Assessing the potential contribution of roads to variation in British bird populations

Roads and their traffic are known to affect bird species at both individual and population levels. Collisions with vehicles can cause direct mortality, and noise, light and chemical pollution can have sub-lethal impacts. Additionally, roads can cause habitat degradation, fragmentation and edge effects. However, thus far, the published literature on this topic comprises only relatively small-scale studies and our understanding of the impacts of roads on bird populations at landscape or national scales is limited. I use bird count and road data from across Great Britain to assess the spatial associations between the density and traffic volumes of roads, and bird populations in the surrounding areas. In Chapter 1, I provide background detail on the impacts of roads on birds and introduce the premise and necessity of my thesis. In Chapter 2, I quantify changes in the detectability of birds in field surveys in relation to road exposure. I find that, while some species are significantly harder to detect in areas of higher road exposure, others are easier. I therefore suggest that, in analyses of bird populations around roads, where possible, variation in detectability with exposure to roads should be accounted for, to avoid under- or over-estimation of road impacts on birds. In Chapter 3, I incorporate my detectability models into a spatial analysis of bird populations and roads across Britain, for 51 common and widespread species. This methodology allows independent assessment of the associations between roads and bird abundance, accounting for the potentially confounding impacts of roads on detectability. I find the abundances of 30 species to vary significantly with exposure to roads, some negatively and others positively. Across the interquartile range of road exposure, the mean decrease in bird abundance (for species with significant negative associations) was -19% and the mean increase (for species with significant positive associations) was +47%. In Chapter 4, in order to explore interspecific variation in these associations, I analyse a further 24 rarer species, and then test my results for all 75 species in relation to five characteristics. In this analysis I find 58 species to vary significantly in abundance with exposure to roads and the mean changes in bird abundance across the interquartile range of road exposure to increase to -39% and +48%. I also find that, with increasing road exposure, species with higher national populations have relatively higher abundance, while nationally rarer species have relatively lower abundance. Smaller-bodied and migratory species are also more negatively associated with road exposure. The distances over which negative associations between road exposure and bird abundance can be detected reach a mean of 700 m from a road, an area covering over 70% of Britain and 41% of the total area of terrestrial protected sites. I suggest that roads may, like some other forms of human disturbance, create conditions that benefit generally common species at the expense of others, thus having the potential to contribute to large-scale simplification of bird communities. Finally, in Chapter 5, I give an overall discussion of my thesis and highlight the importance of further work to understand in more detail the impacts of roads on birds in Britain and elsewhere, and to mitigate them effectively.NER

Roads as a contributor to landscape-scale variation in bird communities.

Roads and their traffic can affect wildlife over large areas and, in regions with dense road networks, may influence a high proportion of the ecological landscape. We assess the abundance of 75 bird species in relation to roads across Great Britain. Of these, 77% vary significantly in abundance with increasing road exposure, just over half negatively so. The effect distances of these negative associations average 700 m from a road, covering over 70% of Great Britain and over 40% of the total area of terrestrial protected sites. Species with smaller national populations generally have lower relative abundance with increasing road exposure, whereas the opposite is true for more common species. Smaller-bodied and migratory species are also more negatively associated with road exposure. By creating environmental conditions that benefit generally common species at the expense of others, road networks may echo other anthropogenic disturbances in bringing about large-scale simplification of avian communities

Roads as a contributor to landscape-scale variation in bird communities

Abstract: Roads and their traffic can affect wildlife over large areas and, in regions with dense road networks, may influence a high proportion of the ecological landscape. We assess the abundance of 75 bird species in relation to roads across Great Britain. Of these, 77% vary significantly in abundance with increasing road exposure, just over half negatively so. The effect distances of these negative associations average 700 m from a road, covering over 70% of Great Britain and over 40% of the total area of terrestrial protected sites. Species with smaller national populations generally have lower relative abundance with increasing road exposure, whereas the opposite is true for more common species. Smaller-bodied and migratory species are also more negatively associated with road exposure. By creating environmental conditions that benefit generally common species at the expense of others, road networks may echo other anthropogenic disturbances in bringing about large-scale simplification of avian communities

Roads as a contributor to landscape-scale variation in bird communities

Abstract: Roads and their traffic can affect wildlife over large areas and, in regions with dense road networks, may influence a high proportion of the ecological landscape. We assess the abundance of 75 bird species in relation to roads across Great Britain. Of these, 77% vary significantly in abundance with increasing road exposure, just over half negatively so. The effect distances of these negative associations average 700 m from a road, covering over 70% of Great Britain and over 40% of the total area of terrestrial protected sites. Species with smaller national populations generally have lower relative abundance with increasing road exposure, whereas the opposite is true for more common species. Smaller-bodied and migratory species are also more negatively associated with road exposure. By creating environmental conditions that benefit generally common species at the expense of others, road networks may echo other anthropogenic disturbances in bringing about large-scale simplification of avian communities

Soot and smoke aerosol may not warm climate

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94810/1/jgrd10551.pd

Endemic species predation by the introduced smooth-billed ani in Galápagos

Funder: International Community FoundationFunder: Christ's College, University of Cambridge; doi: http://dx.doi.org/10.13039/501100000590Abstract: The introduced smooth-billed ani Crotophaga ani has become widespread across the Galápagos archipelago in the past half-century. It is known to predate upon a range of native and endemic species, and is a potential vector for the spread of invasive plants and parasites. Here we report previously undocumented examples of smooth-billed ani predation in Galápagos, including that of an endemic racer snake and a scorpion. We highlight the possibility of smooth-billed anis having a serious impact on the endemic Galápagos carpenter bee, a major pollinator, as well as native and endemic Lepidopterans and other invertebrates. In addition, we report smooth-billed ani predation of other introduced species and note the importance of further research on the wide-scale impacts of smooth-billed anis in Galápagos and their role within the archipelago’s ecological networks

Assessment of the response of pollinator abundance to environmental pressures using structured expert elicitation

Policy-makers often need to rely on experts with disparate fields of expertise when making policy choices in complex, multi-faceted, dynamic environments such as those dealing with ecosystem services. For policy-makers wishing to make evidence-based decisions which will best support pollinator abundance and pollination services, one of the problems faced is how to access the information and evidence they need, and how to combine it to formulate and evaluate candidate policies. This is even more complex when multiple factors provide influence in combination. The pressures affecting the survival and pollination capabilities of honey bees (Apis mellifera), wild bees, and other pollinators are well documented, but incomplete. In order to estimate the potential effectiveness of various candidate policy choices, there is an urgent need to quantify the effect of various combinations of factors on the pollination ecosystem service. Using high-quality experimental evidence is the most robust approach, but key aspects of the system may not be amenable to experimentation or may be prohibitive based on cost, time and effort. In such cases, it is possible to obtain the required evidence by using structured expert elicitation, a method for quantitatively characterizing the state of knowledge about an uncertain quantity. Here we report and discuss the outputs of the novel use of a structured expert elicitation, designed to quantify the probability of good pollinator abundance given a variety of weather, disease, and habitat scenarios

Addressing antimicrobial resistance through community engagement: a framework for developing contextually relevant and impactful behaviour change interventions.

BackgroundCommunity engagement (CE) interventions often explore and promote behaviour change around a specific challenge. Suggestions for behaviour change should be co-produced in partnership with the community. To facilitate this, it is essential that the intervention includes key content that unpacks the challenge of interest via multiple sources of knowledge. However, where community lived experience and academic evidence appear misaligned, tensions can appear within the co-production dynamic of CE. This is specifically so within the context of antimicrobial resistance (AMR) where ideal behaviours are often superseded by what is practical or possible in a particular community context.MethodsHere we describe a framework for the equitable development of contextually appropriate, clearly evidenced behavioural objectives for CE interventions. This framework explores different sources of knowledge on AMR, including the potentially competing views of different stakeholders.FindingsThe framework allows key content on AMR to be selected based upon academic evidence, contextual appropriateness and fit to the chosen CE approach. A case study of the framework in action exemplifies how the framework is applicable to a range of contexts, CE approaches and One Health topics beyond just AMR.ConclusionsWithin CE interventions, academic evidence is crucial to develop well-informed key content. However, this formative work should also involve community members, ensuring that their contextual knowledge is valued. The type of CE approach also needs careful consideration because methodological constraints may limit the breadth and depth of information that can be delivered within an intervention, and thus the scope of key content