Ecology and control of vertebrate and invertebrate pests of grass and forage © 2013 Proceedings of the 22 nd International Grassland Congress 1600 Impacts and management of invasive burrowing herbivores in grasslands Peter JS Fleming A , Hua Limin B and Desley Whisson C A Vertebrate Pest Research Unit, Biosecurity NSW, Orange Agricultural Institute, 1447 Forest Road, Orange, NSW 2800, Australia, and School of Environmental and Rural Sciences, Northern Ring Road, University of New England, Armidale, NSW 2351, Australia B Gansu Agricultural University, No. 1, Yingmen Village, Anning District, Gansu Province, People’s Republic of China C School of Life and Environmental Sciences, Deakin University, 221 Burwood Hwy, Burwood, Vic 3125 , Australia Contact email: peter.fleming@dpi.nsw.gov.au Abstract. Maintenance of the productivity of the world’s grasslands is critical for livestock production, bio- diversity conservation and ecosystem services. Using case studies from Australasia, North America and China, we identify general principles of managing invasive native and introduced herbivores. Management aims to achieve optimised livestock production while conserving biodiversity and ecosystem services, which are often intangible. We identify similarities and differences in the ecologies and impacts of European wild rabbits, Californian ground squirrel and plateau zokors, discuss management tools and strategies, and the eco- logical, social and cultural factors affecting management. The ecosystem engineering characteristics of these species that make them important for ecosystem function in grasslands are perversely the selfsame ones that bring them into conflict with livestock producers. All three species create habitat patches through their bur- rowing and foraging behaviours, but changes in vegetation floristics and structure, increased soil exposure and decreased litter negatively affect grassland and livestock production when the animals are superabundant. Management is therefore complex and we recommend an adaptive approach that is founded on the scientific knowledge of the local agri-ecosystem, economic principles and social inclusion to increase knowledge and iteratively improve management. Keywords: Rabbits, ground squirrels, zokors, invasive, adaptive management. Introduction Grasslands constitute 40.5% of the world’s terrestrial eco- systems and are critical for livestock production, bio- diversity and environmental services (Suttie et al. 2005a). The forecast growth rate for human population over the next half century is 1.2% per year on the 7 billion reached in 2011 (US Census in Chavas 2011). This places an im- perative to improve production efficiency for all primary industries, including grassland-based meat and fibre pro- duction. Reduction in losses caused by invasive animals, both native and introduced, will be important in improving efficiency of livestock production systems around the world. Degradation of grassland ecosystems, by factors in- cluding herbivorous invasive species, impacts upon their production almost everywhere (Suttie et al. 2005b). How- ever, despite the importance of grasslands for food production, most research on the impacts of invasive herbi- vores has been conducted on those animals that cause damage to high value and intensive food crops (e.g. ro- dents, Jacob and Tkadlec 2010; Stenseth et al. 2003) and their storage, or to forestry (e.g. ungulates and macropods: Jorritsma et al. 1999; Reimoser et al. 1999; Bulinski and McArthur 1999; Di Stefano et al. 2007). A recent review (Davidson et al. 2012) concentrated on losses of ecosystem services and biodiversity responses to declines in burrow- ing, herbivorous mammals but neglected the adverse effects some have on agriculture. Here, we briefly review general principles of invasive animal management, the ecological characteristics of inva- sive herbivores pertaining to their impacts on grazing systems and their management, and technical and social factors that affect management. We address the manage- ment of invasive burrowing herbivores through specific case studies, one each from Australasia, North America and China. The case study animals are all colonial, burrowing, herbivorous small mammals, but one is introduced and the others are native. They are used to demonstrate generalities of management, while identifying crucial differences that must be considered when devising strategies that work for the people involved and their local agri-ecosystems. Principles of invasive animal management Adaptive management Adaptive management (Walters and Hilborn 1978) is a process whereby the knowledge required for implementing efficacious and efficient strategies to achieve production and conservation goals is collected and iteratively im- proved using scientific methods. Because knowledge about an ecosystem of interest is usually deficient and often in-