How grassland plants are distributed over five human-created habitats typical of eucalypt woodlands in a variegated landscape

Abstract

A sample of 212 quadrats in grassland vegetation was collected in eucalypt woodlands in sub-tropical Queensland. These included roadside (53 sites), native pasture (109), riparian zone (20), sown pasture (16) and crop (14) habitats. A total of 350 species and subspecies was recorded of which 89 species were identified as being locally rare (native species of <3% frequency, not specialists of other habitats). Forty-three species were collected in addition to the quadrat records. Multivariate analysis indicated the major difference in floristic composition was between roadsides and native pastures, versus the other three habitats. The second axis separated roadside from native pasture vegetation, and the third axis separated riparian sites from all the rest. Crop and sown pasture habitats were the most similar in composition. The grazing practices in this region have enabled the persistence of grasslands that are of national significance in conservation terms. The variegated nature of the landscape is demonstrated by the occurrence of native grassland species across all the human-created habitats, including native species that were unique to intensive land uses. However, our results also show that intensive land uses (cropping, sown pastures) are more of a threat to the conservation status of grasslands than is cattle grazing, even at commercial levels of stocking. Species at most immediate risk are those that are sensitive to commercial cattle grazing and to intensive land uses such as crops and sown pastures.