Macrophyte distribution and ecological status of the Turiec River (Slovakia): Changes after seven years

Characteristics of diversity, abundance, distribution, and ecological status of aquatic macrophytes were observed in 2000 and 2007 on a circa 4.5 km long section of the Turiec River using Kohler's method. In comparison to 2000, the total number of macrophytes in 2007 increased markedly (from 25 to 35), although only the numbers of amphi?phytes and helophytes were changed substantially. The number of hydrophytes increased from 11 to 12; an invasive, Elodea canadenis, was the only new species. The relative plant mass of hydrophytes represents the bulk of all recorded species (95 and 80% in 2000 and 2007, respectively), and it was changed for most hydrophytes. The most significant changes were detected for Myriophyllum spicatum (decrease), filamentous algae (decrease), and Potamogeton crispus (increase). In 2007, the mean mass total (MMT) sum of hydrophytes decreased from 16.46 to 14.5. On the other hand, the MMTsum of amphiphytes and helophytes doubled in value (7.4 and 14.1 in 2000 and 2007, respectively). Within hydrophytes, Batrachium species (including B. aquatile and B. trichophyllum), Myriophyllum spicatum, and Potamogeton crispus were ubiquitous (distribution ratio d > 0.5) in 2000, whereas in 2007 only Batrachium species and Potamogeton crispus were ubiquitous. At all times, Batrachium species were the most frequent species in the study area, and their abundance was relatively high (MMT> 2.5). A poor ecological status (MMP = 0.378 and MMP = 0.333 in 2000 and 2007, respectively) of the surveyed river section was found in both years, but a slight decline of quality as determined on the basis of aquatic plants was observed after 7 years.