Inland Atlantic-Mediterranean transitional territories in the Obarenes Natural Park (Burgos). The trip will go from Atlantic to Mediterranean areas allowing us to see the changes in the vegetation across this gradient. Our first stop at Portillo de Busto will give us the opportunity to observe the great contrast between the vegetation of the southern and northern slopes. Quercus rotundifolia forests and their succesional communities develop on the southern slopes due to the rain shadow effect and intense sunshine, whilst beech forests are the most widespread potential vegetation on the northern slopes. There we will observe different types of scrubs, dry grasslands and chasmophytic communities. We will continue our itinerary through areas with Quercus faginea and Q. pyrenaica forests. We will also take a short walk to observe the flora of Pistacio-Rhamnetalia and Festuco-Poetalia communities. The walk will finish in the medieval town of Frías where we will have a chance to visit its castle.

The difficulty is low.

Leader: Itziar García-Mijangos.