Temporal and spatial variation in abundances of native bee species on an altitudinal gradient in southern Tasmania

Bee assemblages were investigated in heathy coastal forest, shrubby dry scl erophyll forest, and shrubby subalpine forest near Hobart, in southern Tasm ania, during spring, summer, and autumn between September 1996 and October 1997. Several taxa previously unknown from the state were encountered, incl uding the first Tasmanian records of the halictid subfamily Nomiinae. Assem blages varied both temporally and spatially. Temporal variation within part icular vegetation types was due to interspecific differences in flight peri ods. Spatial variation resulted from most species being restricted to one o r two of these vegetation types, with species richness being substantially lower in the subalpine area than the two vegetation types at lower altitude . This variation also involved several species being more or less restricte d to one habitat. In particular, Lasioglossum (Austrevylaeus pertribuarium) was a subalpine specialist while numerous species were more or less restri cted to either coastal or dry sclerophyll forests. There was also an intera ction between these two forms of variation, in the form of divergence in th e flight periods of individual species in different vegetation types.