Understory plant diversity and composition across a postfire tree density gradient in a Siberian Arctic boreal forest
Understory plant diversity and composition across a postfire tree density gradient in a Siberian Arctic boreal forest
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西伯利亚北极北方森林火灾后树木密度梯度的林下植物多样性和组成
DOI：
10.1139/cjfr-2020-0483
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发表时间：
2021
影响因子：
2.2
通讯作者：
Natali, Susan M.
中科院分区：
文献类型：
--
作者：
Paulson, Alison K.;Peña, Homero;Alexander, Heather D.;Davydov, Sergei P.;Loranty, Michael M.;Mack, Michelle C.;Natali, Susan M.
卡扬德落叶松(Larix cajanderMayr.)随着气候变暖，西伯利亚北极的森林正在经历更多的野火活动。这些变化可能会影响火灾后树木和林下植物群落密度和排列的变化。为了更好地了解林下植物组成、丰富度和多样性如何随着树木密度的变化而变化，我们调查了25个林分内的林下植物群落和林分特征(例如，郁闭度、活动层深度和土壤有机层深度)，这些林分代表了1940年俄罗斯切尔斯基附近一场火灾后建立的同龄落叶松的密度梯度。林下植物多样性和平均总植物丰富度随着盖度的增加而降低。冠层盖度也是影响个体物种丰富度的最重要变量。一般来说，高大灌木(如白桦)在光能利用率高的低密度林分中更为丰富，而苔藓(如Sanion iaspp.)在光能利用率较低的高密度林分中更为丰富。这些结果表明，随着林分成熟，林木更新在火后的变化会影响林下植物群落组成和多样性。因此，预计西伯利亚北极野火活动的增加可能会对覆盖层和林下植物群落的森林结构和组成产生连锁影响。
Cajander larch (Larix cajanderiMayr.) forests of the Siberian Arctic are experiencing increased wildfire activity in conjunction with climate warming. These shifts could affect postfire variation in the density and arrangement of trees and understory plant communities. To better understand how understory plant composition, abundance, and diversity vary with tree density, we surveyed understory plant communities and stand characteristics (e.g., canopy cover, active layer depth, and soil organic layer depth) within 25 stands representing a density gradient of similarly-aged larch trees that established following a 1940 fire near Cherskiy, Russia. Understory plant diversity and mean total plant abundance decreased with increased canopy cover. Canopy cover was also the most important variable affecting individual species’ abundances. In general, tall shrubs (e.g.,Betula nanasubsp.exilis) were more abundant in low-density stands with high light availability, and mosses (e.g.,Sanioniaspp.) were more abundant in high-density stands with low light availability. These results provide evidence that postfire variation in tree recruitment affects understory plant community composition and diversity as stands mature. Therefore, projected increases in wildfire activity in the Siberian Arctic could have cascading impacts on forest structure and composition in both overstory and understory plant communities.