University of New England Ecological, biophysical and animal production responses to strategic-rest grazing in Australia and worldwide Submitted by Rachel Lawrence B.Sc. Hons. For the award of Doctor of Philosophy, 29th October, 2019. Financial and in-kind support Financial support for this dissertation was a scholarship from the Northern Tablelands Local Land Services and the North West Local Land Services, NSW, as part of the Brigalow– Nandewar Biolinks Projects funded by the Australian Government Biodiversity Fund (Projects LSP-991865-1429 and LSP-944752-1076). Operating funds and in-kind support were provided by the School of Environmental and Rural Science, University of New England, NSW. Ethics approval for our survey of grazing managers was granted by the Human Research Ethics Committee, University of New England, approval number: HE15-021. ii Acknowledgements My sincere thanks to my supervisors Romina Rader, Nick Reid and Wal Whalley for their support, patience, encouragement and diversity of input and my non-supervisory co-authors, Sarah McDonald and Liam Kendall. Thank you to my family for their support and encouragement and unwavering support and belief in my ability to complete this thesis, and for encouraging me to be open- minded despite the challenges that sometimes presents. To my son especially for putting up with what at times to him must have seemed a never-ending journey. Thank you also to my Armidale friends who helped me along the way, your support was greatly appreciated. I also thank landholders who generously allowed me to work on their properties and provided me with necessary information. I am especially grateful to those who contributed generously to discussions of related issues for the duration of this project. Boyd Wright of Botany (UNE) gave me invaluable help with statistical analyses and David Tongway taught me to apply landscape function analysis. I am also grateful to Graham Hall for early discussions regarding this project and to staff from the Australian National Insect Collection who helped me with identification of parasitoid wasps. I want to acknowledge the late Bob 'Bobby Jack' Waugh for inspiring discussions around grazing practices in the New England region prior to commencing this study. Finally, thank you to anonymous reviewers for their comments for the two peer- reviewed journal articles that are a part of this thesis. iii Note to the examiners The thesis has been written in the style of a thesis by publication. Two of the chapters have been published in peer-reviewed journals (Journal of Applied Ecology and Agriculture, Ecosystems and Environment). In this thesis two separate terms are used for rotational grazing practices that incorporate extended rest: (i) In the global review, the term “strategic-rest grazing” encompasses all variations on grazing incorporating rest; (ii) in the regional study the term “short-duration grazing” relates to a sub-set of broader strategic-rest grazing practices in the region. For consistency, formatting of the thesis aligns with that suggested by the University of New England. As Chapters 2 through to 6 have been prepared as manuscripts, there is some repetition, for which I apologise in advance. iv Sheep grazing, New England Tablelands, New South Wales “The care of the Earth is out most ancient and most worthy, and after all our most pleasing responsibility” (Wendell Berry) v “It is important to be cautious about how 'grazing' is characterized. When properly managed on a sustainable basis grazing can be an effective practice for maintaining the biodiversity of most indigenous grasslands. In many cases unsustainable grazing and the removal of moribund biomass by domestic livestock is inappropriately undertaken, whereas if managed sustainably grazing can be an effective practice, in particular if used with an appropriate fire regime. We need to be careful 'not to judge' grazing practices and any decision-making needs to be based on sound conservation biology principles, and getting the right balance among conservation, traditional cultural values and development.” (From IUCN, 2008, 'Life in a Working Landscape: Towards a Conservation Strategy for the World's Temperate Grasslands') vi Abstract Livestock grazing can facilitate the maintenance of biodiversity in landscapes or cause landscape degradation and biodiversity loss. With a global population expected to surpass 9 billion people by 2050, there will be increasing pressure on the world's grazing lands to produce protein while minimising impacts on landscapes. This thesis explores the potential for grazing that incorporates extended and planned rest (Strategic-rest grazing, hereafter SRG) to enable continuing livestock production while also maintaining biodiversity and biophysical functions. In Chapter 2, I conducted a global meta-analysis comparing impacts of SRG to continuously grazed or ungrazed areas. I found that total groundcover and animal production per hectare were significantly greater with SRG compared to continuous grazing, while biomass, plant richness, plant diversity and animal weight gain did not differ between grazing treatments. Where the length of rest, relative to graze time increased with SRG, there were significant increases in biomass and further increases in groundcover and animal production per hectare in comparison to continuous grazing. These findings highlight the importance of incorporating the length of rest relative to graze duration into analyses comparing grazing systems. I found that the main focus of research around SRG differed between major geographic regions and climate zones. North American, Australian and New Zealand research mostly focused on short-term animal productivity, as did research in temperate areas. In contrast, research from Europe predominantly focused on biodiversity conservation. Research in more arid areas has focused largely on general sustainability for continuing animal production. Where richness and diversity of flora and fauna were compared between SRG and continuously grazed areas, responses were mostly favourable in SDG areas, or there was no difference. There were few examples of negative outcomes in SRG areas. Where vii richness and diversity in SRG areas were compared to ungrazed areas there was often no difference between SRG and ungrazed. Despite the often-favourable responses for production and ecological outcomes with SRG, a very small number of studies have considered the potential to achieve animal production and biodiversity conservation simultaneously with SRG approaches. This suggests we have limited understanding of trade-offs and synergies between these two goals. A localised study was undertaken of ground-layer biodiversity and landscape function outcomes in naturalised pastures in NSW, Australia. This study assessed grasslands on six properties managed with short-duration grazing (hereafter SDG, a form of SRG) and compared with outcomes on properties managed in ways more typical of the region (largely continuous and with unplanned rest; hereafter RP). With SDG management there was approximately 19% greater perennial herbaceous cover and a corresponding 14% lower cover of undesirable introduced annual plants. Significant improvement in attributes relating to landscape functioning were also seen with SDG management, with environmental factors less important in influencing these attributes. Pasture composition also differed between management approaches with increased cover of favourable forage species and reduced cover of species that increase under heavy grazing pressure with SDG management. Greater richness of native forbs was seen under RP, but no other identifiable differences in richness and Shannon-Wiener diversity was seen in the ground-layer of pastures managed in contrasting ways. Insects are an important component of overall landscape biodiversity and are sensitive to changes in land-use and agricultural intensification. Insect richness and abundance were assessed on RP and SDG properties and found to be significantly higher on SDG sites. These increases were likely largely due to the greater cover of tall perennial plants and litter cover viii and increased structural heterogeneity of the pasture sward with SDG management. These increases suggest there is potential for altered grazing practices to improve the capacity of grazed landscapes to provide ecosystem services from insects such as natural pest control and pollination, as well as provide food resources for wildlife. This thesis has highlighted the potential to balance animal production, biophysical and biodiversity outcomes with grazing incorporating extended rest and that research to-date has largely been on animal production outcomes rather than biodiversity responses. Importantly, it highlights that minimal research has considered trade-offs and synergies between animal production and biodiversity conservation outcomes, and the potential to achieve both simultaneously. If we are to meet the growing demand for protein from the world's grazing lands, while also preventing landscape degradation and sustaining biodiversity, it is essential to fill this knowledge gap. ix Please be advised that this is a thesis by publication. Earlier versions of the following chapters have been retained in this version of the thesis: Chapter 2 McDonald, S. E., Lawrence, R., Kendall, L., & Rader, R. (2019). Ecological, biophysical and production effects of incorporating rest into grazing regimes: A global meta‐analysis. Journal of Applied Ecology, 56(12), 2723–2731.