Table 3. Results of the Generalized Additive Model (GAMM) analysing the changes in population sizes of five Anatidae species from 2001 to 2012 in 25 wetlands with different protection statuses in the Yangtze floodplain.

	Species	Smooth terms					Explanatory variable
		UBRE	Deviance explained (%)	edf	χ2	p	site
National nature reserve (n = 6)	BG	6735	22.2	8.976	20598	<0.001	<0.001
	GWFG	7570	43.7	8.992	121895	<0.001	<0.001
	LWFG	4488	17.5	8.964	22898	<0.001	<0.001
	SG	9486	51.5	8.978	174450	<0.001	<0.001
	TS	3849	54.2	8.980	115464	<0.001	<0.001
Provincial nature reserve (n = 11)	BG	6655	13.8	8.922	50873	<0.001	<0.001
	GWFG	354	45.5	8.987	11794	<0.001	<0.001
	LWFG	39	46.1	8.888	805	<0.001	<0.001
	SG	3352	11.5	8.959	33164	<0.001	<0.001
	TS	4388	10.7	8.971	20799	<0.001	<0.001
County nature reserve (n = 8)	BG	286	22.9	8.932	4616	<0.001	<0.001
	GWFG	339	24.9	8.988	5505	<0.001	<0.001
	LWFG	22	58.3	6.746	253	<0.001	<0.001
	SG	957	24.3	8.983	13950	<0.001	<0.001
	TS	2725	11.1	8.979	13923	<0.001	<0.001

BG: bean goose; GWFG: greater white-fronted goose; LWFG: lesser white -fronted goose; SG: swan goose; TS: tundra swan. UBRE: Un-Biased Risk Estimator; edf: effective degrees of freedom.