Bee Conservation: Evidence for the effects of interventions

Published by Pelagic Publishing

www.pelagicpublishing.com

PO Box 725, Exeter, EX1 9QU

Bee Conservation

Evidence for the effects of interventions

Synopses of Conservation Evidence, Volume 1

ISBN 978-1-907807-00-8 (Pbk)

ISBN 978-1-907807-01-5 (Hbk)

Copyright © 2010 Lynn V. Dicks, David A. Showler & William J. Sutherland

All rights reserved. Apart from short excerpts for use in research or for reviews, no part of this document may be printed or reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, now known or hereafter invented or otherwise without prior permission from the publisher.

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library.

Contents

Advisory board

About the authors

Acknowledgements

1. Introduction

1.1 The purpose of Conservation Evidence synopses

1.2 Who this synopsis is for

1.3 The Conservation Evidence project

1.4 Scope of the Bee Conservation synopsis

1.5 How we decided which bee conservation interventions to include

1.6 How we reviewed the literature

1.7 How the evidence is summarised

1.8 Terminology used to describe evidence

1.9 How you can help to change conservation practice

2. Threat: residential and commercial development

2.1 Plant parks and gardens with appropriate flowers

2.2 Practise ‘wildlife gardening’

2.3 Protect brownfield sites

2.4 Conserve old buildings or structures as nesting sites for bees

3. Threat: land use change due to agriculture

3.1 Protect existing natural or semi-natural habitat to prevent conversion to agriculture

3.2 Increase the proportion of natural or semi-natural habitat in the farmed landscape

3.3 Provide set-aside areas in farmland

3.4 Restore species-rich grassland vegetation

3.5 Restore heathland

3.6 Connect areas of natural or semi-natural habitat

3.7 Reduce tillage

3.8 Increase areas of rough grassland for bumblebee nesting

3.9 Create patches of bare ground for ground-nesting bees

3.10 Provide grass strips at field margins

3.11 Manage hedges to benefit bees

3.12 Increase the use of clover leys on farmland

3.13 Plant dedicated floral resources on farmland

3.14 Sow uncropped arable field margins with an agricultural ‘nectar and pollen’ mix

3.15 Sow uncropped arable field margins with a native wild flower seed mix

3.16 Leave arable field margins uncropped with natural regeneration

3.17 Increase the diversity of nectar and pollen plants in the landscape

3.18 Reduce the intensity of farmland meadow management

3.19 Reduce grazing intensity on pastures

4. Threat: pollution - agricultural and forestry effluents

4.1 Introduce agri-environment schemes that reduce spraying

4.2 Convert to organic farming

4.3 Restrict certain pesticides

4.4 Reduce pesticide or herbicide use generally

4.5 Reduce fertilizer run-off into margins

4.6 Leave field margins unsprayed within the crop (conservation headlands)

5. Threat: transportation and service corridors

5.1 Restore species-rich grassland on road verges

5.2 Manage land under power lines for wildlife

6. Threat: biological resource use

6.1 Manage wild honey bees sustainably

6.2 Replace honey-hunting with apiculture

6.3 Legally protect large native tress

6.4 Re-plant native forest

6.5 Retain dead wood in forest management

7. Threat: natural system modification - natural fire and fire suppression

7.1 Control fire risk using mechanical shrub control and/or prescribed burning

8. Threat: invasive non-native species

8.1 Eradicate existing populations

8.2 Control deployment of hives/nests

8.3 Prevent escape of commercial bumblebees from greenhouses

8.4 Prevent spread of the small hive beetle

8.5 Ensure commercial hives/nests are disease free

8.6 Keep pure breeding populations of native honey bee subspecies

8.7 Exclude introduced European earwigs from nest sites

9. Threat: problematic native species

9.1 Exclude bumblebee nest predators such as badgers and mink

9.2 Exclude ants from solitary bee nesting sites

10. Providing artificial nest sites for bees

10.1 Provide artificial nest sites for solitary bees

10.2 Provide artificial nest sites for bumblebees

10.3 Provide nest boxes for stingless bees

11. Captive breeding and rearing of wild bees (ex-situ conservation)

11.1 Rear declining bumblebees in captivity

11.2 Re-introduce laboratory-reared bumblebee queens to the wild

11.3 Re-introduce laboratory-reared bumblebee colonies to the wild

