Grass, fire, kangaroos and cattle: The nexus between fire and herbivory in northern Australia, 2015-2019
This project was a multi-scale approach to encompass both large- and small-scale variation in the complex relationships between forage, fire and large herbivores in tropical savannas. Aboriginal elders in the North Kimberley Region of Western Australia had called attention to declining populations of important macropod species across their traditional lands that were impacted by changing fire regimes and introduced large herbivores. Sites were established in two regions characterised as tropical savanna, Arnhem Land and the North Kimberley, focusing on two habitats, sandsheet savanna (Arnhem Land and North Kimberley) and basalt savanna (North Kimberley). The two study regions were dominated by different large introduced herbivores, Asian water buffalo in Arnhem Land and feral cattle in North Kimberley.
The primary research site was the North Kimberley on Wunambal Gaambera Country (WGC) which represents an 800,000 hectare area with a long history of Aboriginal occupation and intensive fire management followed by a more uncontrolled fire regime after mission development and population settlement in the early 1900s. Contemporary fire management on WGC aimed to replicate the historical mosaic burning on a larger scale using both aerial and ground-based ignition techniques. Wunambal Gaambera Aboriginal Corporation, was a partner in this research and the Uunguu Rangers and staff (the team responsible for implementing land management and research objectives) and other Traditional Owners were highly involved in site selection and implementation of all methodology by providing local knowledge and guidance. Research objectives for the project were closely tied to the Wunambal Gaambera Healthy Country Plan in order to provide answers to both scientific questions and important management concerns. Arnhem Land was chosen as a secondary site where a subset of methodology was applied. The Arnhem Land site represented a family outstation that had near continual Aboriginal occupation and management since European colonization in the 1950’s (Yibarbuk et al. 2001) where fire was primarily managed on the ground by the family group. The Rostron and Campion families provided approval and guidance on the research activities at the outstation.
The main objective of the project was to use landscape-scale surveys and field experiments to discover relationships and feedbacks between fire regime and the occurrence of large native (kangaroos) and non-native (feral stock) herbivores in the savannas of northern Australia. Specifically, we wanted to (1) explore mechanisms that drive large herbivore distributions, (2) determine feedbacks between large herbivores and the quantity and quality of forage, and (3) compare the role of different large feral herbivores. Field work for this project was conducted during the dry seasons of 2015-2017. Aerial surveys, road transects, camera trapping, scat counts, grazing exclosures, forage nutrient analyses, scat isotopic analyses, vegetation sampling with transects and quadrats for cover, production, percent curing and species composition, and GIS analyses of landscape features were all conducted during the field program.
This project was in fulfillment of a doctoral degree at the University of Tasmania (UTAS) and was a joint partnership between UTAS, Charles Darwin University (CDU), Bush Heritage Australia (BHA) and Wunambal Gaambera Aboriginal Corporation (WGAC) . My supervisory team included Prof. David Bowman (UTAS), Dr. Brett Murphy (CDU), and Dr. Tom Vigilante (BHA and WGAC). The project was funded by Australian Research Council Grant-Linkage Projects No. LP150100025 (2015 – 2019) held by Bowman DMJS; Murphy B; Appleby M; Ritchie E; Vigilante T supported by BHA and WGAC.
Publications arising from this project include:
Reid, A.M., Murphy, B.P., Vigilante, T., and Bowman, D.M.J.S. (2020), Distribution and abundance of large herbivores in a northern Australian tropical savanna: A multi‐scale approach. Austral Ecology. doi:10.1111/aec.12860
Reid, A.M., Murphy, B.P., Vigilante, T., , Barry, L.A. and Bowman, D.M. (2020), Carbon isotope analysis shows introduced bovines have broader dietary range than the largest native herbivores in an Australian tropical savanna. Austral Ecology, 45: 109-121. doi:10.1111/aec.12834
Reid, A.M. (2019), Grass, fire, kangaroos and cattle: The nexus between fire and herbivory in northern Australia. PhD thesis, University of Tasmania, Hobart, TAS, Australia.
Yibarbuk, D., Whitehead, P.J., Russell-Smith, J., Jackson, D., Godjuwa, C., Fisher, A., Cooke, P., Choquenot, D. & Bowman, D.M.J.S. (2001), Fire ecology and Aboriginal land management in central Arnhem Land, northern Australia: a tradition of ecosystem management. Journal of Biogeography, 28, 325–343.