The most important weed species within Europe - especially in the Pannonian Plain in Central Europe - is the invasive common ragweed (Ambrosia artemisiifolia L.). The object of this study is the field survey taken during summer 2014, 2015 and 2016 in Ostrovné lúky (Žitný ostrov, Slovakia). This region belongs to Natura 2000. Natura 2000 is a network of protected sites of the European Union member states. The main reason for establishment of the network is an effort to maintain European natural heritage. Invasive species have a negative impact on the natural ecosystems. Monitoring of invasive plant species is a very important task. On the prepared map, we placed a grid net. The randomly selected areas based on plots of a standard size of 10 m2. An 11-point scale was used for the assessment of population density and the subjective category of presence varied from weak to heavy infestation on this arable land (mostly stubble fields). To understand the distribution of ragweed in the territory a geospatial analysis was applied to create 2D map in ArcGIS environment. The geospatial analysis enables not only to clearly understand frequency and dominancy of ragweed in the territories, but it also offers useful data to forecast potential Ambrosia spreading. However, the number of weeds on plots was very different and the deviation in the several years was different, the statistical analysis has shown that the average of the infected ragweed samples from this land belonging to Natura 2000 in the years of 2014-15-16 were not significantly different (p>0.05).