11.4 Translocate bumblebee colonies in nest boxes

11.5 Rear and manage populations of solitary bees

11.6 Translocate solitary bees

11.7 Introduce mated females to small populations to improve genetic diversity

12. Education and awareness-raising

12.1 Enhance bee taxonomy skills through higher education and training

12.2 Provide training to conservationists and land managers on bee ecology and conservation

12.3 Raise awareness amongst the general public through campaigns and public information

Index

Advisory board

We thank the following people for advising on the scope and content of this synopsis.

Professor Andrew Bourke, University of East Anglia, UK

Dr Claire Carvell, Centre for Ecology and Hydrology, UK

Mike Edwards, Bees, Wasps and Ants Recording Society, UK

Professor Dave Goulson, University of Stirling & Bumblebee Conservation Trust, UK

Dr Claire Kremen, University of California, Berkeley, USA

Dr Peter Kwapong, International Stingless Bee Centre, University of Cape Coast, Ghana

Professor Ben Oldroyd, University of Sydney, Australia

Dr Juliet Osborne, Rothamsted Research, UK

Dr Simon Potts, University of Reading, UK

MattShardlow, Director, Buglife, UK

Dr David Sheppard, Natural England, UK

Dr Nick Sotherton, Game and Wildlife Conservation Trust, UK

Professor Teja Tscharntke, Georg-August University, Göttingen, Germany

Mace Vaughan, Pollinator Program Director, The Xerces Society, USA

Sven Vrdoljak, University of Stellenbosch, South Africa

Dr Paul Williams, Natural History Museum, London, UK

About the authors

Lynn Dicks is a Research Associate in the Department of Zoology, University of Cambridge.

David Showler is a Research Associate in the School of Biological Sciences, University of East Anglia and the Department of Zoology, University of Cambridge.

William Sutherland is the Miriam Rothschild Professor of Conservation Biology at the University of Cambridge.

Acknowledgements

This synopsis was prepared with funding from Arcadia. The Conservation Evidence project has also received funding from the Natural Environment Research Council (NERC) and the British Ecological Society (BES).

We also thank Dr Barbara Gemmill-Herren, Dr Rob Pople and Dr Stephanie Prior for their help and advice.

1. Introduction

1.1 The purpose of Conservation Evidence synopses

This book, Bee Conservation, is the first in a series of synopses that will cover different species groups and habitats, gradually building into a comprehensive summary of evidence on the effects of conservation interventions for all biodiversity throughout the world.

By making evidence accessible in this way, we hope to enable a change in the practice of conservation, so it can become more evidence-based. We also aim to highlight where there are gaps in knowledge.

1.2 Who this synopsis is for

If you are reading this, we hope you are someone who has to make decisions about how best to support or conserve biodiversity. You might be a land manager, a conservationist in the public or private sector, a farmer, a campaigner, an advisor or consultant, a policymaker, a researcher or someone taking action to protect your own local wildlife. Our synopses summarise scientific evidence relevant to your conservation objectives and the actions you could take to achieve them.

We do not aim to make your decisions for you, but to support your decision-making by telling you what evidence there is (or isn’t) about the effects that your planned actions could have.

When decisions have to be made with particularly important consequences, we recommend carrying out a systematic review, as the latter is likely to be more comprehensive than the summary of evidence presented here. Guidance on how to carry out systematic reviews can be found from the Centre for Evidence-Based Conservation at the University of Wales, Bangor (www.cebc.bangor.ac.uk).

Table 1.1 The Conservation Evidence synopses concept

1.3 The Conservation Evidence project

The Conservation Evidence project has three parts:

1. An online, open access journal Conservation Evidence publishes new pieces of research on the effects of conservation management interventions. All our papers are written by, or in conjunction with, those who carried out the conservation work and include some monitoring of its effects.

2. An ever-expanding database of summaries of previously published scientific papers, reports, reviews or systematic reviews that document the effects of interventions.

