Mid-sized mountain streams [Elektronische Ressource] : typology, assessment and reliability of sampling and assessment methods / vorgelegt von Armin Lorenz

Armin Sommer

Informations

• Publié par: universitat_duisburg-essen
• Publié le: 01 janvier 2005
• Nombre de lectures: 28
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Mid-sized Mountain Streams
–
Typology, Assessment and Reliability of Sampling
and Assessment Methods


Inaugural-Dissertation

zur

Erlangung des Doktorgrades

Dr. rer. nat.

des Fachbereichs
Bio- und Geowissenschaften,
Landschaftsarchitektur

an der
Universität Duisburg-Essen

vorgelegt von
Armin Lorenz
geboren in Leiden/NL


Abgabe Juli, 2004
Mündliche Prüfung 20.10.2004

Gutachter: PD Dr. Daniel Hering, Prof. Dr. Helmut Schuhmacher
Die der vorliegenden Arbeit zugrundeliegenden Experimente wurden am Institut für Ökologie
in der Abteilung Hydrobiologie der Universität Duisburg-Essen durchgeführt.


1. Gutachter:
PD Dr. Daniel Hering

2. Gutachter:
Prof. Dr. Helmut Schuhmacher

Vorsitzender des Prüfungsausschusses:
Prof. Dr. Hans Hagenmaier

Tag der mündlichen Prüfung:
20.10.2004









The current that with gentle murmur glides,
Thou know´st, being stopped, impatiently does rage.
But when his fair course is not hindered
He makes sweet music with th´enamelled stones,
Giving a gentle kiss to every sedge
He overtaketh in his pilgrimage.
And so by many winding nooks he strays
With willing sport to the wild ocean.


[Julia in Act 2 in “The two Gentlemen of Verona”
(Shakespeare 1598 in Wells & Taylor 1988)]










Dedicated to my parents and the working group of Hydrobiology
at the University of Duisburg-Essen.

Table of Contents
Table of Contents

Preface…………………………………………………………………………………………………………….1

Definitions – Abbreviations...................................................................................4

1 Validation of the German stream typology using benthic invertebrates.............8
Abstract................................................................................................................... 8
1.1 Typology of streams in Germany sampled with various protocols ......................... 9
1.1.1 Introduction .............................................................................................. 9
1.1.2 Materials and methods..............................................................................10
1.1.3 Results.....................................................................................................14
1.1.4 Discussion................................................................................................17
1.1.5 Conclusion ...............................................................................................19
1.2 Comparison of NMS resolution for taxonomic levels and quantitative differences
between two stream types...............................................................................20
1.2.1 Introduction .............................................................................................20
1.2.2 Materials and methods..............................................................................21
1.2.3 Results.....................................................................................................25
1.2.4 Discussion................................................................................................29
1.3 Typology of streams in Germany sampled with a consistent method ...................31
1.3.1 Introduction .............................................................................................31
1.3.2 Materials and methods32
1.3.3 Results36
1.3.4 Discussion41
1.4 Differences and similarities of mid-sized and large mountain streams..................46
1.4.1 Introduction46
1.4.2 Characterisation of mid-sized and large mountain streams in Germany ........47
1.4.3 Materials and methods..............................................................................47
1.4.4 Results.....................................................................................................48
1.4.5 Discussion................................................................................................52




Table of Contents
2 Development of an assessment system for mid-sized streams in lower
mountainous areas of Germany.................................................................. 54
Abstract..................................................................................................................54
2.1 A new method for assessing the impact of hydromorphological degradation on the
macroinvertebrate fauna..................................................................................55
2.1.1 Introduction .............................................................................................55
2.1.2 Materials and methods..............................................................................57
2.1.3 Results.....................................................................................................65
2.1.4 Discussion................................................................................................71

3 Statistical tests for applying a minimum number of individuals for AQEM-method
samples…. 74
Abstract..................................................................................................................74
3.1 “Electronic subsampling” of invertebrate samples: how many individuals are
needed for a valid assessment result?...............................................................75
3.1.1 Introduction .............................................................................................75
3.1.2 Materials and methods..............................................................................76
3.1.3 Results.....................................................................................................79
3.1.4 Discussion................................................................................................88

Summary and Conclusions ................................................................................. 93

Deutsche Kurzfassung der Dissertation ............................................................... 96

References……………………………………………………………………………………………………106

Acknowledgements ......................................................................................... 117

Appendices……………………………………………………………………………………………………118


Preface
Preface
Research in ecology is like an unending staircase, which widens up the more steps you take.
The closer one approaches a solution for one scientific problem, the more unanswered ones
turn up elsewhere. Streams of the mountainous areas of Germany and their inhabiting
aquatic invertebrate fauna were the starting point of this thesis leading to several wider
perspectives. Investigating these mountain streams reveals questions about their faunal
characteristics compared to lowland rivers and to high alpine rivers and even about the
variability between mountain streams. At the same time, statistical theory requires us to
consider the reliability and repeatability of any research result.
The subsequent thesis consists of three chapters. Each chapter has its own self-contained
introduction and sub-chapters on methods, results and discussion. Overall conclusions and a
summary are given to integrate these pieces of research jigsaw.

In the first chapter, I will try to answer questions about differences in the aquatic biota
between German lowland, mountain and alpine streams, but concentrating on the
mountainous and alpine regions. There have been many publications on this topic
(e.g. Huet 1946; Illies 1961; Braukmann 1987; Sommerhäuser 1998; LUA 1999b;
Sommerhäuser & Schuhmacher 2003) but a comprehensive statistical evaluation based on
the benthic invertebrate community has not yet been conducted. Filling this gap I started
from two sides with two different data sets: (1) taxa lists from all parts of Germany applying
a variety of sampling protocols; (2) a smaller number of taxa lists from certain regions of
Germany applying a consistent sampling protocol. The taxonomic resolution of the first and
larger data set is low (mainly genus level) compared to the second data set (species level).
Within the first data set the taxa lists were reduced to just presence/absence level and only
a subset of taxonomic groups was considered. In the second data set abundance data and
the complete benthic invertebrate community were used instead. Linking abiotic parameters
to the benthic invertebrate taxa lists helped to determine the major factors, which influence
macroinvertebrates to inhabit a stream reach.
The question, which taxonomic resolution and data type is necessary to create stream
typologies, is answered in a second step. A homogeneous data set in terms of sampling,
sorting and identification was evaluated to identify the effects of different resolutions.
Species level is compared to family level, using the complete taxa list is compared to using
the taxonomic groups Ephemeroptera, Plecoptera, Trichoptera, Coleoptera, Odonata and