Vertical distribution and assemblages of corticolous myxomycetes on five tree species in the Great Smoky Mountains National Park

Abstract

Corticolous myxomycetes of the Great Smoky Mountains National Park were studied in relation to their association with certain tree species and height of occurrence in the forest canopy. Using the double-rope climbing method, bark was collected at 3 m increments to the tops of trees of five different species. Bark samples from 25 trees were used to prepare 418 moist chamber cultures maintained and observed 4 wk. Eighty-four myxomycete species were identified, including 30 species not known to occur in the park. Tree species, pH, height in tree and water-holding capacity of the bark samples were analyzed to determine the relationships of myxomycete assemblages cultured on the bark. Results suggested that myxomycete community composition among selected tree species were similar, but occurrence and abundance of certain species were related to differences in bark pH. Community similarity values among trees of different species show that trees with the most similar myxomycete communities also have the most similar bark pH. Most myxomycete species in this study have a pH optimum. No variation in species richness was detected at different heights in the trees, and most species were obtained at all heights up to at least 24 m. The water-holding capacity of the bark could not be correlated with species richness or abundance of myxomycetes that inhabit the bark of living trees. This is the first study to characterize myxomycete communities of tree canopies.

• bark
• ecology
• Great Smoky Mountains National Park
• Mycetozoa
• Myxomycetes
• tree canopy
• tree climbing

This research project was conducted originally as a master's thesis. We would like to thank Central Missouri State University Graduate School for two awards: first place for the Graduate Student Thesis Award and the Reid Hemphill Outstanding Graduate Scholar Award to Kenneth L. Snell. We also would like to thank James “Buck” Counts, Damon Lesmeister and Melissa Skrabal for their help in making tree-canopy collections and to Charly Pottorff for teaching us how to climb trees. Dr. Jay Raveill identified the trees and Professor Uno Eliasson helped to identify myxomycetes. We are grateful to Drs. Stefan Cairns, Steven L. Stephenson and Steve Wilson for their assistance with the statistics and editorial corrections. Park employee Keith Langdon and Jeanie Hilten of Discover Life in America were important to the climbing and ground crews in the park, helping with access, directions, equipment and lodging. This project was financed by grants from the National Science Foundation (DEB#0079058) and Discover Life in America (#2001-26).