Lichen Flora of Joshua Tree National Park An Annotated Checklist Natural Resource.

摘要

Lichens are frequent in Joshua Tree National Park; their white, yellow, red, and orange colors adorn the numerous quartz monzonite rock outcrops, and attract the attention of visitors. Prior to initial surveys in 2005 and 2006 (Knudsen and La Doux 2005 and 2006) the Lichens of Joshua Tree National Park were practically unknown. This report and annotated checklist are the product of those initial surveys and additional field work conducted at Joshua Tree National Park between 2010 to 2012 to further document the lichen flora. Specimens from these surveys are deposited in the University of California, Riverside Herbarium (UCR). As a result of this work, a total of 145 taxa of lichens are reported from the park. Three species were previously reported new for California from this survey (Knudsen and Kocourkova 2012a). In this paper, a fourth species, Buellia imshaugii, is also reported new for California from the park. Sarcogyne mitziae K. Knudsen, Kocourk. & McCune, a new species to science, was described from a discovery in Joshua Tree National Park as well as single populations found in Washington and Idaho (Knudsen et al. 2013). Four other taxa, possibly new to science, were discovered and are currently being studied. This report provides an annotated checklist of the currently documented lichen flora at Joshua Tree National Park. Detailed information on distribution and habit and identification for the 145 taxa are included in this list. The largest diversity of lichens in Joshua Tree National Park is concentrated in the northwestern region of the park. The distribution and species composition in the park appears to be mainly affected by relative annual humidity. The majority of rare and infrequent lichens in the park appear to be relics from a wetter Pleistocene climate and are more common in Arizona (which has a more well established monsoon cycle) or in the mountains at higher elevations with greater rain or snowfall. Growing aridity in the southwestern United States could lead to the extirpation of many rare lichens in the northwestern region of Joshua Tree National Park and lower total lichen diversity for the park as a whole. Further inventories would improve the historical record of lichen diversity at this critical time of global climate change and establish a robust baseline of lichen diversity. These data, along with future inventories, would allow Joshua Tree National Park to complete a field guide, create public education programs, and develop long-term monitoring of lichens.