During recent decades and centuries, pools and fluxes of C, N and P in UK ecosystems have been transformed by the spread and fertiliser-based intensification of agriculture, by atmospheric pollution, and now by fossil-fuel induced climate change. We need to understand the processes that determine these effects, in order to improve the sustainability of agriculture, preserve carbon stocks, control the eutrophication of terrestrial and freshwater ecosystems, and reduce nutrient delivery to the sea and greenhouse gas emissions. Contemporary pools of C, N and P in soils and sediments reflect processes occurring on a range of timescales (up to 1000 years or more for organic matter turnover in soils) and also over a range of spatial scales. We propose research to address long-term, large scale processing of C, N and P in the environment. The principal objective is to account for observable terrestrial and aquatic pools, concentrations and fluxes of C, N and P on the basis of past inputs, biotic and abiotic interactions, and transport processes, in order to address the following scientific questions; 1. Over the last 200 years, what have been the temporal responses of soil C, N and P pools in different UK catchments to nutrient enrichment? 2. What have been the consequent effects on C, N and P transfers from land to the atmosphere, freshwaters and estuaries? 3. How have terrestrial and freshwater biodiversity responded to increases in ecosystem productivity engendered by nutrient enrichment at different locations? We aim at an integrated quantitative description of the interlinked land and water pools and annual fluxes of C, N and P for the UK over time. Central to the project is the application, development and parameterisation of mechanistically-based models applicable over long timescales and at a broad spatial scale. The models will be designed to exploit the large number of existing biogeochemical data for the UK, with new targeted measurements to fill important gaps. A key ingredient is radiocarbon data for natural organic matter in soils and waters, which provide a unique means of estimating longer-term turnover rates of organic matter. The project is organised into seven workpackages, as follows. WP1 Data. This involves the collation and management of monitoring and survey data and literature searches. Data will be required for driving and parameterising models. WP2 New measurements. Gap-filling information will be obtained about C & N releases from fuels, soil concentrations of C, N, P, and radiocarbon, vegetation contents of C, N and P, a major effort on soil denitrification, riverine organic matter including radiocarbon contents. WP3 Atmospheric model. This will use a variety of data, and atmospheric physics, to describe N deposition at 5 km2 resolution for the UK from 1800 to the present, and take into account emissions from industry and agriculture. WP4 Terrestrial models. Models will be developed and parameterised to describe (a) biogeochemical cycling of C, N and P in natural and agricultural soils, simulating losses by gaseous evasion and solute leaching, and (b) physical erosion. WP5 Aquatic models. These will describe sediment transport of organic matter (including C, N and P), lake processing, denitrification, and groundwater transport. Point source inputs will be quantified. WP6 Integrated Model. The IM will bring together the models from WP3-5 within a grid-based hydrological system, applicable to the whole of the UK. Through the IM we will answer Questions 1 and 2, producing temporal and spatial terrestrial and aquatic outputs for representative catchments. The IM will include estimates of uncertainty and be applicable for future scenario analysis. WP7 Biodiversity. Model output from WP3-6 will be used to analyse terrestrial plant diversity and diatom diversity in lake sediments, thereby addressing Question 3.

