Spatially Differentiated Construction Pressure on Small Mediterranean Islands: Tourism, Off-Plan Development, and a Geographically Weighted Regression Approach for Serifos, Greece

This study quantitatively evaluates the relationships among selected factors and describes the spatial distribution of construction activity and tourism development on small-scale Mediterranean islands, using Serifos as a case study. It demonstrates how Geographically Weighted Regression can serve as a planning support tool for an in-depth analysis of the island, contributing to the debate on whether the current planning approach should change. A Building Pressure Index, defined as the ratio of built to unbuilt footprint within each grid cell, was calculated for 1360 grid cells. Short-term rental activity, accessibility, terrain, and statutory environmental protection were then used as explanatory variables in a Geographically Weighted Regression model to examine how their association with construction pressure varies across the island. Compared with a global Ordinary Least Squares model, the Geographically Weighted Regression model indicates that construction pressure is highest in the southeast, in coastal areas and often outside settlement limits. Short-term rental density and accessibility are the two most significant factors associated with construction pressure, whereas steep slopes, high altitudes, and location within a protected area all reduce it. Based on these results, the island can be divided into five zones, each requiring a different level of spatial-policy intervention.