LONG-TERM TRENDS IN THE STRUCTURE AND DYNAMICS OF THE FISH COMMUNITIES IN BUŠKO BLATO RESERVOIR

Akumulacija Buško Blato, treća najveća hidroakumulacija u Europi, smještena je u jugoistočnom dijelu krškog Livanjskog polja. Ovaj vodeni ekosustav odlikuje se vrlo bogatom ihtiofaunom i prisutnošću četiri endemske vrste riba. Ihtiološka istraživanja navedene akumulacije bila su u fokusu brojnih istraživanja. Ihtiofauna Buškog Blata bila je izložena promjenama različitih ekoloških čimbenika, što se odrazilo na strukturu i sastav ribljih populacija. Glavni cilj ovog rada bio je procijeniti trenutno stanje i predvidjeti buduće trendove u strukturi i dinamici ihtiofaune na temelju prikupljenih terenskih podataka i sveobuhvatnih analiza iz literaturnih podataka. Rezultati istraživanja pokazali su prisutnost 11 vrsta riba iz četiri porodice, što je najveći broj vrsta riba ikada zabilježenih u ovom ekosustavu. Sander lucioperca, Lepomis gibbosus, Pseudorasbora parva, i Tinca tinca prvi su put zabilježeni u ovom ekosustavu, dok neke prethodno zabilježene vrste nisu pronađene. Rezultati analiza jasno ukazuju na prisutnost prirodne interspecifične konkurencije i značajnu razinu ugroženosti endemskih vrsta riba uzrokovanu ljudskim aktivnostima.Buško Blato Reservoir, the third largest hydro accumulation in Europe, is situated in the south-eastern part of the karstic Livanjsko Polje Valley. This aquatic ecosystem is distinguished by a very rich ichthyofauna and the presence of four endemic fish species. Numerous studies focus on ichthyological researches of Buško Blato Reservoir. Its ichthyofauna has been exposed to changes in ecological factors, which in turn reflected on the structure and composition of fish populations. The main objective of this paper was to assess the current state and predict future trends in the ichthyofauna structure and dynamics based on the field data and comprehensive analyses of literature data. The results of the research indicated the presence of 11 fish species from four families, which is the largest number of fish species ever recorded in this ecosystem. Sander lucioperca, Lepomis gibbosus, Pseudorasbora parva and Tinca tinca were recorded for the first time in this ecosystem, while some previously recorded species were not found. The results of the analyses clearly indicate the presence of natural interspecific competition and significant level of threats to the endemic fish species caused by human activities

THE QUALITATIVE-QUANTITATIVE CONTENT OF JUVENILE STONEFLIES (PLECOPTERA) IN MACROZOOBENTHOS

A study was carried out on the changes in content and abundance of local juvenile stonefly communities species at the sites Garež, Delijaš and Balbašići during autumn of 2009 and spring and summer of 2010. A total of 1585 specimens were collected using a mash for zoobentos, out of which 541 were collected at the site Garež, 486 at the site Delijaš and 558 at the site Balbašići. The specimens were categorized into five families and 20 species. The most abundant species out of the total number at the site Garež was Leuctra nigra (73,94%), at the site Delijaš Perla marginata (19,96%), and at the site Balbašići Leuctra nigra (25,63%). The highest diversity indeces were at the site Delijaš, and the highest eveness was at site Balbašići.\ud \ud Key words: Crna Rijeka River, communities of juvenile stoneflies, Plecopter

Long-Term Trends in the Structure and Dynamics of the Fish Communities in Buško Blato Reservoir

Buško Blato Reservoir, the third largest hydro accumulation in Europe, is situated in the south-eastern part of the karstic Livanjsko Polje Valley. This aquatic ecosystem is distinguished by a very rich ichthyofauna and the presence of four endemic fish species. Numerous studies focus on ichthyological researches of Buško Blato Reservoir. Its ichthyofauna has been exposed to changes in ecological factors, which in turn reflected on the structure and composition of fish populations. The main objective of this paper was to assess the current state and predict future trends in the ichthyofauna structure and dynamics based on the field data and comprehensive analyses of literature data. The results of the research indicated the presence of 11 fish species from four families, which is the largest number of fish species ever recorded in this ecosystem. Sander lucioperca, Lepomis gibbosus, Pseudorasbora parva and Tinca tinca were recorded for the first time in this ecosystem, while some previously recorded species were not found. The results of the analyses clearly indicate the presence of natural interspecific competition and significant level of threats to the endemic fish species caused by human activities