For each intervention, the book summarises studies captured by the Conservation Evidence project, where that intervention has been tested and its effects on birds quantified. The result is a thorough guide to what is known, or not known, about the effectiveness of bird conservation actions throughout the world.
The preparation of this synopsis was funded by the Natural Environment Research Council and Arcadia.
About the Author
David Williams is a Research Assistant in the Department of Zoology, University of Cambridge.
Robert G. Pople is a former Research Assistant 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.
Matthew F. Child is a Research Assistant in the Department of Zoology, University of Cambridge.
Lynn Dicks is a Research Associate in the Department of Zoology, University of Cambridge.
Erasmus K.H.J. zu Ermgassen is a student in the Department of Veterinary Medicine, University of Cambridge.
William J. Sutherland is the Miriam Rothschild Professor of Conservation Biology at the University of Cambridge.
Read an Excerpt
About this book
The purpose of Conservation Evidence synopses
Who is this synopsis 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 Bangor (www.cebc.bangor.ac.uk).
The Conservation Evidence project
The Conservation Evidence project has three parts:
An online, open access journalConservation 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.
An ever-expanding database of summaries of previously published scientific papers, reports, reviews or systematic reviews that document the effects of interventions.
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 3,000 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 322 bird conservation interventions identified in this synopsis, five are the subjects of current systematic reviews:
How does the impact of grazing on heathland compare with the impact of burning, cutting or no management? http://www.environmentalevidence.org/SR14.html
Is predator control an effective strategy for enhancing bird populations? http://www. environmentalevidence.org/SR38.html.
Do matrix features affect species movement? http://www.environmentalevidence.org/ SR43.html
Does structural connectivity facilitate dispersal of native species in Australia's fragmented terrestrial landscape? http://www.environmentalevidence.org/SR44.html
How do thinning and burning treatments in south-western conifer forests in the United States affect wildlife distribution, abundance and population performance? http://www. environmentalevidence.org/SR66.html
In addition, three systematic reviews provide important information on the impacts of threats on bird populations:
Effects of wind turbines on bird abundance. http://www.environmentalevidence.org/ SR4.html
What is the impact of public access on the breeding success of ground-nesting and cliff-nesting birds? http://www.environmentalevidence.org/SR16.html
What are the impacts of human recreational activity on the distribution, nest-occupancy rates and reproductive success of breeding raptors? http://www.environmentalevidence. org/SR27.html
Another provides evidence for how to apply an intervention:
Do trapping interventions effectively reduce or eradicate populations of the American mink (Mustela vison)? http://www.environmentalevidence.org/SR7.html.
There are several interventions which we feel would benefit significantly from systematic reviews:
Interventions to reduce the impact of electricity pylons and power lines
Interventions to reduce seabird bycatch
The provision of artificial nest sites
The provision of supplementary food
Scope of the Bird Conservation synopsis
This synopsis covers evidence for the effects of conservation interventions for native (see below), wild birds.
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.
We have gathered evidence from all around the world, and the apparent over (or under-representation) of some regions reflects the current biases in published research papers available to Conservation Evidence.
Native vs. non-native species
This synopsis does not include evidence from the substantial literature on husbandry of domestic birds, or non-native gamebirds (e.g. common pheasants Phasianus colchicus in Europe and North America). However, where these interventions affect native species, or are relevant to the conservation of native, wild species, they are included (e.g. management of farmland for common pheasants has a significant impact on several declining native songbirds in the UK, see Stoate (2002) in 'Manage hedges to benefit wildlife', 'Plant nectar flower mixture/wildflower strips', 'Plant wild bird seed cover strips', 'Provide supplementary food for birds', 'Create beetle banks', 'Control predators not on islands – songbirds', 'Reduce pesticide or herbicide use generally'.
How we decided which 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 bird 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 birds.
