Department of Geography, Florida State University, 113 Collegiate Loop, Tallahassee, 32306, FL, USA.
Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, 32304, FL, USA.
Sci Rep. 2020 May 21;10(1):8483. doi: 10.1038/s41598-020-65436-9.
Global biodiversity hotspots (GBHs) are increasingly vulnerable to human stressors such as anthropogenic climate change, which will alter the ecology of these habitats, even where protected. The longleaf pine (Pinus palustris) ecosystem (LPE) of the North American Coastal Plain is a GBH where disturbances are integral for ecosystem maintenance. However, stronger storms due to climate change may be outside their historical norm. In this study, we estimate the extent of Florida LPE that was directly affected by Hurricane Michael in 2018, an unprecedented Category 5 storm. We then leveraged a unique data set in a Before-After study of four sites within this region. We used variable-area transects and generalized linear mixed-effects models to estimate tree densities and logistic regression to estimate mortality by size class. We found at least 28% of the global total remaining extent of LPE was affected in Florida alone. Mortality was highest in medium sized trees (30-45 cm dbh) and ranged from 4.6-15.4% at sites further from the storm center, but increased to 87.8% near the storm center. As the frequency and intensity of extreme events increases, management plans to mitigate climate change need to account for large-scale stochastic mortality events to preserve critical habitats.
全球生物多样性热点地区（GBHs）越来越容易受到人为气候变化等人类压力源的影响，即使在受到保护的情况下，这些栖息地的生态也会发生变化。北美滨海平原的长叶松（Pinus palustris）生态系统（LPE）是一个生物多样性热点地区，其干扰是维持生态系统的重要因素。然而，气候变化导致的强风暴可能超出了它们的历史常态。在这项研究中，我们估计了 2018 年佛罗里达州长叶松生态系统直接受到飓风迈克尔影响的程度，这是一场前所未有的 5 级风暴。然后，我们利用该地区四个地点的独特数据集进行了一项前后研究。我们使用可变面积样带和广义线性混合效应模型来估计树木密度，并使用逻辑回归按大小类来估计死亡率。我们发现，仅在佛罗里达州，就有全球长叶松生态系统总剩余面积的至少 28%受到了影响。死亡率在中等大小的树木（30-45cm 胸径）中最高，在离风暴中心较远的地点，死亡率范围为 4.6-15.4%，但在风暴中心附近，死亡率增加到 87.8%。随着极端事件的频率和强度的增加，减轻气候变化的管理计划需要考虑大规模的随机死亡率事件，以保护关键栖息地。