Ongoing climate change in the 21st century will instigate profound societal transformations in the 21st century. Yet, our knowledge of how such transformations can be achieved in an equitable and sustainable manner is limited. The HUMANOR project investigates historical transformations of mobile pastoralist social-ecological systems (SESs) for clues about which pathways may lead to such transformations. We comparatively study SESs that have undergone profound climatic fluctuations in the last centuries (indigenous Sámi, Nenets, Evenki and Mongolian pastoralists) while maintaining their livelihoods through a host of incremental and qualitative shifts. Although these systems are increasingly being exposed to rapid climate change (e.g. the Arctic warming faster than lower latitudes), our understanding of SES response capacities is limited to adaptations within the current systems. We propose that a long-term focus on human-animal relations and the general socio-economic contexts may illustrate how people can deal with abrupt changes (including massive environmental shocks) and re-create these systems. Our focus is on the complex drivers of social-ecological transformations of recent decades and centuries that include climate variation, land use change, governance forms, institutional change (including legislation and social norms) and markets. We expect to show that although it is an ancient livelihood, still practiced across vast areas of N Eurasia, pastoralism is constantly undergoing shifts in the nexus of feedbacks between humans, animals and the environment. This comparative trans-disciplinary study is performed across several timescales (centennial changes since the Middle Ages- marking reindeer domestication in Fennoscandia and Siberia and the height of the pastoralist Mongolian Empire, and decadal changes since the mid-20th century) in order to illustrate the historical context of change and provide key insights into people as active agents or passive receptors of change. For instance, we know that even at low human population densities, large livestock herds can alter ecosystem structure and function but we know comparatively little about how social, economic and political changes foster or impede deliberate, desirable changes in the ecosystems and societies underlying these SESs. We propose that projecting future transformations will benefit from the retrospective partitioning of: (1) socio-economic and political from climate drivers over decadal scales; and (2) human-animal agency from climate drivers over centennial scales. We use an interdisciplinary mix of methods to first reconstruct historical human-animal-environment relationships and environmental histories by documenting current oral environmental histories (myths, legends, life stories) and environmental reconstruction from pollen records and other soil signatures. We use indigenous residents current environmental knowledge to uncover the recent changes (climatic, vegetation, etc.) in their environments and participant observations to uncover the complex socio-economic realities of their SESs. Our analysis draws strength from: (1) contrasting SESs across diverse geographic scales; and (2) accounting for heterogeneous perceptions of risk concerning the future viability of (reindeer) pastoralism in the European Research Area. We envision our project making a significant contribution to the design of ethical and sustainable transformations of SESs in Europe and beyond.

Trees take in carbon from the atmosphere as they grow, but this is eventually released when they die. The sheer number of trees in tropical forests means that small changes in these rates of growth and death, and the resulting change in the balance of carbon taken in or released, can have a big effect on the climate. While a lot of research has focused on how changes in temperature and rainfall affects the growth and death of tropical forest trees, the potential effects of lightning have been largely neglected. A study tracking lightning strikes in Panama found that they caused more than half of all deaths of large trees, a previously undocumented effect despite being in one of the most intensively studied forests in the world. This project will provide important steps towards assessing whether this strong impact of lightning is a more widespread phenomenon. Forests in Africa are characterised by a greater dominance of large trees than elsewhere in the tropics, so based on results from Panama they would be expected to be more vulnerable to lightning. Alternatively, the high frequency of lightning in Africa may have selected for trees that are better able to withstand its effects. Knowing whether or not lightning has a consistent effect across continents is important for determining whether future work should focus on understanding the causes of variation in the impact of lightning, or can instead explore the wider implications these effects. The new international collaborator (Evan Gora) has developed an approach for detecting lightning damage from drone surveys and follow-up investigation on foot that allows large areas of forest to be surveyed. We will apply this at four sites along a dramatic gradient of lightning frequency in the Albertine Rift (on the boundary of the Democratic Republic of the Congo, Rwanda and Uganda) to (1) test whether trees at different sites in Africa are more or less vulnerable to being killed by lightning than those in Panama, (2) determine how forest structure varies with lightning frequency and (3) use these observations to assess the potential effect of lightning on carbon stocks and dynamics. The project team will have regular online meetings throughout the project, will all meet in Rwanda to receive training from Gora in how to detect lightning damage, and a subset of the team will also meet in the UK after fieldwork. Collectively, these meetings provide considerable space to share ideas as the project develops, culminating in a five-year plan for future collaboration. We will seek wider input from scientist and stakeholders through a regular series of seminars and roundtable discussions, and will hold online training workshops to build capacity in monitoring the effects of lightning on tropical forests.

