Prediction of Grassland Biodiversity Using Measures of Spectral Variance: A Meta-Analytical Review
Over the last 20 years, there has been a surge of interest in the use of reflectance data collected using satellites and aerial vehicles to monitor vegetation diversity. One methodological option to monitor these systems involves developing empirical relationships between spectral heterogeneity in s...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-01-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/15/3/668 |
| _version_ | 1797623368667627520 |
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| author | Rachael H. Thornley France F. Gerard Kevin White Anne Verhoef |
| author_facet | Rachael H. Thornley France F. Gerard Kevin White Anne Verhoef |
| author_sort | Rachael H. Thornley |
| collection | DOAJ |
| description | Over the last 20 years, there has been a surge of interest in the use of reflectance data collected using satellites and aerial vehicles to monitor vegetation diversity. One methodological option to monitor these systems involves developing empirical relationships between spectral heterogeneity in space (spectral variation) and plant or habitat diversity. This approach is commonly termed the ‘Spectral Variation Hypothesis’. Although increasingly used, it is controversial and can be unreliable in some contexts. Here, we review the literature and apply three-level meta-analytical models to assess the test results of the hypothesis across studies using several moderating variables relating to the botanical and spectral sampling strategies and the types of sites evaluated. We focus on the literature relating to grasslands, which are less well studied compared to forests and are likely to require separate treatments due to their dynamic phenology and the taxonomic complexity of their canopies on a small scale. Across studies, the results suggest an overall positive relationship between spectral variation and species diversity (mean correlation coefficient = 0.36). However, high levels of both within-study and between-study heterogeneity were found. Whether data was collected at the leaf or canopy level had the most impact on the mean effect size, with leaf-level studies displaying a stronger relationship compared to canopy-level studies. We highlight the challenges facing the synthesis of these kinds of experiments, the lack of studies carried out in arid or tropical systems and the need for scalable, multitemporal assessments to resolve the controversy in this field. |
| first_indexed | 2024-03-11T09:27:56Z |
| format | Article |
| id | doaj.art-faaada9e33db427180b2a4eea40f78f1 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-11T09:27:56Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-faaada9e33db427180b2a4eea40f78f12023-11-16T17:52:31ZengMDPI AGRemote Sensing2072-42922023-01-0115366810.3390/rs15030668Prediction of Grassland Biodiversity Using Measures of Spectral Variance: A Meta-Analytical ReviewRachael H. Thornley0France F. Gerard1Kevin White2Anne Verhoef3Department of Geography and Environmental, University of Reading, Reading RG6 6AH, UKUK Centre for Ecology and Hydrology, Wallingford OX10 8BB, UKDepartment of Geography and Environmental, University of Reading, Reading RG6 6AH, UKDepartment of Geography and Environmental, University of Reading, Reading RG6 6AH, UKOver the last 20 years, there has been a surge of interest in the use of reflectance data collected using satellites and aerial vehicles to monitor vegetation diversity. One methodological option to monitor these systems involves developing empirical relationships between spectral heterogeneity in space (spectral variation) and plant or habitat diversity. This approach is commonly termed the ‘Spectral Variation Hypothesis’. Although increasingly used, it is controversial and can be unreliable in some contexts. Here, we review the literature and apply three-level meta-analytical models to assess the test results of the hypothesis across studies using several moderating variables relating to the botanical and spectral sampling strategies and the types of sites evaluated. We focus on the literature relating to grasslands, which are less well studied compared to forests and are likely to require separate treatments due to their dynamic phenology and the taxonomic complexity of their canopies on a small scale. Across studies, the results suggest an overall positive relationship between spectral variation and species diversity (mean correlation coefficient = 0.36). However, high levels of both within-study and between-study heterogeneity were found. Whether data was collected at the leaf or canopy level had the most impact on the mean effect size, with leaf-level studies displaying a stronger relationship compared to canopy-level studies. We highlight the challenges facing the synthesis of these kinds of experiments, the lack of studies carried out in arid or tropical systems and the need for scalable, multitemporal assessments to resolve the controversy in this field.https://www.mdpi.com/2072-4292/15/3/668Spectral Variation Hypothesisgrasslandsbiodiversityremote sensingmeta-analysis |
| spellingShingle | Rachael H. Thornley France F. Gerard Kevin White Anne Verhoef Prediction of Grassland Biodiversity Using Measures of Spectral Variance: A Meta-Analytical Review Remote Sensing Spectral Variation Hypothesis grasslands biodiversity remote sensing meta-analysis |
| title | Prediction of Grassland Biodiversity Using Measures of Spectral Variance: A Meta-Analytical Review |
| title_full | Prediction of Grassland Biodiversity Using Measures of Spectral Variance: A Meta-Analytical Review |
| title_fullStr | Prediction of Grassland Biodiversity Using Measures of Spectral Variance: A Meta-Analytical Review |
| title_full_unstemmed | Prediction of Grassland Biodiversity Using Measures of Spectral Variance: A Meta-Analytical Review |
| title_short | Prediction of Grassland Biodiversity Using Measures of Spectral Variance: A Meta-Analytical Review |
| title_sort | prediction of grassland biodiversity using measures of spectral variance a meta analytical review |
| topic | Spectral Variation Hypothesis grasslands biodiversity remote sensing meta-analysis |
| url | https://www.mdpi.com/2072-4292/15/3/668 |
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