Prescribed fire is increasingly used to accomplish management goals in fire-adapted systems, yet our understanding of effects on non-target organisms remains underdeveloped. Terricolous lichens in the genus Cladonia P. Browne, particularly cushion-forming reindeer lichens belonging to Cladonia subgenus Cladina Nyl., fit into this category, being characteristic of fire-adapted ecosystems, yet highly vulnerable to damage or consumption during burns. Moreover, inherently slow dispersal and growth rates raise questions about how to conserve these taxa in the context of fire-mediated restoration management. This research was undertaken to identify factors that contribute to Cladonia persistence within areas subject to repeated burning and involved tracking the fate of 228 spatially isolated individuals distributed across seven sites previously burned zero to two times. Site selection was determined by edaphic factors associated with a rare inland dune woodland community type known to support relatively high densities of Cladonia. Evaluated across all sites, the post-burn condition of Cladonia subtenuis (Abbayes) Mattick samples, categorized as intact (32%), fragmented (33%), or consumed (36%) individuals, approximated a uniform distribution. However, their status was highly variable at the different sites, where from 0 to 70% were assessed as intact and 11 to 60% consumed. Machine-learning statistical techniques were used to identify the factors most strongly associated with fire damage, drawing from variables describing the proximate fuel bed, growth substrate, and fire weather. The final descriptive model was dominated by variables characterizing the understory fuel matrix. Areas with highly contiguous fuels dominated by pyrogenic pine needles were most likely to result in consumption of individual Cladonia, whereas those growing in areas with low fuel continuity or in areas dominated by hardwood litter were more likely to persist (intact or as fragments). Further, substrates including bare soil and moss mats afforded more protection than coarse woody debris or leaf litter in settings where fuels were both contiguous and highly flammable. Our findings describe the characteristics of within-site fire refugia, the abundance of which may be enhanced over time through restoration and maintenance treatments including thinning, promotion of mixed-species overstory composition, and periodic burning. Because lichens contribute to, and are considered reliable indicators of forest health, fire-based restoration management efforts will benefit from improved understanding of how these vulnerable organisms are able to persist.

中文翻译：

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在美国中大西洋沿岸平原频繁发生火灾的环境中影响驯鹿地衣（Cladonia亚属Cladina）持续存在的因素

在针对火灾的系统中，越来越多地使用处方火来实现管理目标，但是我们对非目标生物的影响的理解仍未得到充分发展。属于Cladonia P. Browne属的陆生地衣，特别是属于Cladonia亚种Cladina Nyl的形成垫层的驯鹿地衣，属于适应火的生态系统的特征，但在燃烧过程中极易受到破坏或消耗。此外，固有的缓慢扩散和增长速度引发了有关在火媒修复管理中如何保存这些分类单元的问题。进行了这项研究，以找出导致科拉多尼亚在反复燃烧的区域内持久存在的因素，并涉及追踪分布在七个曾经燃烧过零至两次的地点的228个空间孤立的个体的命运。选址是由与稀少的内陆沙丘林地群落类型相关的土壤环境因素决定的，已知该群落类型可支持相对较高的克拉德尼亚密度。在所有地点进行了评估，Cladonia subtenuis（Abbayes）Mattick样本的燃烧后状况被分类为完整（32％），零碎（33％）或消耗（36％）的个体，近似均匀分布。但是，它们的状态在不同的地点变化很大，其中0％至70％被认为是完整的，而11％至60％被消耗了。机器学习统计技术被用来识别与火灾破坏最密切相关的因素，这些变量来自描述最接近的燃料床，生长基质和火灾天气的变量。最终的描述性模型由表征底层燃料矩阵的变量主导。以高热的松树针为主的高度邻接燃料的地区最有可能导致单个克拉德尼亚的消耗，而那些在燃料连续性较低的地区或以硬木垃圾为主的地区中生长的地区则更有可能持续（完整或碎裂）。此外，在燃料既连续又高度易燃的环境中，包括裸露的土壤和苔藓垫在内的基层比粗糙的木屑或落叶更能提供更多的保护。我们的发现描述了场内火灾避难所的特征，随着时间的流逝，可以通过恢复和维护处理（包括减薄，促进混合物种的过度故事组成和定期燃烧）来增加其丰度。由于地衣有助于森林健康并且被认为是森林健康的可靠指标，基于火的恢复管理工作将受益于对这些脆弱生物如何持续生存的更好理解。