The early effects of fire and grazing on bryophytes and lichens in tussock grassland and hummock sedgeland in north-eastern Tasmania

Abstract

Little is known of the interactive effects of fire and grazing on cryptogam species and assemblages. These effects were observed for bryophyte and lichen species in Tasmanian tussock grassland and hummock sedgeland several months after experimental burning and fencing. A factorial design was used on 40 randomly located and treated pairs of 1 m × 1 m quadrats in each of the vegetation types. In total, 24 cryptogam taxa were found, with grassland having a greater taxon richness, as well as higher total cryptogam cover and a different species composition, to the hummock sedgeland. There was greater cryptogam cover in the burned quadrats than the unburned quadrats in the grassland. However, only bryophytes had different species composition between burned and unburned quadrats. There was a small but significant difference in richness in hummock sedgeland, with burned being richer than unburned. Three species were more abundant in the burned than in the unburned treatments in the grassland, whereas no species responded to treatment in the sedgeland and no species responded to grazing. The fact that no species or assemblage of species was significantly reduced in cover by the burns testifies to a high degree of cryptogam resilience to this disturbance. The total lack of negative grazing effects suggests cryptogams are not a major source of sustenance for the local vertebrate herbivores. These conclusions differ from those made elsewhere in the world.