Andrew S. Pullin

One Hundred Questions of Importance to the Conservation of Global Biological Diversity

We identified 100 scientific questions that, if answered, would have the greatest impact on conservation practice and policy. Representatives from 21 international organizations, regional sections and working groups of the Society for Conservation Biology, and 12 academics, from all continents except Antarctica, compiled 2291 questions of relevance to conservation of biological diversity worldwide. The questions were gathered from 761 individuals through workshops, email requests, and discussions. Voting by email to short-list questions, followed by a 2-day workshop, was used to derive the final list of 100 questions. Most of the final questions were derived through a process of modification and combination as the workshop progressed. The questions are divided into 12 sections: ecosystem functions and services, climate change, technological change, protected areas, ecosystem management and restoration, terrestrial ecosystems, marine ecosystems, freshwater ecosystems, species management, organizational systems and processes, societal context and change, and impacts of conservation interventions. We anticipate that these questions will help identify new directions for researchers and assist funders in directing funds.

Poor evidence-base for assessment of windfarm impacts on birds

Concerns about anthropogenic climate change have resulted in promotion of renewable energy sources, especially wind energy. A concern raised against widespread windfarm development is that it may negatively impact bird populations as a result of bird collision with turbines, habitat loss and disturbance. Using systematic review methodology bird abundance data were synthesized from 19 globally-distributed windfarms using meta-analysis. The effects of bird taxon, turbine number, power, location, latitude, habitat type, size of area, time since operation, migratory status of the species and quality of evidence were analysed using meta-regression. Although the synthesized data suggest a significant negative impact of windfarms on bird abundance, there is considerable variation in the impact of individual windfarm sites on individual bird species, and it is unclear if the negative impact is a decline in population abundance or a decline in use owing to avoidance. Anseriformes experienced greater declines in abundance than other taxa, followed by Charadriiformes, Falconiformes and Accipitriformes, and Passeriformes. Time since windfarms commenced operation also had a significant impact on bird abundance, with longer operating times resulting in greater declines in abundance than short operating times. Other variables, including turbine number and turbine power either had very weak but statistically significant effects or did not have a significant effect on bird abundance. Windfarms may have significant biological impacts, especially over longer time scales, but the evidence-base is poor, with many studies being methodologically weak, and more long-term impact assessments are required. There is clear evidence that Anseriformes (wildfowl) and Charadriiformes (waders) experience declines in abundance, suggesting that a precautionary approach should be adopted to windfarm development near aggregations of these taxa in offshore and coastal locations. The impact of windfarm developments on bird populations must also be viewed in the context of the possible impact of climate change in the absence of windfarms.

Support for decision making in conservation practice: an evidence-based approach

Abstract Conservation managers are challenged with the task of compiling management plans in which they have to decide on appropriate actions to meet specific objectives. We argue that support for such decision-making is poor and that decision-makers have little opportunity to capture and evaluate the evidence for effectiveness of alternative management options. The result is that decisions are often made without access to the best quality evidence thus increasing the probability that inappropriate management options will be adopted. The aim of this paper is to propose a mechanism for increasing support by improving information flow to decision-makers within an evidence-based framework. The model of evidence-based practice in medicine and public health is used to explore possibilities for parallel practice in conservation. The processes of management plan and action plan formulation are used as examples of how this model provides opportunities to enhance information flow between scientists and practitioners and to encourage formation of productive partnerships and decision support systems, thereby improving effectiveness. Accessibility of evidence is a key issue addressed through the production of systematic reviews and their results being actively disseminated, in a usable format, to the point of need. The role of funding bodies and particularly governments in catalysing this process is seen as key to achieving more evidence-based conservation practice.

