Fragmentation-Driven Divergent Trends in Burned Area in Amazonia and Cerrado
Fragmentation-Driven Divergent Trends in Burned Area in Amazonia and Cerrado
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DOI：
10.3389/ffgc.2022.801408
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发表时间：
2022-02
期刊：
影响因子：
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通讯作者：
T. Rosan;S. Sitch;L. Mercado;Viola H. A. Heinrich;P. Friedlingstein;L. Aragão
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文献类型：
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作者：
T. Rosan;S. Sitch;L. Mercado;Viola H. A. Heinrich;P. Friedlingstein;L. Aragão
巴西的两个主要生物群落，亚马逊和塞拉多（热带稀树草原），越来越容易受到火灾的影响。亚马逊森林是一个对火灾敏感的生态系统，火灾通常是罕见的干扰，而塞拉多自然依赖火灾。人类活动，例如景观破碎化和土地使用管理，已经改变了塞拉多的火灾制度，并将火灾引入亚马逊森林。在亚马逊河流域和塞拉多地区，人们对景观破碎化对火灾发生的作用了解有限。由于各生物群系的植被结构、组成和土地利用特征的差异，我们假设新出现的烧毁面积（BA）模式是由生物群系对破碎化的火灾响应引起的。本研究的目的是测试亚马逊河流域和塞拉多生物群系BA、景观破碎化和农业用地之间的一般关系。为了估计景观破碎化的趋势和现状，基于MapBiomas土地覆盖数据集计算了2002 - 2018年两个生物群落的森林面积密度（FAD）指数。对原生植被的BA分数与FAD和农用地分数进行了对比分析。我们的研究结果显示，16%的亚马逊地区和15%的塞拉多地区的景观破碎化程度有所增加。我们发现BA分数与景观破碎化和农业分数之间存在相反的关系。在亚马逊地区，由于人类点火活动的增加，景观破碎化和农业组分都增加了BA组分。另一方面，塞拉多的景观破碎化和农业成分增加导致原生植被内BA成分减少。对于这两个生物群系，我们发现在干旱年，BA增加，而在两个对比的全球生物群系中，破碎化驱动的分化趋势保持不变。这一认识对于为气候预测和未来生态系统服务提供提供火灾动态全球植被模型和地球系统模型中的火灾动力学表示提供信息至关重要。
The two major Brazilian biomes, the Amazonia and the Cerrado (savanna), are increasingly exposed to fires. The Amazonian Forest is a fire sensitive ecosystem where fires are a typically rare disturbance while the Cerrado is naturally fire-dependent. Human activities, such as landscape fragmentation and land-use management, have modified the fire regime of the Cerrado and introduced fire into the Amazonian Forest. There is limited understanding of the role of landscape fragmentation on fire occurrence in the Amazonia and Cerrado biomes. Due to differences in vegetation structure, composition, and land use characteristics in each biome, we hypothesize that the emerging burned area (BA) patterns will result from biome-specific fire responses to fragmentation. The aim of this study was to test the general relationship between BA, landscape fragmentation, and agricultural land in the Amazonia and the Cerrado biomes. To estimate the trends and status of landscape fragmentation a Forest Area Density (FAD) index was calculated based on the MapBiomas land cover dataset for both biomes between 2002 and 2018. BA fraction was analyzed within native vegetation against the FAD and agricultural land fraction. Our results showed an increase in landscape fragmentation across 16% of Amazonia and 15% of Cerrado. We identified an opposite relationship between BA fraction, and landscape fragmentation and agricultural fraction contrasting the two biomes. For Amazonia, both landscape fragmentation and agricultural fraction increased BA fraction due to an increase of human ignition activities. For the Cerrado, on the other hand, an increase in landscape fragmentation and agricultural fraction caused a decrease in BA fraction within the native vegetation. For both biomes, we found that during drought years BA increases whilst the divergent trends driven by fragmentation in the two contrasting global biomes is maintained. This understanding will be critical to informing the representation of fire dynamics in fire-enable Dynamic Global Vegetation Models and Earth System Models for climate projection and future ecosystem service provision.