title: Environmental unpredictability and inbreeding depression select for mixed dispersal syndromes.
abstract: BACKGROUND
  Mixed dispersal syndromes have historically been regarded as a bet-hedging mechanism that enhances survivorship in unpredictable environments, ensuring that some propagules stay in the maternal environment while others can potentially colonize new sites. However, this entails paying the costs of both dispersal and non-dispersal. Propagules that disperse are likely to encounter unfavorable conditions, while non-dispersing propagules might form inbred populations of close relatives. Here, we investigate the conditions under which mixed dispersal syndromes emerge and are evolutionarily stable, taking into account the risks of both environmental unpredictability and inbreeding.
  
  
  RESULTS
  Using mathematical and computational modeling, we show that high dispersal propensity is favored whenever environmental unpredictability is low and inbreeding depression high, whereas mixed dispersal syndromes are adaptive under high environmental unpredictability, more particularly if inbreeding depression is small. Although pure dispersal is frequently adaptive, mixed dispersal represents the optimal strategy under many different parameterizations of our models, indicating that this strategy is likely to be favored in a wide variety of contexts. Furthermore, monomorphic populations go inevitably extinct when environmental and genetic costs are high, whilst mixed strategies can maintain viable populations even under very extreme conditions.
  
  
  CONCLUSIONS
  Our models support the hypothesis that the interplay between inbreeding depression and environmental unpredictability shapes dispersal syndromes, often resulting in mixed strategies. Moreover, mixed dispersal seems to facilitate persistence whenever conditions are critical or nearly critical for survival.
authors.affiliation: Instituto Carlos I de Física Teórica y Computacional and Departamento Electromagnetismo y Física de la Materia, Universidad de Granada, Granada, 18071, Spain.|Dipartimento di Fisica 'G. Galilei' and CNISM, INFN, Universitá di Padova, Via Marzolo, 8, Padova, 35131, Italy.
authors.forename: Jorge
authors.initials: J
authors.lastname: Hidalgo
authors.affiliation: Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, Granada, 18071, Spain. rubiodecasas@ugr.es.|Estación Experimental de Zonas Áridas, EEZA-CSIC, Carretera de Sacramento s/n, La Cañada de San Urbano, Almería, 04120, Spain. rubiodecasas@ugr.es.|UMR 5175 Centre Ecologie Fonctionnelle et Evolutive, CEFE-CNRS, 1919 Route de Mende, 34293Montpellier Cedex 05, France. rubiodecasas@ugr.es.
authors.forename: Rafael Rubio de
authors.initials: RR
authors.lastname: Casas
authors.affiliation: Instituto Carlos I de Física Teórica y Computacional and Departamento Electromagnetismo y Física de la Materia, Universidad de Granada, Granada, 18071, Spain. mamunoz@onsager.ugr.es.
authors.forename: Miguel
authors.initials: M
authors.lastname: Á Muñoz
mesh_terms: D005075:Biological Evolution; D003198:Computer Simulation; D004777:Environment; D007178:Inbreeding; D027807:Lathyrus / Q000235:genetics* / Q000502:physiology; D008954:Models, Biological; D058614:Seed Dispersal; D031306:Vicia / Q000235:genetics* / Q000502:physiology
keywords: Amphicarpy; Bet-hedging; Environmental noise; Heterocarpy; Individual based models; Mixed dispersal; Mixed mating; Selfing