Fig. 2.

Temporal trends in relative abundances (6-month averages) of the four most common rodent species on the control plots. Trends since the beginning of the study (1978–2005) are shown in A, C, E, and G, and trends only since the arrival of C. baileyi in September 1995 are shown in B, D, F, and H. The solid trend lines represent the ordinary least squares regression lines (see Table 1 for relevant statistics) and are extrapolated by using dashed lines. The relative abundances of the two species of pocket mice (Chaetodipus spp.) are significantly higher than expected after the flood and have remained so through the present, whereas those of the historically most abundant species, Merriam's kangaroo rat (D. merriami), and its congener, D. ordii, are significantly lower than expected.