Naslov
Increased sediment load disturbance effects on stream macroinvertebrates

Autori
Miliša, Marko ; Živković, Vesna ; Matoničkin Kepčija, Renata ; Sertić-Perić, Mirela

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Scientific Programme and Abstracts, The 6th Symposium for European Freshwater Sciences / Geta Risnoveanu i sur. - Sinaia, 2009

Skup
The 6th Symposium for European Freshwater Sciences

Mjesto i datum
Sinaia, Rumunjska, 17-21. 8

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
quarry; fine sediment; mining; macroinvertebrates; disturbance; stream; Croatia

Sažetak
Increased sediment loads may severely affect conditions in freshwater habitats (turbidity, water temperature, oxygen content, quality of benthic habitats, food sources, water chemistry, introduction of contaminants and pathogens). Such disturbance can be a result of natural processes (bank erosion) or of human activity. Here we deal with the latter- fine sediments produced by quarrying and rinsing the extracted material in stream. We analyzed effects of increased sediment load disturbance on water chemistry and macroinvertebrate assemblages focusing on the changes in occurrence of: 1) permanent against temporary fauna in the benthic habitats and 2) early (1st-3rd) against late (4th-5th) larval instars of Ephemeroptera, Plecoptera and Trichoptera. This approach was employed to assess the effects on organisms of different preferences and sensitivity in order to attain insight on recovery potential of the stream. The study was conducted at ‘ Jelenje vode’ stream on the northern slope of Medvednica Mountain, NW Croatia. Sampling was done on four dates using Surber sampler at four sites along the stream, one was a control site situated upstream of the quarry. Permanent fauna was decimated at sites downstream of the quarry. Total numbers and diversity decreased severely along the entire study reach. Similar effect was noted for the temporary fauna however 3 km downstream of the quarry temporary fauna recovered in numbers. Chironomidae fauna dominate at this site (>60%) so the structure and the diversity of the assemblage is significantly diminished compared to the control site. Both the early and the late EPT instars were severely affected by the disturbance (more than 84% loss downstream of the quarry). The abundance of EPT instars 3 km downstream recovered significantly and reached 31% and 54% of the control site numbers for early and late instars respectively. We found that the specific cause for such a destructive effect were significantly increased temperature and decreased dissolved O2 content and pH value. Given the vitality of the upstream area, vicinity of similar habitats as well as lack of toxic effects of the sediment load we believe that the recovery of affected sites would be swift and successful upon the closure of the quarry.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA