Controlling feral ruminants to reduce greenhouse gas emissions: a case study of buffalo in northern Australia

Abstract

ABSTRACT Context. The bourgeoning carbon economy is creating novel ways to incentivise conservation management activities that have the co-benefits of reducing greenhouse gas (GHG) emissions and social inequality. Aims. To estimate the monetary value of carbon credits that landowners could generate by reducing ecologically destructive feral populations of the Asian water buffalo (Bubalus bubalis) in northern Australia. Methods. First, we estimated buffalo enteric emissions based on the population structure of feral buffalo in northern Australia, and discounted the reduction of fire emissions due to the consumption of grassy fuel by feral buffalo. We then predicted the change in buffalo population size across the South Alligator River region of Kakadu National Park under four buffalo management scenarios: (1) no buffalo control; (2) low-intensity buffalo control; (3) moderate-intensity buffalo control; and (4) high-intensity buffalo control. We quantified the reduction of GHG emissions under the three buffalo control scenarios, relative to the scenario of no buffalo control, while discounting the GHG emissions that directly result from buffalo control actions (e.g. helicopter emissions). Key results. All three buffalo control scenarios substantially reduced the estimated GHG emissions that would otherwise have been produced. The low-intensity buffalo control scenario was predicted to abate 790 513 t CO2-e over the 20-year simulation, worth USD15 076 085 (or USD753 804 year−1). Our high-intensity buffalo control scenario had the greatest reduction in GHG emissions, with a total net abatement of 913 231 t CO2-e, worth USD17 176 437 (or USD858 822 year−1). Conclusions. The potential value of carbon credits generated by controlling feral buffalo populations in northern Australian savannas far exceeds the management costs. Implications. The management of feral ruminants could be incentivised by the generation of carbon credits. Such management could simultaneously avoid GHG emissions, generate income for landowners and offer significant ecological benefits.