Developing a Mammal Monitoring Programme for the UK
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BTO Research Report No.223 Developing a mammal monitoring programme for the UK M.P. Toms, G.M. Siriwardena & J.J.D. Greenwood (Part III.A.1 written by S.N. Freeman & G.M. Siriwardena) July 1999 A report by the British Trust for Ornithology under contract to the Joint Nature Conservation Committee (Contract No: F76-01-241). British Trust for Ornithology,The Nunnery, Thetford, Norfolk, IP24 2PU. Registered Charity No. 216652 M.P. Toms, G.M. Siriwardena & J.J.D. Greenwood (Part III.A.1 written by S.N. Freeman & G.M. Siriwardena) DEVELOPING A MAMMAL MONITORING PROGRAMME FOR THE UK A report by the British Trust for Ornithology under contract to the Joint Nature Conservation Committee (Contract No: F76-01-241). Published in July and 1999 by the British Trust for Ornithology The Nunnery, Thetford, Norfolk IP24 2PU, U.K. Copyright © British Trust for Ornithology 1999 Report to be cited as: Toms, M.P., Siriwardena, G.M. & Greenwood, J.J.D. (1999) Developing a mammal monitoring programme for the UK. BTO Research Report No.223. BTO, Thetford. ISBN 1-902576-19-5 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form, or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publishers. BTO Research Report No.223 July 1999 CONTENTS Page No. List of Tables ............................................................................................................9 List of Figures........................................................................................................... 11 List of Species Covered............................................................................................ 13 Key References......................................................................................................... 15 PART I. AIMS AND OBJECTIVES OF UK MAMMAL MONITORING...... 17 1. WHY SUCH MONITORING IS NEEDED ................................................ 17 1.1 What is monitoring?................................................................................... 17 1.2 The status of British and Irish mammals................................................. 18 1.3 Objectives of mammal monitoring ........................................................... 19 1.4 Aims of mammal monitoring .................................................................... 20 1.4.1 Information .................................................................................... 20 1.4.2 Geographical scope.......................................................................... 21 1.4.3 Habitat information......................................................................... 22 1.4.4 Monitoring range............................................................................. 22 1.4.5 Monitoring abundance.................................................................... 24 1.4.6 Demographic rates........................................................................... 26 2. THE BACKGROUND TO THE CURRENT PROJECT .............................. 27 2.1 Current mammal monitoring in the UK .................................................. 27 2.2 MMR proposals .................................................................................... 27 2.2.1 What species?.................................................................................. 28 2.2.2 What is to be measured?................................................................ 28 2.2.3 Integration across species .............................................................. 28 2.2.4 The three-tiered structure and the Master Squares ................... 28 2.2.5 The seven-year cycle....................................................................... 28 2.2.6 Rich Interest Kilometre Squares .................................................. 29 2.2.7 Focus Zones .................................................................................... 29 2.2.8 Manpower and costs....................................................................... 29 2.2.9 Utilising existing ancillary schemes .............................................. 29 2.2.10 Setting up the MaMoNet................................................................ 31 2.2.11 Sampling with partial replacement (SPR) ................................... 31 2.3 Aims of the current project ....................................................................... 31 2.3.1 General aims and species to be considered .................................. 31 2.3.2 What is to be measured?................................................................ 32 2.3.3 Integration across species .............................................................. 32 2.3.4 The Master Squares ....................................................................... 33 2.3.5 The seven-year cycle....................................................................... 33 2.3.6 Rich Interest Kilometre Squares .................................................. 34 2.3.7 Focus Zones .................................................................................... 34 2.3.8 Manpower and costs....................................................................... 34 2.3.9 Utilising existing and ancillary schemes....................................... 34 2.3.10 Setting up the mammal monitoring programme......................... 35 2.3.11 Sampling with partial replacement............................................... 35 3. HOW THE MONITORING OF MAMMALS IS DIFFERENT FROM THAT OF BIRDS .............................................................................................. 37 BTO Research Report No.223 July 1999 1 3.1 Mammals are less easily detectable than birds........................................ 37 3.2 Identification............................................................................................... 37 3.3 More species-specific techniques are needed for mammals than for birds........ .............................................................................................. 37 3.4 Availability of personnel............................................................................ 37 3.5 Diversity of existing inputs is greater for mammal monitoring............. 38 3.6 There is no commitment to long-term monitoring of mammals............ 38 3.7 Mammals are generally less mobile than birds ....................................... 38 3.8 Many mammals occur in many different habitats .................................. 39 PART II.........CONSIDERATIONS OF DESIGN AND STATISTICS .............. 41 1. INTRODUCTION.............................................................................................. 41 1.1 Why revisit these issues?............................................................................ 41 1.2 Statistical nicety or practical pragmatism? ............................................. 41 2. THE SPATIAL DISTRIBUTION OF SAMPLING ....................................... 43 2.1 Generalising from samples....................................................................... 43 2.2 Sources of imprecision in sample surveys............................................... 43 2.3 What population is of interest?................................................................ 44 2.4 Randomisation .......................................................................................... 46 2.5 Species restricted to special habitats of limited extent.......................... 47 2.6 Systematic surveys.................................................................................... 47 2.7 Study sites chosen by the observers......................................................... 48 2.8 Sampling at more than one level ............................................................. 49 2.9 Many small samples or fewer larger ones? ............................................ 50 2.10 Stratification: general............................................................................... 50 2.11 Focus Zones may be strata....................................................................... 52 2.12 Stratification by observer availability..................................................... 52 2.13 Statistical power........................................................................................ 53 3. THE TEMPORAL DIMENSION TO SAMPLING ....................................... 55 3.1 The importance of historical continuity of sample sites........................55 3.2 Partially replacing samples...................................................................... 56 3.3 Building on previous surveys ................................................................... 57 3.4 Within-year variation............................................................................... 58 4. NOTES ON STATISTICAL INTERPRETATION........................................ 61 4.1 Estimation and hypothesis testing........................................................... 61 4.2 Remarks on appropriate statistical models............................................ 61 4.3 Post-stratification, regression and other modelling as means of increasing precision and understanding................................................. 62 PART III.......MULTI-SPECIES SCHEMES ....................................................... 63 INTRODUCTION.................................................................................................... 63 BTO Research Report No.223 July 1999 2 A. EVALUATION OF EXISTING SOURCES OF DATA................................