{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T03:39:09Z","timestamp":1769744349035,"version":"3.49.0"},"reference-count":49,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,2,15]],"date-time":"2022-02-15T00:00:00Z","timestamp":1644883200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"POCI-FEDER","award":["POCI-01-0247-FEDER-070123"],"award-info":[{"award-number":["POCI-01-0247-FEDER-070123"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Drones"],"abstract":"<jats:p>Efficient detection and monitoring procedures of invasive plant species are required. It is of crucial importance to deal with such plants in aquatic ecosystems, since they can affect biodiversity and, ultimately, ecosystem function and services. In this study, it is intended to detect water hyacinth (Eichhornia crassipes) using multispectral data with different spatial resolutions. For this purpose, high-resolution data (&lt;0.1 m) acquired from an unmanned aerial vehicle (UAV) and coarse-resolution data (10 m) from Sentinel-2 MSI were used. Three areas with a high incidence of water hyacinth located in the Lower Mondego region (Portugal) were surveyed. Different classifiers were used to perform a pixel-based detection of this invasive species in both datasets. From the different classifiers used, the results were achieved by the random forest classifiers stand-out (overall accuracy (OA): 0.94). On the other hand, support vector machine performed worst (OA: 0.87), followed by Gaussian naive Bayes (OA: 0.88), k-nearest neighbours (OA: 0.90), and artificial neural networks (OA: 0.91). The higher spatial resolution from UAV-based data enabled us to detect small amounts of water hyacinth, which could not be detected in Sentinel-2 data. However, and despite the coarser resolution, satellite data analysis enabled us to identify water hyacinth coverage, compared well with a UAV-based survey. Combining both datasets and even considering the different resolutions, it was possible to observe the temporal and spatial evolution of water hyacinth. This approach proved to be an effective way to assess the effects of the mitigation\/control measures taken in the study areas. Thus, this approach can be applied to detect invasive species in aquatic environments and to monitor their changes over time.<\/jats:p>","DOI":"10.3390\/drones6020047","type":"journal-article","created":{"date-parts":[[2022,2,15]],"date-time":"2022-02-15T22:43:22Z","timestamp":1644965002000},"page":"47","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":46,"title":["Water Hyacinth (Eichhornia crassipes) Detection Using Coarse and High Resolution Multispectral Data"],"prefix":"10.3390","volume":"6","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7570-9773","authenticated-orcid":false,"given":"Lu\u00eds","family":"P\u00e1dua","sequence":"first","affiliation":[{"name":"Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Tr\u00e1s-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4966-2227","authenticated-orcid":false,"given":"Ana M.","family":"Ant\u00e3o-Geraldes","sequence":"additional","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o de Montanha (CIMO), Instituto Polit\u00e9cnico de Bragan\u00e7a, Campus de Santa Apol\u00f3nia, 5300-253 Bragan\u00e7a, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4533-930X","authenticated-orcid":false,"given":"Joaquim J.","family":"Sousa","sequence":"additional","affiliation":[{"name":"Engineering Department, School of Science and Technology, University of Tr\u00e1s-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"Centre for Robotics in Industry and Intelligent Systems (CRIIS), INESC Technology and Science (INESC-TEC), 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5367-1129","authenticated-orcid":false,"given":"Manuel \u00c2ngelo","family":"Rodrigues","sequence":"additional","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o de Montanha (CIMO), Instituto Polit\u00e9cnico de Bragan\u00e7a, Campus de Santa Apol\u00f3nia, 5300-253 Bragan\u00e7a, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6012-920X","authenticated-orcid":false,"given":"Ver\u00f3nica","family":"Oliveira","sequence":"additional","affiliation":[{"name":"New Organic Planet (NOP), 9000-058 Funchal, Portugal"},{"name":"Colina Generosa, 6000-193 Castelo Branco, Portugal"},{"name":"Research Centre for Natural Resources, Environment and Society (CERNAS), 3045-601 Coimbra, Portugal"}]},{"given":"Daniela","family":"Santos","sequence":"additional","affiliation":[{"name":"Research Centre for Natural Resources, Environment and Society (CERNAS), 3045-601 Coimbra, Portugal"},{"name":"Escola Superior Agr\u00e1ria-Instituto Polit\u00e9cnico de Coimbra, 3045-601 Coimbra, Portugal"}]},{"given":"Maria Filomena P.","family":"Miguens","sequence":"additional","affiliation":[{"name":"Escola Superior Agr\u00e1ria-Instituto Polit\u00e9cnico de Coimbra, 3045-601 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0647-8892","authenticated-orcid":false,"given":"Jo\u00e3o Paulo","family":"Castro","sequence":"additional","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o de Montanha (CIMO), Instituto Polit\u00e9cnico de Bragan\u00e7a, Campus de Santa Apol\u00f3nia, 5300-253 Bragan\u00e7a, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,15]]},"reference":[{"key":"ref_1","first-page":"62","article-title":"Summary for Policymakers of the Global Assessment Report on Biodiversity and Ecosystem Services","volume":"34","author":"Kass","year":"2020","journal-title":"Nat. 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