Biodiversity from the Sky: Testing the Spectral Variation Hypothesis in the Brazilian Atlantic Forest
Tropical forests have high species richness, being considered the most diverse and complex ecosystems in the world. Research on the variation and maintenance of biodiversity in these ecosystems is important for establishing conservation strategies. The main objective of this study was to test the Sp...
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MDPI AG
2024-11-01
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| Online Access: | https://www.mdpi.com/2072-4292/16/23/4363 |
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| author | Tobias Baruc Moreira Pinon Adriano Ribeiro de Mendonça Gilson Fernandes da Silva Emanuel Maretto Effgen Nívea Maria Mafra Rodrigues Milton Marques Fernandes Jerônimo Boelsums Barreto Sansevero Catherine Torres de Almeida Henrique Machado Dias Fabio Guimarães Gonçalves André Quintão de Almeida |
| author_facet | Tobias Baruc Moreira Pinon Adriano Ribeiro de Mendonça Gilson Fernandes da Silva Emanuel Maretto Effgen Nívea Maria Mafra Rodrigues Milton Marques Fernandes Jerônimo Boelsums Barreto Sansevero Catherine Torres de Almeida Henrique Machado Dias Fabio Guimarães Gonçalves André Quintão de Almeida |
| author_sort | Tobias Baruc Moreira Pinon |
| collection | DOAJ |
| description | Tropical forests have high species richness, being considered the most diverse and complex ecosystems in the world. Research on the variation and maintenance of biodiversity in these ecosystems is important for establishing conservation strategies. The main objective of this study was to test the Spectral Variation Hypothesis through associations between species diversity and richness measured in the field and hyperspectral data collected by a Remotely Piloted Aircraft (RPA) in areas with secondary tropical forest in the Brazilian Atlantic Forest biome. Specific objectives were to determine which dispersion measurements, standard deviation (SD) or coefficient of variation (CV), estimated for the n pixels occurring within each sampling unit, better explains species diversity; the effects of pixel size on the direction and intensity of this relationship; and the effects of shaded pixels within each sampling unit. The spectral variability hypothesis was confirmed for the Atlantic Forest biome, with R<sup>2</sup> of 0.83 for species richness and 0.76 and 0.69 for the Shannon and Simpson diversity indices, respectively, using 1.0 m illuminated pixels. The dispersion (CV and SD) of hyperspectral bands were most strongly correlated with taxonomic diversity and richness in the red-edge and near-infrared (NIR) regions of the electromagnetic spectrum. Pixel size affected R<sup>2</sup> values, which were higher for 1.0 m pixels (0.83) and lower for 10.0 m pixels (0.71). Additionally, illuminated pixels had higher R<sup>2</sup> values than those under shadow effects. The main dispersion variables selected as metrics for regression models were mean CV, CV for the 726.7 nm band, and SD for the 742.3 and 933.4 nm bands. Our results suggest that spectral diversity can serve as a proxy for species diversity in the Atlantic Forest. However, factors that can affect this relationship, such as taxonomic and spectral diversity metrics used, pixel size, and shadow effects in images, should be considered. |
| format | Article |
| id | doaj-art-3eef4c080b0a4d629e7b2f1fc2be8cfc |
| institution | OA Journals |
| issn | 2072-4292 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | MDPI AG |
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| series | Remote Sensing |
| spelling | doaj-art-3eef4c080b0a4d629e7b2f1fc2be8cfc2025-08-20T02:38:36ZengMDPI AGRemote Sensing2072-42922024-11-011623436310.3390/rs16234363Biodiversity from the Sky: Testing the Spectral Variation Hypothesis in the Brazilian Atlantic ForestTobias Baruc Moreira Pinon0Adriano Ribeiro de Mendonça1Gilson Fernandes da Silva2Emanuel Maretto Effgen3Nívea Maria Mafra Rodrigues4Milton Marques Fernandes5Jerônimo Boelsums Barreto Sansevero6Catherine Torres de Almeida7Henrique Machado Dias8Fabio Guimarães Gonçalves9André Quintão de Almeida10Department of Forestry and Wood Sciences, Federal University of Espírito Santo, Jerônimo Monteiro 29550-000, ES, BrazilDepartment of Forestry and Wood Sciences, Federal University of Espírito Santo, Jerônimo Monteiro 29550-000, ES, BrazilDepartment of Forestry and Wood Sciences, Federal University of Espírito Santo, Jerônimo Monteiro 