6 Developing the desert potential effects on wildlife 69 Brush-tailed mulgara (Fig. 6.3) populations also fluctuated with rainfall, although peaks in the capture rate were usually 9–12 months after heavy summer rain (Fig. 6.4d). Unlike the rodents, this carnivorous marsupial has a fixed breeding time in winter and produces only a single litter. Its delayed response to summer rainfall arises from breeding adults taking advantage of the flush of rodent prey in winter, which improves survival of adults and their young, increasing the population in the following spring (Dickman et al. 2001). As dry periods increase, populations of all species fall to low levels (Fig. 6.4), with many retreating to refuges in the landscape where food, shelter and other resources are more consistently and reliably available (Dickman et al. 2011 Greenville et al. 2013). After 1995, we extended our study to eight other sites in the sand dune environment, using the same methods of trapping, and found very similar changes in populations (Greenville et al. 2016). Other, short-term studies from sites in the nearby region describe very similar patterns (Letnic et al. 2011 D’Souza et al. 2013 Wardle et al. 2013). 0 10 20 30 40 50 60 19 90 19 91 19 92 19 93 19 94 19 95 19 96 19 97 19 98 19 99 20 00 20 01 20 02 20 03 20 04 20 05 20 06 20 07 20 08 20 09 20 10 20 11 Captures (100 trap nights ) (c) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 19 90 19 91 19 92 19 93 19 94 19 95 19 96 19 97 19 98 19 99 20 00 20 01 20 02 20 03 20 04 20 05 20 06 20 07 20 08 20 09 20 10 20 11 Captures (100 trap nights ) (d) Fig. 6.4. (cont.) (c) sandy inland mouse (Pseudomys hermannsburgensis), and (d) brush-tailed mulgara (Dasycercus blythi). (Redrawn from Dickman et al. 2014).
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