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 bird conservation:
Fifteen specialist bird conservation journals, from their first publication to the end of 2010 (African Bird Club Bulletin, The Auk, Bird Conservation International, Bird Study, BTO Research Reports, Emu, Ibis, Journal of Avian Biology – formerly Ornis Scandinavica, Journal of Field Ornithology, Journal Raptor Research – formerly Raptor Research, Ornitologia Neotropical, RSPB Research Reports, The Condor, Waterbirds – formerly Colonial Waterbirds, Wilson Journal of Ornithology – formerly Wilson Bulletin)
Twenty general conservation journals over the same time period.
Where we knew of an intervention which we had not captured evidence for, we performed keyword searches on ISI Web of Science and www.scholar.google.com for this intervention.
Individual studies covered in this synopsis are 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, but present no evidence.
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/classificationschemes/ habitats-classification-scheme-ver3). In most cases, it is clear which main threat a particular intervention is meant to alleviate or counteract.
Not all IUCN threat types are included, only those that threaten birds, and for which realistic conservation interventions have been suggested.
Some important interventions can be used in response to many different threats, and it would not make sense to split studies up depending on the specific threat they were studying. We have therefore separated out these interventions, following the IUCN's Classification of Conservation Actions (http://www.iucnredlist.org/technical-documents/classificationschemes/ conservation-actions-classification-scheme-ver2). The actions we have separated out are: 'Habitat protection', 'Education and community development', 'Habitat restoration and creation', 'General responses to small/declining populations' and 'Captive breeding, rearing and releases (ex situ conservation)'. These respectively match the following IUCN categories: 'Land/water protection', 'Education and awareness' and 'Livelihood, economic and other incentives', 'Land/water management – Habitat and natural process restoration', and 'Species Management'.
Normally, no intervention is listed in more than one place, and when there is ambiguity about where a particular intervention should fall there is clear cross-referencing. Some studies describe the effects of multiple interventions. When this is the case, cross-referencing is again used to direct readers to the other interventions investigated. Where a study has not separated out the effects of different interventions, the study is only described once, but readers are directed to it from the other interventions.
In the text of each section, studies are presented in chronological order, so the most recent evidence is presented at the end. The summary text at the start of each section groups studies according to their findings.
At the start of each chapter, a series of key messages provides a rapid overview of the evidence. These messages are condensed from the summary text for each intervention.
Background information is provided where we feel recent knowledge is required to interpret the evidence. This is presented separately and relevant references included in the reference list at the end of each intervention section.
References containing evidence for the effects of interventions are summarised in more detail on the Conservation Evidence website. In electronic versions of the synopsis, they are hyperlinked directly to the summary. If you do not have access to the electronic version of the synopsis, searching for the reference details or the species name on www.conservationevidence.com is the quickest way to locate summaries.
The information in this synopsis is available in three ways:
As a book, printed by Pelagic Publishing and for sale from www.nhbs.com
As a pdf to download from www.conservationevidence.com
As text for individual interventions on the searchable database at www.conservation-evidence.com.
Terminology used to describe evidence
Unlike systematic reviews of particular conservation questions, we do not quantitatively assess the evidence, or weight it according to quality. However, to allow you to interpret evidence, we make the size and design of each trial we report clear. The table below defines the terms that we have used to do this.
The strongest evidence comes from randomised, replicated, controlled trials with pairedsites and before and after monitoring.
We have followed the taxonomy used in BirdLife International's 2011 checklist (http://www. birdlife.org/datazone/info/taxonomy), updating the names used in original papers where necessary. We have always referred to the species name used in the original paper as well. Where possible, common names and Latin names are both given the first time each species is mentioned within each intervention.
Where interventions have a large literature associated with them we have sometimes divided studies along taxonomic or functional lines. These do not follow strict taxonomic divisions, but instead are designed to maximise their utility. For example, storks, herons and ibises are often included together as both groups are large wading birds and may respond to interventions in similar ways.
