The effects of experimental patch burning and rainfall on small mammals in the Simpson Desert, Queensland

Abstract

Patch-burning is frequently advocated as a management tool to enhance the biodiversity and pasture values of spinifex (Triodia) grasslands. In the northern Simpson Desert, Queensland, pastoralists use fire to reduce the likelihood of broad-scale wildfires and improve pastures for cattle. I conducted a before–after–control–impact experiment to investigate the response of small mammals to the short-term (<1 year) effects of patch-burning between August 1999 and June 2001. The experiment was replicated at three locations subject to differing rainfalls, with two 1-ha study grids remaining unburnt as controls, and two being burnt at each location. The areas burnt ranged from 1 to 3 ha. Dasycercus cristicauda and Pseudomys desertor responded negatively to the fire treatment. Notomys alexis responded positively to the fire treatment in the final trapping session but only at one location. Factors indicative of temporal and spatial variation in rainfall, time and site had a greater effect on the abundance of small mammals than the fire treatment. Heavy rainfalls in 2000 increased seed production and prompted increases in the populations of rodent species and Dasycercus cristicauda. The greatest numbers of captures were made at the sites that received the highest rainfalls. Patch-burning regimes are likely to increase the resilience of 'fire-sensitive' species dependent on dense spinifex by reducing the extent of wildfires.