Soil seed reserves in arid grazing lands of central Australia. Part 2: availability of ‘safe sites’

Abstract

In the arid grazing lands of central Australia, a previous study found that the size and composition of seed banks were changed by heavy grazing. In this concurrent study we found that grazing decreased the number of ‘safe sites’ for seeds by reducing soil stability and damaging broad-scale resource traps. The loss of ‘safe sites’ was likely to have had a greater initial impact on seed bank size than the direct effect of grazing on seed-bearing plants. In this environment, changes to the soil preceded changes to the vegetation, so that soil-based rather than vegetation-based indicators may provide a better early warning of rangeland deterioration.