Bardenas Reales

Las Bardenas Reales cover nearly 42,000 hectares in southeastern Navarre, between the merindades of Tudela, Tafalla and Sangüesa. This semi-arid desert is surprising at this latitude: the rain shadow cast by the Sierra de Cantabria and the persistent cierzo wind — the north-westerly that blows more than 150 days a year — have shaped over millions of years a landscape of clay ravines, white plateaus and mushroom-shaped formations called bardales, which evoke the American Southwest more than the Spanish interior. UNESCO recognised this fragile balance between pastoral communities, wildlife and bare terrain by designating it a Biosphere Reserve in 2000.

The territory divides into three main subzones. La Bardena Blanca concentrates the most photogenic scenery and the most recognisable formations: Pisquerra, Aguilucho and Castildetierra, that 44-metre clay-and-gypsum totem that dominates the horizon, sculpted over tens of thousands of years by differential water erosion. Colours shift from white to beige, ochre and reddish brown depending on the time of day and season, and on misty mornings the silence takes on an almost solid quality. La Bardena Negra to the north has a sector under military use — the firing range that provides space for NATO manoeuvres — and combines low scrub of black juniper, common juniper and Aleppo pine with ridges above 600 metres. El Caídas in the centre gathers historic transit corridors where transhumant flocks have walked for centuries between the Roncal Valley and the Navarrese lowlands, leaving a network of drove roads and drinking troughs that can still be walked today.

Wildlife in the Bardenas adapts to aridity with precise evolutionary strategies. The Montagu's harrier nests in cereal plots along the edges and hunts over the wastelands with a low, silent flight. The great bustard, the heaviest flying bird on the Iberian Peninsula, becomes a landmark of the winter landscape: in January and February, groups of more than twenty birds can be spotted on the plains of Bardena Negra. The horseshoe whip snake — Europe's largest snake, reaching two metres — the electrically coloured ocellated lizard and the natterjack toad are regular presences in warm months. After autumn rains, the clay soil retains water in temporary pools that attract migrating waders: snipe, little ringed plover and common sandpiper fill these small seasonal oases for days at a time. The Visitor Centre in Arguedas provides updated sighting data and interpretive panels on the geology and ethnography of the area.

The most direct access is from Arguedas via road NA-5720, which enters the heart of Bardena Blanca in about seven kilometres. The signed 55 km loop trail covers the main formations by car or mountain bike without needing a guide; the estimated driving time with stops is around three hours. For walkers, trail PR-NA 38 crosses less frequented sectors and the GR-13 links several points of the natural space with adequate waymarking. Extreme temperatures — summer highs of 40 °C and winters with freezing cierzo that push wind-chill values below zero — make spring and autumn the best times to visit. Entry to the public-use zone requires no advance booking, though a vehicle fee is charged at main access points during peak season.