Beierkuhnlein Carl, Nogales Manuel, Field Richard, Vetaas Ole R, Walentowitz Anna, Weiser Frank, Stahlmann Reinhold, Guerrero-Campos María, Jentsch Anke, Medina Félix M, Chiarucci Alessandro
Biogeography, University of Bayreuth, Universitätsstr. 30, 95440, Bayreuth, Germany.
Instituto de Productos Naturales y Agrobiología (IPNA-CSIC), La Laguna, Tenerife, Canary Islands, Spain.
NPJ Biodivers. 2023 Jul 1;2(1):14. doi: 10.1038/s44185-023-00018-2.
The high proportion of woody plant species on oceanic islands has hitherto been explained mainly by gradual adaptation to climatic conditions. Here, we present a novel hypothesis that such woodiness is adaptative to volcanic ash (tephra) deposition. Oceanic islands are subject to frequent eruptions with substantial and widespread ash deposition on evolutionary time scales. We postulate that this selects for woodiness through an increased ability to avoid burial of plant organs by ash, and to re-emerge above the new land surface. We sense-checked using observations of plant occurrences and distributions on La Palma (Canary Islands) in April 2022, 4 months after the end of the eruptions of the Tajogaite volcano (Cumbre Vieja ridge). In contrast to herbs and grasses, most woody plants persisted and were already in full flower in areas with 10+ cm ash deposition. Remarkably, these persisting woody plants were almost exclusively endemics.
迄今为止，海洋岛屿上木本植物物种的高比例主要是通过对气候条件的逐渐适应来解释的。在这里，我们提出了一个新的假设，即这种木质化是对火山灰沉积的适应性表现。在演化的时间尺度上，海洋岛屿频繁发生火山喷发，火山灰大量且广泛地沉积。我们推测，这通过增强植物器官避免被火山灰掩埋以及在新陆地表面重新生长的能力，从而选择了木质化特征。我们于2022年4月，在塔约加泰火山（坎布雷维耶哈山脊）喷发结束4个月后，利用拉帕尔马岛（加那利群岛）上植物的出现情况和分布进行了实地验证。与草本植物和草类不同，在火山灰沉积厚度超过10厘米的地区，大多数木本植物存活下来且已完全开花。值得注意的是，这些存活下来的木本植物几乎全是特有物种。
