5. Conclusions
Our study improves the knowledge of the regional spatial and
inter-annual response of the EVI (our proxy for ANPP) to climate
and how vegetation and lithology modulate this response in
Mediterranean drylands. In this study, we take advantage of linear
mixed-effects models (LMM), long time-series of EVI and climate
data, and high-resolution vegetation and lithology maps, to evaluate
the ANPP response to environmental controls at the regional
scale. Along the spatial gradient, precipitation increased the EVI
mean even compensating for the greater evapotranspiration of
warmer sites, though with differences among substrates. The
inverse relationship between the increases in MAP and in annual
EVI_mean suggested the necessity of looking at the seasonal timing
of the climatic and EVI trends in Mediterranean drylands. An
important outcome was the effect of early-autumn climate on the
EVI of the following growing season. The earlier arrival of rain after
the summer drought and the cooler temperatures during early autumn
caused very strong increases in the EVI at the beginning
of the growing season that may also favor the rest of the growing season.