B-Béres et al. (2014) Hydrobiologia

Viktória B-Béres, Péter Török, Zsuzsanna Kókai, Enikő T. Krasznai, Béla Tóthmérész, István Bácsi (2014): Ecological diatom guilds are useful but not sensitive enough as indicators of extremely changing water regimes. Hydrobiologia, DOI 10.1007/s10750-014-1929-y

Abstract
Classification of taxa into ecological guilds is based on the relation of respective taxa to nutrient enrichment and their resistance to physical disturbance. We hypothesized that ecological guild’s proportion and their taxa composition were strongly effected both by extremely changing water regime and nutrient contents. Diatom composition, guild dynamics and the diatom-based ecological status assessment index were studied in the Sebes-Körös River (South-East Hungary) in a year with extremely changing water regimes. There were highly pronounced changes in species composition during the whole vegetation period including the formation of running and standing water segments in autumn. While the proportions of ecological guilds showed no significant correlations with the studied environmental parameters, they were more balanced in high water discharge period than in the low water discharge period. Taxa compositions of segments were mainly determined by the preferences and strategies of a respective species and/or genera, regardless to their guild affiliation. These results point out that ecological guild characterisation should be refined using ecological knowledge at the subgenus level. We suggest to establish several subdivisions within the guilds to consider the differences in life strategies (CSR model) and life forms, and to implement the accumulated knowledge of nutrient preferences/indication of a respective taxa.

 

Keywords
Diatom species composition, Diversity, Ecological guilds, Medium-sized river, Water quality

Erdős et al. (2014) Ecological Complexity

L. Erdős, Cs. Tölgyesi, M. Horzse, D. Tolnay, Á. Hurton, N. Schulcz, L. Körmöczi, A. Lengyel, Z. Bátori: Habitat complexity of the Pannonian forest-steppe zone and its nature conservation implications. Ecological Complexity, in press, DOI: http://dx.doi.org/10.1016/j.ecocom.2013.11.004

Abstract

Eurasian forest-steppes are among the most complex ecosystems in the northern temperate zone. Alternating forest and grassland patches form a mosaic-like landscape, stretching in a stripe from eastern Europe almost to the Pacific coast. Although the edges (contact zones between woody and herbaceous vegetation) may play an important ecological role, their study has been neglected in the forest-steppes. In this study, we aimed to perform a comprehensive analysis on the components of a sandy forest-steppe in the Pannonian ecoregion (Hungary), with special regard to the edges. 2 m × 1 m coenological relevés were made in forest interiors, in edges and in grassland interiors. We carried out microclimate measurements in each habitat type. Compositional and structural characteristics of the forests, edges and grasslands were compared, including species number, Shannon diversity, summarized cover, life-form and geoelement spectra. Diagnostic species for each habitat type were identified, and the role of the habitats in harbouring protected and endemic species was also assessed. Based on the frequencies and cover values of tree seedlings and saplings in the three habitat types, we formulated tentative assumptions on vegetation dynamics. We found that edges possessed their own distinct species composition, having a considerably higher species number, Shannon diversity and vegetation cover than habitat interiors. Edges hosted relatively large numbers of edge-related species, and proved to be highly different from habitat interiors with regard to life-form and geoelement spectra. It seemed that the spatial interaction of two neighbouring communities resulted in the emergence of a third, unique community, the edge. The microclimate of the forests and the grasslands differed strikingly, whereas that of the edges fell between them. Except Populus alba, trees had very few seedlings and no saplings, which may have serious consequences if the current warming and drying trend continues. We conclude that in the study area, intermediate microclimate of the edges supports a community that is not intermediate compositionally and structurally: the edge should be recognized as a distinct community, although strongly connected to the neighbouring communities. As a consequence, forest-steppes have three integral components: forest, grassland and edge. Our results emphasize the conservation importance of all components. The conservation value of the sandy grasslands has long been recognized, but the contribution of edges and forest patches to species and habitat diversity should not be neglected either. Conservation activities should focus on maintaining the complexity of the forest-steppe ecosystem, with all of its integral components.

Keywords

Diversity, Edge, Endemic plants, Microclimate

Ferincz et al. (2012) Acta Zoologica Academiae Scientiarum Hungaricae

Ferincz, Á., Staszny, Á., Ács, A., Weiperth, A., Tátrai, I. and Paulovits, G. (2012): Long-term development of fish assemblage in Lake Fenéki (Kis-Balaton Water Protection System, Hungary): succession, invasion and stabilization. Acta Zoologica Academiae Scientiarum Hungaricae 58 (Supplement 1): 3–18.

Abstract

This analysis of long-term (1992–2011) changes in the fish assemblage of the partially operating shallow, hypertrophic reservoir (Ingói-marsh, Lake Fenéki) was carried out on the occasion of the planned completion of the impoundment. Samplings were performed in standard localities with electrofishing. Three phases could be distinguished in fish fauna development. The first phase is characterized by two allochtonous marsh-species: the Mud-minnow (Umbra krameri) and the Crucian carp (Carassius carassius), and was fast replaced by the second invasion phase, characterized by the invasion of non-native gibel carp (Carassius gibelio),and the third phase by the dominance of roach (Rutilus rutilus) and bleak (Alburnus alburnus). The cumulative relative abundance of non-indigenous species reached a peak in the third year of the impoundment (1995; 56.4%), and remained high (>>50%) until 2001. The number of species, Shannon-Weaver diversity, and relative abundance of piscivorous species correlated positively with the age of reservoir. The shift of the fish fauna between the two phases was dynamic and dramatic, since the all previously dominant species disappeared within 4 years. The impact of invasive gibel carp is considered as high, because it has completely replaced its native relative (C. carassius), but in the other hand it only was able to delay the natural successive process, not completely transform it.

 

Keywords

gibel carp, diversity, assemblage structure, shallow reservoir