Repository of University of Nova Gorica

Show document
A+ | A- | SLO | ENG

Title:STRUCTURE AND FUNCTIONING OF THE HYPORHEIC ZONES IN THE GRAVEL-BEDS OF FIVE RIVERS IN RELATION TO CATCHMENT LAND USE
Authors:Debeljak, Barbara (Author)
Brancelj, Anton (Mentor) More about this mentor... New window
Files:.pdf Barbara_Debeljak.pdf (5,31 MB)
 
Language:English
Work type:Doctoral dissertation (mb31)
Tipology:2.08 - Doctoral Dissertation
Organization:FPŠ - Graduate School
Abstract:The hyporheic zone has been recognised as a functionally important component of streams and rivers. Due to increasing human impact on ecosystems, studies that assess ecological responses of the hyporheic zone are of great importance. The objectives of the thesis are to study the responses of abiotic parameters, sediment biofilm characteristics (the in situ respiration (R), potential respiratory activity (ETSA), protein content), and invertebrate assemblages (analysed as total assemblages, EPT assemblages and Copepoda assemblages) in the hyporheic zones related to different land use patterns (forest, agricultural and urban areas). The focus of study also includes the impact of clogging. This research is comprised of three sampling campaigns conducted in summer (2013), winter (2013) and spring (2014) in five pre-Alpine Slovenian rivers. For each river, three or six sampling locations were chosen in the downwelling hyporheic sections of three dominant land uses (forest, agriculture and urban) within a 250 m wide impact zone. Three sampling points per location were sampled from two depths (5 –15 cm and 20 – 40 cm) using PVC tube and Bou-Rouch method. The results indicate a significant spatial and temporal heterogeneity of measured hyporheic zone components. Physical and chemical parameters of water revealed moderate response to land use. The effect of land use on the amounts of suspendable fine sediments in the hyporheic zone was observed only in the spring season. The effect of land use was significant for in situ R during summer and spring and for ETSA and protein content in all seasons, indicating that land use, such as agriculture, near a stream can affect biogeochemical processes. A relatively high diversity of invertebrates was recognised in the hyporheic zone. Groups such as Nematoda, Oligochaeta, Copepoda and Chironomidae were found in all samples. Within EPT taxa as representatives of occasional hyporheic invertebrates, 35 taxa were identified. Within Copepoda, as representatives of permanent hyporheic invertebrates, 14 Cyclopoida and 19 Harpacticida taxa were identified. Both assemblages were characterised by high abundance of widespread taxa, such as Baetis sp., Leuctra sp., Diacylops cladestinus and Acanthocyclops hispanicus. Statistically significant differences were observed among land uses in Copopoda assemblages but not for EPT assemblages. Calculated metrics on EPT assemblages showed statistically significant differences in land use in the number of EPT taxa, Simpson index and Shannon-Wiener index. Within Copepoda assemblages, the numbers of Copepoda taxa were significantly higher at forest sites. The hyporheic assemblages were relatively well explained by environmental parameters. This thesis presents a comprehensive study of the hyporheic zone, where both structural and functional measures reflected the ecological integrity of the hyporheic zone. The in situ R and ETSA were generally higher in agriculture stream reaches, indicating that hyporheic functioning responded to nutrients and carbon runoff-derived inputs from agricultural activities within the 250 m impact zone. Thus functional parameters in situ R and ETSA were more efficient indicators of land use impacts in the hyporheic zone than physical and chemical parameters. The potential of using hyporheic invertebrates as bioindicators of environmental conditions was confirmed but should be tested with wider gradients of environmental parameters. The results obtained by this study underlined that the hyporheic zone should be integrated as an additional ecological element by assessing the ecological conditions of surface water bodies.
Keywords:hyporheic zone, ecosystem functioning, land use, biofilm characteristics, invertebrates
Year of publishing:2018
Source:Ljubljana
COBISS_ID:5172219 Link is opened in a new window
URN:URN:SI:UNG:REP:LO6HF5TJ
Views:128
Downloads:3
Metadata:XML RDF-CHPDL DC-XML DC-RDF
Categories:Document is not linked to any category.
:
  
Average score:(0 votes)
Your score:Voting is allowed only for logged in users.

