Is foliar flammability of woody species related to time since fire and herbivory in northwest Patagonia, Argentina?
Is foliar flammability of woody species related to time since fire and herbivory in northwest Patagonia, Argentina?
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DOI：
10.1111/j.1654-1103.2012.01405.x
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发表时间：
2012-10-01
影响因子：
2.8
通讯作者：
Veblen, Thomas T.
中科院分区：
文献类型：
--
作者：
Blackhall, Melisa;Raffaele, Estela;Veblen, Thomas T.
问题 在巴塔哥尼亚西北部，燃烧耐火森林会产生社区一级的积极反馈，导致火灾发生率增加，因为易燃灌木丛相继取代。我们假设与上次火灾以来的时间和牛的食草相关的植物性状的变异可能会影响叶的可燃性，从而提供在个体植物水平上运作的易燃性促进机制。我们研究了影响可燃性的植物叶性状在不同物种和从最近的火灾中恢复的地点（与一年相似的 50 次，无论有牛还是没有牛的情况下）的差异。地点纳韦尔瓦皮国家公园，巴塔哥尼亚西北部，阿根廷。方法我们测量了四种预计会影响可燃性的叶性状：叶子湿度、叶子大小、比叶面积和叶子强度，并对六种常见植物的叶子进行了可燃性测试（点燃时间和燃烧持续时间）。高灌木和小树种：不可口的 Lomatia hirsuta 和 Diostea juncea，中等适口的 Nothofagus antarctica 和 Schinus patagonicus 以及高度适口的 Maytenus boaria 和 Ribes magellanicum 我们使用 ANOVA 和 PCA 来检查物种可燃性特征、火灾发生后的时间和牛的存在或不存在之间的潜在关系。与上次火灾以来的时间密切相关，而牛的影响在不同物种和处理中变化更大，与未烧毁的森林相比，灌木丛中的主要木本物种表现出叶片湿度、叶片尺寸和比叶面积的减少，在牛的压力下，与南极洲相似的灌木丛中最重要的木本物种之一，显示出一些叶性状的变化，预计会增强可燃性（例如，点火时间缩短）。结论 目前的研究表明，最近燃烧和未燃烧地点的植物叶子性状有所不同，这些变化可能会增强灌木丛群落的叶子可燃性。
Question In northwest Patagonia burning of fire-resistant forests creates a community-level positive feedback towards increased fire occurrence because of successional replacement by fire-prone shrublands. We hypothesize that variability in plant traits related to time since last fire and to herbivory by cattle may affect foliar flammability, thus providing a flammability-promoting mechanism operating at the level of individual plants. We examine how plant foliar traits affecting flammability vary across species and at sites recovering from recent fires (similar to 50 similar to yr, both in the presence and absence of cattle. Location Nahuel Huapi National Park, northwest Patagonia, Argentina. Methods We measured four foliar traits expected to affect flammability: leaf moisture, leaf size, specific leaf area and leaf strength, and conducted tests of ignitability (time to ignition and duration of combustion) on leaves of six common tall shrub and small tree species: non-palatable Lomatia hirsuta and Diostea juncea, moderately palatable Nothofagus antarctica and Schinus patagonicus and highly palatable Maytenus boaria and Ribes magellanicum. We used ANOVA and PCA to examine potential relationships among species flammability traits, time since fire and presence or absence of cattle. Results At plant level, variability in flammability-related foliar properties is strongly and consistently related to time since last fire, whereas effects of cattle are more variable across species and treatments. In comparison with unburned forests, the dominant woody species at shrubland sites showed reduced leaf moisture, leaf size and specific leaf area. Under pressure from cattle, N.similar to antarctica, one of the most important woody species in these shrublands, showed changes in some foliar traits expected to enhance flammability (e.g. shorter time to ignition) but overall the influence of cattle on flammability was not consistent. Conclusions The current study demonstrates that plant foliar traits vary between recently burned and unburned sites, and that these variations may enhance foliar flammability in shrubland communities.