FUV flux experienced by discs in the Serpens region. Based on the sub-region in Serpens where they are located, the discs were divided into NE, Main, South, and the most southern part, Far South. Our flux estimates using Method 1, Method 2, and Method 3 (Sect. 4) are shown in yellow, purple, and orange, respectively. The lines show the median fluxes resulting from the three approaches. x-axis: Distance from the most massive star, or the centre of the region (if no strong dependence on the most massive star was found).