Are hedgerows effective corridors between fragments of woodland habitat? An evidence-based approach

Anthropogenic modification of the countryside has resulted in much of the landscape consisting of fragments of once continuous habitat. Increasing habitat connectivity at the landscape-scale has a vital role to play in the conservation of species restricted to such remnant patches, especially as species may attempt to track zones of habitat that satisfy their niche requirements as the climate changes. Conservation policies and management strategies frequently advocate corridor creation as one approach to restore connectivity and to facilitate species movements through the landscape. Here we examine the utility of hedgerows as corridors between woodland habitat patches using rigorous systematic review methodology. Systematic searching yielded 26 studies which satisfied the review inclusion criteria. The empirical evidence currently available is insufficient to evaluate the effectiveness of hedgerow corridors as a conservation tool to promote the population viability of woodland fauna. However, the studies did provide anecdotal evidence of positive local population effects and indicated that some species use hedgerows as movement conduits. More replicated and controlled field investigations or long-term monitoring are required in order to allow practitioners and policy makers to make better informed decisions about hedgerow corridor creation and preservation. The benefits of such corridors in regard to increasing habitat connectivity remain equivocal, and the role of corridors in mitigating the effects of climate change at the landscape-scale is even less well understood.

Persistence of species in a fragmented urban landscape: the importance of dispersal ability and habitat availability for grassland butterflies

Some species cope with, and survive in, urban areas better than others.From a conservation viewpoint it is important to understand why some species arerare or are excluded in the urban landscape, in order that we might take actionto conserve and restore species. Two ecological factors that might explain thedistribution and abundance of butterfly species in the urban landscape aredispersal ability and the availability of suitable habitat. The influence ofthese factors was assessed by examining the distribution and genetic structureof four grassland butterfly species in the West Midlands conurbation, UK. Thefour species differ in their distribution and abundance, mobility and habitatspecificity. No significant fit to the isolation-by-distance model was found forany of the study species at this spatial scale. MeanFST values revealed a non-significant level ofpopulation structuring for two species, Pieris napi (L.)and Maniola jurtina (L.), but moderate and significantpopulation differentiation for Pyronia tithonus (L.) andCoenonympha pamphilus (L.). Results suggest that thesespecies are limited more by the availability of suitable habitat than by theirability to move among habitat patches. Conservation strategies for thesegrassland species should initially focus on the creation and appropriatemanagement of suitable habitat. More sedentary species that have already beenexcluded from the conurbation may require a more complex strategy for theirsuccessful restoration.

Effectiveness of predator removal for enhancing bird populations.

Predation pressure on vulnerable bird species has made predator control an important issue for international nature conservation. Predator removal by culling or translocation is controversial, expensive, and time-consuming, and results are often temporary. Thus, it is important to assess its effectiveness from all available evidence. We used explicit systematic review methodology to determine the impact of predator removal on four measurable responses in birds: breeding performance (hatching success and fledging success) and population size (breeding and postbreeding). We used meta-analysis to summarize results from 83 predator removal studies from six continents. We also investigated whether characteristics of the prey, predator species, location, and study methodology explained heterogeneity in effect sizes. Removing predators increased hatching success, fledging success, and breeding populations. Removing all predator species achieved a significantly larger increase in breeding population than removing only a subset. Postbreeding population size was not improved on islands, or overall, but did increase on mainlands. Heterogeneity in effect sizes for the four population parameters was not explained by whether predators were native or introduced; prey were declining, migratory, or game species; or by the study methodology. Effect sizes for fledging success were smaller for ground-nesting birds than those that nest elsewhere, but the difference was not significant. We conclude that current evidence indicates that predator removal is an effective strategy for the conservation of vulnerable bird populations. Nevertheless, the ethical and practical problems associated with predator removal may lead managers to favor alternative, nonlethal solutions. Research is needed to provide and synthesize data to determine whether these are effective management practices for future policies on bird conservation.

