Got shrubs? Precipitation mediates long-term shrub and introduced grass dynamics in chaparral communities after fire

Smith, April G.; Newingham, Beth A.; Hudak, Andrew T.; Bright, Benjamin C.

doi:10.1186/s42408-019-0031-2

Fire Ecology

Table 2 Results from structural equation model of variables affecting chaparral ecosystem recovery one and twelve years after the southern California, USA, Old and Simi fires of 2003. Direct relationships with P < 0.05 in bold and italics; P < 0.10 in italics; dNBR = differenced Normalized Burn Ratio

From: Got shrubs? Precipitation mediates long-term shrub and introduced grass dynamics in chaparral communities after fire

Independent variable	Dependent variable	Model estimate	Standard error	Z-value	Lower CI	Upper CI	Standardized estimate	P-value
*Mean annual precipitation*	*dNBR 2003*	*5.9*	*1.2*	*5.1*	*3.5*	*8.2*	*0.46*	*<0.0001*
*Mean annual precipitation*	*dNBR 2008*	*4.8*	*1.4*	*3.5*	2	*7.5*	*0.37*	*0.001*
*Mean annual precipitation*	*Time between fires 2004*	*0.6*	*0.1*	*4.7*	*0.3*	*0.8*	*0.32*	*<0.0001*
*Mean annual precipitation*	*Time between fires 2015*	*0.5*	*0.1*	*4.3*	*0.3*	*0.8*	*0.27*	*<0.0001*
*Mean annual precipitation*	*Number of fires 2004*	*−0.03*	*0.01*	*−4.2*	0	*−0.01*	*−0.37*	*<0.0001*
*Mean annual precipitation*	*Number of fires 2015*	*−0.03*	*0.01*	*−3.9*	0	*−0.01*	*−0.33*	*<0.0001*
*Mean annual precipitation*	*Introduced cover 2015*	*−0.7*	*0.2*	*−3.9*	−1	*−0.3*	*−0.33*	*<0.0001*
*Rock 2015*	*Introduced cover 2015*	*−0.6*	*0.2*	*−3.4*	*−0.9*	*−0.2*	*−0.23*	*0.001*
Rock 2015	Shrub cover 2015	−0.2	0.2	−1.3	−0.6	0.1	−0.13	0.2
*dNBR 2003*	*dNBR 2008*	*−0.7*	*0.2*	*−4.6*	*−0.9*	*−0.3*	*−0.68*	*<0.0001*
*dNBR 2003*	*Introduced cover 2004*	*−0.1*	*0.02*	*−2.9*	*−0.1*	*−0.02*	*−0.62*	*0.004*
dNBR 2003	Shrub cover 2004	0.01	0.01	1.3	−0.01	0.02	0.13	0.2
*dNBR 2008*	*Introduced cover 2015*	*0.1*	*0.01*	*4.8*	*0.04*	*0.1*	*0.44*	*<0.0001*
dNBR 2008	Shrub cover 2015	−0.01	0.02	−0.5	0	0.03	−0.07	0.6
Time between fires 2004	Introduced cover 2004	0.01	0.1	0.1	−0.1	0.1	0.01	0.9
*Time between fires 2015*	*Shrub cover 2015*	*0.3*	*0.1*	*2.1*	0	*0.5*	*0.39*	*0.04*
Number of fires 2004	Introduced cover 2004	−3.9	2.7	−1.5	−9.1	1.1	−0.23	0.1
*Number of fires 2004*	*Shrub cover 2004*	*3.9*	*1.3*	*3.1*	*1.5*	*6.7*	*0.31*	*0.002*
*Number of fires* 2015	*Shrub cover 2015*	*6.3*	*2.6*	*2.4*	1	*11.4*	*0.35*	*0.02*
Introduced cover 2004	Introduced cover 2015	0.3	0.2	1.7	−0.01	0.7	0.19	0.09
Shrub cover 2004	Shrub cover 2015	0.4	0.2	1.9	−0.1	0.8	0.24	0.05
*Shrub cover 2004*	*Introduced cover 2004*	*−0.2*	*0.1*	*−2.2*	*−0.4*	*−0.01*	*−0.15*	*0.03*
*Shrub cover 2015*	*Introduced cover 2015*	*−0.5*	*0.1*	*−4.3*	*−0.7*	*−0.2*	*−0.33*	*<0.0001*

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