Microspatial population genetic structure of the Mediterranean shrub Fumana thymifolia |
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Authors: | A S Jump L Rico F Lloret & J Peñuelas |
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Institution: | Unitat d'Ecofisiologia i Canvi Global CSIC-CEAB-CREAF, CREAF (Centre de Recerca Ecològica i Aplicacions Forestals), Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain; Departament de Genètica Molecular, Consorci Laboratori CSIC-IRTA de Genetica Molecular Vegetal, Barcelona, Spain; Unitat d'Ecologia (Dept. Biologia Animal, Biologia Vegetal i Ecologia) i CREAF, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain; Present address: School of Biological and Environmental Sciences, University of Stirling, Stirling, UK |
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Abstract: | Fumana thymifolia (Cistaceae) is an insect-pollinated, gravity-dispersed evergreen shrub, which is a common component of fire-prone Mediterranean shrubland ecosystems. Despite the availability of basic knowledge on its ecology, little is known of its breeding system and no information is available on its population genetic structure. We explored the within-population genetic structure of this species using amplified fragment length polymorphism (AFLP) molecular markers and related this to predictions based on its breeding system, pollen and seed dispersal. Existing information on the reproductive ecology of F. thymifolia was supplemented by artificial pollination experiments. We determined that self-fertilisation can occur in F. thymifolia but results in reduced fruit set. Significant genetic structuring was detected within the population, a likely consequence of localised seed dispersal in combination with a mixed mating system. In a study site covering approximately 0.5 ha, amova revealed that approximately 9% of genetic variability was distributed among population subsamples. Significant spatial genetic structure was detected, with kinship coefficients being significantly elevated above the null expectation in the first six distance classes (maximum 5 m), and a value of Sp of up to 0.0342, comparable with species having similar ecological characteristics. Weak isolation by distance at the plot scale was detected, suggesting that insect-mediated pollen flow is non-random, despite being more extensive than seed dispersal. Fumana thymifolia provides a promising model for the investigation of both short- and long-term population dynamics in relation to fire frequency within this plant community. |
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Keywords: | AFLP amova IBD insect-pollinated isolation by distance spatial genetic structure SGS |
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