Second-generation anticoagulant rodenticides (SGARs) are widely used to control rodent populations, resulting in the serious secondary exposure of predators to these contaminants. In the United Kingdom (UK), professional use and purchase of SGARs were revised in the 2010s. Certain highly toxic SGARs have been authorized since then to be used outdoors around buildings as resistance-breaking chemicals under risk mitigation procedures. However, it is still uncertain whether and how these regulatory changes have influenced the secondary exposure of birds of prey to SGARs. Based on biomonitoring of the UK Common Buzzard (Buteo buteo) collected from 2001 to 2019, we assessed the temporal trend of exposure to SGARs and statistically determined potential turning points. The magnitude of difenacoum decreased over time with a seasonal fluctuation, while the magnitude and prevalence of more toxic brodifacoum, authorized to be used outdoors around buildings after the regulatory changes, increased. The summer of 2016 was statistically identified as a turning point for exposure to brodifacoum and summed SGARs that increased after this point. This time point coincided with the aforementioned regulatory changes. Our findings suggest a possible shift in SGAR use to brodifacoum from difenacoum over the decades, which may pose higher risks of impacts on wildlife.

Trace elements are chemical contaminants spread in the environment by anthropogenic activities and threaten wildlife and human health. Many studies have investigated this contamination in apex raptors as sentinel birds. However, there is limited data for long-term biomonitoring of multiple trace elements in raptors. In the present study, we measured the concentrations of 14 essential and non-essential trace elements in the livers of the common buzzard (Buteo buteo) collected in the United Kingdom from 2001 to 2019 and investigated whether concentrations have changed during this period. In addition, we estimated the importance of selected variables for modelling element accumulations in tissues. Except for cadmium, hepatic concentrations of harmful elements in most buzzards were lower than the biological significance level of each element. Hepatic concentrations of certain elements, including lead, cadmium, and arsenic, varied markedly seasonally within years. Their peak was in late winter and trough in late summer, except copper which showed an opposite seasonal pattern. In addition, lead in the liver consistently increased over time, whereas strontium showed a decreasing trend. Hepatic concentrations of cadmium, mercury, and chromium increased with age, whereas selenium and chromium were influenced by sex. Hepatic concentrations of arsenic and chromium also differed between different regions. Overall, our samples showed a low risk of harmful effects of most elements compared to the thresholds reported in the literature. Seasonal fluctuation was an important descriptor of exposure, which might be related to the diet of the buzzard, the ecology of their prey, and human activities such as the use of lead shot for hunting. However, elucidating reasons for these observed trends needs further examination, and biomonitoring studies exploring the effects of variables such as age, sex, and seasonality are required.

Long-term change and shorter-term variability in the atmospheric deposition of pollutants and marine salts can have major effects on the biogeochemistry and ecology of soils and surface water ecosystems. In the 1980s, at the time of peak acid deposition in the UK, deposition loads were highly dependent on prevailing weather types, and it was postulated that future pollution recovery trajectories would be partly dependent on any climate change-driven shifts in weather systems. Following three decades of substantial acidic emission reductions, we used monitoring data collected between 1992 and 2015 from four UK Environmental Change Network (ECN) sites in contrasting parts of Great Britain to examine the trends in precipitation chemistry in relation to prevailing weather conditions. Weather systems were classified on the basis of Lamb weather type (LWT) groupings, while emissions inventories and clustering of air mass trajectories were used to interpret the observed patterns. Concentrations of ions showed clear differences between cyclonic-westerly-dominated periods and others, reflecting higher marine and lower anthropogenic contributions in Atlantic air masses. Westerlies were associated with higher rainfall, higher sea salt concentrations, and lower pollutant concentrations at all sites, while air mass paths exerted additional controls. Westerlies therefore have continued to favour higher sea salt fluxes, whereas emission reductions are increasingly leading to positive correlations between westerlies and pollutant fluxes. Our results also suggest a shift from the influence of anthropogenic emissions to natural emissions (e.g., sea salt) and climate forcing as they are transported under relatively cleaner conditions to the UK. Westerlies have been relatively frequent over the ECN monitoring period, but longer-term cyclicity in these weather types suggests that current contributions to precipitation may not be sustained over coming years.

