Bryophytes and Lichens of North America: Diversity, Function and Importance
Mathieson, Krystal , Frego, Katherine .
Bryophyte-substrate associations in the Acadian Forest of southern New Brunswick.
The role of microhabitat in bryophyte community assembly is poorly understood, but many species are believed to have narrow ranges of substrate tolerance. Reduced species diversity, e.g. in disturbed habitats, has been attributed to reduced substrate diversity, assuming bryophyte-substrate specificity. However, few such claims effectively evaluate substrate associations, as they do not account for the relative abundance of substrates. This study rigorously tests bryophyte-substrate associations by abundance (% cover) and frequency of occurrence of species in the Acadian Forest in southern New Brunswick. Bryophyte species and substrates in 440 quadrats were subjected to randomization tests, in which the abundance and number of occurrences of 590 species-substrate combinations were compared to those expected, based on random occupancy of substrates. Of 80 bryophyte taxa, 66 were positively associated with at least one substrate. In total, 202 significant positive associations were found, significantly more than expected by chance (p < 0.0001): 92 in both abundance and occurrence, 52 in abundance only, and 58 in occurrence only. Similar patterns were shown in mosses and liverworts. This work confirms many previously reported associations, but 115 were new reports. The highest number of associations was with dead wood in late stages of decay. Many species (26), identified in other studies to decline under intensive forest management, are associated with substrates that also decline in these treatments. This study identifies species for which substrate is a potential limiting factor that must be considered in conservation efforts.
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1 - University of New Brunswick, Saint John campus, Biology Department, P.O. Box 5050, Saint John, NB, E2L4L5, Canada
coarse woody debris.
Presentation Type: Symposium or Colloquium Presentation
Date: Tuesday, July 29th, 2008
Time: 4:30 PM