Does community forest management provide global environmental benefits and improve local welfare

Global financial donors have invested billions of dollars in “Sustainable Forest Management” to conserve forests and the ecosystem services they provide. A major contributing mechanism, community forest management (CFM), aims to provide global environmental benefits (reduce deforestation, maintain biodiversity), while also improving local human welfare (alleviate poverty). We have systematically reviewed available evidence of CFM effectiveness and consider the implications of our findings for future investment in CFM programs. There is evidence of CFM being associated with greater tree density and basal area but not with other indicators of global environmental benefits. We found no data on local human welfare amenable to meta-analysis. Poor study design, variable reporting of study methodology or context, and lack of common indicators make evidence synthesis difficult. Given the policy interest in and the planned donor expenditure on CFM, evaluation must be improved so that informed decisions can be made...

Conservation Focus on Europe: Major Conservation Policy Issues That Need to Be Informed by Conservation Science

Europe is one of the worlds most densely populated continents and has a long history of human-dominated land- and seascapes. Europe is also at the forefront of developing and implementing multinational conservation efforts. In this contribution, we describe some top policy issues in Europe that need to be informed by high-quality conservation science. These include evaluation of the effectiveness of the Natura 2000 network of protected sites, implications of rapid economic and subsequent land-use change in Central and Eastern Europe, conservation of marine biodiversity and sustainability of fisheries, the effect of climate change on movement of species in highly fragmented landscapes, and attempts to assess the economic value of ecosystem services and biodiversity. Broad policy issues such as those identified are not easily amenable to scientific experiment. A key challenge at the science-policy interface is to identify the research questions underlying these problem areas so that conservation science can provide evidence to underpin future policy development.

Effectiveness of engineered in‐stream structure mitigation measures to increase salmonid abundance: a systematic review

Engineered in-stream structures are often installed to increase salmonid abundance, either for commercial gain in fisheries or for conservation purposes in degraded habitats. Having been in widespread use for the last 80 years, at an estimated cost of hundreds of millions of U.S. dollars each year, the effectiveness of these structures is still widely debated in the literature. Many studies of varying quality have been undertaken that attempt to address this issue, but it has proved difficult for practitioners to develop a consensus regarding the utility of these structures, despite their continued use. Systematic review methodology was used to formally synthesize empirical evidence regarding the effectiveness of engineered in-stream structures as a management tool to increase salmonid abundance. Meta-analysis shows that evidence regarding the effectiveness of in-stream devices is equivocal. Heterogeneity is significant both for population size and local habitat preference. This heterogeneity is related to stream width, with in-stream devices being less effective in larger streams. Consequently, widespread use of in-stream structures for restoration, particularly in larger streams, is not supported by the current scientific evidence base.

Are current management recommendations for saproxylic invertebrates effective? A systematic review

Conservation management recommendations for saproxylic invertebrates advocate the continuous provision of the dead and decaying wood microhabitats that they require for survival. Accepted site-based management practices include leaving fallen dead and decaying wood in situ, providing supplementary coarse woody material (CWM), inducing decay in mature trees and strategic planting in order to maintain a balanced age structure of trees in both space and time. Here we examine the empirical evidence regarding the effectiveness of such interventions using rigorous systematic review methodology. Systematic searching yielded 27 studies containing pertinent information. The evidence presently available is insufficient to critically appraise the utility of any specific intervention for conserving saproxylic species, or assemblages, in the long-term. However, there are a range of studies, conducted over relatively short periods of time, which do describe changes in saproxylic fauna in response to management practices. In the absence of robust, high quality evidence, recommendations relating to the use of specific site-based conservation interventions should only be regarded as speculative. Nonetheless, general proposals for the maintenance of suitable microhabitats, such as the protection of veteran trees within the landscape, are based on sound ecological principles and should be encouraged even though experimentally controlled and replicated evidence is lacking. Further primary research and long-term monitoring are required to fill the gaps in our ecological knowledge that potentially weaken the case for the effectiveness of current saproxylic invertebrate conservation action and would enable practitioners to make better informed decisions with regard to dead wood protection and provision.