Where interventions have a large literature associated with them and effects could vary between habitats, we have divided the literature using the IUCN Habitat Classification Scheme (Version 3.0), available from www.iucnredlist.org.
Throughout the synopsis we have quoted results from papers. Unless specifically stated, these results reflect statistical tests performed on the results.
Many studies investigate several interventions at once. When the effects of different interventions are separated, then the results are discussed separately in the relevant sections. However, often the effects of multiple interventions cannot be separated. When this is the case, the study is included in the section on each intervention, but the fact that several interventions were used is highlighted.
How you can help to change conservation practice
If you know of evidence relating to bird conservation that is not included in this synopsis, we invite you to contact us, via the www.conservationevidence.com website. Following guidelines provided on the site, you can submit a summary of a previously published study, or submit a paper describing new evidence to the Conservation Evidence journal. We particularly welcome summaries written by the authors of papers published elsewhere, and papers submitted by conservation practitioners.
Habitat destruction is the largest single threat to biodiversity, and the spread of agriculture into natural habitats alone threatens 1,065 species of birds (87% of all threatened species) (BirdLife International 2008). Habitat protection is therefore one of the most frequently used conservation interventions, particularly in the tropics and in other areas with large areas of surviving natural vegetation.
Habitat protection can be through the designation of legally protected areas (PAs), using national or local laws; through the designation of Important Bird Areas (IBAs) or similar schemes, which, whilst providing no formal protection, may increase the profile of a site and make its conversion more difficult; or through the protection of entire habitat types, for example through the EU's Habitats Directive.
However, it can be difficult to measure the effectiveness of such areas: there may be no suitable controls; monitoring often only begins with the designation of the PA and PAs tend to be located in areas that would be less likely to be cleared even if it was not protected, making the prevention of agricultural expansion less politically difficult (Joppa & Pfaff 2011). Analysis of PAs often, therefore, requires large datasets, and this means that most studies investigating them use either satellite imagery (e.g. Joppa et al. 2008) or overall 'condition' scores (e.g. Mwangi et al. 2010), rather than data on bird populations, which are much harder to collect.
It is worth noting that the designation of a habitat or area as 'protected' (also known as de jure protection) does not necessarily mean protection in practical terms (de facto protection). The chapter on 'Threat: Biological resource use' contains several studies that examine the effect of greater de facto protection on bird populations.
Legally protect habitats
Four studies from Europe found that populations increased after habitat protection and a review from China found high use of protected habitats by cranes. A replicated, randomised and controlled study from Argentina found that some, but not all bird groups had higher species richness or were at higher densities in protected habitats.
Ensure connectivity between habitat patches
Two studies of a replicated, controlled experiment in Canadian forests found that some species (not forest specialists) were found at higher densities in forest patches connected to continuous forest, compared to isolated patches and that some species used corridors more than clearcuts between patches.
Provide or retain un-harvested buffer strips
Three replicated studies from the USA found that species richness or abundances were higher in narrow (<100 m) strips of forest, but five replicated studies from North America found that wider strips retained a community more similar to that of uncut forest than narrow strips. Two replicated studies from the USA found no differences in productivity between wide and narrow buffers, but that predation of artificial nests was higher in buffers than in continuous forest.
Excerpted from "Bird Conservation"
Copyright © 2013 William J. Sutherland.
Excerpted by permission of Pelagic Publishing.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.
Table of Contents
1. About this book
2. Habitat protection
3. Education and awareness raising
4. Threat: Residential and commercial development
5. Threat: Agriculture
6. Threat: Energy production and mining
7. Threat: Transportation and service corridors
8. Threat: Biological resource use
9. Threat: Human intrusions and disturbance
10. Threat: Natural system modifi cations
11. Habitat restoration and creation
12. Threat: Invasive alien and other problematic species
13. Threat: Pollution
14. Threat: Climate change, extreme weather and geological events
15. General responses to small/declining populations
16. Captive breeding, rearing and releases (ex situ conservation)