Lake Eyre Basin Rivers 68 drought, but irrupted within a few months of each of the major rainfall events (Fig. 6.4b). Sandy inland mouse populations were similar but were always detectable, even in dry periods (Fig. 6.4c). This species also showed a small response to moderate rainfall in the summer of 1997, contrasting with the lack of effect on spinifex hopping-mouse populations at that time. These two rodent species had different-sized responses to summer rainfalls, although the highest capture rates were in the most recent irruptions (Fig. 6.4b and c). These population booms were triggered by increases in primary productivity due to rainfall, providing food for breeding (Dickman et al. 1999 Breed and Leigh 2011). 0 50 100 150 200 250 300 350 (a) 0 10 20 30 40 50 60 (b) Fig. 6.4. (a) Monthly rainfall (mm) at Ethabuka Reserve, Simpson Desert, western Queensland from 1990 to 2012 (mean annual rainfall for this site is less than 200 mm), and mean capture rates (± s.e.) expressed as captures/100 trap-nights for (b) spinifex hopping-mouse (Notomys alexis). 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Mo nthlrainfall( y ) 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Captures (100 trap nights)