20.500.12556/RUL-140040 Struktura združbe makroinvertebratov v različnih odsekih reke Stržen po renaturaciji struge Structure of the macroinvertebrate community in different sections of the Stržen River after the renaturation of the channel Proučevali smo, kako se je spreminjala struktura združbe makroinvertebratov (MIZ) na reki Stržen, na območju Cerkniškega jezera po revitalizaciji dela struge. Glavni namen renaturacije dvojnega okljuka je bil podaljšati zadrževalni čas vode v strugi in s tem izboljšati stabilnost ekosistema ter povečati samočistilno sposobnost reke. Revitalizacija struge je, kljub namenu izboljšati stanje, grob poseg v ekosistem, ki mu sledi proces rekolonizacije življenjske združbe. Zanimalo nas je, kako sta se v času enega in dveh let po revitalizaciji spremenili pestrost in diverziteta MIZ na različnih odsekih (renaturirana odseka, referenčna odseka, regulacijski kanal). Na zmožnost terenskega dela so močno vplivali hidrološki dejavniki. Makroinvertebrate (MI) smo vzorčili po standardni metodi, na podlagi podatkov pa izračunali različne diverzitetne (H', d, D) in biotske (EPTO, GOLD) indekse. Na vzorčnih odsekih smo izmerili tudi fizikalne, kemijske in hidromorfološke dejavnike ter popisali substrat. Korelacije med okoljskimi dejavniki in parametri MIZ smo ugotavljali s Spearmanovimi korelacijskmi koeficienti. V vzorcih smo našli 18 468 osebkov, ki smo jih uvrstili v 62 družin. V enem letu od renaturacije je na območju velikega okljuka prišlo do rekolonizacije 24 družin MI, diverziteta pa je bila tam v primerjavi z ostalimi odseki nižja. Poglobitveni poseg je poleti 2021 prekinil sukcesijo združbe, sedimentacija erodiranega materiala pa je poslabšala ekološke razmere dolvodno. Med letoma 2020 in 2021 smo opazili znaten upad pestrosti in diverzitete MIZ na vseh proučevanih odsekih. Sklepamo, da je bil glavni razlog za to zelo nizek vodostaj in posledično neugodne temperaturne in kisikove razmere. The structure of the macroinvertebrate community (MIC) after restoration of the Stržen riverbed was analysed. The renaturation of the double meander aims to increase the water holding capacity of the streambed and therefore improve ecological conditions in the area of intermittent Lake Cerknica. River revitalisation is a disturbance, which is followed by a process of recolonisation of the biotic community. We investigated how variability and diversity of the MIC changed in different sections of the river (restored sites, reference sites, regulation channel) one and two years after restoration. Hydrological factors affected our fieldwork considerably. MI were sampled according to standard methods. Different diversity (H', d, D) and biotic indices (EPTO, GOLD, ...) were calculated. At the same time, physical, chemical and hydromorphological variables were measured and substrate was monitored. Correlations between the environmental factors and MIC's parameters were investigated using Spearman's coefficients. 18 468 individuals belonging to 62 distinct families were detected in the samples. In the revitalised section recolonisation of 24 families had taken place one year after the construction works, but its diversity was lower compared to the unrestored sites. The succession of MIC of the restored sites was interrupted by the deepening works in the summer of 2021 while downstream MIC was affected by sedimentation of eroded material. The diversity of MIC of all the sampling sections decreased from 2020 to 2021, most likely due to unfavourable oxygen and temperature conditions. renaturacija reke revitalizacija reke makroinvertebrati Stržen Cerkniško jezero obnovitvena ekologija motnja rekolonizacija sukcesija river revitalisation streambed restoration benthic macroinvertebrates disturbance recovery succession intermittent Cerknica Lake Stržen river true true false [P. Pavšič] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2022-09-10 07:16:59 2022-09-10 07:17:07 2022-09-20 11:45:07 0000-00-00 00:00:00 2022 0 Ljubljana 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 574 209019 122086659 24893.pdf 24893.pdf 1 6C8FDA0F0DACFF97BE6DD6EB0F906B3A 2d75e7522e631aa6fb45c7c33091127585e38476cf5110ea245c4c8f0f070de0 c2482f6a-30c7-11ed-92af-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=160705 Biotehniška fakulteta 0 0 0