drones Article Calibrating Sentinel-2 Imagery with Multispectral UAV Derived Information to Quantify Damages in Mediterranean Rice Crops Caused by Western Swamphen (Porphyrio porphyrio) Magda Pla 1,* , Gerard Bota 1 , Andrea Duane 1, Jaume Balagué 1, Antoni Curcó 4, Ricard Gutiérrez 5 and Lluís Brotons 1,2,3 1 InForest JRU (CTFC-CREAF), Carretera de Sant Llorenç de Morunys Km 2, 25280 Solsona, Lleida, Spain;
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[email protected] (L.B.) 2 Centre for Ecological Research and Forestry Applications (CREAF), 08193 Cerdanyola del Vallès, Spain 3 Spanish National Research Council (CSIC), 08193 Cerdanyola del Vallès, Spain 4 Ebro Delta Natural Park, Government of Catalonia, Av. Catalunya, 46, 43580 Deltebre, Spain;
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[email protected]; Tel.: +34-973-481-752 Received: 22 March 2019; Accepted: 13 May 2019; Published: 21 May 2019 Abstract: Making agricultural production compatible with the conservation of biological diversity is a priority in areas in which human–wildlife conflicts arise. The threatened Western Swamphen (Porphyrio porphyrio) feeds on rice, inducing crop damage and leading to decreases in rice production. Due to the Swamphen protection status, economic compensation policies have been put in place to compensate farmers for these damages, thus requiring an accurate, quantitative, and cost-effective evaluation of rice crop losses over large territories. We used information captured from a UAV (Unmanned Aerial Vehicle) equipped with a multispectral Parrot SEQUOIA camera as ground-truth information to calibrate Sentinel-2 imagery to quantify damages in the region of Ebro Delta, western Mediterranean.