Allocation to sexual and asexual reproduction was uniform in spite of environmental gradients in case of the moss Polytrichum juniperinum in the low arctic

The relative allocation within a plant species of asexual vs. sexual reproduction is predicted to vary according to changing environmental conditions. In bryophytes, sex expression is predicted to be reduced in unfavourable environments because sporophyte maturation is resource‒limited. The allocation between reproductive strategies in the bryophyte, Polytrichum juniperinum was examined in the low‒arctic Torngat Mountains (Labrador, Canada) in 2008/2009 along both an elevation and moisture gradient. Using genetic markers, no pattern was observed in the allocation between sexual and asexual reproductive strategies among the different environmental conditions. Although all populations showed evidence of sexual reproduction, effective sexual reproduction was depressed along both gradients. All populations showed high rates of fertilization among closely related ramets that resulted in inbreeding. This might limit the capacity to maintain high genetic diversity in local populations, which would be favoured in an environment experiencing warming.