The viability of bush in cities - ten years of change in an urban grassy woodland

Abstract

The Queens Domain, Hobart, is an area of grassy woodland that has been surrounded by urban development for over 70 years. Floristic and structural data were collected from 70 quadrats in both 1974 and 1984 to test whether the relatively high fertility, large size and compact shape of the reserve allowed it to avoid the dramatic deterioration of native vegetation that has been recorded for less favoured reserves in other Australian cities. Over the decade an increased incidence and spread of fire was associated with increased quadrat species richness, increases in tree density, especially of Casuarina stricta, and a decrease in the density of the larger size classes. However, despite large increases in exotic species richness in two out of three communities defined for the Domain its nature conservation value did not decline, as many of the species that increased in frequency over the decade were native herbs that are now rare in Tasmania. A high fire frequency or the reintroduction of large native herbivores may be necessary to encourage these species and to help prevent a thickening of the tree stratum.