Abstract Detail

Bryology and Lichenology

Pasiche Lisboa, Carlos Jose [1], Belland, Rene [2], Piercey-Normore, Michele D. [3].

Survival of fragments from three boreal mosses to extreme temperatures.

Moss propagules must survive and establish populations after dispersal, but little is known about the effects of temperature and other factors on the survival of fragments of different sizes and species. The goal of this study was to examine the ability of moss fragments to begin growth after exposure for one to six months to abrupt or gradual temperature changes. Three boreal forest mosses were studied, Dicranum polysetum Sw., Orthotrichum obtusifolium Brid., and Pleurozium schreberi (Bridel) Mitten. For each species, gametophyte stem fragments of different sizes (0.5 and 1.0 cm) were exposed directly (abrupt) or gradually to one to four changes in temperatures (43, 22, 6, -18, -40, -80 °C) for time periods of exposure (1 to 6 months). Fragments were cultured in vitro and at six weeks these were assessed for survival (green or brown) and growth (production of protonemata/branches from the gametophyte). Logistic regression analyses evaluated the association between survival and growth to the four predictors (temperature type, temperatures, time, and size of fragments). The logistic regression suggests that survival and protonemata production significantly increased when species were exposed to gradual rather than abrupt temperatures, lower than higher temperatures, and when the fragments had larger than smaller sizes. Only O. obtusifolium’s survival and protonemata production significantly increased with time of exposure. Gametophyte branches increased in gradual as opposed to abrupt temperature, decreases at higher temperatures, increased with time exposed, and increased when the fragments were larger than small sizes. However, O. obtusifolium producing branches neither increased nor decrease with temperature type, and P. schreberi decreased in gradual temperatures. Although most of the predictors and combinations were significant, regression models including the four predictors best explained the survival and growth response for the three moss species. Our study suggests that temperature type, temperature, time of exposure, and fragment size all influence survival and growth of moss species after dispersal, with species-specific survival and growth responses that allows for adaptation in a habitat. These adaptations may include clonal growth via the production of growth gametophyte branches and protonemata, or mostly protonemata (D. polysetum and P. schreberi, respectively), even when high temperatures negatively affect growth. In addition, these adaptations may aid with population maintenance for species that compete similar for substrata (D. polysetum and P. schreberi). Further studies including humidity and light would provide better insight on survival and growth responses of moss species in the boreal biome.

1 - University of Manitoba, 66 Chancellors Cir, Winnipeg, Manitoba, R3T 2N2, Canada
2 - University of Alberta, 775 General Services, Edmonton, Alberta, T6G 2H1, Canada
3 - Memorial University of Newfoundland, School of Science and Environment, Grenfell Campus, Memorial University of NL, Corner Brook, NL, A2H 5G4, Canada

Keywords:
none specified

Presentation Type: Oral Paper
Session: 5, Bryology and Lichenology (ABLS) I
Location: Sundance 2/Omni Hotel
Date: Monday, June 26th, 2017
Time: 10:45 AM
Number: 5007
Abstract ID:379
Candidate for Awards:A. J. Sharp Award