1) The specific beach physical environment was highly similar between the two periods (1999–2000 and 2010–2011) for both Cabedelo and Quiaiosbeaches (Table 1).
The topographic transverse profiles drawn in 2010 and 2011 for both beaches revealed a stable shoreline slope with no clear differences between the years (Fig. 1c and d).
In addition, the physical measurements (mean width and extension of the intertidal area ) were highly similar between the periods at both beaches (p > 0.05), being Quiaios wider than Cabedelo (Table 1).
Furthermore, paired t-tests applied to the overall physical variables on both beaches did not detect any significant temporal variations (Table 1).
According to the the Quiaios beach had coarser sediments (mean grain size of 761.78 _m in 1999–2000 and 829.12 _m in 2010–2011), while the Cabedelo beach had medium sands (291.15 _m in 1999–2000 and 319.56 _m in 2010–2011) in both periods (Table 1).
Since the physical environment of those beaches did not change significantly between the first sampled period (1999–2000) and ten years after (2010–2011),special attention was given to the increased human pressures recorded between these periods, namely those related with tourism.
The precise human beach use effecton the beach on both periods was not possible to assess (there is no available data on the number of tourists on the beach itself), in this sense we analysed the number of tourists staying in the central region of Portugal during the period of 1999 to 2011 (Fig. 2).
During this 10-years interval there was a clear increase in the number of tourists in the central region of Portugal (Fig. 2a), with a higher number being recorded in the urban zone (Cabedelo) when compared with the rural area of Quiaios (Fig. 2c).
A seasonal pattern was also recorded in both periods, with higher number of tourists being recorded during the spring–summer months (from May to September, Fig. 2c).