PL
Opisano nowe stanowisko kotewki orzecha wodnego Trapa natans L. w zbiorniku zaporowym w Rzeszowie. Pojedyncze rozety kotewki w zbiorniku rzeszowskim obserwowano już w 2007 roku, nie wiadomo jednak, kiedy pojawiły się pierwsze osobniki. Średnia głębokość zbiornika wynosi obecnie ok. 1,5 m. Dominuje miękkie, muliste dno. Stężenie związków biogennych jest dość duże (zawartość fosforanów 0,3 mg l-1), a pH wody jest lekko zasadowe. Kotewka w zbiorniku w 2010 roku była bardzo liczna i pokrywała 10% powierzchni zbiornika (ok. 4 ha)
EN
Water chestnut is a critically endangered plant species in Poland. This paper describes the species location in the dam reservoir in Poland where it spreads rapidly. At present, the average depth of the water is approximately 1.5 m throughout the reservoir. The bottom of the reservoir is mostly soft and muddy. The concentration of biogenic compounds is quite high (the content of phosphates is 0.3 mg l-1), and pH is slightly alkaline. Single rosettes of water chestnut in the Rzeszów reservoir were found in 2007, but there is no information when exactly the first specimens appeared. In September 2010, the total area of water chestnut patches was approximately 4 hectares. The water chestnut population in the reservoir was extremely large − the total area of rosettes was 10% of the actual surface of the reservoir. Large patches of the species were found mainly in the central part of the reservoir, and smaller patches were observed in shallow areas with low water flow in different parts of the reservoir