Saxafraga
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Integrated monography of the genus Saxifraga L.

Saxifraga as a window on the evolution of the European alpine flora.

Project details

Funded By: 
The Harding Alpine Plant and Fungal Research Programme

Objectives and outputs

Evolution of alpine floras

Mountains are hotspots of terrestrial biodiversity, harbouring far more species than expected based on their area, including large numbers of narrowly endemic taxa (those occurring only in one small region). In spite of their remarkable diversity, satisfactory answers to some of the most fundamental questions regarding the origins of mountain biota are still lacking. This lack of fundamental knowledge needs to be addressed by integrated eco‐evolutionary studies of appropriate model lineages.

Saxifraga as a model system

This project aims to use the species‐rich, predominantly alpine genus Saxifraga L. as a model to elucidate the eco‐evolutionary assembly of mountain floras, with emphasis on the European Alps. With 51 of its ~440 species occurring in the Alps, Saxifraga is the ideal candidate for an integrated study on the origins of Europe’s alpine flora. In spite of being primarily arctic/alpine, Saxifraga is ecologically highly diverse, which is reflected in a wealth of morphological variation: for instance, leaf area varies by at least a factor of 2500 among species (ranging 25cm2 to < 1mm2), and the variation in growth form is striking, ranging from dense cushions to large unbranched rosettes and delicate broad‐leaved herbs. Understanding the Saxifraga model lineage will provide important new insights not only into the relative importance of inter‐regional dispersal and intra‐regional evolution of alpine taxa, but also into the intrinsic and extrinsic factors that induce or hamper those processes. By including morphological and ecological characteristics as potential determinants of the focal processes, the project will go beyond previous efforts to understand the assembly of mountain floras. The project will also be an opportunity to develop new phylogenetic approaches for jointly analysing dispersal, evolution of niches and the morphological and ecological traits that constitute them.

Relevance to Kew Science strategic outputs

By reconstructing the phylogeny of a diverse plant lineage, this project contributes directly to Kew’s Plant and Fungal Trees of Life (PaFToL) strategic output, which includes species‐level phylogenetics of groups of ecological and evolutionary importance. The project will also contribute genomic data for up to 48 genera to the PaFToL genus level target through outgroup sampling within Saxifragaceae. During our field campaign we will also make a systematic effort to collect DNA of any genus that is useful for PaFToL, including non‐saxifragaceous genera. Similarly, seed collecting for the Millennium Seed Bank Partnership (Kew Strategic Output 'Banking the World’s Seeds') will be built into our field campaign as a priority.

Objectives

  • Expand Kew's Saxifraga collections in a series of field campaigns and inter-institutional collaborations.
  • Use a next-generation HybSeq approach to obtain genomic data for all available Saxifraga species.
  • Build Saxifraga-centered databases: (i) Global occurrences and characterisations of climatic niches; (ii) Ecological and morphological trait data, including characterisation of population‐level variation in natural environments; (iii) Characters of putative systematic relevance.
  • Jointly analyse the phylogenomic, geographic, ecological and morphological trait datasets to test selected evolutionary hypotheses regarding the origin and diversification of alpine taxa.

Outputs

  • High impact scientific papers on the origin and diversification of alpine plants, based on findings from Saxifraga.
  • Establishment of Saxifraga as a model lineage for evolutionary studies, including availability of comprehensive species-level datasets.
  • An integrated monographic account of Saxifraga that will be useful to botanists, evolutionary biologists, and amateur enthusiasts alike.

Partners and collaborators

International

Crop Trust

UK

University of Birmingham