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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 variableDependent variableModel estimateStandard errorZ-valueLower CIUpper CIStandardized estimateP-value
Mean annual precipitationdNBR 20035.91.25.13.58.20.46<0.0001
Mean annual precipitationdNBR 20084.81.43.527.50.370.001
Mean annual precipitationTime between fires 20040.60.14.70.30.80.32<0.0001
Mean annual precipitationTime between fires 20150.50.14.30.30.80.27<0.0001
Mean annual precipitationNumber of fires 2004−0.030.01−4.20−0.01−0.37<0.0001
Mean annual precipitationNumber of fires 2015−0.030.01−3.90−0.01−0.33<0.0001
Mean annual precipitationIntroduced cover 2015−0.70.2−3.9−1−0.3−0.33<0.0001
Rock 2015Introduced cover 2015−0.60.2−3.4−0.9−0.2−0.230.001
Rock 2015Shrub cover 2015−0.20.2−1.3−0.60.1−0.130.2
dNBR 2003dNBR 2008−0.70.2−4.6−0.9−0.3−0.68<0.0001
dNBR 2003Introduced cover 2004−0.10.02−2.9−0.1−0.02−0.620.004
dNBR 2003Shrub cover 20040.010.011.3−0.010.020.130.2
dNBR 2008Introduced cover 20150.10.014.80.040.10.44<0.0001
dNBR 2008Shrub cover 2015−0.010.02−0.500.03−0.070.6
Time between fires 2004Introduced cover 20040.010.10.1−0.10.10.010.9
Time between fires 2015Shrub cover 20150.30.12.100.50.390.04
Number of fires 2004Introduced cover 2004−3.92.7−1.5−9.11.1−0.230.1
Number of fires 2004Shrub cover 20043.91.33.11.56.70.310.002
Number of fires 2015Shrub cover 20156.32.62.4111.40.350.02
Introduced cover 2004Introduced cover 20150.30.21.7−0.010.70.190.09
Shrub cover 2004Shrub cover 20150.40.21.9−0.10.80.240.05
Shrub cover 2004Introduced cover 2004−0.20.1−2.2−0.4−0.01−0.150.03
Shrub cover 2015Introduced cover 2015−0.50.1−4.3−0.7−0.2−0.33<0.0001