. 2020 Feb 27;15(2):e0229689. doi: 10.1371/journal.pone.0229689

Table 2. Influence of climate variables and latitude on freshwater turtle life-history traits.

Generalized Additive Models were used to predict responses of four freshwater turtle life-history traits: clutch size, clutch frequency, age at sexual maturity and adult survival.

Model		ln clutch size (n = 165)			ln clutch frequency (n = 102)			ln age at sexual maturity (n = 75)			arcsine adult survival (n = 37)
Continuous latitude		Est. ^a	SE	p	Est. ^a	SE	p	Est. ^a	SE	p	Est. ^a	SE	p
Intercept		0.78	0.05	*******	0.12	0.05	*	0.75	0.02	*******	0.12	0.03	***
Log carapace length		0.29	0.02	*******	0.01	0.03		0.09	0.02	*******	0.01	0.03
Latitude		0.13	0.00	*******	-0.09	0.04	*	0.06	0.02	**	0.04	0.03
Smooth		Edf/ref	F	p	Edf/ref	F	p	Edf/ref	F	p	Edf/ref	F	p
Family		8.1/11	6.48	***	5.0 / 11	1.2	*	0.0 / 10	0.0		0.0 / 7	0.0
R² ajust / Dev. Exp ^b		0.78 / 77.6%			0.12 / 17.9%			0.19 / 20.2			0.01 / 6.7
Categorical latitude		Est. ^a	SE	p	Est. ^a	SE	p	Est. ^a	SE	p	Est. ^a	SE	p
Intercept		0.85	0.06	***	0.12	0.06	.	0.76	0.05	***	0.10	0.06
Log carapace length		0.29	0.02	***	0.01	0.03		0.06	0.03	*	-0.01	0.04
Latitude	temp-trop	0.04	0.05		-0.06	0.08		0.02	0.05		0.08	0.06
	trop-temp	-0.13	0.05	*	0.06	0.09		-0.11	0.07		0.07	0.09
	tropical	-0.21	0.05	***	0.04	0.09		-0.02	0.08		-0.05	0.12
Smooth		Edf/ref	F	p	Edf/ref	F	p	Edf/ref	F	p	Edf/ref	F	p
Family		7.9/11	6.27	***	2.7 / 11	0.4		4.7 / 10	0.9	.	2.5 / 7	0.6
R² ajust / Dev. Exp ^b		0.76 / 75.8%			0.03 / 9.3%			0.24 / 32.2%			0.07 / 23.8%
Bioclimate - temp		Est. ^a	SE	p	Est. ^a	SE	p	Est. ^a	SE	p	Est. ^a	SE	p
Intercept		0.76	0.05	***	0.12	0.04	**	0.72	0.04	***	0.11	0.03	**
Log carapace length		0.27	0.02	***	0.01	0.03		0.07	0.03	**	0.02	0.03
Temp. warm quarter (bio10)		-0.01	0.02		0.03	0.03		-0.06	0.02	**	-0.08	0.03	*
Smooth		Edf/ref	F	p	Edf/ref	F	p	Edf/ref	F	p	Edf/ref	F	p
Family		7.0 / 11	4.39	***	3.4 / 11	0.6	.	5.4 / 10	1.2	*	0.0 / 7	0.0
R² ajust / Dev. Exp ^b		0.72 / 69.8%			0.05 / 9.9%			0.31 / 37.7%			0.12 / 16.7%
Bioclimate - rain		Est. ^a	SE	p	Est. ^a	SE	p	Est. ^a	SE	p	Est. ^a	SE	p
Intercept		0.76	0.05	***	0.12	0.04	**	0.73	0.05	***	0.15	0.03	***
Log carapace length		0.27	0.02	***	0.01	0.03		0.06	0.03	*	-0.01	0.03
Rain dry quarter (bio17)		-0.03	0.02	.	0.02	0.03		0.00	0.02		0.02	0.04
Smooth		Edf/ref	F	p	Edf/ref	F	p	Edf/ref	F	p	Edf/ref	F	p
Family		7.4/11	5.71	***	2.5 / 11	0.3		5.7 / 10	1.5	*	0.0 / 7	0.0
R² ajust / Dev. Exp ^b		0.72 / 70.5%			0.02 / 7.0%			0.24 / 31.6%			-0.04 / 1.4%

Each model contained Family as a random effect (smooth GAM term specified with “re” basis) and body size (ln transformed carapace length) as a parametric term; Asterisks indicate significant level of estimated parameters (*** P < 0.001; ** P < 0.01; * P < 0.05; ‘.’ P < 0.1).

^a Standardized regression coefficient (obtained by dividing the centered response values by their standard deviations) and associated standard error (SE).

^b Model adjusted r-squared and deviance explained (%)