Adaptations in desert organisms: even the bad times may be good
Author: SJ Milton and WRJ Dean
Publication: South African Journal of Science, volume 100
Date: September/October 2004
AT THIS TIME OF SERIOUS CONCERN about climate change and the implications for the continued existence of many kinds of life on Earth, a colloquium† that reviewed survival strategies and the natural history of desert organisms is pertinent. Here we draw attention to highlights of the meeting.
Desert organisms that are resident and persistent through dry and wet spells may be expected to have evolved mechanisms that enable them to tolerate extreme water deprivation, heat, cold, food shortages and, in the case of plants, continual exposure to herbivory. Extremely harsh conditions require extreme adaptations and limit the morphology and diversity of sedentary desert organisms.
Michael Pfiz1 showed that the diversity of lichen growth forms could only partly be explained by the microclimatic parameters measured. Coastal fog, dew and relatively high humidity allowed foliose and fructicose lichens to survive near the coast, whereas crustose lichens could tolerate the extremely desiccating conditions caused by the warm, dry winds that blow from inland.