How, Guerrero wondered, was poaching affecting the desert’s cacti? He looked to Copiapoa, a diverse genus of cacti found primarily in the Atacama that has been “a hot commodity” in recent years.

Located on the edge of the tiny town of San Pedro de Atacama, it sits on the outskirts of one of the few outposts in the expanses of the Atacama Desert. It’s a destination Charles Darwin once ...