Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. considers the importance of conserving pollinator diversity to maintain a suite of functional 79 traits to provide a diverse set of pollinator services. We explore how we can better understand 80 and mitigate the factors that threaten insect pollinator richness, placing our discussion within 81 the context of populations in predominantly agricultural landscapes in addition to urban 82 environments. We highlight a selection of important evidence gaps, with a number of 83 complementary research steps that can be taken to better understand: i) the stability of 84 pollinator communities in different landscapes in order to provide diverse pollinator services; 85 ii) how we can study the drivers of population change to mitigate the effects and support 86 stable sources of pollinator services; and, iii) how we can manage habitats in complex 87 landscapes to support insect pollinators and provide sustainable pollinator services for the 88 future. We advocate a collaborative effort to gain higher quality abundance data to 89 understand the stability of pollinator populations and predict future trends. In addition, for 90 effective mitigation strategies to be adopted, researchers need to conduct rigorous field-91 testing of outcomes under different landscape settings, acknowledge the needs of end-users 92 when developing research proposals and consider effective methods of knowledge transfer to 93 ensure effective uptake of actions. 94 95 96 5 | P a g e | P a g e

Summary 1.Increased demand for food and energy is leading to changes in the global nitrogen cycle. These changes are resulting in increasing levels of nitrogen in the environment in its pollutant forms with consequences for both biodiversity and human health. In this paper, we discuss the impacts in the UK and give examples of the steps that are being taken by the Department for Environment, Food and Rural Affairs (Defra) to tackle these problems. 2. Over 70% of the UK land area is farmland. The farmed environment is composed of a wide range of semi-natural habitats including heather moorland, chalk downland, wet grasslands farm woodlands and hedgerows. As a result, much of the UK's cherished biodiversity is an integral part of agriculture and therefore vulnerable to changes in farming practices. 3. Defra's overall goal is to build a sustainable future for the UK. With regard to nitrogen pollution, this involves finding ways of continuing to meet our food and energy requirements whilst causing little or no harm to the environment. 4. Defra's science programme has a central role to play in the development of its nitrogen pollution policies. These pollution policies provide a key input to the Department's evidence base for policy formulation, and support international negotiations on pollution targets. 5. The Department's science programme has addressed the major components of the nitrogen cycle associated with harmful impacts on the environment and human health. The main aims have been the understanding and quantification of impacts through monitoring and modelling and the development of abatement measures. 6. Synthesis and application. It is becoming increasingly apparent that whilst advances can and have been made in the reduction of emissions from combustion processes, the problem of nitrogen pollution from agriculture is far more intractable. This scientific challenge, when taken together with emerging regulatory initiatives, will require imaginative solutions if the UK Government is to forge a sustainable way forward.

The results of scientific research have played a central role in convincing decision-makers of the plight of farmland birds and in the development of land management measures and policies designed to reverse the population declines. Several types of study have contributed to what is now a considerable knowledge base on the ecological requirements of key species, the reasons for their declines and the remedial measures necessary to bring about population recovery. They include: monitoring; analyses of large-scale datasets; detailed studies of particular species, land-uses or land management practices; and the development and testing of solutions. As a consequence, there is now an excellent qualitative understanding of farmland bird ecology, which is well reflected in the suite of land management schemes and other policy initiatives that currently operate in England. Future research efforts should focus on the further development and testing of solutions and gaining a better understanding of the quantitative relationship between the provision of resources (especially nesting and foraging habitats) and the population response of target bird species. Such work should ensure that land management measures are deployed at the required scale, in appropriate locations and are of sufficient quality to influence the national populations of the declining species.

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