Field validation of an automatic coefficient of pasture eligibility in mountain areas
2016
Busqué, J | Rodríguez, J R | Maestro, G
In most Spanish regions the quantification of permanent pastures eligible for Common Agricultural Policy payments is based on a recent remote sensing method (CPEauto) that combines terrain slope and greenness, and vegetation height. In complex landscapes with herbaceous-shrub-tree mosaics, such as in many mountain areas, this method aims to distinguish used from abandoned pasture land. During 2015 we performed in Cantabria (north of Spain) a field validation of the CPEauto based on information collected in 343 transects covering the most common extensive grazing habitat types of the region, each homogenous in vegetation and CPEauto values. Measured plant composition, vegetation structure and grazing signs were integrated in a single index of land grazability (GI), which was confronted against CPEauto values using regression models. GI was robustly and unbiasedly related to CPEauto when the latter was corrected by the slope (R2 equal to 0.83). Analysing separately shrub-dominated, tree-dominated and grassland transects, the rela- tionship GI-CPEauto was only kept in shrublands, while woods and grasslands showed frequent cases of under- and overestimation respectively
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