Quantifying the Variation in Reflectance Spectra of <i>Metrosideros polymorpha</i> Canopies across Environmental Gradients
Imaging spectroscopy is a burgeoning tool for understanding ecosystem functioning on large spatial scales, yet the application of this technology to assess intra-specific trait variation across environmental gradients has been poorly tested. Selection of specific genotypes via environmental filterin...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-03-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/15/6/1614 |
| _version_ | 1797609210999996416 |
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| author | Megan M. Seeley Roberta E. Martin Nicholas R. Vaughn David R. Thompson Jie Dai Gregory P. Asner |
| author_facet | Megan M. Seeley Roberta E. Martin Nicholas R. Vaughn David R. Thompson Jie Dai Gregory P. Asner |
| author_sort | Megan M. Seeley |
| collection | DOAJ |
| description | Imaging spectroscopy is a burgeoning tool for understanding ecosystem functioning on large spatial scales, yet the application of this technology to assess intra-specific trait variation across environmental gradients has been poorly tested. Selection of specific genotypes via environmental filtering plays an important role in driving trait variation and thus functional diversity across space and time, but the relative contributions of intra-specific trait variation and species turnover are still unclear. To address this issue, we quantified the variation in reflectance spectra within and between six uniform stands of <i>Metrosideros polymorpha</i> across elevation and soil substrate age gradients on Hawai‘i Island. Airborne imaging spectroscopy and light detection and ranging (LiDAR) data were merged to capture and isolate sunlit portions of canopies at the six <i>M. polymorpha</i>-dominated sites. Both intra-site and inter-site spectral variations were quantified using several analyses. A support vector machine (SVM) model revealed that each site was spectrally distinct, while Euclidean distances between site centroids in principal components (PC) space indicated that elevation and soil substrate age drive the separation of canopy spectra between sites. Coefficients of variation among spectra, as well as the intrinsic spectral dimensionality of the data, demonstrated the hierarchical effect of soil substrate age, followed by elevation, in determining intra-site variation. Assessments based on leaf trait data estimated from canopy reflectance resulted in similar patterns of separation among sites in the PC space and distinction among sites in the SVM model. Using a highly polymorphic species, we demonstrated that canopy reflectance follows known ecological principles of community turnover and thus how spectral remote sensing addresses forest community assembly on large spatial scales. |
| first_indexed | 2024-03-11T05:57:21Z |
| format | Article |
| id | doaj.art-7faeeaa2bca24bfc84a2ca1694b74014 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-11T05:57:21Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-7faeeaa2bca24bfc84a2ca1694b740142023-11-17T13:39:33ZengMDPI AGRemote Sensing2072-42922023-03-01156161410.3390/rs15061614Quantifying the Variation in Reflectance Spectra of <i>Metrosideros polymorpha</i> Canopies across Environmental GradientsMegan M. Seeley0Roberta E. Martin1Nicholas R. Vaughn2David R. Thompson3Jie Dai4Gregory P. Asner5Center for Global Discovery and Conservation Science, Arizona State University, Tempe, AZ 85281, USACenter for Global Discovery and Conservation Science, Arizona State University, Tempe, AZ 85281, USACenter for Global Discovery and Conservation Science, Arizona State University, Tempe, AZ 85281, USAJet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USACenter for Global Discovery and Conservation Science, Arizona State University, Tempe, AZ 85281, USACenter for Global Discovery and Conservation Science, Arizona State University, Tempe, AZ 85281, USAImaging spectroscopy is a burgeoning tool for understanding ecosystem functioning on large spatial scales, yet the application of this technology to assess intra-specific trait variation across environmental gradients has been poorly tested. Selection of specific genotypes via environmental filtering plays an important role in driving trait variation and thus functional diversity across space and time, but the relative contributions of intra-specific trait variation and species turnover are still unclear. To address this issue, we quantified the variation in reflectance spectra within and between six uniform stands of <i>Metrosideros polymorpha</i> across elevation and soil substrate age gradients on Hawai‘i Island. Airborne imaging spectroscopy and light detection and ranging (LiDAR) data were merged to capture and isolate sunlit portions of canopies at the six <i>M. polymorpha</i>-dominated sites. Both intra-site and inter-site spectral variations were quantified using several analyses. A support vector machine (SVM) model revealed that each site was spectrally distinct, while Euclidean distances between site centroids in principal components (PC) space indicated that elevation and soil substrate age drive the separation of canopy spectra between sites. Coefficients of variation among spectra, as well as the intrinsic spectral dimensionality of the data, demonstrated the hierarchical effect of soil substrate age, followed by elevation, in determining intra-site variation. Assessments based on leaf trait data estimated from canopy reflectance resulted in similar patterns of separation among sites in the PC space and distinction among sites in the SVM model. Using a highly polymorphic species, we demonstrated that canopy reflectance follows known ecological principles of community turnover and thus how spectral remote sensing addresses forest community assembly on large spatial scales.https://www.mdpi.com/2072-4292/15/6/1614imaging spectroscopyleaf traitsenvironmental filteringcommunity assemblyenvironmental gradient<i>Metrosideros polymorpha</i> |
| spellingShingle | Megan M. Seeley Roberta E. Martin Nicholas R. Vaughn David R. Thompson Jie Dai Gregory P. Asner Quantifying the Variation in Reflectance Spectra of <i>Metrosideros polymorpha</i> Canopies across Environmental Gradients Remote Sensing imaging spectroscopy leaf traits environmental filtering community assembly environmental gradient <i>Metrosideros polymorpha</i> |
| title | Quantifying the Variation in Reflectance Spectra of <i>Metrosideros polymorpha</i> Canopies across Environmental Gradients |
| title_full | Quantifying the Variation in Reflectance Spectra of <i>Metrosideros polymorpha</i> Canopies across Environmental Gradients |
| title_fullStr | Quantifying the Variation in Reflectance Spectra of <i>Metrosideros polymorpha</i> Canopies across Environmental Gradients |
| title_full_unstemmed | Quantifying the Variation in Reflectance Spectra of <i>Metrosideros polymorpha</i> Canopies across Environmental Gradients |
| title_short | Quantifying the Variation in Reflectance Spectra of <i>Metrosideros polymorpha</i> Canopies across Environmental Gradients |
| title_sort | quantifying the variation in reflectance spectra of i metrosideros polymorpha i canopies across environmental gradients |
| topic | imaging spectroscopy leaf traits environmental filtering community assembly environmental gradient <i>Metrosideros polymorpha</i> |
| url | https://www.mdpi.com/2072-4292/15/6/1614 |
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