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From UAV to planetscope: upscaling fractional cover of an invasive species Rosa rugosa / Thaísa F. Bergamo in Journal of environmental management, 336 (2023) 

Public Citation [article]  inJournal of environmental management > 336 (2023) . - 117693 Titre : From UAV to planetscope: upscaling fractional cover of an invasive species Rosa rugosa Type de document : Imprimé Auteurs : Thaísa F. Bergamo ; Raul Sampaio de Lima ; Tiiu Kull ; Raymond D. Ward ; Kalev Sepp ; Miguel Villoslada Année de publication : 2023 Article en page(s) : 117693 Catégories : [CBNPMP-Thématique] Télédétection Mots-clés : Rosa rugosa Résumé : Invasive plant species pose a direct threat to biodiversity and ecosystem services. Among these, Rosa rugosa has had a severe impact on Baltic coastal ecosystems in recent decades. Accurate mapping and monitoring tools are essential to quantify the location and spatial extent of invasive plant species to support eradication programs. In this paper we combined RGB images obtained using an Unoccupied Aerial Vehicle, with multispectral PlanetScope images to map the extent of R. rugosa at seven locations along the Estonian coastline. We used RGB-based vegetation indices and 3D canopy metrics in combination with a random forest algorithm to map R. rugosa thickets, obtaining high mapping accuracies (Sensitivity = 0.92, specificity = 0.96). We then used the R. rugosa presence/absence maps as a training dataset to predict the fractional cover based on multispectral vegetation indices derived from the PlanetScope constellation and an Extreme Gradient Boosting algorithm (XGBoost). The XGBoost algorithm yielded high fractional cover prediction accuracies (RMSE = 0.11, R2 = 0.70). An in-depth accuracy assessment based on site-specific validations revealed notable differences in accuracy between study sites (highest R2 = 0.74, lowest R2 = 0.03). We attribute these differences to the various stages of R. rugosa invasion and the density of thickets. In conclusion, the combination of RGB UAV images and multispectral PlanetScope images is a cost-effective method to map R. rugosa in highly heterogeneous coastal ecosystems. We propose this approach as a valuable tool to extend the highly local geographical scope of UAV assessments into wider areas and regional evaluations. Lien pérenne : DOI : 10.1016/j.jenvman.2023.117693 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=151576 Bergamo, Thaísa F., Lima, Raul Sampaio de, Kull, Tiiu, Ward, Raymond D., Sepp, Kalev, Villoslada, Miguel 2023 From UAV to planetscope: upscaling fractional cover of an invasive species Rosa rugosa. Journal of environmental management, 336: 117693.

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Reindeer control over shrubification in subarctic wetlands: spatial analysis based on unoccupied aerial vehicle imagery / Miguel Villoslada in Remote Sensing in Ecology and Conservation, 9 (2023) 

Public Citation [article]  inRemote Sensing in Ecology and Conservation > 9 (2023) . - 687-706 Titre : Reindeer control over shrubification in subarctic wetlands: spatial analysis based on unoccupied aerial vehicle imagery Type de document : Imprimé Auteurs : Miguel Villoslada ; Henni Ylänne ; Tina H. M. Kolari ; Pasi Korpelainen ; Teemu Tahvanainen ; Franziska Wolff ; Timo Kumpula Année de publication : 2023 Article en page(s) : 687-706 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Télédétection Résumé : Herbivores can exert a controlling effect on the reproduction and growth of shrubs, thereby counter-acting the climate-driven encroachment of shrubs in the Arctic and the potential consequences. This control is particularly evident in the case of abundant herbivores, such as reindeer (Rangifer tarandus tarandus), whose grazing patterns are affected by management. Here, we tested how different reindeer grazing practices on the border between Finland and Norway impact the occurrence of willow (Salix spp.) dominated patches, their above-ground biomass (AGB) and the ability of willows to form dense thickets. We used a combination of multispectral and RGB imagery obtained from unoccupied aerial vehicles field data and an ensemble of machine-learning models, which allowed us to model the occurrence of plant community types (Overall accuracy = 0.80), AGB fractions (maximum R2 = 0.90) and topsoil moisture (maximum R2 = 0.89). With this combination of approaches, we show that willows are kept in a browsing-trap under spring and early summer grazing by reindeer, growing mostly small and scattered in the landscape. In contrast, willows under the winter grazing regime formed dense stands, particularly within riparian areas. We confirm this pattern using a random forest willow habitat distribution model based on topographical parameters. The model shows that willow biomass correlated with parameters of optimal habitat quality only in the winter grazing regime and did not respond to the same parameters under spring and summer grazing of reindeer. Lien pérenne : DOI : 10.1002/rse2.337 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=155071 Villoslada, Miguel, Ylänne, Henni, Kolari, Tina H. M., Korpelainen, Pasi, Tahvanainen, Teemu, Wolff, Franziska, Kumpula, Timo 2023 Reindeer control over shrubification in subarctic wetlands: spatial analysis based on unoccupied aerial vehicle imagery. Remote Sensing in Ecology and Conservation, 9: 687-706.

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Consultable Article (2023) URL