Grazing systems and natural capital: Influence of grazing management on natural capital in extensive livestock production systems

Abstract

Using a weight of evidence approach, natural capital outcomes associated with regenerative grazing and silvopastoral systems were compared to those associated with conventional grazing systems. The aim of the review was to better understand how grazing management influences 16 natural capital indicators likely to be material from both an economic and sustainability perspective for grazing enterprises and to assess the evidence for associated impacts, positive or negative, on the natural capital resources required to sustain the system. Material natural capital issues reviewed included water availability and security, water quality, soil health and pasture productivity, biodiversity and climate change and greenhouse gas emissions.

The review confirms previous evidence that moderate to high levels of grazing tends to degrade natural capital, relative to light to moderate levels of grazing. In relation to regenerative grazing practices the responses were less clear. Regenerative grazing practices may have a positive impact on natural capital, particularly in relation to soil biodiversity and live weight gain on a per head basis. However, the evidence base suggests that the effect size may be small and may take some years to be realised. For 12 of the 16 indicators reviewed, the natural capital outcomes were inconclusive or unresolved even though for five of these indicators, the evidence base was considered to be robust. For the remainder of these the evidence base was insufficient to support an analysis of potential impacts. Similarly, for silvopastoral grazing management systems, there was some evidence to suggest that this type of grazing management could lead to improved natural capital outcomes. However, the evidence base was generally insufficient to definitively attribute the changes in grazing management practices to natural capital outcomes.

Although the evidence base for many of the natural capital outcomes associated with differing grazing management practices is incomplete, it should not be interpreted that this indicates a lack of a beneficial response, where a beneficial response would be characterised by improved natural capital and enterprise productivity. Rather it highlights shortcomings in the underlying evidence. Very few studies have the capacity to fully account for the benefits of changes in management practices on the natural capital outcomes and the productivity of the enterprise simultaneously and over a sufficient period of time to observe change. This was particularly evident in relation to carbon storage. While there have been many studies that have examined changes in the individual stocks, e.g. soil carbon or emissions in relation to grazing management very few studies have examined the whole farm carbon balance. Increased adoption of processes such as natural capital accounting, although in their infancy, could help to address this challenge and facilitate a more systematic analysis an enterprises natural capital and financial performance.