Table 1. Best-fit generalized linear model representing variation in RIFA counts.
We present results from the best-fit generalized linear model that examined the effect of RIFA suppression/treatment (i.e., prairies that were treated with insecticide and left untreated) and time on RIFA count data collected from April–July 2015 at our study site in the Attwater Prairie Chicken National Wildlife Refuge (APCNWR). This top-ranked model specified a Type 2 Negative Binomial error distribution with with intercepts randomly varying among prairies. A significantly higher rate of decrease or increased suppression of RIFA in treated areas over time was observed.
| Variable | Estimate | SE | Z | P value |
|---|---|---|---|---|
| Intercept | 2.319 | 0.332 | 6.99 | <0.001 |
| Treatment | −1.159 | 0.556 | −2.08 | 0.037 |
| Week | −0.091 | 0.040 | −2.28 | 0.023 |
| TreatmentTRT:Week | −0.257 | 0.088 | −2.93 | 0.003a |
Notes.
a
Estimate = slope parameter or β; SE, standard error of the estimate; Z, Wald Z-test statistic; P, probability value.