The regulation of the Danube River has caused a decline in species diversity in riparian habitats throughout Europe. Aquatic macrophytes adapted to the ecology of backwaters are particularly affected by this decline. One such macrophyte is the water soldier (Stratiotes aloides L.) The water soldier, a suitable indicator for assessing the development of riparian ecosystems, could be found in only six locations of the eastern Danube floodplains in Austria in surveys from 2014 to 2017. While primarily endangered by gradual siltation due to a lack of regular flooding events, a large number of anthropogenic disturbing factors were also found to significantly compromise the habitats of water soldiers. The most desirable conservation approach would be to create or promote natural backwater dynamics for water soldiers’ habitats. In the short term, however, less extensive local measures are also suitable for delaying the succession process.
Keywords: Stratiotes aloides, aquatic macrophyte, endangered plant species, Danube floodplains, Austria
