Table 2. Extrinsic influences on per survey detection and abundance of black-necked gartersnakes (Thamnophis cyrtopsis) in Sabino Canyon Recreation Area, Tucson, Arizona, 2018–2021.
Selection of generalized linear models was performed using corrected Akaike Information Criterion (∆AICc <2). Table is split by (A) logistic regression for survey presence, i.e., detection; and (B) Poisson regression for abundance per survey. Model represents the model covariates; k is the number of model parameters; AICc is corrected AIC score; ∆AICc is the change in AICc scores; loglik is the model maximum log likelihood; and R2 is McFadden’s pseudo r-squared value.
| Model | k | AICc | ∆AICc | loglik | R2 | |
|---|---|---|---|---|---|---|
| A) Presence | ~ TA + dur + year | 4 | 37.73 | 0.00 | −14.32 | 0.51 |
| ~ TA + flow + dur + season + year | 7 | 40.61 | 2.88 | −11.66 | 0.60 | |
| ~ TA + dur + season + year | 6 | 41.50 | 3.77 | −13.15 | 0.53 | |
| ~ RH + TA + flow + dur + season + year | 8 | 43.29 | 5.57 | −11.47 | 0.60 | |
| ~ RH + TA + w + flow + dur + season + year | 9 | 45.22 | 7.49 | −10.80 | 0.63 | |
| ~ dur + year | 3 | 45.34 | 7.61 | −19.41 | 0.44 | |
| ~ RH + BP + TA + W + flow + dur + season + year | 10 | 48.54 | 10.81 | −10.72 | 0.63 | |
| ~ 1 | 1 | 71.08 | 33.35 | −34.50 | — | |
| B) Abundance | ~ TA + dur + season + year | 6 | 118.64 | 0.00 | −52.12 | 0.48 |
| ~ BP + TA + flow + dur + season + year | 8 | 118.90 | 0.25 | −49.27 | 0.51 | |
| ~ BP + TA + dur + season + year | 7 | 119.64 | 1.00 | −51.17 | 0.49 | |
| ~ RH + BP +TA + flow + dur + season + year | 9 | 122.16 | 3.51 | −49.27 | 0.51 | |
| ~ TA + dur + year | 4 | 122.73 | 4.08 | −56.82 | 0.43 | |
| ~ RH + BP + TA + W + flow + dur + season + year | 10 | 125.61 | 6.97 | 49.26 | 0.51 | |
| ~ dur + year | 3 | 177.98 | 59.34 | −85.73 | 0.32 | |
| ~ 1 | 1 | 252.83 | 134.18 | −125.37 | — |
Note:
Model parameter abbreviations: BP, ambient barometric pressure (millibars); dur, survey duration (minutes); RH, ambient relative humidity (%); flow, maximum stream flow (m3/s); TA, ambient temperature (°C); season, seasonality (pre-monsoon, monsoon, post-monsoon); W, ambient wind speed (m/s). Covariates are described in Dataset S1.