3. Synopses of the evidence captured in parts one and two on particular species groups or habitats. Synopses bring together the evidence for each possible intervention. They are freely available online and available to purchase in printed book form.

These resources currently comprise over 2,000 pieces of evidence, all available in a searchable database on the website www.conservationevidence.com.

Alongside this project, the Centre for Evidence-Based Conservation (www.cebc.bangor.ac.uk) and the Collaboration for Environmental Evidence (www.environmentalevidence.org) carry out and compile systematic reviews of evidence on the effectiveness of particular conservation interventions. These systematic reviews are included on the Conservation Evidence database.

Of the 59 bee conservation interventions identified in this synopsis, one is the subject of a current systematic review (Systematic Review number 72: Does delaying the first mowing date increase biodiversity in European farmland meadows? www.environmentalevidence.org/SR72.html).

We identify an immediate need for a systematic review in relation to one other set of interventions (agri-environment schemes), and a potential need for systematic reviews for three further interventions, should they become more widely practised (nest boxes for solitary bees and captive rearing of bumblebees or solitary bees).

1.4 Scope of the Bee Conservation synopsis

This synopsis covers evidence for the effects of conservation interventions for native, wild bees.

It is restricted to evidence captured on the website www.conservationevidence.com. It includes papers published in the journal Conservation Evidence, evidence summarised on our database and systematic reviews collated by the Collaboration for Environmental Evidence.

It does not include evidence from the substantial literature on husbandry methods for the largely domesticated honey bee Apis mellifera. It does include husbandry methods where they are relevant to native, wild bee species that are declining or threatened, such as bumblebees (Bombus spp.) and stingless bees (Meliponinae). Although the number of managed honey bee colonies is known to have declined in Europe and America, it is seldom the native subspecies that is kept and so we consider this to be outside the remit of Conservation Evidence. We do include some interventions and evidence relating to the conservation of subspecies of Apis mellifera in areas where they are native.

Evidence from all around the world is included. If there appears to be a bias towards evidence from northern European or North American temperate environments, this reflects a current bias in the published research that is available to us.

1.5 How we decided which bee conservation interventions to include

Our list of interventions has been agreed in partnership with an Advisory Board made up of international conservationists and academics with expertise in bee conservation. Although the list of interventions may not be exhaustive, we have tried to include all actions that have been carried out or advised to support populations or communities of wild bees.

1.6 How we reviewed the literature

In addition to evidence already captured by the Conservation Evidence project, we have searched the following sources for evidence relating to bee conservation: four specialist bee or insect conservation journals, from their first publication date to the end of 2009 (Apidologie, Journal of Apicultural Research, Insect Conservation and Diversity, Journal of Insect Conservation); ISI Web of Knowledge searched for papers with ‘bee’ as a search term, from 1997 to 2009 inclusive; all reports concerning bees published by Natural England or the UK Bumblebee Working Group up to 2009; other relevant papers or books frequently cited within the bee conservation literature, going back to 1912.

In total, 168 individual studies are covered in this synopsis, all included in full or in summary on the Conservation Evidence website.

The criteria for inclusion of studies in the Conservation Evidence database are as follows:

• There must have been an intervention that conservationists would do

• Its effects must have been monitored quantitatively

In some cases, where a body of literature has strong implications for conservation of a particular species group or habitat, although it does not directly test interventions for their effects, we refer the reader to this literature. For example, the proportion of natural habitat in farmland has often been shown to affect bee diversity, but no studies have yet intervened by restoring natural or semi-natural habitat and monitoring the effect on bees in surrounding farmland. In cases such as these, we briefly refer to the relevant literature, but present no evidence.

1.7 How the evidence is summarised

Conservation interventions are grouped primarily according to the relevant direct threats, as defined in the International Union for the Conservation of Nature (IUCN)’s Unified Classification of Direct Threats (www.iucnredlist.org/technical-documents/classification-schemes). In most cases, it is clear which main threat a particular intervention is meant to alleviate or counteract. Interventions to help bees threatened by agricultural land use change are very different from those intended to avoid the adverse effects of invasive species, for example.

Not all IUCN threat types are included, only those that threaten bees, and for which realistic conservation