Table 3. Simpson’s index of diversity: effects of log₁₀ total dose and confounding variables.

Random effects:
Groups	Variance	SD
Site	0.002	0.042
Census Day	0.001	0.028
Transect	0.004	0.063
Residual	0.026	0.160
Fixed effects:
	Estimate	SE	df	t	p
(Intercept)	0.687	0.035	3.40	19.846	<0.001
Total Dose Log	0.053	0.023	55.30	2.302	0.025
	(0.045)b	(0.020)b
Time	−0.084	0.015	145.90	−5.643	<0.0001
Time2	0.008	0.023	974.40	0.323	0.747
Cloud cover	0.006	0.015	123.20	0.389	0.698
Temp	−0.001	0.019	18.20	−0.033	0.974
Wind1a	0.009	0.026	48.10	0.335	0.739
Wind2	0.007	0.023	26.80	0.306	0.762
Wind3	−0.150	0.031	309.90	−4.806	<0.0001
Wind4	−0.125	0.043	20.90	−2.901	0.009
Wind5	−0.026	0.037	19.20	−0.682	0.503
Altitude	−0.040	0.014	318.90	−2.888	0.004
Grass	0.005	0.011	292.60	0.456	0.649
Farmland	0.089	0.014	299.20	6.594	<0.0001
Coniferous	0.010	0.011	282.60	0.928	0.354

Effect size was standardised by two SD. Parameters with a significant effect (p < 0.05) are highlighted in bold.

^aWind 0 was the reference category.

^bUnstandardised partial slope values obtained after model fit with the same fixed and random effects, but without standardization of the input variables.