EDAFOLOGÍA, Vol 12. (2), pp 75-89 2005
EROSIÓN POTENCIAL Y GESTIÓN DE PASTOS EN EL PARQUE NATURAL DE AIAKO HARRIA (GIPUZKOA)
O. ARTIEDA1, I. ALBIZU2, I. AMEZAGA3, A. CANTERO4, D. SAENZ4, G. BESGA2
1 U. de Extremadura. Centro Universitario de Plasencia (Explotaciones Forestales). Avda. Virgen del Puerto, 2, Plasencia (Cáceres). [email protected]
2 NEIKER, A.B. C/ Berreaga, 1. 48160 Derio (Bizkaia)
3 Universidad del País Vasco. Dpt. de Biología Vegetal y Ecología. Apdo. 644. 48080 Bilbao
4 IKT, S.A.Granja Modelo, s/n. 01192 Arkaute (Araba).
In the Basque Country (northern Spain), the Natural Resources Management Plan (NRMP) designed for the different natural parks located in the region has been made using the erosion prediction model (the so-called USLE). In this context, the lack of soil data needed to calculate the erodibility factor, together with the utilization of small scale vegetation inventories, have compelled us to carry out approxi- mations that, in many cases, lead to clear overestimations of the real erosion values. The current work shows erosion data obtained in the “Aiako Harria” Natural Park (Gipuzkoa, Basque Country) when applying the above mentioned USLE model at a more precise level. The utilization of these data for the working-out of rangeland management plans in areas approved by the NRMP is also described here. In addition, the difficulties encountered when applying our prediction model to steep sloped areas and high organic matter content soils are discussed. To apply our model, soils were cartographied and erodibility values calculated for each defined unit. In order to estimate C values, vegetation maps and slope inventories were used. Finally, to evaluate both the slope (S) and length (L) of the sloping grounds, a digital model of the area was designed using a 5 x 5 m grid for the calculations. With this very same grid, all USLE factors were integrated using the Arc/Info Ge- ographic Information System. From the obtained results, several scenarios were simulated, so that areas where rangeland introduction leads to lower increments of erosion risk could be delimited. These areas were mainly covered by shrub-brac- kens, brackens and coniferous plantations, and had estimated erosion rate values lower than 10 Tn/ha/year.
Key words: USLE, GIS, pasture, soil erosion