For all sources of radioactivity, radiological risk assessments are essential for safeguarding human and environmental health. But assessments often have to rely upon simplistic assumptions, such as the use of simple ratios in risk calculations which combine many processes. This pragmatic approach has largely arisen due to the lack of scientific knowledge and/or data in key areas. The resultant uncertainty has been taken into account through conservative approaches to radiological risk assessment which may tend to overestimate risk. Uncertainty arises at all stages of the assessment process from the estimation of transfer to human foodstuffs and wildlife, exposure and risk. Reducing uncertainty is important as it relates directly to scientific credibility, which will always be open to challenge given the highly sensitive nature of radiological risk assessment in society. We propose an integrated, multi-disciplinary, programme to assess and reduce the uncertainty associated with radiological risk assessment to protect human health and the environment. At the same time we will contribute to building the capacity needed to ensure that the UK rebuilds and maintains expertise in environmental radioactivity into the future. Our project has four major and highly inter-related components to address the key goal of RATE to rebuild UK capacity and make a major contribution to enhancing environmental protection and safeguarding human health. The first component will study how the biological availability of radionuclides varies in soils over time. We will investigate if short-term measurements (collected in three year controlled experiments) can be used to predict the long-term availability of radionuclides in soils by testing our models in the Chernobyl exclusion zone. The second component will apply the concepts of 'phylogeny' and 'ionomics' to characterise radionuclide uptake by plants and other organisms. These approaches, and statistical modelling methods, are increasingly applied to describe uptake of a range of elements in plant nutrition, and we are pioneering their use for studying radionuclide uptake in other organisms and human foods. A particularly exciting aspect of the approach is the possibility to make predictions for any plant or animal. This is of great value as it is impossible to measure uptake for all wildlife, crops and farm animals. The third component of the work will extend our efforts to improve the quantification of radiation exposure and understanding of resultant biological effects by investigating the underlying mechanisms involved. A key aim is to see whether what we know from experiments on animals and plants in the laboratory is a good representation of what happens in the real world: some scientists believe that animals in the natural environment are more susceptible to radiation than laboratory animals: we need to test this to have confidence in our risk assessments. Together these studies will enable us to reduce and better quantify the uncertainties associated with radiological risk assessment. By training a cohort of PDRA and PhDs our fourth component will help to renew UK capacity in environmental radioactivity by providing trained, experienced researchers who are well networked within the UK and internationally through the contacts of the investigators. Our students will be trained in a wide range of essential skills through their controlled laboratory studies and working in contaminated environments. They will benefit from being a member of a multidisciplinary team and opportunities to take placements with our beneficiaries and extensive range of project partners. The outputs of the project will benefit governmental and non-governmental organisations with responsibility for assessing the risks to humans and wildlife posed by environmental radioactivity. It will also make a major contribution to improved scientific and public confidence in the outcomes of environmental safety assessments.

Communities living near coasts are increasingly at risk from coastal flooding as climate change raises sea-levels and causes storms to occur more frequently. Mangrove forests can help protect communities from this threat, as they reduce the energy of waves and storm surges, and trap sediment to help coasts keep pace with rising sea levels. Despite their benefit, a third of mangroves in West Africa have been lost since 1980. Mangrove wood is an important source of fuel and construction material for communities living nearby, and there are also pressures to use the land mangroves grow on for salt production and rice farming. Many interventions have been tried to protect mangroves, but these can have far-reaching consequences for people and the environment, and create novel mangrove landscapes which may not protect communities in the same way as natural mangroves. This project will generate new knowledge about the feedbacks from different interventions and the effectiveness of different mangrove landscapes at protecting communities, and use this to support communities in Guinea, Liberia and Sierra Leone to design solutions to protect and restore mangroves, and protect themselves from climate change risks. We will build on the knowledge communities have of mangroves, their changes and their relationship with people, and work with communities to imagine different ways of living with mangroves. We will then collect the evidence needed to evaluate these different scenarios. This includes making measurements and models of how different mangrove landscapes protect communities from flooding, looking at how sensitive this protection is to processes such as mining or forest loss along the rivers upstream of the mangroves, and seeing whether different strategies to protect mangroves affect some people more than others. We will examine these results with communities, refining scenarios and models to arrive at co-designed solutions. We will then work with communities to identify whether they have the power to implement these solutions, and identify how governments and other organisations can help support communities to protect and restore mangroves. We will assess whether the suitability of different approaches for protecting and restoring mangroves depends on the environment or on social factors. For example, some rivers carry a lot of sediment which could be trapped by small areas of mangroves, while other rivers have less sediment which may not be effectively trapped by small patches of mangroves. Likewise, options for people to switch from cutting mangroves to getting wood from alternative sources will depend on how close other forests are, the amount of land available for planting new trees, and the ease of bringing wood in from further afield. We will work in six different river catchments in three countries in West Africa, which differ in many environmental and social characteristics including how close they are to urban areas where products can be easily bought or sold, the amount of forest loss along the rivers and experience of past civil conflicts. We will work with communities in three areas within each catchment, allowing us to see the effect of differences in livelihoods and customs on possible solutions. These lessons learnt about the importance of context will be valuable for informing efforts to protect and restore mangroves across the region.