The Environmental Change Network (ECN) is the UK's long-term ecosystem monitoring network and supports the detection, interpretation and forecasting of environmental change and its impacts on Natural Capital (e.g. soils, waters, organic carbon stores, biodiversity etc.) in a wide range of terrestrial and freshwater habitats. As part of a broader base of evidence, ECN data have contributed to various local, regional and national state-of-the-environment assessments, including the recent Review of Transboundary Air Pollution (RoTAP) and the National Ecosystem Assessment, while ECN sites individually are nationally important platforms for focussed environmental scientific research. The primary strengths of the ECN approach stem from the co-location of measurement of several key physical, chemical and biological environmental indicators, often at high temporal resolution and according to tightly defined protocols. This allows process-based links between potential driver and ecological response variables to be explored in considerable detail and for comparisons to be made across sites. The network has particular value in providing: a) short term variability context for environmental observations drawn from more spatially extensive, but lower frequency, monitoring and survey initiatives such as the UK Countryside Survey; b) supporting explanatory data for assessment of pressures on specific elements of soil and water biogeochemistry (e.g. organic carbon, nitrogen species etc.) and biodiversity monitored by taxon-specific networks such as the UK Light Trap Network; and c) ground-truthing biogeochemical and ecological models. ECN Monitoring is sponsored by 14 governmental organisations and research institutes, and covers 12 terrestrial and 45 freshwater sites that span much of the UK. CEH supports approximately 90% of the operation of the ECN Central Coordination Unit (CCU) by CEH staff in the Lancaster Environment Centre. The remaining 10% of support for the ECN CCU is provided by Defra. CEH derive considerable “added value” through the contribution of data to the ECN from the remaining nine terrestrial and 42 freshwater sites, and also benefits from the associated links with researchers from the other partner organisations. The ECN CCU: 1) guides scientific development of the network; 2) oversees the implementation of sampling and analysis protocols across both networks, 3) coordinates activities by ECN site managers, 4) oversees receipt of data, its quality control and storage in a central database; 5) maintains an interactive website; 6) disseminates data to scientists and other interested parties both directly and via the CEH Information Gateway and the gov.net website on request 7) conducts frequent assessments of environmental change in ECN datasets, contributes data and expertise to a number of externally and internally funded studies, and publishes finding in the scientific literature, 8) communicates ECN activities and outputs to a wide audience of researchers, policy makers and schools. Growing experience in the handling of complex integrated environmental datasets is leading to increased involvement of ECN CCU staff in CWI projects that include elements of integrated environmental monitoring and data management. Recent successes include the Habitats Monitoring Project funded by the Electrical Supply Industry which is solely run by ECN CCU staff, and key involvement in the UK Lake Ecological Observatory (funded by the NERC Sensor Network Programme) (PI: Stephen Maberly). CEH also provide the operation, maintenance and support for scientific research at three terrestrial ECN sites (Moor House, Wytham and Cairngorm), in addition to some monitoring of water chemistry at three CEH flagship freshwater sites (Windermere, Esthwaite and Loch Leven). These sites are among the most widely used field research platforms run by CEH, and are highly valued by academic and stakeholder partner organisations (e.g. Universities of Lancaster, Leeds and Durham, and Natural England at ECN Moor House; Scottish Natural Heritage and the Cairngorm National Park Authority at ECN Cairngorm; Oxford University at Wytham). The ECN Cairgorm site now contributes to the the UK’s first and only Long Term Socio-Ecological Research site, founded in 2013.

This digest is one of a series of annual data summaries produced by the Environmental Change Network (ECN), a UK research initiative concerned with the long-term monitoring, analysis and prediction of environmental change. The digest series provides a concise summary of the main features of the data collected by ECN each year. This volume summarises ECN data collected in 2008 from the Terrestrial sites, and makes comparisons with the results from previous years. Data from the Freshwater ECN sites, for which data collection started in 1995, are published in a separate volume.