With this publication, we provide literature-based insights as to how each organismal group contributes to the formation and maintenance of the structural and functional attributes of BSCs, how they reproduce, and how they are dispersed. The various BSC organismal groups demonstrate several common characteristics including-desiccation and extreme temperature tolerance, production of various soil binding chemistries, a near exclusive dependency on asexual reproduction, a pattern of aerial dispersal over impressive distances, and a universal vulnerability to a wide range of human-related perturbations. The list of organismal groups that make up BSC communities in various and unique combinations include-free living, lichenized, and mycorrhizal fungi, chemoheterotrophic bacteria, cyanobacteria, diazotrophic bacteria and archaea, eukaryotic algae, and bryophytes.
BSCs vary in terms of soil chemistry and texture as well as the environmental parameters that combine to support unique combinations of organisms-including cyanobacteria dominated, lichen-dominated, and bryophyte-dominated crusts.
5Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, United States.4School of Life Sciences, University of Nevada, Las Vegas, NV, United States.3Monte Lafayette Bean Life Science Museum, Brigham Young University, Provo, UT, United States.2Department of Biology, Brigham Young University, Provo, UT, United States.Forest Service, Rocky Mountain Research Station, Provo, UT, United States Lewis 5, Nuttapon Pombubpa 6, Tania Kurbessoian 6, Jason E. Data can be analyzed in a simple fashion or via advanced mixed models.Steven D. Relatively sophisticated students could test whether parasites have a random dispersion pattern by comparing the histogram they generate to that of a Poisson distribution.
Significant quantities of data can be generated in relatively short order and pooled for a class many patterns can emerge that challenge students to find logical interpretations. I describe one way to randomly sample leaves to quantify dispersion of such parasites and test whether dispersion is related to a variety of explanatory variables. Fungi are commonly observed parasites on leaves of trees. Accordingly, many researchers, including ecologists and medical practitioners, study dispersion of parasites in detail. The way in which parasites are distributed among hosts (their dispersion) can have profound importance for how they and their hosts coevolve, and for many other facets of their biology. Symbioses can range from mutualisms to parasitisms the latter are the foci of this exercise.