Decline of aquatic plants in an iconic European protected natural area

We examined occurrence patterns over time for aquatic vascular plant species in a major European natural protected area: Doñana National Park (southwestern Spain). We used all available records (1965 to the present) for aquatic vascular plants found in the park’s pond network. Information was available for 38 species across 263 sites, including more than 100 ponds that were intensively monitored between 2001 and 2023. Our results show that aquatic vascular plant species began to decline in the last third of the 20th century. Two phases were apparent: 1) an early phase (late 20th century), during which declines in aquatic vascular plant populations were largely provoked by the arrival of an invasive species, Procambarus clarkii , and 2) a more recent phase during which the overexploitation of the aquifer has resulted in many ponds drying up and in shorter flooding periods in the remaining ponds. At present, nine species have disappeared, and 72% of the remaining species have smaller ranges. Our findings suggest that the dramatic local extinction and decline of Doñana’s various aquatic plant populations is a consequence of the rapid habitat loss that has occurred in recent decades. Historically, the park’s pond network acted as a refuge for many endangered and unique species facing major threats to their survival. Such no longer appears to be the case.