Hover the mouse pointer over a document title to show the abstract or click on the title to get all document metadata.

Secondary language

Language:Slovenian
Title:ZGRADBA IN DELOVANJE HIPOREIČNIH CON PETIH PRODONOSNIH REK V POVEZAVI Z RABO TAL V PRISPEVNEM OBMOČJU
Abstract:Hiporeična cona je prepoznana kot funkcionalno pomembna komponenta potokov in rek. Zaradi povečanega človeškega vpliva na ekosisteme so študije, ki ocenjujejo stanje hiporeične cone s strukturnimi in funkcionalnimi elementi, zelo pomembne. Cilji raziskave so bili oceniti odziv abiotskih parametrov, odziv biofilma na sedimentih in odziv vodnih nevretenčarjev na rabo tal v prispevnem območju. Odziv biofilma smo izmerili z in situ respiracijo (R), respiratornim potencialom (ETSA) in vsebnostjo proteinov. Združbo vodnih nevretenčarjev smo analizirali bodisi kot celoto na višjem taksonomskem nivoju, EPT združbo (enodnevnice, vrbice, mladoletnice) in združbo ceponožcev (harpaktikoidi, ciklopoidi). Osredotočili smo se tudi na učinek finih suspendiraih delcev kot rezultat rabe prostora v prispevnem območju. Raziskava je potekala v treh časovnih obdobjih: poleti (2013), pozimi ( 2013) ter pomladi (2014) v petih predalpskih slovenskih rekah. Na vsaki reki smo izbrali 6 ali 3 vzorčna mesta, glede na prevladujočo rabo tal v 250 m širokem prispevnem območju. Na vsakem vzorčnem mestu smo nabrali po 3 vzorce na dveh globinah (5 − 15cm, 20 − 40cm). Zgornji sloj smo vzorčili s posebnim plastičnim vzorčevalnikom, spodnji sloj pa z Bou-Rouch metodo. Rezultati potrjujejo veliko prostorsko in časovno heterogenost merjenih parametrov hiporeične cone. Fizikalni in kemijski parametri vode kažejo zmeren odziv na rabo tal. Učinek rabe tal je bil statistično značilen za in situ R poleti in pomladi, medtem ko je za učinek rabe tal na ETSA in vsebnost proteinov statistično značilen v vseh sezonah kar kaže, da kmetijstvo ob reki vpliva na biogeokemične procese. V hiporeični coni smo prepoznali razmeroma veliko diverziteto nevretenčarjev. Gliste, maloščetince, ceponožce in trzače smo našli v vseh vzorcih. Med predstavniki EPT (občasni nevretenčarji v hiporeiku) smo določili 35 taksonov, med ceponožnimi raki pa 14 ciklopoidov in 19 harpaktikoidi. Za obe združbi je značilno veliko generalistov kot so Baetis sp., Leuctra sp., Diacylops cladestinus in Acanthocyclops hispanicus. Med različnimi rabami tal so bile ugotovljene razlike v združbi ceponožcev, ne pa za EPT združbe. Izračunane metrike so pokazale statistične razlike med rabami tal v številu EPT taksonov, Simpsonovem indeksu in Shannon-Wienerjevem indeksu. Med ceponožci smo določili več vrst na mestih, kjer je prevladoval gozd. Združbe nevretenčarjev so bile razmeroma dobro pojasnjene z okoljskimi parametri. Disertacija predstavlja kompleksno raziskavo, kjer strukturni in funkcionalni elementi odražajo stanje hiporeične cone. In situ R in ETSA sta bili na območjih s prevladujočim kmetijstvom višji kar kaže na odziv biofilma na antropogen vir hranil. Funkcionalni parametri so se izkazali za bolj učinkovite pokazatelje vpliva rabe tal kot fizikalno-kemijski parametri vode. Ugotovili smo tudi odziv vodnih nevretenčarjev na rabo prostora, vendar bi bilo potrebno raziskavo ponoviti na širšem gradientu okoljskih parametrov. Rezultati dobljeni pri tej študiji so potrdili, da bi morala biti hiporeična cona vključena kot dodaten element za ocenjevanje stanja površinskih voda.
Keywords:hiporeična cona, delovanje ekosistema, raba tal, biofilm, nevretenčarji


Back