Proposal for estimating volume based relative abundance of aquatic macrophytes

In aquatic macrophyte ecology, species abundance is usually estimated by cover values expressed on the ordinal scale. Recently, there has been increasing demand for three-dimensional estimates of plant abundance. To extend ordinal cover data into three dimensions, a new formula is proposed which considers the vertical developmental types of plants. In this, a constant k is used with three different values reflecting three groups of macrophytes, namely the “free floating leaved”; “rooted, floating leaved” and “submersed leaved” species. By using the new formula, inappropriate conversion and evaluation of ordinal abundance data occurring frequently in the literature may also be avoided

Chemical composition of the plants of loess steppes in Hungary

The first two stages of the successional series on loess (Agropyro-Kocliietum, Salvio-Festucetum rupicolae) differ from each other in their Holistic composition, the total element content of their soils and plant species as well as their water demand. Chrysopogon gryllus, a characteristic species of the loess steppe, belongs to the calciotroph physiotype according to the Ca/K ratio in its leaves. The leaves of this species contain relatively high concentrations of Ca and Mg and a low concentration of N. The high C/N ratio in the leaves and roots of Chrysopogon gryllus should indicate that the mineralization dynamics is slowed down in the stands dominated by this species. Barbula cordata, a moss species of the Salvio-Festucetum rupicolae community, accumulates very high amounts of heavy metals from its surroundings. In the Agropyro-Kochietum community, Bromus species accumulated the highest amounts of heavy metals in their leaves

Chemical composition of the plants of loess steppes in Hungary

The first two stages of the successional series on loess (Agropyro-Kocliietum, Salvio-Festucetum rupicolae) differ from each other in their Holistic composition, the total element content of their soils and plant species as well as their water demand. Chrysopogon gryllus, a characteristic species of the loess steppe, belongs to the calciotroph physiotype according to the Ca/K ratio in its leaves. The leaves of this species contain relatively high concentrations of Ca and Mg and a low concentration of N. The high C/N ratio in the leaves and roots of Chrysopogon gryllus should indicate that the mineralization dynamics is slowed down in the stands dominated by this species. Barbula cordata, a moss species of the Salvio-Festucetum rupicolae community, accumulates very high amounts of heavy metals from its surroundings. In the Agropyro-Kochietum community, Bromus species accumulated the highest amounts of heavy metals in their leaves

Nitzschia austriaca Hustedt: a characteristic diatom of Hungarian inland saline waters including a morphological comparison with the type material

A detailed scanning electron microscopic investigation was carried out to clarify the taxonomic status of a small sigmoid Nitzschia species, a potential indicator of Central European soda waters. We found this taxon to be one of the dominant epiphytic diatoms collected from sodic bomb crater ponds at Apaj (Hungary). The large population allowed for a morphometric comparison based on frustule ultrastructure with the type material of the most similar species, Nitzschia austriaca Hustedt that was originally described from a soda pan in the region. The results clearly demonstrated an overlap between the Apaj population and the type material of N. austriaca (based on NMDS analysis), therefore we argue that they represent the same taxon. An emended diagnosis of N. austriaca is given. Total suspended solids and total phosphorous proved to be the most important factors predicting the occurrence of the species, with possible interactive effects of conductivity and pH. We then expanded the distribution of the species by revisiting data originating from previous large-scale surveys targeting sodic habitats in Hungary. On the basis of our results, N. austriaca is a characteristic species for Central European soda waters, including the protected astatic soda pans, indicating their typical chemical and physical characteristics.</jats:p