Distribució, ecologia i estat de conservació de Potamogeton lucens i P. schweinfurthii a Catalunya (NE de la península Ibèrica)

Abstract

Potamogeton lucens L. and P. schweinfurthii A. Benn. are two aquatic species of similar morphology that have been confused in Europe until recent times. This study aims at elucidating and updating information about the current and historical distribution of both taxa in Catalonia. Data sources were herbaria specimen revisions and field observations. Habitat characteristics of the current populations were also studied. Despite verifying five P. lucens populations, only one has persisted in a high-altitude lake in the Pyrenees. The four disappeared populations were located in lowland areas in the basins of the rivers Tordera and Llobregat. This historical decline relates to changes in land uses and urban sprawl during the 20th century that have led to numerous desiccations and a large degree of eutrophication in the persisting lowland stagnant water bodies. In contrast, P. schweinfurthii was first reported from Catalonia in 2010 and three populations are currently known. They are located in mid-altitude areas at the center and north of the study area and two may be of recent colonization. Vouchers of this species were not found in the surveyed herbaria. Based on the current knowledge, the IUCN category assigned to P. lucens is Critically Endangered (CR) and to P. schweinfurthii is Vulnerable (VU). Regarding hybrids, only P. x salicifolius hybrid between P. lucens and P. perfoliatus was reported from Catalonia at the end of the 19th century at Banyoles lake and has not been found again.