干旱区生态环境知识资源中心

Vagrant lichens are most common in windswept arid environments around the world where they grow unattached to any substrate. Many species are associated with sites where water ponds during the cool season and where plant litter does not accumulate. Vagrant lichen species are presently recognized in several genera, some capable of moving with the wind like a tumbleweed. These genera have a rich history in Asia and the Middle East in particular where they are referred to as "manna" lichens. The genus Xanthoparmelia, commonly known as range lichen, contains the largest number of vagrant species and is the most widely distributed, followed by the genus Aspicilia. Aspicilia fruticulosa (Eversm.) Flag. is reported here new from the states of Nevada and Colorado. Reproduction in vagrant lichens is typically by large unspecialized vegetative fragments. Due to wide scale land disturbances, livestock overgrazing, altered fire frequencies, and the dispersal strategies of vagrant lichens, some of these species are so fragmented in their distribution that they may become extinct. The conservation and management of vagrant lichens will face many challenges in the future.