Effects of local-scale management on herbaceous plant communities in Brigalow (Acacia harpophylla) agroecosystems of southern Queensland, Australia

Remnant vegetation in agricultural landscapes is assumed to contain the majority of biodiversity, although few Australian studies have considered the contribution made by the surrounding production matrix. In this study, herbaceous plant communities from Brigalow (Acacia harpophylla) remnants and adjoining areas of the matrix were sampled to determine differences in plant species composition at the core and edge of four distinct land management categories. Nineteen sites consisting of Brigalow remnant and adjacent matrix were selected in the Brigalow Belt Bioregion of southern Queensland, Australia. This region has undergone recent agricultural development relative to the older, well studied landscapes of western Europe. Edge and core transects in four different land management categories were sampled for herbaceous plant species richness, composition and cover. Brigalow remnants contained significantly higher mean herbaceous richness than all other land management categories, and cultivated areas contained the lowest. Species richness, cover and composition did not differ between previously cultivated and uncultivated grasslands. Unlike other studies, there were no detectable edge effects for plant species richness, herbaceous cover and composition in any of the land management categories. Biodiversity conservation in agricultural landscapes in Australia should maintain a focus on the remnant vegetation components; however, our results suggest that there is the potential for enhancing plant biodiversity and ecological functioning by targeted management in modified grassland communities. Management and restoration efforts to conserve agroecosystem plant biodiversity should therefore integrate a range of different landscape elements.

► We examine plant diversity and edge effects along a land management intensity gradient.
► Remnant brigalow vegetation contained the highest plant biodiversity.
► Modified grasslands and regenerating cropping lands contributed to overall diversity.
► Edge effects were not evident in this recently developed Australian landscape.
► Conservation efforts should consider both remnant and matrix landscape elements.