The Open Traits Network (OTN) was formed to address the challenge of synthesising trait data across all organisms. We follow a decentralised, but connected, network structure where knowledge is aggregated up from taxon-specific research groups to larger synthesis nodes. This network model preserves the knowledge of experts about the relevant traits for specific organisms and how these should be interpreted and allow for synthesis solutions to emerge that preserve this knowledge when data is harmonised. We adhere to the principles of Open Science - a movement towards making all aspects of the scientific process transparent and accessible to a wide audience. Despite the recognised importance of species traits to ecological and evolutionary science, some common research practices limit our capacity to easily synthesise trait data, including:

• Failure to publish usable datasets alongside new findings
• Missing or inadequate metadata
• Minimal descriptions of methods used to collate, clean and analyse trait datasets in published works
• Inadequate coordination between researchers and institutions with common goals

Our limited ability to access and redistribute trait data also directly contributes to the widespread reproducibility crisis within science.

OTN members represent a range of taxa and interests, including data infrastructure providers, scientific researchers, and software specialists. The network was formed from a series of international meetings in 2017 and 2018 which highlighted the need for a fresh approach to trait data synthesis across all organisms. The OTN seeks to undertake five key activities as a starting point for the synthesis of trait data, which are:

Activity 1: Maintaining a global registry of trait-based initiatives
Activity 2: Sharing reproducible workflows and tools for aggregating trait data
Activity 3: Advocating for a free flow of data and appropriate recognition of efforts
Activity 4: Creating a trait core to facilitate synthesis and standardisation
Activity 5: Facilitating consistent approaches to measuring traits within major groups