Comparación de la altura y unidades del medidor de placa como estimadores de la biomasa en los pastos de montaña del área de Gorbeia (Bizkaia)

Abstract

In the Basque Country (northern Spain), the primary activity in rangelands has always been conditioned by the strong limitations imposed by the environment, forcing the economy to be based, almost exclusively, on cattle raising. In fact, stockbreeding is certainly a deep-rooted activity in those áreas, with 26% of the región being covered with pastures and scrublands. These rangelands constitute a highly complex ecosystem, as a result of the interactions between cattle, vegetation and soil characteristics, with humans acting as a revitalizing agent of these systems. In these conditions, and in order to reach a sustainable management of the natural resources available, it is essential to be able to accurately estimate the productivity potential of their mountain pastures. Methods to estímate plant (grass) biomass have been classified as: (i) destructive, if the pasture needs to be cut, and (ii) non-destructive. This work deals with the comparison of the efficiency of two non-destructive methods of plant biomass estimation in rangelands, i.e., height vs. units given by the plate-meter, as well as with the identification of determining factors in the relationship between method of estimation and biomass in sown and seminatural pastures of the Gorbeia Natural Park (Bizkaia). Our results indicate that the relationship between both methods of biomass estimation is of a linear nature, getting a better fit, in general terms, in sown than in seminatural pastures. Temporal variability is a characteristic that stands out in all studied rangelands, with increasing slopes being found as the period of grazing activity goes on. Due to a very large variability, it was not possible conclude that one method of estimation was better than the other