29550-000, ES, BrazilInstitute of Agricultural and Forestry Defense of Espírito Santo, Vitória 29010-935, ES, BrazilDepartment of Forestry and Wood Sciences, Federal University of Espírito Santo, Jerônimo Monteiro 29550-000, ES, BrazilDepartment of Forestry Engineering, Federal University of Sergipe, São Cristóvão 49100-000, SE, BrazilDepartment of Environmental Sciences, Federal Rural University of Rio de Janeiro, Seropédica 23890-000, RJ, BrazilDepartment of Fisheries Resources and Aquaculture, São Paulo State University (Júlio de Mesquita Filho), Registro 11900-000, SP, BrazilDepartment of Forestry and Wood Sciences, Federal University of Espírito Santo, Jerônimo Monteiro 29550-000, ES, BrazilCanopy Remote Sensing Solutions, Florianópolis 88032-005, SC, BrazilDepartment of Agricultural Engineering, Federal University of Sergipe, São Cristóvão 49100-000, SE, BrazilTropical forests have high species richness, being considered the most diverse and complex ecosystems in the world. Research on the variation and maintenance of biodiversity in these ecosystems is important for establishing conservation strategies. The main objective of this study was to test the Spectral Variation Hypothesis through associations between species diversity and richness measured in the field and hyperspectral data collected by a Remotely Piloted Aircraft (RPA) in areas with secondary tropical forest in the Brazilian Atlantic Forest biome. Specific objectives were to determine which dispersion measurements, standard deviation (SD) or coefficient of variation (CV), estimated for the n pixels occurring within each sampling unit, better explains species diversity; the effects of pixel size on the direction and intensity of this relationship; and the effects of shaded pixels within each sampling unit. The spectral variability hypothesis was confirmed for the Atlantic Forest biome, with R<sup>2</sup> of 0.83 for species richness and 0.76 and 0.69 for the Shannon and Simpson diversity indices, respectively, using 1.0 m illuminated pixels. The dispersion (CV and SD) of hyperspectral bands were most strongly correlated with taxonomic diversity and richness in the red-edge and near-infrared (NIR) regions of the electromagnetic spectrum. Pixel size affected R<sup>2</sup> values, which were higher for 1.0 m pixels (0.83) and lower for 10.0 m pixels (0.71). Additionally, illuminated pixels had higher R<sup>2</sup> values than those under shadow effects. The main dispersion variables selected as metrics for regression models were mean CV, CV for the 726.7 nm band, and SD for the 742.3 and 933.4 nm bands. Our results suggest that spectral diversity can serve as a proxy for species diversity in the Atlantic Forest. However, factors that can affect this relationship, such as taxonomic and spectral diversity metrics used, pixel size, and shadow effects in images, should be considered.https://www.mdpi.com/2072-4292/16/23/4363unmanned aerial vehiclehyperspectral RPAred-edge vegetation indexsecondary forestShannonSimpson |
| spellingShingle | Tobias Baruc Moreira Pinon Adriano Ribeiro de Mendonça Gilson Fernandes da Silva Emanuel Maretto Effgen Nívea Maria Mafra Rodrigues Milton Marques Fernandes Jerônimo Boelsums Barreto Sansevero Catherine Torres de Almeida Henrique Machado Dias Fabio Guimarães Gonçalves André Quintão de Almeida Biodiversity from the Sky: Testing the Spectral Variation Hypothesis in the Brazilian Atlantic Forest Remote Sensing unmanned aerial vehicle hyperspectral RPA red-edge vegetation index secondary forest Shannon Simpson |
| title | Biodiversity from the Sky: Testing the Spectral Variation Hypothesis in the Brazilian Atlantic Forest |
| title_full | Biodiversity from the Sky: Testing the Spectral Variation Hypothesis in the Brazilian Atlantic Forest |
| title_fullStr | Biodiversity from the Sky: Testing the Spectral Variation Hypothesis in the Brazilian Atlantic Forest |
| title_full_unstemmed | Biodiversity from the Sky: Testing the Spectral Variation Hypothesis in the Brazilian Atlantic Forest |
| title_short | Biodiversity from the Sky: Testing the Spectral Variation Hypothesis in the Brazilian Atlantic Forest |
| title_sort | biodiversity from the sky testing the spectral variation hypothesis in the brazilian atlantic forest |
| topic | unmanned aerial vehicle hyperspectral RPA red-edge vegetation index secondary forest Shannon Simpson |
| url | https://www.mdpi.com/2072-4292/16/23/4363 |
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