The Long-stalked Pondweed (Potamogeton praelongus Wulfen) is a critically endangered aquatic plant species in the Czech Republic, surviving at its last native site in an oxbow lake of the Orlice River in Malšova Lhota near the city of Hradec Králové.
The last native Czech population of P. praelongus is endangered by sedimentation due to nutrient-rich sediment in the standing oxbow reach, covering leaf surfaces in fine sedimentary particles. High concentrations of mineral nutrients in the water also lead to the growth of detrimental filamentous algae, and the disturbance of plants and micropopulations during flood events is of potential concern. The last native site of P. praelongus has been under protection as a temporarily protected area „Rameno u Stříbrného rybníka“ pond during 1998–2017.
The rescue programme for P. praelongus was approved by the Ministry of Environment in 2003. Implementation of the rescue programme is executed by the Nature Conservation Agency of the Czech Republic (NCA CR). Monitoring of the abundance and vitality of the last population and the state of its habitat is regularly executed in the frame of the Rescue programme. Management is provided at the temporarily protected area and rescue micropopulations in the protected landscape area Kokořínsko. Ex situ rescue cultivation, analysis of the genetic variability of the micropopulations, sterile in vitro culture, seed germination tests and growth experiments are also parts of the rescue programme. Suitable sites for outplanting in the Poorličí and Českolipsko regions have been selected every year.
Norwegian, southern Swedish sites and several Polish localities with P. praelongus populations have also been observed. The aim of these expeditions was to learn what are the ecological requirements and limiting factors for its growth and to compare them with the results of research conducted in Czech localities and their micropopulations.
Studium bylo podpořeno ze zdrojů EHP/Norska a Ministerstva životního prostředí ČR (č. 06/01/CZ0072 v letech 2009–2010, MGSII-15 v letech 2015–2017). Diplomové a doktorské práce věnované tomuto tématu byly podpořeny ze zdrojů Specifického výzkumu financovaného Ministerstvem školství ČR č. 2121/2011, 2122/2012, 2106/2013, 2112/2014, 2111/2015, 2107/2016.