Ecological analysis of macrozoobenthos communities in the Nišava River

Doktorska disertacija obuhvata ekološku analizu zajednica makrozoobentosa reke Nišave i njihovu zavisnost od biotičkih i abiotičkih faktora. Istraživanja su obavljena mesečnom dinamikom na dvanaest lokaliteta od maja 2006. do aprila 2007. godine. U disertaciji se diskutuje zavisnost koncentracije hlorofila a i mase perifitona od abiotičkih faktora. Sa druge strane, razmatran je pritisak (na osnovu brojnosti) filtratornih vrsta zajednice makroinvertebrata na količinu fitoplanktona (izraženu preko hlorofila a) i pritisak grebača na masu perifitona. Dobijen je predikcioni model za izračunavanje koncentracije hlorofila a korišćenjem multiple linearne regresije. Model ima značajnu predikcionu moć (sig=0,003). Na osnovu Pirsonovog koeficijenta korelacije konstatovano je da postoji značajna povezanost koncentracije hlorofila a sa mutnoćom (p=0,000), sa ukupnim fosforom (p=0,029) i sa kombinovanom (zbirnom) koncentracijom ukupnog azota i fosfora (p=0,036). Nije utvrđena značajna povezanost sa brojnošću filtratornih organizama, što govori da njihov pritisak nije dovoljno jak da bi limitirao količinu fitoplanktona. Taksonomskom analizom makroinvertebrata reke Nišave utvrđeno je prisustvo 132 vrste iz 4 različita filuma. Filum Platyhelminthes je predstavljen sa 3 vrste iz 2 familije. Filum Annelida obuhvata 23 vrste iz 6 familija. Najveći broj vrsta ovog filuma pripada potklasi Oligochaeta (16 vrsta). Filum Mollusca obuhvata 13 vrsta iz 5 familija, od kojih 11 pripada klasi Gastropoda, a 2 klasi Bivalvia. Najveći broj vrsta faune makroinvertebrata pripada filumu Arthropoda (92 vrste iz 33 familije), od kojih 3 pripadaju subfilumu Crustacea, a sve ostale podfilumu Hexapoda, odnosno klasi Insecta. Rezultati taksonomske analize pojedinačnih grupa u okviru zajednice makroinvertebrata pokazuju da najveći broj vrsta pripada grupi Ephemeroptera (28 vrsta), zatim slede Diptera (26 vrsta) i Trichoptera (20 vrsta). Ostale grupe su zastupljene sa manjim brojem vrsta. Diskutovana je sezonska i longitudinalna dinamika grupa makroinvertebrata i njihova uslovljenost faktorima sredine. Razmatrani su indeksi diverziteta i adekvatnost njihovog korišćenja kao pokazatelja zagađenosti ekosistema, posebno za svaku grupu...This doctoral dissertation comprises the ecological analysis of macrozoobenthos communities in the Nišava River and their dependence on biotic and abiotic factors. The studies followed the monthly dynamics at 12 sites, from May 2006 to April 2007. The dissertation is discussing the dependence of chlorophyll a concentration and periphyton mass on abiotic factors, as well as the pressure (based on abundance) of filtrating species in the macroinvertebrate community on the amount of phytoplankton (expressed as chlorophyll a) and pressure of scraper species on periphyton mass. The prediction model for calculating chlorophyll a concentration was derived from the multiple linear regression. This model has a significant prediction power (sig=0.003). The Pearson's correlation coefficient was used to determine the correlation of chlorophyll a concentration with water turbidity (p=0.000), total phosphorus (p=0.029) and combined (summative) concentration of total nitrogen and total phosphorus (p=0.036). No significant connection with the abundance of filtrating organisms was determined, which indicates that their pressure was not strong enough to limit the quantity of phytoplankton. The taxonomic analysis of macroinvertebrates in the Nišava River yielded the presence of 132 species from 4 different phyla. The phylum Platyhelminthes was represented with 3 species from 2 families. The phylum Annelida was represented with 23 species from 6 families. Most recorded species from this phylum belong to the subclass Oligochaeta (16 species). The phylum Mollusca was represented with 13 species from 5 families, of which 11 were from the class Gastropoda and 2 from the class Bivalvia. Most species of the macroinvertebrate fauna belong to the phylum Arthropoda (92 species from 33 families), of which 3 were from the subphylum Crustacea, while all others belong to the subphylum Hexapoda and class Insecta. The results of the taxonomic analysis of individual groups within the macroinvertebrate community have shown that most species belong to the group Ephemeroptera (28 species), followed by Diptera (26 species), and Trichoptera (20 species). Other groups were represented with a smaller number of species. The study also includes the discussion on seasonal and longitudinal dynamics of macroinvertebrate groups and the effect of environmental factors on their presence. The diversity indices and their suitability as indicators of ecosystem pollution were discussed for each group separately..