Rotational grazing management strategies have been promoted as a way to improve the sustainability of native grass-based pasture systems. From disturbance ecology theory, rotational grazing relative to continuous grazing can increase pasture productivity by allowing vegetation to recover after short intense grazing periods. This project sought to assess whether soil organic carbon (SOC) stocks would also increase with adoption of rotational grazing management. Twelve pairs of rotationally and continuously grazed paddocks were sampled across a rainfall gradient in South Australia. Pasture productivity approximated as the normalized difference vegetation index (NDVI) was on average no different between management categories, but when the data from all sites were aggregated as log response ratios (rotational/continuous) a significant positive trend of increasing NDVI under rotational grazing relative to continuous grazing was found (R2 = 0.52). Mean SOC stocks (0–30 cm) were 48.3 Mg C ha-1 with a range of 20–80 Mg C ha-1 across the study area with no differences between grazing management categories. SOC stocks were well correlated with rainfall and temperature (multiple linear regression R2 = 0.61). After removing the influence of climate on SOC stocks, the management variables, rest periods, stocking rate and grazing days, were found to be significantly correlated with SOC, explaining 22% of the variance in SOC, but there were still no clear differences in SOC stocks at paired sites. We suggest three reasons for the lack of SOC response. First, changes in plant productivity and turnover in low-medium rainfall regions due to changes in grazing management are small and slow, so we would only expect at best small incremental changes in SOC stocks. This is compounded by the inherent variability within and between paddocks making detection of a small real change difficult on short timescales. Lastly, the management data suggests that there is a gradation in implementation of rotational grazing and the use of two fixed categories (i.e. rotational v. continuous) may not be the most appropriate method of comparing diverse management styles.

Demonstrating sustainable land management (SLM) requires an understanding of the linkages between grazing management and environmental stewardship. Grazing management practices that incorporate strategic periods of rest are promoted internationally as best practice. However, spatial and temporal trends in unmanaged feral (goat) and native (kangaroo) populations in the southern Australian rangelands can result land managers having, at times, control over less than half the grazing pressure, precluding the ability to rest pastures. Few empirical studies have examined the impacts of total grazing pressure (TGP) on biodiversity and resource condition, while the inability to manage grazing intensity at critical times may result in negative impacts on ground cover, changes in pasture species composition, increased rates of soil loss and reduce the ability for soils to store carbon. The widespread adoption of TGP control through exclusion fencing in the southern Australian rangelands has created unprecedented opportunities to manage total grazing pressure, although there is little direct evidence that this infrastructure leads to more sustainable land management. Here we identify several key indicators that are either outcome- or activity-based that could serve as a basis for verification of the impacts of TGP management. Since TGP is the basic determinant of the impact of herbivory on vegetation it follows that the ability for rangeland pastoral management to demonstrate SLM and environmental stewardship will rely on using evidence-based indicators to support environmental social licence to operate.

In the southern rangelands of Australia, the capability of land managers to manage total grazing pressure, with support from their service providers, influences resource condition, livestock production and pastoral business profitability. This study investigated the perspectives of people who face the challenge of managing total grazing pressure. Self-administered surveys were used to collect the perspectives of 220 land managers and 46 service providers to total grazing pressure management and the impacts of grazing animals. Land managers and service providers agreed that, on average, 40 to 50% of the total demand for forage is due to non-domestic animals, that a reduction in this component is required, and that current levels are at least double the desirable level. The majority of respondents (>54%) assessed both livestock and non-domestic animals to have a negative impact on soils and pastures. However, livestock were more frequently assessed to have a positive impact on soils and pastures than non-domestic animals. The respondents commonly suggested that the impact livestock have on soils and pastures depends on management. Non-domestic animals were assessed by the majority of respondents to have a negative impact on livestock production and business profitability, apart from unmanaged goats where opinions were divided. Both land managers and service providers used the ‘large negative’ category to describe the impact on livestock production and business profitability more frequently for kangaroos than for any other herbivore. There were significant differences in the respondents’ perspectives among the States. Respondents in New South Wales and Queensland estimated a higher proportion of demand for forage from non-domestic animals than respondents from other States. The respondents in New South Wales also more frequently assessed unmanaged goats to have a positive impact on business profitability compared with the other States. Total grazing pressure management was rated as a high priority issue by 66% of respondents. ‘Improved kangaroo management’ and ‘fencing’ were the two main factors identified with potential to make a substantial difference to total grazing pressure management in the next ten years.

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