Freshwater communities can vary greatly across space and time. Studying these variations, 2 that is spatial and temporal beta diversity, provides fundamental information on the processes 3 that maintain diversity and on the consequences of environmental changes on communities. 4 Recently, drying events have been shown to strongly affect the spatial and temporal beta 5 diversity of temperate freshwater ecosystems, but the effects of such events are mostly 6 unknown for freshwater communities in semi-arid climates that are frequently submitted to 7 drying up. In addition, studies have so far focused on variations in species composition that is 8 species beta diversity, while variations in species trophic interactions that is food-web beta 9 diversity can give additional insights on how community functioning vary in space and time. 10 Here, we combine species and food-web perspectives to explore the spatiotemporal beta 11 diversity of plankton species and their trophic interactions in waterholes undergoing different 12 water-level regimes: either an alternation between dry and water-full states, or a permanent 13 water-full state due to water pumping. Our results show that waterholes with artificial water 14 pumping do not differ from natural waterholes in their contribution to spatiotemporal beta 15 diversity. Instead, beta diversity is strongly driven by temporal variations of species 16 composition and food-web structure during the dry season, which is characterized by 17 degraded planktonic communities with a low richness, diversity and connectance. Species-18 and interaction-based approaches give complementary information on the spatiotemporal beta 19 diversity, as they highlight different planktonic communities with contrasted functioning. 20