Do Plant Invasions Change the Effects of Fire on Animals?

Fire Ecology

Table 1 Factors assessing differences in abundance^a of small mammals between burned and control plots (n = 9 plot-pairs) in southeastern Arizona, 2000–2004. The term “invasion” represents the biomass of nonnative grass on plots and “time-since-fire” represents the number of sampling periods (1–9) after fire.

	Dipodomys merriami		Onychomys leucogaster		Sigmodon arizonae
Factors	F^a	P	F	P	F	P
Fire × Invasion	0.03	0.87	5.86	0.052	13.16	0.011
Fire × Time-since-fire	1.70	0.20	0.51	0.48	0.75	0.39
Fire × Invasion × Time-since-fire	1.14	0.29	1.49	0.23	3.32	0.073
Pre-treatment abundance^b	0.56	0.48	6.73	0.041	3.25	0.12

^a F-statistics have 70 denominator degrees of freedom for tests that include time-since-fire and 6 degrees of freedom for all other tests.
^b Included as a covariate to account for inherent differences in abundance among plots.