Looking back to look ahead: the temporal dimension of conservation seed bank collections.

A wealth of plant material and data is stored globally in conservation seed banks. This material represents not only a repository of plant genetic resources but also an asset for nature-based solutions (NbS), such as ecological restoration and reforestation, and research in plant science. Here, we explore the temporal and spatial dimensions of seed collections and the challenges limiting their use in NbS and research, while highlighting how they could be a source of material for adaptation and evolution studies. However, existing seed lots originally collected for conservation purposes will not be sufficient to support NbS and research on their own. We propose a long-term experimental approach that, together with new targeted collecting programmes, can leverage the temporal dimension of seed collections by carrying out repeated sampling from the same population. At the same time, we stress how these approaches will benefit from new dedicated collections holding seeds from each maternal line separately. By moving towards a bidimensional (space and time) collecting approach, conservation seed banks can go beyond long-term conservation per se and transform their collections into dynamic repositories capable of addressing pressing ecological, evolutionary, and conservation questions and help to understand and shape plant communities of the future.