Mapping the suitability of groundwater dependent 1 vegetation in a semi-arid Mediterranean area 2 3

Mapping the suitability of groundwater dependent vegetation in semi-arid Mediterranean areas is 15 fundamental for the sustainable management of groundwater resources and groundwater dependent 16 ecosystems (GDE) under the risks of climate change scenarios. For the present study the distribution of 17 deep-rooted woody species in southern Portugal was modeled using climatic, hydrological and 18 topographic environmental variables; and the density of Quercus suber, Quercus ilex and Pinus pinea 19 were used as proxy species of Groundwater Dependent Vegetation (GDV). Model fitting was performed 20 between the proxy species Kernel density and the selected environmental predictors using 1) a simple 21 linear model and 2) a Geographically Weighted Regression (GWR), to account for auto-correlation of the 22 spatial data and residuals. When comparing the results of both models, the GWR modelling results 23 showed improved goodness of fitting, as opposed to the simple linear model. Climatic indices were the 24 main drivers of GDV density closely followed by groundwater depth, drainage density and slope. 25 Groundwater depth did not appear to be as pertinent in the model as initially expected, accounting only 26 for about 7% of the total variation against 88% for climate drivers 27