The piosphere revisited: plant species patterns close to waterpoints in small, fenced paddocks in chenopod shrublands of South Australia

Abstract

The Waite–Nicolson rangeland management method for semi-arid chenopod shrublands predicts that smaller paddocks with medium to moderate stocking rates help to preserve the native vegetation. Vegetation cover around waterpoints in three small paddocks (<2000 ha) from Middleback Station, South Australia was studied using multivariate analysis. Data from quadrats sampled along radiating transects were tested for correlations with a number of site features and grazing history factors. Two significant associations were detected: quadrats with an abundance of Rhagodia parabolica and less palatable species such as Maireana pyramidata, and Atriplex stipitata were correlated positively with proximity to water points, paddock age and stocking rate, and negatively with paddock size. In contrast, quadrats with species such as Rhagodia ulicina and the more palatable M. sedifolia were correlated with increasing distance from the water points and paddock size, but negatively with age and stocking rates. Transect direction was not correlated with either group. Twelve of the 20 species examined, including the important forage species A. vesicaria, also were not correlated with those paddock and grazing features included here. These results suggest that the distribution of some chenopod shrub species in fenced paddocks is still possibly affected by a combination of these factors in the long term by grazing at densities of 6 ha sheep⁻¹ and that the method, although maintaining the fodder species, may not be preserving biodiversity at these grazing levels, although further study is needed.