UNIVERSITY OF NOVA GORICA GRADUATE SCHOOL Uroš ŽIBRAT DEVELOPMENT OF A NEW BIOTIC INDEX BASED ON HYPORHEIC FAUNA FOR WATER QUALITY DETERMINATION IN LOTIC ECOSYSTEMS Dissertation Supervisor: prof. dr. Anton Brancelj Nova Gorica 2012 Ţibrat, U.: Development of a new biotic index based on hyporheic fauna for water quality determination in lotic ecosystems. PhD thesis. University of Nova Gorica, Graduate school, 2012 Auch dem Wasser darf es in Kanälen Nie am Laufe, nie an Reine fehlen. J. W. von Goethe II ABSTRACT We assess water quality and the status of water bodies with numerous variables, both abiotic and biotic. Up to date, few water quality assessment and ecoremediation measures took the surface water – groundwater ecotone (i.e. the hyporheic zone) into consideration. We developed a new index based on hyporheic copepod fauna. The copepod biodiversity in the hyporheic of 26 Slovenian rivers, belonging to all five river basins, was assessed, and 49 species, belonging to 6 families were found. Species accumulation curves and richness estimators indicated that our sampling effort was sufficient, all estimates pointed toward a richness of 50 species. Two biodiversity hotspots were identified, but one of them was found to have an uneven species distribution, indicating human-impacted sites. One species (Moraria radovnae) appears to be endemic. Differences in relative abundances of the most common species accounted for most of the differences between river basins. The hyporheic copepod community, combined with an accurate typology and diversity measures, and while considering the limitations of our model, can be used for water quality assessment. The obtained final model is most accurate in mid-range classes, while being inaccurate at extreme values. By developing this index and promoting its use in water quality assessment and environmental impact studies, we can expand currently applied methods. Keywords: hyporheic copepods, water quality assessment, biodiversity, data mining. POVZETEK Kakovost vode in stanje vodnih teles ocenjujemo s številnimi spremenljivkami, tako abiotskimi kot biotskimi. Doslej je le malo metod za oceno kakovosti vode in ekoremediacijskih ukrepov upoštevalo ekoton med površinskimi in podzemnimi vodami. Razvili smo nov indeks, ki temelji na zdruţbi ceponoţnih rakov v rečnem hiporeiku. Raziskali smo biotsko pestrost ceponoţnih rakov 26 slovenskih rek, ki iz vseh petih porečij. Našli smo 49 vrst, ki pripadajo 6 druţinam. Krivulje akumulacije vrst in ocene vrstnega bogastva nakazujejo, da je bil naš napor vzorčenja zadosten za dobro oceno števila vrst. Vse ocene nakazujejo prisotnost 50 vrst ceponoţnih rakov. Odkrili smo dve vroči točki biodiverzitete, vendar smo pri eni ugotovili neenakomerno razporeditev vrst, kar nakazuje na vpliv človeških dejavnosti. Za eno vrsto (Moraria radovnae) trenutno izgleda, da je endemična. Razlike v relativnih abundancah najpogostejših vrst so največ prispevale k razlikam med porečji. Ocenjevanje kvalitete površinske vode je moţno z uporabo zdruţbe ceponoţnih rakov v hiporeiku. Za to so potrebni natančni tipologija površinskih voda in ustrezni diverzitetni indeksi, upoštevati pa je potrebno tudi omejitve našega modela. Končni model je najbolj zanesljiv v srednjih razredih, medtem ko je netočen pri ekstremnih vrednostih. Z razvojem tega indeksa in spodbujanjem njegove uporabe pri metodah ocenjevanja kakovosti površinskih voda in presojah vplivov na okolje, ţelimo razširiti metodologijo, ki je trenutno v uporabi. Ključne besede: ceponoţni raki, hiporeik, ocenjevanje kvalitete voda, biodiverziteta, biotska pestrost, strojno učenje. Ţibrat, U.: Development of a new biotic index based on hyporheic fauna for water quality determination in lotic ecosystems. PhD thesis. University of Nova Gorica, Graduate school, 2012 CONTENTS ABSTRACT ................................................................................................................... I I LIST OF FIGURES .................................................................................................... IV II LIST OF TABLES ...................................................................................................... V III LIST OF APPENDICES ........................................................................................... VI 1 INTRODUCTION ....................................................................................................... 1 1.1 The importance of subsurface water ..................................................................... 1 1.2 The hyporheic zone .............................................................................................. 1 1.3 Water quality assessment ..................................................................................... 4 1.4 The concept of ecosystem health ......................................................................... 5 1.4.1 Ecosystem health indicators ......................................................................... 5 1.5 Study organisms ................................................................................................... 6 1.5.1 Copepods in ecotoxicological studies ............................................................ 7 1.6 The reference condition ........................................................................................ 7 1.6.1 Defining the reference condition .................................................................... 8 1.6.1.1 Minimally Disturbed Condition (MDC) ...................................................... 9 1.6.1.2 Historical Condition (HC) .......................................................................... 9 1.6.1.3 Least Disturbed Condition (LDC) ........................................................... 10 1.6.1.4 Best Attainable Condition (BAC) ............................................................ 10 1.6.2 Methods of estimating reference conditions ................................................ 11 1.6.2.1 Reference-site approach ........................................................................ 11 1.6.2.2 Interpreting historical condition ............................................................... 11 1.6.2.3 Extrapolating from empirical models ...................................................... 11 1.6.2.4 Ambient distributions .............................................................................. 11 1.6.2.5 Best professional judgment .................................................................... 12 1.7 Aim of this study ................................................................................................. 13 1.8 Study area .......................................................................................................... 14 II Ţibrat, U.: Development of a new biotic index based on hyporheic fauna for water quality determination in lotic ecosystems. PhD thesis. University of Nova Gorica, Graduate school, 2012 2 MATERIAL AND METHODS .................................................................................... 15 2.1 Sampling ............................................................................................................ 15 2.2 Laboratory analyses ........................................................................................... 17 2.3 Statistical analyses ............................................................................................. 17 2.3.1 Environmental variables .............................................................................. 17 2.3.2 River typology and defining reference states ............................................... 18 2.3.3 Species-environment relations .................................................................... 20 2.3.4 Machine learning methods .......................................................................... 21 3 RESULTS ................................................................................................................ 23 3.1 Environmental parameters .................................................................................. 23 3.2 Copepod biogeography and biodiversity ............................................................. 27 3.3 Species – environment relations ......................................................................... 42 3.5 Model development ............................................................................................ 46 4 DISCUSSION .......................................................................................................... 52 4.1 Environmental conditions .................................................................................... 52 4.2 Species richness ................................................................................................ 53 4.3 Copepod biogeography and biodiversity ............................................................. 54 4.4 Species-environment relations ............................................................................ 56 4.5 Model development ............................................................................................ 57 5 CONCLUSIONS ...................................................................................................... 60 6 SUMMARY .............................................................................................................. 61 7 REFERENCES ........................................................................................................ 63 ACKNOWLEDGEMENTS ..........................................................................................