Germination and seedling growth of bog plants in relation to the recolonization of milled peatlands

Two controlled experiments were conducted to evaluate the potential for vascular plants to germinate and establish in milled peatlands and to assess whether easily measured plant traits can be used to predict their probable success. Study species included twenty species of perennial herbs, shrubs and trees occurring frequently in undisturbed bogs or abandoned milled bogs in Quebec, Canada. First, a glasshouse experiment was performed to test the effect of burial under peat on germination and seedling emergence. Second, a growth chamber experiment was conducted to measure relative growth rate and other growth parameters of seedlings between 1 and 3 weeks of age. In the burial experiment, seedling emergence decreased exponentially with peat depth for most species examined. The slope of the exponential decline varied between species and was strongly correlated to seed mass. Seeds less than 0.1 mg in mass were most sensitive to burial. In the seedling growth experiments, Betula species had the highest absolute and relative growth rates, which may help to explain their prevalence in milled bogs. Relative growth rate (RGR) was not correlated with seed mass, however it was strongly correlated with leaf area ratio (LAR) and especially specific leaf area (SLA) of seedlings, except for species with seed mass less than 0.01 mg. Screening of species for seed mass and SLA should help predict their germination and establishment success or failure in milled peatlands and allow more directed interventions to favour the establishment of desirable species in milled bogs.