Abstract Detail

Ecology

Pasiche-Lisboa, Carlos J. [1], Piercey-Normore, Michele D. [2].

Dispersal of lichen and moss asexual propagules by wind may influence community structure in boreal forests.

Bryophyte and lichen communities produce asexual propagules in different quantities, sizes, and morphological types (here called propagule load) that are dispersed mainly by wind. Habitat and geographic location of the lichen and bryophyte community, the asexual propagule load, dispersal vector (wind), and propagule establishment may influence the population structure within the community. However, little is known about the dispersal of asexual propagules produced by boreal moss and lichen communities. The goal of this study was to better understand the wind dispersal of asexual propagules produced by boreal mosses and lichens. Moss gametophore and lichen thallus material of nine species from tree and forest floor substrata were collected from a boreal forest in Manitoba. In the laboratory, the material was crushed to form varied-sized propagules, which were exposed to a wind tunnel experiment. Horizontal winds from a fan blew the material at wind speeds of 9.05 ± 0.06 km/hr allowing the propagules to deposit on a one-meter tape extending away from the fan. Dispersal of these species was studied by assessing if there were significant associations (Pearson's r) of number and sizes of asexual propagules with distance traveled (cm) away from the wind source. Asexual propagule sizes were compared (ANOVA) between substrata, and mosses and lichens. Results showed that small fragments (204.10 ± 5.83 ?m) of the moss gametophore and thallus fragments of lichens were mostly dispersed within 10 cm from the source. Pearson's r indicates that the size and quantity of propagules decreased with an increase in dispersal distance. However, the ground rather than epiphytic communities, and mosses rather than lichens had a stronger negative association between numbers of propagules or sizes and distance suggesting a limited dispersal in boreal forests. Furthermore, ANOVA showed that significantly larger sizes of asexual propagules were deposited from ground communities rather than epiphytic communities, and mosses rather than lichens. Our study suggests that the community structure in boreal forests may result from dispersal limitations (dispersal close to the source) of mosses and lichens from the ground and trees. Dispersal limitations may affect community structure by the high deposition and establishment of asexual propagules of select species limiting the occupancy of other species on a substratum, but aiding with the population maintenance of the resident species. The contribution of each species on community structure can be elucidated if experiments on the dispersal, deposition, and establishment of the propagule load are further explored.

1 - Pasichcj@myumanitoba.ca, Biological Science, General Office 212B Bio-Sci Bldg., 50 Sifton Road, University Of Manitoba, Winnipeg, MB, R3T 2N2, Canada
2 - Memorial University of Newfoundland (Grenfell Campus), School of Science and the Environment, 20 University Drive, Corner Brook, NL, A2H 5G4, CA

Keywords:
bryophyte
community ecology
dispersal
lichen
propagule size
asexual
wind tunnel.

Presentation Type: Oral Paper
Session: 7, Ecology Section - Community Interactions and Responses
Location: 106/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 10:45 AM
Number: 7009
Abstract ID:685
Candidate for Awards:A. J. Sharp Award