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Table 1 Results of the logistic regressions of cactus mortality, with burn, canopy type, and growth strategy as explanatory variables on data collected in 2014-2015 at El Faro, Puerto Rico. The analysis was conducted with and without Leptocereus quadricostatus and Harrisia portoricensis data. Odds ratio is the probability of being killed by the fire versus surviving the fire (e.g., burned cacti were more than 62 times as likely to die as unburned cacti); Z-value is the regression coefficient divided by its standard error; P-value represents the probability of a Type I error

From: Effects of fire on native columnar and globular cacti of Puerto Rico: a case study of El Faro, Cabo Rojo

Parameter Odds ratio (±SE) Z-value P-value
Intercept 0.016 (2.75) −4.086 <0.001
Burned 61.868 (2.83) 3.833 <0.001
Open Canopy (Grasses and shrubs) 6.495 (4.01) 1.342 0.180
Globular Cactus 1.428 (3.46) 0.287 0.774
Burned x Open Canopy 0.623 (4.26) −0.328 0.743
Burned x Globular Cactus 0.809 (3.67) −0.162 0.870
Without Leptocereus quadricostatus and Harrisia portoricencis
Intercept 0.012 (3.03) −3.963 <0.001
Burned 69.200 (3.09) 3.743 <0.001
Open Canopy (Grasses and shrubs) 2.924 (5.31) 0.642 0.521
Globular Cactus 13.131 (5.37) 1.533 0.125
Burned x Open Canopy 1.632 (5.37) 0.292 0.770
Burned x Globular Cactus 0.259 (5.21) −0.819 0.413