title: Mating system and early viability resistance to habitat fragmentation in a bird-pollinated eucalypt.
abstract: Habitat fragmentation has been shown to disrupt ecosystem processes such as plant-pollinator mutualisms. Consequently, mating patterns in remnant tree populations are expected to shift towards increased inbreeding and reduced pollen diversity, with fitness consequences for future generations. However, mating patterns and phenotypic assessments of open-pollinated progeny have rarely been combined in a single study. Here, we collected seeds from 37 Eucalyptus incrassata trees from contrasting stand densities following recent clearance in a single South Australian population (intact woodland=12.6 trees ha(-1); isolated pasture=1.7 trees ha(-1); population area=10 km(2)). 649 progeny from these trees were genotyped at eight microsatellite loci. We estimated genetic diversity, spatial genetic structure, indirect contemporary pollen flow and mating patterns for adults older than the clearance events and open-pollinated progeny sired post-clearance. A proxy of early stage progeny viability was assessed in a common garden experiment. Density had no impact on mating patterns, adult and progeny genetic diversity or progeny growth, but was associated with increased mean pollen dispersal. Weak spatial genetic structure among adults suggests high historical gene flow. We observed preliminary evidence for inbreeding depression related to stress caused by fungal infection, but which was not associated with density. Higher observed heterozygosities in adults compared with progeny may relate to weak selection on progeny and lifetime-accumulated mortality of inbred adults. E. incrassata appears to be resistant to the negative mating pattern and fitness changes expected within fragmented landscapes. This pattern is likely explained by strong outcrossing and regular long-distance pollen flow.
authors.affiliation: 1] Australian Centre for Evolutionary Biology and Biodiversity (ACEBB) and School of Earth and Environmental Sciences, University of Adelaide, North Terrace, SA, Australia [2] Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen, Uppsala, Sweden.
authors.forename: M F
authors.initials: MF
authors.lastname: Breed
authors.affiliation: 1] Australian Centre for Evolutionary Biology and Biodiversity (ACEBB) and School of Earth and Environmental Sciences, University of Adelaide, North Terrace, SA, Australia [2] Science Division, Department of Environment and Conservation, Perth, WA, Australia.
authors.forename: K M
authors.initials: KM
authors.lastname: Ottewell
authors.affiliation: 1] Australian Centre for Evolutionary Biology and Biodiversity (ACEBB) and School of Earth and Environmental Sciences, University of Adelaide, North Terrace, SA, Australia [2] School of Biological Sciences, Flinders University, Adelaide, SA, Australia.
authors.forename: M G
authors.initials: MG
authors.lastname: Gardner
authors.affiliation: 1] Australian Centre for Evolutionary Biology and Biodiversity (ACEBB) and School of Earth and Environmental Sciences, University of Adelaide, North Terrace, SA, Australia [2] Department of Limnology, Uppsala University, Evolutionary Biology Centre, Uppsala University, Norbyvägen, Uppsala, Sweden.
authors.forename: M H K
authors.initials: MH
authors.lastname: Marklund
authors.affiliation: Australian Centre for Evolutionary Biology and Biodiversity (ACEBB) and School of Earth and Environmental Sciences, University of Adelaide, North Terrace, SA, Australia.
authors.forename: M G
authors.initials: MG
authors.lastname: Stead
authors.affiliation: 1] Australian Centre for Evolutionary Biology and Biodiversity (ACEBB) and School of Earth and Environmental Sciences, University of Adelaide, North Terrace, SA, Australia [2] Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, NJ, USA.
authors.forename: J B C
authors.initials: JB
authors.lastname: Harris
authors.affiliation: 1] Australian Centre for Evolutionary Biology and Biodiversity (ACEBB) and School of Earth and Environmental Sciences, University of Adelaide, North Terrace, SA, Australia [2] State Herbarium of South Australia, Science Resource Centre, Department of Environment and Natural Resources, Hackney Road, Adelaide, SA, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Lowe
mesh_terms: D000818:Animals; D001717:Birds; D018744:DNA, Plant / Q000235:genetics; D017753:Ecosystem; D005052:Eucalyptus / Q000235:genetics*; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D007178:Inbreeding; D016014:Linear Models; D018895:Microsatellite Repeats; D008957:Models, Genetic; D054817:Pollination; D011156:Population Density; D012098:Reproduction / Q000235:genetics; D012639:Seeds / Q000235:genetics; D017422:Sequence Analysis, DNA; D013021:South Australia
chemical_list: D018744:DNA, Plant