In this study, I assessed the effect of two driving
forces (environmental heterogeneity and human
management) on regional-scale land-cover diversity
in an area of ecological transition from mountains
to lowlands. I used the area of Navarra to exemplify
and test our model, and found that environmental
heterogeneity explains 65 per cent of the total variance of land-cover diversity (for the model with
24 land classes). The relationship between the
residuals obtained from the environmental model
and productive specialization (40% of accounted
variance) indicates that although environmental
factors exert a greater control over land-cover
diversity (Del Barrio
et al.
1997), human influence
alters land-cover diversity to an important degree.
The combined model explains 80.75 per cent of
observed variance in land-cover diversity by adding
the variance explained by human factors to the
variance explained by physical ones (the sum of
65% explained by physical variables and 40% of
the unexplained variance of the natural model
explained by productive specialization). Consequently,
these quantitative results corroborate the character
of the landscape, as with the synthesis of human
and bio-geo-physical systems.