title: Symbiosis limits establishment of legumes outside their native range at a global scale.
abstract: Microbial symbiosis is integral to plant growth and reproduction, but its contribution to global patterns of plant distribution is unknown. Legumes (Fabaceae) are a diverse and widely distributed plant family largely dependent on symbiosis with nitrogen-fixing rhizobia, which are acquired from soil after germination. This dependency is predicted to limit establishment in new geographic areas, owing to a disruption of compatible host-symbiont associations. Here we compare non-native establishment patterns of symbiotic and non-symbiotic legumes across over 3,500 species, covering multiple independent gains and losses of rhizobial symbiosis. We find that symbiotic legume species have spread to fewer non-native regions compared to non-symbiotic legumes, providing strong support for the hypothesis that lack of suitable symbionts or environmental conditions required for effective nitrogen-fixation are driving these global introduction patterns. These results highlight the importance of mutualisms in predicting non-native species establishment and the potential impacts of microbial biogeography on global plant distributions.
authors.affiliation: Commonwealth Scientific and Industrial Research Organization (CSIRO), Land &Water, Clunies Ross Street, Acton, Australian Capital Territory 2601, Australia.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Simonsen
authors.affiliation: Research School of Biology, The Australian National University, 116 Daley Road, Acton, Australian Capital Territory 2601, Australia.
authors.forename: Russell
authors.initials: R
authors.lastname: Dinnage
authors.affiliation: CSIRO Agriculture and Food, Canberra, Clunies Ross Street, Acton, Australian Capital Territory 2601, Australia.
authors.forename: Luke G
authors.initials: LG
authors.lastname: Barrett
authors.affiliation: CSIRO Land &Water, Private Bag 5, Wembley, WA 6913, Australia.
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Prober
authors.affiliation: CSIRO Agriculture and Food, Canberra, Clunies Ross Street, Acton, Australian Capital Territory 2601, Australia.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Thrall
mesh_terms: D007887:Fabaceae / Q000145:classification / Q000254:growth & development* / Q000382:microbiology*; D006801:Humans; D009586:Nitrogen Fixation; D010802:Phylogeny; D012231:Rhizobium / Q000502:physiology; D013045:Species Specificity; D013559:Symbiosis