Effects of socioeconomic and human-modified landscape variables on medicinal species richness at a macroscale: the case of the Caatinga, Brazil

Table 1 Generalized additive model (GAM): number of medicinal woody species as a function of the human development index (HDI) and human-modified landscapes (forest loss), including the interaction between these variables

	Estimate	Std. error	t value	p-value
socioeconomic—HDI	− 14.62	57.76	0.253	0.803
	*edf*	*Ref. df*	*F statistic*	*p-value*
s(HDI)	1.35	14	0.430	0.038
ti(HDI, forest loss)	1.37	16	1.709	0.027
Intercept coefficient = 25.56 ± 39.09	Adjusted r² = 0.30; Deviance explained = 39.1%

The parameters ‘s’ and ‘ti’ represent different smoothing functions used in GAM. The ‘s’ parameter defines individual smoothing terms in the model formula, while the ‘ti’ parameter is used to model interactions between variables through tensor products of smoothing functions

ISSN: 1746-4269