Fire Effects on Understory Forest Regeneration in Southern Amazonia
Fire Effects on Understory Forest Regeneration in Southern Amazonia
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DOI：
10.3389/ffgc.2020.00010
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发表时间：
2020-02
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通讯作者：
N. D. S. Prestes;K. Massi;Estevao Alves Silva;D. S. Nogueira;E. A. de Oliveira;Renata Freitag;B. Marimon;B. H. Marimon‐Junior;M. Keller;T. Feldpausch
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作者：
N. D. S. Prestes;K. Massi;Estevao Alves Silva;D. S. Nogueira;E. A. de Oliveira;Renata Freitag;B. Marimon;B. H. Marimon‐Junior;M. Keller;T. Feldpausch
热带森林的火灾增加了树木死亡率，破坏了森林结构，减少了碳储存。目前，在了解火灾如何影响林下森林结构和组成，与火灾复发的相互作用以及长期影响方面存在很大差距。了解这些变化对于评估热带森林目前和未来对火灾的反应至关重要。我们研究了巴西亚马逊河流域南部马托格罗索州森林林下植被更新的火后变化，旨在回答以下问题：（i）森林结构（断面积）和树木群落组成是否随火灾频率和时间而变化？(ii)响应在层之间是否不同（例如，树苗，大树）？(iii)多样性的变化是否与森林结构的变化有关？我们调查了以前结构完整的森林中的树木和藤本植物，这些森林经历了选择性砍伐，随后经历了不同的火灾历史，包括一次燃烧后5年和16年、三次燃烧后5年以及未燃烧（对照）。总体而言，物种组成（丰度，丰富度和家庭数量）和多样性最高的未燃烧的治疗和最低的经常性烧伤地区。火灾频率的负面影响植物结构和断面积;断面积的小型，中型和大型植物显着下降了50%以上，在最频繁烧毁的地区。三次火烧迹地和16年更新迹地各层位的丰度与断面积均呈正相关。我们的研究结果表明，频繁的火灾对亚马逊森林中的小树的组成和结构的负面影响。这些小型树木群的变化可能会持续下去，并对森林结构产生长期影响，影响森林恢复的能力和方向。随着野火在整个地区的蔓延和频率的增加，火灾可能会对剩余的选择性砍伐森林的树木多样性产生负面影响，并影响区域碳循环，对全球植被碳汇产生影响。
Fire in tropical forests increases tree mortality, degrades forest structure, and reduces carbon stocks. Currently, there are large gaps in understanding how fire affects understory forest structure and composition, interactions with fire recurrence, and long-term impacts. Understanding these changes is critical to evaluate the present and future response of tropical forests to fire. We studied post-fire changes in understory regeneration in forests in Mato Grosso State, southern Amazonia, Brazil, aiming to answer the following questions: (i) does forest structure (basal area) and tree community composition vary with fire frequency and time since the last fire? (ii) does the response differ among strata (e.g., sapling, larger trees)? (iii) are changes in diversity associated with changes in forest structure? We surveyed trees and lianas in previously structurally intact forests that underwent selective logging, followed by different fire histories, including 5 and 16 years after once-burned, 5 years after three times burned, and unburned (control). Overall, species composition (abundance, richness, and number of families) and diversity were highest for the unburned treatment and lowest for the recurrent burned areas. Fire frequency negatively affected plant structure and basal area; basal area of small, medium, and large plants declined significantly by more than 50% in the most frequently burned areas. Richness was positively related to basal area in the three times burned sites and in the 16 years regenerating site for all strata. Our results demonstrate the negative influence of frequent fires on both the composition and structure of small trees in Amazonian forest. These changes to the cohort of small-sized trees may persist and have long-term impacts on forest structure, affecting the capacity, and direction of forest recovery. With wildfire widespread across the region and increasing in frequency, fire may negatively affect tree diversity in remaining selectively logged forests, and affect regional carbon cycling with consequences for the global vegetation carbon sink.