Plant functional traits are key drivers of ecosystem processes. However, plot-based monitoring of functional composition across both large spatial and temporal extents is a time-consuming and expensive undertaking. Airborne and satellite remote sensing platforms collect data across large spatial expanses, often repeatedly over time, raising the tantalising prospect of detection of biodiversity change over space and time through remotely sensed methods. Here, we test the degree to which in situ measurements of taxonomic and functional β-diversity, defined as pairwise dissimilarity either between sites, or between years within individual sites, is detectable in airborne hyperspectral imagery across both space and time in an alpine vascular plant community in the Front Range, Colorado, USA. Functional and taxonomic dissimilarity were significantly related to spectral dissimilarity across space, but lacked robust relationships with spectral dissimilarity over time. Biomass showed stronger relationships with spectral dissimilarity than either taxonomic or functional dissimilarity over space, but exhibited no significant associations with spectral dissimilarity over time. Comparative analyses using NDVI revealed that NDVI alone explains much of the variation explained by the full-range spectra. Our results support the use of hyperspectral data to detect fine-scale changes in vascular plant β-diversity over space, but suggest that methodological limitations still preclude the use of this technology for long-term monitoring and change detection.

中文翻译：

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评估高光谱数据在跨空间和时间监测局部尺度β多样性的效用


植物功能性状是生态系统过程的关键驱动因素。然而，在大空间和时间范围内对功能组成进行基于地块的监测是一项耗时且昂贵的工作。机载和卫星遥感平台在大面积空间范围内收集数据，通常随着时间的推移而重复收集数据，这为通过遥感方法检测生物多样性随空间和时间的变化提供了诱人的前景。在这里，我们测试了分类和功能β多样性的原位测量程度，定义为地点之间或单个地点内年份之间的成对差异，在美国科罗拉多州弗兰特山脉的高山维管植物群落中跨空间和时间的机载高光谱图像中可以检测到。功能和分类学差异与跨空间的光谱差异显著相关，但与随时间变化的光谱差异缺乏稳健的关系。生物量与光谱相异性的关系比分类学或功能相异性在空间上表现出更强的关系，但随着时间的推移与光谱相异性没有显著关联。使用 NDVI 的比较分析表明，仅 NDVI 就可以解释全范围光谱解释的大部分变化。我们的结果支持使用高光谱数据来检测维管植物β多样性随空间变化，但表明方法学限制仍然排除了使用该技术进行长期监测和变化检测的可能性。