10 research outputs found

    Using UAV‐mounted thermal cameras to detect the presence of nesting nightjar in upland clear‐fell: A case study in South Wales, UK

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    1. Confirming the presence and location of European Nightjar Caprimulgus europaeus nests is a significant fieldwork challenge in ecological monitoring. Nest sites can be located through direct observation or capture and radio tracking of breeding individuals; however, such work is time consuming, disturbing and costly.2. Unmanned aerial vehicles (UAV) equipped with thermal sensors may enable rapid survey over large areas by detecting nest locations based on the contrast of relatively warm nests and the surrounding cooler ground. The application of this concept using UAV‐mounted thermal sensors was trialled in two upland clear‐fell forestry sites in South Wales, UK.3. Detection trials were undertaken at five known nightjar nest sites to assess optimal timing and flight height for surveys. Nest heat signatures were clear during dusk and dawn, but not during the daytime. Nests were identifiable at flight heights up to 25 m, but flight heights of 12–20 m were optimal for the numbers of pixels per nest.4. This approach was tested in a field trial of a 17‐ha forestry site where the presence and position of nesting nightjars were unknown. An automated transect at dusk and dawn at 15 m flight elevation identified two active nightjar nests and four male nightjar roost sites. Without image analysis automation, the process of manual inspection of 2607 images for ‘hotspots’ of the approximate size and shape of nightjar nests was laborious.5. The UAV approach took around 18 h including survey time, processing and ground verification, whilst a nightjar nest finding survey would take 35 h for the same area. The small size of nightjars and the low resolution of the thermal sensors requires low altitude flight in order to maximize detectability and pixel coverage. Low flight elevation requires more consideration of the risk of collision with trees or posts. Consequently, the approach would not be suitable for covering areas of highly variable terrain

    Testing for effects of tail mounted radio tags and environmental variables on European Nightjar Caprimulgus europaeus nest survival

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    Capsule Monitoring of European Nightjar Caprimulgus europeaus nest sites over seven years produced no evidence of a negative effect of tail-mounted radio tag deployment on nest success. Aims To test whether nest success of European Nightjars was affected by radio tag deployment. Methods The breeding success of European Nightjars was monitored at the Brechfa West Wind Farm, Carmarthenshire, Wales, from 2013 to 2019. A total of 85 nests were located through a combination of capture and radio tracking of breeding individuals, and direct observation combined with focused searching. All located nests were subsequently monitored through a combination of visual checks and trail camera deployment until their natural conclusion. Results No evidence was identified to support a negative effect of tail-mounted radio tag deployment on the nest success of European Nightjars. However, nesting success (at least one chick fledged) was positively associated with mean temperature during the nesting period, although the strength of this effect varied through time. Conclusion The use of tail-mounted radio tags on European Nightjars had no significant negative effect on nest success

    Multi-scale habitat selection throughout the annual cycle of a long-distance avian migrant

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    Long-distance migrants are constrained by widely separated hospitable habitats in geographically isolated locations, making them vulnerable to environmental change, both through natural and anthropogenic causes. Knowledge about their resource selection decisions is imperative to understand the drivers of their declines. The distinct periods within an annual cycle, when individuals experience different environmental circumstances, are inextricably linked through carry-over effects which can have important consequences for the individual, and consequently the population. In this study, we employ precise archival GPS-tracking data of European Nightjars (Caprimulgus europaeus) and high-resolution global land cover data to examine habitat selection during the sedentary wintering and breeding periods, as well as during autumn and spring migration, using a correlational approach. We demonstrate how nightjars use general habitat characteristics, such as landscape diversity, for high-order habitat selection, while resource selection at a finer spatial scale is reliant on fine-scale variables related to a habitat’s suitability, such as surface area of grassland and shrubland. We show that nightjars favour spatially diverse landscapes, which allows them to minimize time spent searching for optimal habitats. The considerable variation in the drivers of habitat selection between and within seasons shows how anthropogenic land-use change can have an array of different impacts on migrants by influencing large- and fine-scale habitat selection. This study shows the advantages of an individual based GPS-tracking approach, combined with high spatial resolution remote sensing data, and highlights the need for full annual-cycle research on scale dependent habitat selection of long-distance avian migrants

    A novel method for targeting survey effort to identify new bat roosts using habitat suitability modelling

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    In the UK, four out of 18 bat species are listed on the EU Habitats Directive, including the lesser horseshoe bat (Rhinolophus hipposideros), and their population status is closely monitored by visiting known roosts. R. hipposideros predominantly form maternity roosts in buildings, but roosts are impermanent features in the landscape and their distribution changes as bats form new roosts and abandon others. Locating new roosts requires intensive surveys which are challenging and inefficient. In this study, we provide a novel model-based strategy to identify potential R. hipposideros maternity roost sites that can be used to monitor bat populations. First, we model potential maternity roost habitat using record centre data on roost locations across Wales, Great Britain. We then constrain the area identified from modelling using record centre data on locations of bats in areas with no known roosts. We used two variable selection methods and three pseudo-absence data sets (random background points, random points in buildings and target group selection of mammal records) to produce six habitat suitability models. The three pseudo-absence data sets produced different habitat suitability maps, demonstrating the influence of pseudo-absence selection on species distribution models. The six models were combined using weighted mean average to produce an ensemble model that performed better than individual models and that indicated high levels of congruence in areas predicted to have high habitat suitability for maternity roosts. Our model revealed an extensive area (6523 km 2 ; 31% of the area of Wales) containing 18,051 buildings in suitable habitat. Using record centre data on bat activity outside commuting range from known roosts reduced the potential survey area to 133 km 2 (0.6% of the area of Wales) and 207 buildings. Our modelling outputs can be used to direct volunteers and bat surveyors in more targeted and efficient searches

