Lichens cover approximately 8% of land surface, primarily in alpine and polar habitats. Lichen biomass is often correlated with cover and thallus height, but quick and effective methods of lichen biomass estimation have not been tested across large areas. We utilize a dataset of over 7800 height measurements made throughout the Arctic Network of National Parks in the US to model mat-forming macrolichen height by species as a function of morphological, climatic, and habitat factors. Our goal was to understand how lichen height, as proxy for biomass, varied by species in different areas, and determine which factors best predict lichen height. We found that the single best predictor of lichen height was surface downwelling shortwave radiation. Climatic, vegetative, and other physiographic variables were moderate predictors of lichen height. We determined that differences in height observed between species were not explained by the degree of branching nor thallus width. Our findings highlight that the key factors predicting lichen height may not be easy to mitigate through management (e.g., radiation, vapor pressure deficit, length of growing season), yet may be altered in future climate change scenarios. Further, rapid height field measurements, like those used in our study, could improve our understanding of the drivers of lichen biomass, underscore its variability across species, and could be used for other applications. Accurate biomass measurements are necessary for landscape-scale monitoring and predictions of future lichen biomass in the face of climate perturbations.

中文翻译：

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美国北极阿拉斯加地衣物种高度的气候、植物和干扰预测因子

地衣约占陆地表面的 8%，主要位于高山和极地栖息地。地衣生物量通常与覆盖率和叶绿体高度相关，但尚未在大面积范围内测试过快速有效的地衣生物量估算方法。我们利用在美国北极国家公园网络中进行的超过 7800 次高度测量的数据集，将物种形成的大地衣高度建模为形态、气候和栖息地因素的函数。我们的目标是了解作为生物量代表的地衣高度如何因不同地区的物种而异，并确定哪些因素最能预测地衣高度。我们发现地衣高度的唯一最佳预测指标是地表下涌短波辐射。气候、植物和其他地貌变量是地衣高度的中等预测因子。我们确定，物种之间观察到的高度差异不能用分枝程度和叶状体宽度来解释。我们的研究结果强调，预测地衣高度的关键因素可能不容易通过管理减轻（例如，辐射、蒸气压不足、生长季节的长度），但在未来的气候变化情景中可能会改变。此外，像我们研究中使用的那样，快速的高度场测量可以提高我们对地衣生物量驱动因素的理解，强调其跨物种的可变性，并可用于其他应用。面对气候扰动，准确的生物量测量对于景观尺度监测和预测未来地衣生物量是必要的。