Scenario-based modelling is a powerful tool to describe relationships between plausible trajectories of drivers, possible policy interventions, and impacts on biodiversity and ecosystem services. Model inter-comparisons are key in quantifying uncertainties and identifying avenues for model improvement but have been missing among the global biodiversity and ecosystem services modelling communities. The biodiversity and ecosystem services scenario-based inter-model comparison (BES-SIM) aims to fill this gap. We used global land-use and climate projections to simulate possible future impacts on terrestrial biodiversity and ecosystem services using a variety of models and a range of harmonized metrics.

The goal of this paper is to reflect on the steps taken in BES-SIM, identify remaining methodological challenges, and suggest pathways for improvement. We identified five major groups of challenges; the need to: 1) better account for the role of nature in future human development storylines; 2) improve the representation of drivers in the scenarios by increasing the resolution (temporal, spatial and thematic) of land-use as key driver of biodiversity change and including additional relevant drivers; 3) explicitly integrate species- and trait-level biodiversity in ecosystem services models; 4) expand the coverage of the multiple dimensions of biodiversity and ecosystem services; and finally, 5) incorporate time-series or one-off historical data in the calibration and validation of biodiversity and ecosystem services models.

Addressing these challenges would allow the development of more integrated global projections of biodiversity and ecosystem services, thereby improving their policy relevance in supporting the interlinked international conservation and sustainable development agendas.

基于场景的建模是描述驱动力的合理轨迹，可能的政策干预以及对生物多样性和生态系统服务的影响之间的关系的强大工具。模型间的比较是量化不确定性和确定模型改进途径的关键，但在全球生物多样性和生态系统服务建模社区中却一直缺失。基于生物多样性和生态系统服务情景的模型间比较（BES-SIM）旨在填补这一空白。我们使用全球土地利用和气候预测，使用各种模型和一系列统一指标来模拟未来对陆地生物多样性和生态系统服务的可能影响。

本文的目的是反思BES-SIM中采取的步骤，确定尚存的方法挑战，并提出改进途径。我们确定了五个主要挑战类别：需要：1）更好地说明自然在未来人类发展故事中的作用；2）通过增加土地利用的分辨率（时间，空间和主题）作为生物多样性变化的主要驱动因素，并增加其他相关驱动因素，从而改善情景中驱动因素的代表性；3）明确将物种和特征一级的生物多样性纳入生态系统服务模式；4）扩大对生物多样性和生态系统服务多个层面的覆盖；最后，5）在生物多样性和生态系统服务模型的校准和验证中纳入时间序列或一次性历史数据。

应对这些挑战将使人们能够对生物多样性和生态系统服务进行更综合的全球预测，从而改善它们在支持相互关联的国际保护和可持续发展议程方面的政策相关性。