It is located in upper Rioja. The "soto"of Buicio is a forest situated along the banks of the Ebro river, near Logroño. The area of the reserve belongs to the municipality of Fuenmayor. It covers a total area of 30 h.The "soto" is a fluvial ecosystem. When the waters of the Ebro flow along the fertile plains they undergo a process of constant and progressive mineralization. 

In upper Rioja the river runs below woods and thickets called "sotos", because they grow on the banks of a river. A good variety of trees can be found, being the alder the most characteristic. It grows in areas with a high level of humidity; as opposed to poplars and black poplars, that stand far from the course, and elms, that can grow in soils with a lower phreatic level. Ash trees and willows are also typical of this fluvial ecosystem.

Climate: Hot summers that do not become scorching and very cold winters; frost are frequent from November through April. The annual average temperature is 13ºC, in January the average is above 4ºC, and 20º to 22º in July. There are elms, ash trees, black poplars, willows and centenarian alders, at whose foot stands a curious wood of elders and hawthorn.

Fauna: The thackets that border the banks of the river form a real jungle where can be found insects, amphibia and reptiles (dragonflies, watersnakes, frogs), as well as some bird species. On the upper part of the "soto" live kingfishers, black kites, woodpeckers and rock pigeons. The fluvial waters are home to a reduced number of species, such as grudgeons and barbels.