Spatial and temporal variability of hyporheic invertebrate community within a stream reach of the River Bača (W Slovenia)

Mori, Nataša (author), Brancelj, Anton (author)

V letu 2005 je bila opravljena raziskava združbe nevretenčarjev v hiporeiku reke Bače, kjer smo opazovali prostorsko-časovno spremenljivost združbe nevretenčarjev v 3 vrstah habitatov. Nevretenčarje smo vzorčili iz globine 30 – 60 cm (RB1; 3 podvzorci) in iz globine 60 – 90 cm (RB2; 2 podvzorca) v rečni strugi ter v obrežnem prodišču iz globine 60-90 cm (GB; 3 podvzorci) v januarju, marcu in maju 2005. Merili smo tudi temperaturo vode, prevodnost in vsebnost kisika. Za testiranje razlik v številčnosti nevretenčarjev in številu taksonov med habitatoma (RB1, GB) in datumi smo uporabili dvosmerno analizo variance z vrsto habitata in datumom kot glavnima faktorjema. Sestavo združb med posameznimi habitati in datumi smo primerjali s pomočjo multivariatne analize glavnih komponent (PCA). V hiporeiku reke Bače smo nabrali 21.657 osebkov iz 63 taksonov. Najbolj številčni so bili predstavniki zgodnjih razvojnih stadijev rakov ceponožcev (Cyclopoida, Copepoda), ličinke vrbnic (Leuctra sp.) in trzač (Chironomidae) ter 2 vrsti ceponožnih rakov, Acanthocyclops vernalis (Fischer, 1853) in Diacyclops languidus (G. O. Sars, 1863). Dvosmerna analiza variance je pokazala razlike med RB1 in GB v številu taksonov, medtem ko razlik med datumi ni bilo. Številčnost nevretenčarjev ni bila značilno različna ne med habitati in ne med datumi. Analiza glavnih komponent (PCA) je pokazala gradient v sestavi združbe od plitvega hiporeika (RB1) do globljega hiporeika (RB2) in obrežnega prodišča (GB), najverjetneje zaradi različne strukture sedimenta v izbranih habitatih in bolj pogostih motenj (mešanje sedimenta) zaradi visokih voda v plitvejših slojih hiporeika.

• Language: English
• Keywords: stream reach, hyporheic zone, invertebrates, distribution (biology), community composition, spatial and temporal distribution
• Work type: Not categorized
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publisher: Biotehniška fakulteta Univerze v Ljubljani, Nacionalni inštitut za biologijo
• Year: 2011
• Number of pages: Str. 25-38
• Numbering: Vol. 13, no. 1
• PID: 20.500.12556/RUL-56137
• UDC: 591
• ISSN on article: 1580-0814
• COBISS.SI-ID: 2412879
• Publication date in RUL: 10.07.2015

Record is a part of a journal

• Title: Natura Sloveniae. revija za terensko biologijo
• Publisher: Zveza za tehnično kulturo Slovenije, Biotehniška fakulteta Univerze, Nacionalni inštitut za biologijo
• ISSN: 1580-0814
• COBISS.SI-ID: 102784768

Secondary language

• Language: Unknown
• Title: Prostorsko-časovna spremenljivost združbe nevretenčarjev v hiporeiku reke Bače(Z Slovenija)

Abstract

We studied spatio-temporal distribution of hyporheic invertebrate community at the stream-reach scale in the River Bača on three sampling occasions (January, March, May) in 2005. On each sampling occasion, invertebrates were collected from the shallow hyporheic zone (RB1; depth 30-60 cm, 3 replicates), and deeper hyporheic zone (RB2; depth 60-90 cm, 2 replicates) in the river bed, and adjacent gravel bar (GB; depth 60-90 cm, 3 replicates) using Bou-Rouch piston pump. Concurrently, temperature, conductivity and oxygen were measured in the surface water and in hyporheic water at each sampling station. Differences in hyporheic community between dates and habitats were analysed by using two-way ANOVA (dates and habitats as fixed factors) and explored by principal component analysis (PCA). Altogether, 21,657 specimens from 63 taxa were collected. Cyclopoida juveniles, Leuctra sp. (Plecoptera), Chironomidae (Diptera), Acanthocyclops vernalis (Fischer, 1853) and Diacyclops languidus (G. O. Sars, 1863) were the most abundant in the samples. Two-way ANOVA showed significant differences between habitats (RB1 and GB), but no differences between dates when using taxonomic richness as dependent variable. No differences between habitats and dates were calculated when invertebrate densities were applied. PCA of hyporheic invertebrate data showed a gradient in community composition from shallow hyporheic zone (RB1) to deeper hyporheic zone (RB2) and gravel bar (GB). The differences were most probably due to different sediment composition in the studied habitats and less frequent disturbances due to floods in deeper layers and lateral gravel bars.