Lehrstuhl Für Aquatische Systembiologie

TECHNISCHE UNIVERSITÄT MÜNCHEN Lehrstuhl für Aquatische Systembiologie The impact of stream substratum quality on salmonid reproduction Katharina Sternecker Vollständiger Abdruck der von der Fakultät für Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt der Technischen Universität München zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften genehmigten Dissertation. Vorsitzende: Univ.-Prof. A. Schnieke, Ph.D. Prüfer der Dissertation: 1. Univ.-Prof. Dr. J.P. Geist 2. apl. Prof. Dr. R. Gerstmeier Die Dissertation wurde am 16.01.2013 bei der Technischen Universität München eingereicht und durch die Fakultät Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt am 29.03.2013 angenommen. Danube salmon (Hucho hucho L.) and grayling (Thymallus thymallus L.) spawning in the river Lech. No one steps into the same river twice. Heraclitus of Ephesus (c. 535 - c. 475 BCE) Content I Content List of figures .........................................................................................................................III List of tables .......................................................................................................................... V Summary .............................................................................................................................. VI Zusammenfassung ................................................................................................................ X 1 Introduction..................................................................................................................... 1 2 Salmonids ...................................................................................................................... 5 2.1 Systematics and distribution................................................................................... 5 2.2 Life history ............................................................................................................. 6 3 The effects of stream substratum composition on the emergence of salmonid fry .........11 3.1 Abstract ................................................................................................................11 3.2 Introduction ...........................................................................................................12 3.3 Material and methods ...........................................................................................13 3.3.1 Experimental setup........................................................................................13 3.3.2 Statistical analyses ........................................................................................15 3.4 Results ..................................................................................................................15 3.4.1 The effects of texture on emergence rate and survival ..................................15 3.4.2 The effects of texture on the chronology of emergence .................................17 3.4.3 Chronic effects on survival and growth ..........................................................18 3.5 Discussion ............................................................................................................21 4 The ‘egg sandwich’ - a method for linking spatially resolved salmonid hatching rates with physicochemical habitat variables in stream ecosystems .......................................24 4.1 Abstract ................................................................................................................24 4.2 Introduction ...........................................................................................................25 4.3 Material and methods ...........................................................................................25 4.4 Results ..................................................................................................................29 4.5 Discussion ............................................................................................................30 5 Factors influencing the success of salmonid egg development in river substratum ........32 5.1 Abstract ................................................................................................................32 5.2 Introduction ...........................................................................................................33 5.3 Materials and methods ..........................................................................................34 5.3.1 Study sites ....................................................................................................34 5.3.2 Microhabitat assessment ...............................................................................34 5.3.3 Statistical analysis .........................................................................................38 5.4 Results ..................................................................................................................40 5.4.1 Differences between reference and field exposures ......................................40 Content II 5.4.2 Factors affecting hatching rates at the macro-scale.......................................42 5.4.3 Factors affecting hatching rates at river-specific scale ...................................45 5.4.4 Factors affecting hatching rates at the micro-scale ........................................46 5.5 Discussion ............................................................................................................48 5.5.1 Differences between reference and field exposures ......................................48 5.5.2 Factors affecting hatching rates at the macro-scale.......................................49 5.5.3 Factors affecting hatching rates at the micro-scale ........................................50 5.6 Conclusions ..........................................................................................................52 6 Effects of stream substratum restoration on habitat quality in a subalpine stream .........53 6.1 Abstract ................................................................................................................53 6.2 Introduction ...........................................................................................................54 6.3 Materials and methods ..........................................................................................55 6.3.1 Study area .....................................................................................................55 6.3.2 Restoration method .......................................................................................56 6.3.3 Effects within the restoration area .................................................................56 6.3.4 Downstream effects .......................................................................................58 6.3.5 Statistical analysis .........................................................................................58 6.4 Results ..................................................................................................................59 6.4.1 Effects within the restoration site ...................................................................59 6.4.2 Downstream effects .......................................................................................63 6.5 Discussion ............................................................................................................64 7 Restoration of spawning habitats of brown trout (Salmo trutta) in a regulated chalk stream ...........................................................................................................................68 7.1 Abstract ................................................................................................................68 7.2 Introduction ...........................................................................................................69 7.3 Materials and Methods ..........................................................................................70 7.3.1 River characteristics ......................................................................................70 7.3.2 Restoration of spawning grounds ..................................................................72 7.3.3 Monitoring .....................................................................................................73 7.4 Results ..................................................................................................................75 7.5 Discussion ............................................................................................................79 8 How to improve habitat quality with anthropogenic manipulations .................................85 8.1 Impact of altered stream substratum composition - why monitor interstitial water conditions? ...........................................................................................................85 8.2 Implications for river management - small versus large scale restoration efforts ...88 8.3 Outlook .................................................................................................................91 9 Acknowledgements .......................................................................................................93 10 References ....................................................................................................................94 List of Figures III List of Figures Figure 2-1: Phylogeny of Salmonidae. ..................................................................................

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