Table 4.

Parameters of semi-variograms predicted by RF models.

Indices	Variables	Model	C0(Nugget)	C0+C (Sill)	C0/(C0+C) (%)	Range (m)	R2	RSS
Shannon–Wiener	Original	Exp	0.43×10-2	0.08	5.38***	0.72	0.42	2.24×10-4
	RF-pre	Exp	0.28×10-2	0.03	9.33***	0.82	0.46	3.86×10-5
Simpson	Original	Exp	0.14×10-2	0.03	4.70***	0.77	0.37	4.20×10-5
	RF-pre	Exp	0.60×10-3	0.01	6.00***	0.90	0.42	7.23×10-6
Pielou	Original	Exp	0.25×10-2	0.06	4.17***	0.77	0.27	2.44×10-4
	RF-pre	Exp	0.13×10-2	0.02	6.50***	0.95	0.34	3.99×10-5

Exp is the exponential model. C₀/(C₀+C)< 25% (***) suggest a strong spatial dependence.