and monitored the resulting fires with high-resolution thermocouples placed in vertical profile above- and belowground. We predicted that vegetation response to burning would be inversely related to fuel load owing to relationships among fuels, fire temperature, duration and soil heating. We found that fuel manipulations altered fire properties and vegetation responses, of which soil heating proved to be a highly accurate predictor. Fire duration acting through soil heating was important for vegetation response in our SEMs, whereas fire temperature was not. Our results indicate that in this herbaceous plant community, fire duration is a good predictor of soil heating and therefore of vegetation response to fire. Soil heating may be the key determinant of vegetation response to fire in ecosystems wherein plants persist by resprouting or reseeding from soil-stored propagules.Synthesis. Our SEMs demonstrate how the complex pathways through which fires influence plant community structure and dynamics can be examined simultaneously. Comparative studies of these pathways across different communities will provide important insights into the ecology, evolution and conservation of fire-prone ecosystems.