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 amphiphytes and helophytes were changed substantially. the numbe...

BACKGROUND Heterophyllous aquatic plants show marked phenotypic plasticity. They adapt to environmental changes by producing different leaf types: submerged, floating and terrestrial leaves. By contrast, homophyllous plants produce only submerged leaves and grow entirely underwater. Heterophylly and submerged homophylly evolved under selective pressure modifying the species-specific optima for ...

The FokI family of short interspersed repetitive elements (SINEs) has been found only in the genomes of charr fishes (genus Salvelinus). In an analysis of the insertion of FokI SINEs using PCR, we characterized six loci at which FokI SINEs have been inserted into the genomes of Salvelinus alpinus (Arctic charr) and/or S. malma (Dolly Varden). An analysis of one locus (Fok-223) suggested that a ...

It is critical to study factors that are important for origin and maintenance of biological diversity. A comparative approach involving a large number of populations is particularly useful. We use this approach to study the relationship between ecological factors and phenotypic diversity in Icelandic Arctic charr (Salvelinus alpinus). Numerous populations of small benthic charr have evolved in ...

In salmonid fish, a darker skin colour has been suggested to signal social subordination. Substratum colour is another factor affecting skin pigmentation in fish; in the present experiment, juvenile Arctic charr (Salvelinus alpinus) were acclimated and allowed to interact in pairs for 5 days on a pale or dark background colour. Skin darkness was quantified prior to and following social interact...

1 In an asexually reproducing plant ( Potamogeton pectinatus L.) the competitive advantage of a larger propagule over a smaller one was determined by a single parameter ( α , the competitive asymmetry coefficient), independent of sowing density or average propagule size. Competitive advantage was determined by the relative size difference between propagules instead of their absolute difference....