Cities are challenging environments for human life, because of multiple environmental issues driven by urbanization. These can sometimes be mitigated through ecosystem services provided by different functions supported by biodiversity. However, biodiversity in cities is affected by numerous factors, namely habitat loss, degradation, and fragmentation, as well as pollution, altered climate, and new biotic challenges. To better understand the link between biodiversity and ecosystem functions and services, we need to improve our mechanistic knowledge of these relationships. Trait-based ecology is a promising approach for unravelling the causes and consequences of biodiversity filtering on ecosystem processes and underlying services, but large gaps remain unexplored.

Here, we present a series of research directions that are aimed at extending the current knowledge of the relationship between trait-based biodiversity and ecosystem functions and services in cities. These directions are based on: (1) improving urban habitat mapping; (2) considering often neglected urban habitats and ecological niches; (3) integrating multiple urban gradients; (4) using trait-based approaches to improve our mechanistic understanding of the relationships between biodiversity and ecosystem functions and services; and (5) extending the involvement of citizens.

Pursuing these research directions may support the sustainable management of urban ecosystems and the long-term provision of ecosystem services, ultimately enhancing the well-being of urban populations.

城市是人类生活面临的挑战性环境，原因是城市化推动了许多环境问题。有时可以通过生物多样性支持的不同职能所提供的生态系统服务来减轻这些负担。但是，城市中的生物多样性受到多种因素的影响，即栖息地的丧失，退化和破碎化，污染，气候变化和新的生物挑战。为了更好地理解生物多样性与生态系统功能和服务之间的联系，我们需要提高对这些关系的机械知识。基于特征的生态学是一种有前途的方法，可用于阐明生物多样性过滤对生态系统过程和基础服务的成因和后果，但仍然存在巨大的空白。

在这里，我们提出了一系列研究方向，旨在扩展对基于特征的生物多样性与城市生态系统功能和服务之间关系的当前了解。这些指示基于：（1）改善城市栖息地图；（2）考虑经常被忽视的城市栖息地和生态位；（3）整合多个城市梯度；（4）使用基于特征的方法来提高我们对生物多样性与生态系统功能和服务之间关系的机械理解；（5）扩大公民的参与。

遵循这些研究方向可以支持城市生态系统的可持续管理和长期提供生态系统服务，从而最终改善城市人口的福祉。