By Astrid Arellano The Mexico-U.S. border wall has interrupted the ecological connectivity of a nature reserve that’s a World Heritage Site, and should be addressed to remedy the situation, according to UNESCO. Without urgent mitigation actions, it says, El Pinacate and Gran Desierto de Altar Biosphere Reserve risks joining the List of World Heritage in Danger. The northern part of the reserve, located in the state of Sonora in northwestern Mexico, has been breached by an enormous metal fence. This 9-meter-high (30-foot) structure, more than 100 kilometers (60 miles) long, prevents the passage…