Field Spectroscopy in the VNIR-SWIR Region to Discriminate between Mediterranean Native Plants and Exotic-Invasive Shrubs Based on Leaf Tannin Content
Field Spectroscopy in the VNIR-SWIR Region to Discriminate between Mediterranean Native Plants and Exotic-Invasive Shrubs Based on Leaf Tannin Content
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DOI：
10.3390/rs70201225
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发表时间：
2015-02-01
期刊：
影响因子：
5
通讯作者：
Oldeland, Jens
中科院分区：
文献类型：
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作者：
Lehmann, Jan Rudolf Karl;Grosse-Stoltenberg, Andre;Oldeland, Jens
入侵灌木长叶金合欢原产于澳大利亚东南部，对葡萄牙沙丘生态系统的植被和生态系统功能产生负面影响。为了在光谱上区分 A. longifolia 与其他非本地和本地物种，我们开发了一个基于叶子反射光谱（350-2500 nm）和浓缩叶子单宁含量的分类模型。地中海灌木和树种的叶子单宁含量存在很大差异，特别是固氮树种和非固氮树种之间，以及金合欢属内。然而，葡萄牙西南部沿海沙丘生态系统中叶片单宁含量的变化尚未进行研究。我们假设不同物种的缩合单宁浓度差异很大，进一步可以根据叶子光谱反射数据将入侵的固氮长叶长叶植物与其他植被区分开来。使用连接到 ASD 叶夹的 ASD FieldSpec FR 光谱辐射计进行光谱场测量，以便收集葡萄牙西南部三个研究地点七种常见植物的 750 个原位叶片反射光谱。我们应用偏最小二乘（PLS）回归来预测获得的长叶长叶个体的叶子反射光谱与其相应的单宁浓度。在所有研究的物种中，A. longifolia 的单宁浓度最低。四个波长区域（675-710 nm、1060-1170 nm、1360-1450 nm 和 1630-1740 nm）被确定为与单宁浓度高度相关。使用主成分分析-线性判别分析（PCA-LDA）计算不同植物物种的基于光谱的分类模型。通过使用 1360-1450 nm 和 1630-1740 nm 之间的波长区域实现了 A. longifolia 的最佳预测，用户准确度达到 98.9%。相比之下，选择整个波长范围，长叶木个体的最佳用户准确度仅达到 86.5%。
The invasive shrub, Acacia longifolia, native to southeastern Australia, has a negative impact on vegetation and ecosystem functioning in Portuguese dune ecosystems. In order to spectrally discriminate A. longifolia from other non-native and native species, we developed a classification model based on leaf reflectance spectra (350-2500 nm) and condensed leaf tannin content. High variation of leaf tannin content is common for Mediterranean shrub and tree species, in particular between N-fixing and non-N-fixing species, as well as within the genus, Acacia. However, variation in leaf tannin content has not been studied in coastal dune ecosystems in southwest Portugal. We hypothesized that condensed tannin concentration varies significantly across species, further allowing for distinguishing invasive, nitrogen-fixing A. longifolia from other vegetation based on leaf spectral reflectance data. Spectral field measurements were carried out using an ASD FieldSpec FR spectroradiometer attached to an ASD leaf clip in order to collect 750 in situ leaf reflectance spectra of seven frequent plant species at three study sites in southwest Portugal. We applied partial least squares (PLS) regression to predict the obtained leaf reflectance spectra of A. longifolia individuals to their corresponding tannin concentration. A. longifolia had the lowest tannin concentration of all investigated species. Four wavelength regions (675-710 nm, 1060-1170 nm, 1360-1450 nm and 1630-1740 nm) were identified as being highly correlated with tannin concentration. A spectra-based classification model of the different plant species was calculated using a principal component analysis-linear discriminant analysis (PCA-LDA). The best prediction of A. longifolia was achieved by using wavelength regions between 1360-1450 nm and 1630-1740 nm, resulting in a user's accuracy of 98.9%. In comparison, selecting the entire wavelength range, the best user accuracy only reached 86.5% for A. longifolia individuals.