Table 2. Results of the GAM analysis of the Derwent and Tamar Estuaries final full model.

Parametric Coefficients	Estimate	Std. Error	z value	p value
Intercept	1.859E + 00	6.578E-01	2.827	0.0047
distance	−2.093E + 00	5.432E-01	−3.854	0.0001
estuary side	−1.257E + 00	3.124E-01	−4.024	5.73E-05
onshore wind 1500 hrs	1.745E + 00	6.760E-03	2.582	0.0098
estuary basin	−1.214E + 00	2.903E-01	−4.18	2.92E-05
no. drain outlets in 5 km	3.199E-03	1.401E-03	2.283	0.0224
distance to nearest drain	1.302E-05	2.479E-05	0.525	0.5994
distance to public road	2.202E-05	1.461E-04	0.151	0.8802
population in 25 km	−1.243E-07	2.972E-07	−0.418	0.6758
rock slab	−1.131E + 00	2.991E-01	−3.781	0.0002
sand	−7.706E-02	2.523E-01	−0.305	0.7600
marsh	−1.269E + 00	3.050E-01	−4.16	3.19E-05
pebble/gravel	1.297E + 00	2.985E-01	4.345	1.39E-05
gradient	−3.268E-01	1.657E-01	−1.973	0.0485
straight	2.357E-01	2.439E-01	0.966	0.3339
convex	2.036E-01	3.495E-01	0.583	0.5601
distance * estuary side	2.683E + 00	5.703E-01	4.705	2.54E-06