Leaf traits and canopy structure together explain canopy functional diversity: an airborne remote sensing approach
Leaf traits and canopy structure together explain canopy functional diversity: an airborne remote sensing approach
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DOI：
10.1002/eap.2230
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发表时间：
2020-11-05
影响因子：
5
通讯作者：
Stark, Scott C.
中科院分区：
文献类型：
--
作者：
Kamoske, Aaron G.;Dahlin, Kyla M.;Stark, Scott C.
植物功能多样性与陆地生态系统中的光合作用碳同化密切相关。然而，许多调节光合能力的植物功能性状，包括叶面氮浓度和单位面积叶质量，在植物功能类型之间和内部以及在森林冠层垂直方向上存在显着差异，导致三个维度上相当大的景观尺度异质性。高光谱图像已广泛用于量化一系列生态系统的功能特征，但通常仅限于仅提供冠层叶子的信息。另一方面，激光雷达数据可用于检索森林冠层的垂直结构。由于这些数据很少同时收集，因此关于森林结构对整个生态系统功能特征的三维空间模式的影响尚有待解答的问题。在美国，国家生态观测站网络的机载观测平台 (NEON AOP) 通过在各个生态区域收集激光雷达和高光谱数据，提供了解决这种结构-功能关系的机会。通过融合 NEON AOP 的高光谱和激光雷达数据以及现场收集的叶性状数据，我们评估了森林结构对氮空间格局的影响。此外，我们还研究了由开放长叶松镶嵌组成的 NEON 站点上非生物梯度和管理制度对冠层氮百分比和冠层总氮（即森林冠层内氮总量 [g/m(2)]）的影响。和茂密的阔叶落叶林。我们得出的地图表明，与冠层顶部值相比，整个景观的冠层总氮变化受到抑制，从而形成相对均匀的空间模式。同时，我们发现叶片功能多样性和冠层结构多样性表现出与植物功能类型空间分布相关的独特树突模式。
Plant functional diversity is strongly connected to photosynthetic carbon assimilation in terrestrial ecosystems. However, many of the plant functional traits that regulate photosynthetic capacity, including foliar nitrogen concentration and leaf mass per area, vary significantly between and within plant functional types and vertically through forest canopies, resulting in considerable landscape-scale heterogeneity in three dimensions. Hyperspectral imagery has been used extensively to quantify functional traits across a range of ecosystems but is generally limited to providing information for top of canopy leaves only. On the other hand, lidar data can be used to retrieve the vertical structure of forest canopies. Because these data are rarely collected at the same time, there are unanswered questions about the effect of forest structure on the three -dimensional spatial patterns of functional traits across ecosystems. In the United States, the National Ecological Observatory Network's Airborne Observation Platform (NEON AOP) provides an opportunity to address this structure-function relationship by collecting lidar and hyperspectral data together across a variety of ecoregions. With a fusion of hyperspectral and lidar data from the NEON AOP and field-collected foliar trait data, we assessed the impacts of forest structure on spatial patterns of N. In addition, we examine the influence of abiotic gradients and management regimes on top-of-canopy percent N and total canopy N (i.e., the total amount of N [g/m(2)] within a forest canopy) at a NEON site consisting of a mosaic of open longleaf pine and dense broadleaf deciduous forests. Our resulting maps suggest that, in contrast to top of canopy values, total canopy N variation is dampened across this landscape resulting in relatively homogeneous spatial patterns. At the same time, we found that leaf functional diversity and canopy structural diversity showed distinct dendritic patterns related to the spatial distribution of plant functional types.