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Natura 2000 is the largest network of habitat and biodiversity protection areas. However, it remains unclear how strongly or to what extent the human activities impact the areas or what kind of activities are conducted within. Our objective is to analyze the human impact in all Natura 2000 sites, based on satellite data. We have developed an algorithm in Google Earth Engine using JavaScript, for satellite data temporal analysis of protected areas, the analysis using two datasets. First, we used Landsat archive to derive the biophysical composition index (BCI), allowing to evaluate both impervious surface (positive and relatively high values) and vegetation (negative and low values) abundance. BCI was derived for each year from Landsat scenes acquired in August, from 2000 to 2019. Mean BCI value in each site was plotted to calculate the slope of linear trend line, highlighting both the magnitude and sign of human activities changes per year. Secondly, we calculated the mean value within each site from the Human Modification dataset (gHM) that provides a cumulative measure of human modification of terrestrial lands globally at 1 km2 resolution, in 2016. The results showed an average increase in BCI values of 0.011 per year for the 24262 sites, suggesting a slight increase of impervious surfaces and thus human activities. Only Malta, Belgium, Hungary and Cyprus out of 28 countries recorded a decrease of human activities within sites in the last 20 years. Nine countries recorded a very slight increase (<0.01 per year) and 13 countries recorded increase in BCI value between 0.01 and 0.02 per year. Czech Republic and Estonia registered the highest increase in human activities within sites, with an average of 0.022 and 0.039 per year respectively. The gHM dataset analysis showed an average value of 0.42 for all Natura 2000 sites, suggesting a moderate to high modified land in 2016. The lowest values were recorded in Finland (0.24), Latvia (0.25) and Estonia (0.26), being among the nine countries that recorded moderate modified land within sites (0.1-0.4). The rest of the 19 countries recorded high modified land in Natura 2000 areas with values between 0.4 and 0.7, the highest in Malta (0.68), Luxembourg (0.63), Netherlands (0.56) and Czech Republic (0.55). These results suggest that within Natura 2000 sites, the regulations regarding human activities are too loose or not fulfilled and should be enforced in order to enhance biodiversity protection.
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