REFERENCE ONLY UNIVERSITY OF LONDON THESIS Degree Year Name of Author COPYRIGHT This is a thesis accepted for a Higher Degree of the University of London. It is an unpublished typescript and the copyright is held by the author. All persons consulting the thesis must read and abide by the Copyright Declaration below. COPYRIGHT DECLARATION I recognise that the copyright of the above-described thesis rests with the author and that no quotation from it or information derived from it may be published without the prior written consent of the author. LOANS Theses may not be lent to individuals, but the Senate House Library may lend a copy to approved libraries within the United Kingdom, for consultation solely on the premises of those libraries. Application should be made to: Inter-Library Loans, Senate House Library, Senate House, Malet Street, London WC1E 7HU. REPRODUCTION University of London theses may not be reproduced without explicit written permission from the Senate House Library. Enquiries should be addressed to the Theses Section of the Library. Regulations concerning reproduction vary according to the date of acceptance of the thesis and are listed below as guidelines. A. Before 1962. Permission granted only upon the prior written consent of the author. (The Senate House Library will provide addresses where possible). B. 1962- 1974. In many cases the author has agreed to permit copying upon completion of a Copyright Declaration. C. 1975 - 1988. Most theses may be copied upon completion of a Copyright Declaration. D. 1989 onwards. Most theses may be copied. This thesis comes within category D. This copy has been deposited in the Library of ^ ^ ^ This copy has been deposited in the Senate House Library, Senate House, □ Malet Street, London WC1E 7HU. C:\Documents and Settings\lproctor\Local SettingsNTemporary Internet Files\OLK8\Copyright - thesis (2).doc Zooplankton Ecology and Palaeoecology in Nutrient Enriched Shallow Lakes Thesis submitted for the degree of Doctor of Philosophy University of London by Thomas Alexander Davidson Department of Geography University College London December 2005 UMI Number: U591675 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Dissertation Publishing UMI U591675 Published by ProQuest LLC 2013. Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 Abstract This study sought to determine the potential of sedimentary cladoceran assemblages for inferring changes in shallow lake ecological structure and function. The first stage of the study aimed to isolate and quantify the main structuring forces of the contemporary zooplankton community. Zooplankton populations were sampled from 39 mesotrophic to hyper-eutrophic shallow lakes (<3 m average depth) in the U.K. and Denmark. Additionally, a suite of environmental variables, including: fish, macrophytes, algal crop, nutrient concentrations and water transparency were analysed. A variety of numerical techniques including constrained ordination and logistic regression were employed to determine whole community and individual species response to the environmental variation within the data set. The sedimentary remains of zooplankton were then enumerated from the surface sediments of the 39 ‘training set’ lakes. These data were compared with the contemporary counts. Despite differential preservation of sedimentary remains, the main factors structuring the assemblages were the same in both data sets, zooplanktivorous fish density (ZF) and submerged macrophyte abundance (MA). Furthermore, these factors displayed a similar degree of influence on both assemblages. A multivariate regression tree (MRT) was used to calibrate sedimentary cladoceran assemblage response to ZF and MA. The resultant model places a site in one of five groups based on cladoceran assemblage and corresponding to a range of values of ZF and MA. These groups represent distinct forms of ecosystem structure and function varying from sites with clear water, abundant macrophytes and low ZF to turbid, phytoplankton dominated systems with high ZF. Sedimentary cladoceran assemblages from dated cores for two sites, Felbrigg Lake (Norfolk, England) and Kenfig Pool (Glamorgan, Wales) were analysed. The cladoceran inferred ZF and MA indicated that both sites have undergone dramatic changes in ZF and MA. Comparison with plant macrofossil data and historical records at both sites indicated the veracity of the model. 2 Acknowledgements I would like to thank my supervisors, of whom I have had many of varying permanence. These included, fleetingly, Laurence Carvalho and unofficially but importantly Martin Perrow. Thanks to Rick Battarbee for stepping in with words of wisdom and encouragement when called for. The stalwarts were, however, Helen Bennion and Carl Sayer who have brought different qualities to the task of supervision the combination of which is a heady brew. Thanks, in no particular order, for your guidance, enthusiasm, patience, tolerance, friendship and advice on feeding horses. If we had had an adult present at more meetings I might have finished sooner, but then speed isn’t everything. I would like to thank the various land owners in the U.K. and Denmark for site access. I would also like to thank June and Derek Sayer for their generous hospitality and support. I am indebted to all the staff at NERI in Silkeborg, for all their help. In particular, Eric Jeppesen provided and still provides support and advice. I am also very grateful to the extraordinary Mette for all her help, sorry about all the rowing. Thank also to Laura, Jacob, Marianne, Silke, Thomas, Rasmus and Eric for fun. I would like to thank everyone at the FBI in Bergen, for their hospitality during my time there. In particular, both before and after my fellowship H.J.B. Birks has provided guidance on numerical techniques and kindly read through earlier drafts of this work. Einar Heegaard provided vital assistance with R and some of the most confusing but in the end helpful hours of my life. I hope the work shows I understood at least some of it. Thanks to Bianca and Ulrike and Yves for the beers, fishing trips and their relative sanity. I would finally like to thank everyone at the ECRC who has helped through advice, discussion, assistance in the field and general entertainment. Including, Patrick Rioual for his Frenchness, Ben Goldsmith for help fishing and crayfish eating skills, Carl Sayer for bumpkinery (NFN), Andy ‘horsey’ Henderson, Gina Clarke, Ainsley Martin and Dan Hoare all provided invaluable help in the field. There is also the Lord John Russell appreciaton society, members of which know who they are, which has been both a help and a hindrance in finishing this thing. This work was funded by NERC studentship NER/S/A/2001/06429. 3 Contents Abstract 2 Acknowledgements 3 Table of contents 4 List of Tables 8 List of Figures 9 Glossary of Acronyms 13 1 Chapter 1 - Introduction ____________________________________________ 14 1.1 Backgrou nd _____________________________________________________.14 1.2 Shallow lakes ____________________________________________________.14 1.2.1 Definition of terms ____________________________________________________________ . 15 1.3 Shallow lake ecology and response to eutrophication __________________ .16 1.3.1 The role o f fis h ________________________________________________________________. 16 1.3.2 The role of submerged macrophytes _____________________________________________ . 17 1.3.3 Benthic to pelagic shifts in production ___________________________________________ . 18 1.4 Zooplankton ecology in shallow lakes _______________________________ .19 1.5 Zooplankton palaeoecology _______________________________________ .20 1.6 Overall aim and specific research questions __________________________ .23 1.7 Study sites______________________________________________________.23 1.8 Supporting data sets ______________________________________________ .25 1.9 Structure and outline of thesis _____________________________________ .35 2 Chapter 2 - Zooplankton community structure in shallow lakes: multiple causality, spatial variation and inter-specific competition __________________ 38 2.1 Introduction _____________________________________________________.38 2.2 Study area and sites ______________________________________________ .41 2.3 Methods ________________________________________________________.41 2.3.1 Water Chemistry _______________________________________________________________. 42 2.3.2 Biological sampling ___________________________________________________________ .4 2 2.3.3 Data sets ______________________________________________________________________. 45 2.3.4 Numerical methods ____________________________________________________________ 46 4 2.4 Results_______________________________________________________________48 2.4.1 Physical, chemical and biological characteristics __________________________________________48 2.4.2 Zooplankton data ________________________________________________________________________49 2.4.3 Constrained ordination and variance partitioning __________________________________________53