UBC Theses and Dissertations
Classification of epilithic bryophyte communities in south-western British Columbia Velzen, Johannes Petrus van
The present study attempts to classify the epilithic (=growing on rock) bryophyte vegetation of south-western British Columbia, Canada. During the summer field season of 1980 around 350 releves (=samples) were taken of bryophyte assemblages from rocky habitats that ranged in elevation from sea level to subalpine and alpine areas. Small scale variation was expressed in the segregation of various types of micro-environments on rocks, all characterized by their own bryophyte vegetation. On a larger scale, the releves of these epilithic bryophyte assemblages were divided into four major groups: (1) exposed, dry rocks (2) shaded, humid rocks (3) siliceous rocks along streams and (4) calcareous rocks. Within these major groups cluster analyses and tabular sorting, combined, were utilized to detect patterns in the data set. The subsequent recognition of groups of similar releves formed the basis for the segregation of separate vegetation units (syntaxa). These syntaxa were defined by diagnostic species (character and differential species) and further characterized by micro-site specificity of species and/or communities and their geographic distribution throughout the study area. Comparison to and integration in already existing classification schemes was attempted. In particular, floristic and sociological affinities assigned to the epilithic bryophyte associations in south western British Columbia were related to those in Europe. Where necessary and appropriate, new syntaxa were distinguished and defined. Finally, the application of ordination techniques, although limited in the present study, was utilized as an additional means to display and interpret patterns in the data set. The prior classification, paralleled with field data on ecological site characteristics, already showed some relationship between releves. This provided a basis for interpreting the ordinations, which, in turn, further expressed and clarified relationships of releves to one another and to the environment.
Item Citations and Data