    Moth biomass and diversity in coniferous plantation woodlands

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    Moths are a vital ecosystem component and key food source for many species, but have shown widespread and often severe declines. Multiple factors have been implicated in these declines, although the most important large-scale factors in the temperate zone are considered to be land use change and climate change. The majority of forest cover in the U.K. and elsewhere in Europe is dominated by intensively managed plantation woodlands, and studies have shown reduced broadleaved woodland cover can negatively affect moth diversity and biomass. However, few studies have examined how open habitats within the plantation forest matrix, which often represent a large proportion of the total forest area, are utilised by moth species. Here, we aimed to determine: (1) how moth biomass in open habitats within plantation forests varies seasonally and in response to management; and (2) how species diversity and Welsh conservation priority (“Section 7”) species respond to management at multiple spatial scales. We sampled moth communities in open habitats within five coniferous plantation forests across Wales, using light traps deployed in areas that ranged from 20 years post-felling. We found a significant non-linear relationship between space, time and moth biomass, with a significant peak in biomass in the summer months (∌29th June) suggesting important phenological effects with associated implications for dependent species. Biomass was also strongly affected by time since felling, with older habitats in general supporting a higher moth biomass, although this was dependent on the seasonal variation in habitat ‘greenness’ and productivity, as measured by NDVI. We also found that the abundances of Welsh priority species responded positively to increased extents of open habitats of ages 1–10 years post felling, but the amount of recent clear felling (0 years post felling) in the surrounding landscape had a negative correlation with both abundance and diversity. We conclude that habitat, seasonality/ productivity and short-term weather variations play a key role in determining moth biomass, species diversity and the presence of Welsh priority moth species within managed coniferous plantation woodland. This means there is an opportunity for forest management practices to adopt measures that can not only enhance moth biomass productivity, in turn supporting insectivorous species such as European nightjar Caprimulgus europaeus, but also deliver wider ecosystem services through the provision of habitat matrices that support invertebrate species of conservation concern

    Multi-scale habitat selection throughout the annual cycle of a long-distance avian migrant

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    Abstract: Long-distance migrants are constrained by widely separated hospitable habitats in geographically isolated lo-cations, making them vulnerable to environmental change, both through natural and anthropogenic causes. Knowledge about their resource selection decisions is imperative to understand the drivers of their declines. The distinct periods within an annual cycle, when individuals experience different environmental circumstances, are inextricably linked through carry-over effects which can have important consequences for the individual, and consequently the population. In this study, we employ precise archival GPS-tracking data of European Nightjars (Caprimulgus europaeus) and high-resolution global land cover data to examine habitat selection during the sedentary wintering and breeding periods, as well as during autumn and spring migration, using a correlational approach. We demonstrate how nightjars use general habitat characteristics, such as landscape diversity, for high-order habitat selection, while resource selection at a finer spatial scale is reliant on fine-scale variables related to a habitat's suitability, such as surface area of grassland and shrubland. We show that nightjars favour spatially diverse landscapes, which allows them to minimize time spent searching for optimal habitats. The considerable variation in the drivers of habitat selection between and within seasons shows how anthropogenic land-use change can have an array of different impacts on migrants by influencing large-and fine-scale habitat selection. This study shows the advantages of an individual based GPS-tracking approach, combined with high spatial resolution remote sensing data, and highlights the need for full annual-cycle research on scale dependent habitat selection of long-distance avian migrants

    Rush or relax:migration tactics of a nocturnal insectivore in response to ecological barriers

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    During their annual migration, avian migrants alternate stopover periods, for refuelling, with migratory flight bouts. We hypothesise that European Nightjars (Caprimulgus europaeus) adapt their daily migration tactics in association with biomes. We tracked the autumn migration of 24 European Nightjars, from breeding populations in Mongolia, Belgium and UK, using GPS-loggers and multi-sensor data loggers. We quantified crepuscular and nocturnal migration and foraging probabilities, as well as daily travel speed and flight altitude during active migration in response to biomes. Nightjars adopt a rush tactic, reflected in high daily travel speed, flight altitude and high migration probabilities at dusk and at night, when travelling through ecological barriers. Migration is slower in semi-open, hospitable biomes. This is reflected in high foraging probabilities at dusk, lower daily travel speed and lower migration probabilities at dusk. Our study shows how nightjars switch migration tactics during autumn migration, and suggest nightjars alternate between feeding and short migratory flight bouts within the same night when travelling through suitable habitats. How this may affect individuals’ fuel stores and whether different biomes provide refuelling opportunities en route remains to be investigated, to understand how future land-use change may affect migration patterns and survival probabilities

    Outcomes in Newly Diagnosed Atrial Fibrillation and History of Acute Coronary Syndromes: Insights from GARFIELD-AF

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    BACKGROUND: Many patients with atrial fibrillation have concomitant coronary artery disease with or without acute coronary syndromes and are in need of additional antithrombotic therapy. There are few data on the long-term clinical outcome of atrial fibrillation patients with a history of acute coronary syndrome. This is a 2-year study of atrial fibrillation patients with or without a history of acute coronary syndromes

    Analysis of Outcomes in Ischemic vs Nonischemic Cardiomyopathy in Patients With Atrial Fibrillation A Report From the GARFIELD-AF Registry

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    IMPORTANCE Congestive heart failure (CHF) is commonly associated with nonvalvular atrial fibrillation (AF), and their combination may affect treatment strategies and outcomes
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