Abstract The Atlantic Forest biome, a biodiversity hotspot historically threatened by deforestation and human disturbance, has recently seen a net gain in native forest cover due to changes in land use, enactment of new laws, and substantial investment in restoration. Like many South American and global ecosystems, the Atlantic Forest biome has also experienced an increase in area burned by wildfire largely due to human ignitions, which threatens these gains. Our objective was to understand the vulnerability of protected areas and small patches of neotropical forest to fire in the Paraiba do Sul River Valley, Brazil, a region within the Atlantic Forest biome. Our modeled fire behavior and growth was calibrated to the observed fire size record and simulated fire perimeters that varied from 1-ha to more than 2250-ha. We found a strong positive correlation between pasture area and burn probability, and a negative correlation between burn probability and forest cover, reinforcing the role of pastures in fire ignition and transmission to forest edges and small fragmented patches. While most tropical forest patches (85%) were less than 10 ha, these forest patches only comprised a small portion (10%) of the total forest cover but were most vulnerable to fire exposure. The variables most influential on burn probability were patch size and distance to edge. Specifically, fires were most frequent in patches less than 100-ha in size and relatively absent in patches greater than 1000-ha. Likewise, fires occurred within 180-m of forest patch edges and exposure was minimal deeper into forest patches. Exposure was highest in stands with canopy-cover less than 20%, and then declined monotonically until 90%, after which burn probability was minimal. Our results demonstrate that the relationship between fire and landscape patterns are strongly contingent in Atlantic Forest landscape, where degraded tropical forests are often comprised of small forest patches, large patch edges, and low canopy cover, all of which increase the vulnerability of tropical forest to burning in Southeast Atlantic forest. Continued management of fire is critical to preserving the recovery and securing investments in reforestation in the Atlantic Forest biome.

中文翻译：

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巴西东南部南帕拉伊巴河谷的小森林斑块易受火灾影响：对大西洋森林生物群落恢复的影响

摘要大西洋森林生物群落是一个历史上受到森林砍伐和人类干扰威胁的生物多样性热点，最近由于土地利用的变化、新法律的颁布以及对恢复的大量投资，原生森林覆盖率出现净增长。与许多南美和全球生态系统一样，大西洋森林生物群落也经历了野火烧毁面积的增加，这主要是由于人类点火，这威胁到了这些收益。我们的目标是了解保护区和小块新热带森林在巴西南帕拉伊巴河谷（大西洋森林生物群落内的一个区域）遭受火灾的脆弱性。我们模拟的火灾行为和增长根据观察到的火灾规模记录和模拟火灾周长进行了校准，范围从 1 公顷到超过 2250 公顷不等。我们发现牧场面积与燃烧概率之间存在很强的正相关，而燃烧概率与森林覆盖率之间呈负相关，加强了牧场在着火和传播到森林边缘和小碎片斑块中的作用。虽然大多数热带森林斑块 (85%) 小于 10 公顷，但这些森林斑块仅占森林总覆盖面积的一小部分 (10%)，但最容易受到火灾影响。对烧伤概率影响最大的变量是斑块大小和到边缘的距离。具体而言，火灾在面积小于 100 公顷的斑块中最为频繁，而在面积大于 1000 公顷的斑块中则相对较少。同样，火灾发生在森林斑块边缘 180 米范围内，森林斑块深处的暴露程度最低。在树冠覆盖率低于 20% 的看台上，暴露率最高，然后单调下降，直到 90%，之后烧毁概率最小。我们的研究结果表明，在大西洋森林景观中，火灾和景观模式之间的关系有很强的偶然性，其中退化的热带森林通常由小森林斑块、大斑块边缘和低树冠覆盖组成，所有这些都增加了热带森林对森林的脆弱性。在东南大西洋森林中燃烧。持续管理火灾对于保护大西洋森林生物群落的恢复和确保重新造林投资至关重要。退化的热带森林通常由小森林斑块、大斑块边缘和低树冠覆盖组成，所有这些都增加了热带森林在东南大西洋森林中燃烧的脆弱性。持续管理火灾对于保护大西洋森林生物群落的恢复和确保重新造林投资至关重要。退化的热带森林通常由小森林斑块、大斑块边缘和低树冠覆盖组成，所有这些都增加了热带森林在东南大西洋森林中燃烧的脆弱性。持续管理火灾对于保护大西洋森林生物群落的恢复和确保重新造林投资至关重要。