Regional-scale relationship among biological soil crusts, invasive annual grasses, and disturbance

Ecological Processes

Table 1 GAM model results for the test of Hypothesis A

Model predictor variables	Significance of variable ( p)	Deviance explained by model
Biocrust cover	0.0001	3.03%
Longitude	0.004	1.77%
Latitude	<0.00001	5.55%
Elevation	<0.00001	5.50%
Heat index	0.09	0.50%
Mean annual precipitation	<0.00001	3.05%
Mean maximum temperature in July	<0.002	1.77%
Mean minimum temperature in January	0.00004	3.29%
Mean temperature of dew point in 2010	0.005	1.98%
Cattle disturbance ranks	0.01	1.52%
Salt cover	0.0002	1.69%
Rock cover	0.002	1.75%
Bare soil	<0.00001	26.3%
Biocrust cover	0.009	47.3%
Latitude	0.001
Elevation	<0.00001
Mean annual precipitation	<0.00001
Mean minimum temperature in January	0.002
Mean temperature of dew point in 2010	0.0005
Cattle disturbance ranks	0.001
Rock cover	0.00001
Bare soil	<0.00001