Applied Marine and Estuarine Ecology Laboratory, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.
Applied Marine and Estuarine Ecology Laboratory, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.
Environ Pollut. 2023 Jan 1;316(Pt 1):120533. doi: 10.1016/j.envpol.2022.120533. Epub 2022 Oct 28.
Novel combinations of climatic conditions due to climate change and prolonged fire seasons have contributed to an increased occurrence of "megafires". Such large-scale fires pose an unknown threat to biodiversity due to the increased extent and severity of burn. Assessments of wildfires often focus on terrestrial ecosystems and effects on aquatic habitats are less documented, particularly in coastal environments. In a novel application of eDNA techniques, we assessed the impacts of the 2019-2020 Australian wildfires on the diversity of estuarine benthic sediment communities in six estuaries in NSW, Australia, before and after the fires. Estuaries differed in area of catchment burnt (0-92%) and amount of vegetative buffer that remained post-fire between burnt areas and waterways. We found greater dissimilarities in the composition and abundance of eukaryotic and bacterial sediment communities in estuaries from burnt catchments with no buffer compared to those with an intact buffer or from unburnt catchments. Shifts in composition in highly burnt catchments were associated with increased concentrations of nutrients, carbon, including fire-derived pyrogenic carbon, and copper, which was representative of multiple highly correlated trace metals. Changes in the relative abundances of certain taxonomic groups, such as sulfate-reducing and nitrifying bacterial groups, in the most impacted estuaries indicate potential consequences for the functioning of sediment communities. These results provide a unique demonstration of the use of eDNA to identify wildfire impacts on ecological communities and emphasize the importance of vegetative buffers in limiting wildfire-associated impacts.
由于气候变化和延长的火灾季节导致的新型气候条件组合，促成了“大火”的频发。这种大规模火灾由于燃烧范围和严重程度的增加，对生物多样性构成了未知的威胁。野火评估通常侧重于陆地生态系统，而水生栖息地的影响记录较少，特别是在沿海环境中。在一项 DNA 技术的新应用中，我们评估了 2019-2020 年澳大利亚野火对澳大利亚新南威尔士州六个河口滨岸底栖沉积物群落多样性的影响，在火灾前后进行了评估。这些河口在燃烧流域面积（0-92%）和火灾后燃烧区与水道之间残留的植被缓冲区面积方面存在差异。我们发现，与有完整缓冲区或未燃烧流域的河口相比，没有缓冲区的燃烧流域的河口的真核生物和细菌沉积物群落的组成和丰度存在更大的差异。在高度燃烧的流域中，组成的变化与营养物质、碳（包括源自火灾的热解碳）和铜的浓度增加有关，铜代表了多种高度相关的痕量金属。某些分类群的相对丰度的变化，如硫酸盐还原和硝化细菌群，在受影响最严重的河口表明了对沉积物群落功能的潜在影响。这些结果提供了一个独特的例子，说明了使用 eDNA 来识别野火对生态群落的影响，并强调了植被缓冲区在限制与野火相关的影响方面的重要性。
