Designer niches - a novel approach to assessing the impacts of agricultural change on biodiversity at multiple spatial scales

现在人们普遍认为，在过去的40-50年里，我们所看到的农业集约化已经对英国、欧洲和全球的环境产生了有害的影响。一个显著的变化是生物多样性（一系列不同动植物物种的种群）的丧失。因此，英国和欧洲政府的政策现在寻求促进所谓的“多功能农业”，其中农业生产的需要与环境保护的目标相协调，包括保护生物多样性。这是具有挑战性的，因为生物多样性健康往往在大的空间尺度上进行评估（例如，特定物种的国家人口趋势），而农业变化是在田间和农场尺度上实施的。将田间规模的农业变化与大规模的生物多样性风险联系起来，对于评估这种变化在生物多样性保护方面的可持续性至关重要。如果我们能够了解农业变化在其引入之前或期间所带来的风险，它将使我们能够设计措施来降低风险，从而使变化在生物多样性保护方面更具可持续性。为了应对这些问题，我们最近开发了一个框架，用于评估农业变化对英国400多种动植物的生物多样性风险。我们的方法通过评估农业变化对每个物种生态位需求的不利影响程度，将国家人口趋势与田间规模管理变化联系起来。例如，对于鸟类来说，生态位要求包括筑巢栖息地、觅食栖息地和它们吃的食物类型。利用最近的数据，我们已经表明，随着这些影响的程度增加，人口下降的可能性越来越大，并随后将这一新系统应用于一系列农业变化情景。虽然我们之前的工作很有希望，但它主要在两个方面受到根本上的限制。首先，它只处理风险。当农业土地利用发生变化时，对特定物种可能既有风险也有好处，我们需要了解净影响，而不仅仅是风险。其次，它依赖于对农业变化和物种范围的空间一致性的简单而粗糙的假设来估计国家人口趋势。理想情况下，需要了解多个尺度上的生物多样性响应，以便将农业领域或农场尺度的变化与类似和更大（即区域或国家）空间尺度上的生物多样性响应联系起来。我们提出的项目旨在通过开发一种新的方法来评估农业变化在多个空间尺度上对生物多样性的风险和收益，从而解决这些限制。我们的项目将重点关注英国农田鸟类，这是更广泛的生物多样性的一个有价值的指标，鸟类种群是英国政府对生物多样性保护和可持续农业承诺的重要组成部分。我们提出了一个新的想法，我们称之为“设计师生态位”，试图了解农业土地利用是如何为大约45种鸟类设计生态位的。这包括将土地利用转化为鸟类筑巢和觅食栖息地的质量。然后，我们将利用这些信息来了解鸟类丰度及其种群趋势如何通过生态位设计与土地利用相关，并应用这些想法来帮助我们了解鸟类种群如何应对未来的农业变化。然后，这项工作将被纳入农业环境政策，我们希望这将使我们能够更有效地规划农业变化，以保护生物多样性。

It is now widely accepted that the intensification in agriculture we have seen over the last 40-50 years has had a detrimental impact on the environment in the UK, Europe and across the globe. One conspicuous change has been the loss of biodiversity (populations of a range of different animal and plants species). As a result, UK and European Government policies now seek to promote what is termed 'multi-functional agriculture' in which the needs of agricultural production are reconciled with objectives for environmental protection, including the conservation of biodiversity. This is challenging because biodiversity health is often assessed at large spatial scales (e.g. national population trends of particular species) whilst agricultural change is implemented at the field and farm-scales. Linking field-scale changes in agriculture with large-scale risks to biodiversity is essential for assessing the sustainability of such changes with respect to biodiversity conservation. If we could understand the risks agricultural change poses prior to or during its introduction, it would allow us to design measures to reduce the risk, and in so doing make the change more sustainable in terms of biodiversity conservation. In response to these issues, we have recently developed a framework for assessing the biodiversity risk of agricultural change to over 400 species of animals and plants in the UK. Our approach links national population trends to field-scale management changes by assessing the extent to which an agricultural change detrimentally impacts the niche requirements of each species. For example, for bird species niche requirements would include nesting habitats, foraging habitats, and the type of food they eat. Using data from the recent past, we have shown that as the extent of these impacts increase population decline becomes more likely, and have subsequently applied this new system to a range of agricultural change scenarios. Although our previous work is promising, it is fundamentally limited in two main ways. Firstly, it only deals with risk. When agricultural land-use changes it might have both risks and benefits to particular species, and we need to understand the net impact rather than just the risk. Secondly, it relies on simple but crude assumptions about the spatial congruence of agricultural change and species' ranges in order to estimate national population trends. Ideally, the response of biodiversity at multiple scales needs to be understood, so that field- or farm-scale changes in agriculture can be linked to biodiversity responses at similar and at larger (i.e. regional or national) spatial scales. Our proposed project aims to address these limitations by developing a new approach for assessing the risks and benefits of agricultural change to biodiversity over multiple spatial scales. Our project will focus on UK farmland birds, which are a valuable indicator for wider biodiversity, and bird populations are an important component of the UK Government's commitments to biodiversity conservation and sustainable agriculture. We have developed a new idea that we call 'designer niches' that attempts to understand how agricultural land-use designs the niche components for about 45 bird species. This involves translating land-use into the quality of nesting and foraging habitats for birds. We will then use this information to understand how bird abundance and their population trends relate to land-use via niche design, and apply these ideas to help us understand how bird populations might respond to future agricultural changes. This work will then be fed into agri-environment policy, and we hope that this will allow us to plan agricultural change more effectively to conserve biodiversity.