BONINE, MARY L.*, LLOYD R STARK, D. NICHOLAS MCLETCHIE, AND BRENT D. MISHLER. Department of Biological Sciences, University of Nevada-Las Vegas, Las Vegas, NV 89154-4004. - Spatial Distribution of Desert Bryophyte Populations.
Populations of the desert moss Syntrichia caninervis Mitt. were
sampled on a 1.5 hectare site in order to study spatial distributions
of male, female, and mixed sex populations. Populations were also
categorized in reference to their microhabitat (shaded versus exposed)
and mapped on a coordinate grid system including prominent topographic
trends. Exposed populations were found to be significantly clustered
near trails and washes. Shaded populations, both mixed-sex and
single-sex (female), were clumped in arrangement, but single-sex
populations were more clumped than mixed-sex populations. This study
provides a basis for exploring the potential mechanisms involved in
the origins and maintenance of these patterns. We provide three
potential explanations for these patterns: a leptokurtic hypothesis
of spore dispersal, failure of the species to colonize new habitats
via spores, and limitation of mixed-sex populations by the vegetative
self-propagation of single-sex populations.
Key words: niche partitioning, Pottiaceae, spatial segregation, Syntrichia caninervis