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Kendrick GA, Cambridge ML, Orth RJ, Fraser MW, Hovey RK, Statton J, Pattiaratchi CB, Sinclair EA. The cycle of seagrass life: From flowers to new meadows. Ecol Evol 2023; 13:e10456. [PMID: 37664509 PMCID: PMC10469021 DOI: 10.1002/ece3.10456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/01/2023] [Accepted: 08/11/2023] [Indexed: 09/05/2023] Open
Abstract
Understanding sexual reproduction and recruitment in seagrasses is crucial to their conservation and restoration. Flowering, seed production, seed recruitment, and seedling establishment data for the seagrass Posidonia australis was collected annually between 2013 and 2018 in meadows at six locations around Rottnest Island, Western Australia. Variable annual rates of flowering and seed production were observed among meadows between northern and southern sides of the island and among years. Meadows on the northern shore consistently flowered more intensely and produced more seeds across the years of the survey. Inter-site variation in clonal diversity and size of clones, seed production, wind and surface currents during pollen and seed release, and the large, but variable, impact of seed predation are likely the principal drivers of successful recruitment into established meadows and in colonizing unvegetated sands. The prolific but variable annual reproductive investment increases the probability of low levels of continuous recruitment from seed in this seagrass, despite high rates of abiotic and biotic disturbance at seedling, shoot, and patch scales. This strategy also imparts a level of ecological resilience to this long-lived and persistent species.
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Affiliation(s)
- Gary A. Kendrick
- School of Biological Sciences and UWA Oceans InstituteThe University of Western AustraliaWestern AustraliaCrawleyAustralia
| | - Marion L. Cambridge
- School of Biological Sciences and UWA Oceans InstituteThe University of Western AustraliaWestern AustraliaCrawleyAustralia
| | - Robert J. Orth
- Virginia Institute of Marine ScienceCollege of William and MaryGloucester PointVirginiaUSA
| | - Matthew W. Fraser
- School of Biological Sciences and UWA Oceans InstituteThe University of Western AustraliaWestern AustraliaCrawleyAustralia
| | - Renae K. Hovey
- School of Biological Sciences and UWA Oceans InstituteThe University of Western AustraliaWestern AustraliaCrawleyAustralia
| | - John Statton
- School of Biological Sciences and UWA Oceans InstituteThe University of Western AustraliaWestern AustraliaCrawleyAustralia
| | - Charitha B. Pattiaratchi
- Oceans Graduate School and UWA Oceans InstituteThe University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Elizabeth A. Sinclair
- School of Biological Sciences and UWA Oceans InstituteThe University of Western AustraliaWestern AustraliaCrawleyAustralia
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Sinclair EA, Hovey RK, Krauss SL, Anthony JM, Waycott M, Kendrick GA. Historic and contemporary biogeographic perspectives on range-wide spatial genetic structure in a widespread seagrass. Ecol Evol 2023; 13:e9900. [PMID: 36950371 PMCID: PMC10025079 DOI: 10.1002/ece3.9900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/26/2023] [Indexed: 03/22/2023] Open
Abstract
Historical and contemporary processes drive spatial patterns of genetic diversity. These include climate-driven range shifts and gene flow mediated by biogeographical influences on dispersal. Assessments that integrate these drivers are uncommon, but critical for testing biogeographic hypotheses. Here, we characterize intraspecific genetic diversity and spatial structure across the entire distribution of a temperate seagrass to test marine biogeographic concepts for southern Australia. Predictive modeling was used to contrast the current Posidonia australis distribution to its historical distribution during the Last Glacial Maximum (LGM). Spatial genetic structure was estimated for 44 sampled meadows from across the geographical range of the species using nine microsatellite loci. Historical and contemporary distributions were similar, with the exception of the Bass Strait. Genetic clustering was consistent with the three currently recognized biogeographic provinces and largely consistent with the finer-scale IMCRA bioregions. Discrepancies were found within the Flindersian province and southwest IMCRA bioregion, while two regions of admixture coincided with transitional IMCRA bioregions. Clonal diversity was highly variable but positively associated with latitude. Genetic differentiation among meadows was significantly associated with oceanographic distance. Our approach suggests how shared seascape drivers have influenced the capacity of P. australis to effectively track sea level changes associated with natural climate cycles over millennia, and in particular, the recolonization of meadows across the Continental Shelf following the LGM. Genetic structure associated with IMCRA bioregions reflects the presence of stable biogeographic barriers, such as oceanic upwellings. This study highlights the importance of biogeography to infer the role of historical drivers in shaping extant diversity and structure.
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Affiliation(s)
- Elizabeth A. Sinclair
- School of Biological SciencesUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
- Oceans Institute, University of Western AustraliaCrawleyWestern AustraliaAustralia
- Kings Park Science, Department of Biodiversity Conservation and AttractionsKings ParkWestern AustraliaAustralia
| | - Renae K. Hovey
- School of Biological SciencesUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
- Oceans Institute, University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Siegfried L. Krauss
- School of Biological SciencesUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
- Kings Park Science, Department of Biodiversity Conservation and AttractionsKings ParkWestern AustraliaAustralia
| | - Janet M. Anthony
- School of Biological SciencesUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
- Kings Park Science, Department of Biodiversity Conservation and AttractionsKings ParkWestern AustraliaAustralia
| | - Michelle Waycott
- School of Biological SciencesUniversity of Adelaide and State Herbarium of South AustraliaAdelaideSouth AustraliaAustralia
| | - Gary A. Kendrick
- School of Biological SciencesUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
- Oceans Institute, University of Western AustraliaCrawleyWestern AustraliaAustralia
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Edgeloe JM, Severn-Ellis AA, Bayer PE, Mehravi S, Breed MF, Krauss SL, Batley J, Kendrick GA, Sinclair EA. Extensive polyploid clonality was a successful strategy for seagrass to expand into a newly submerged environment. Proc Biol Sci 2022; 289:20220538. [PMID: 35642363 PMCID: PMC9156900 DOI: 10.1098/rspb.2022.0538] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Polyploidy has the potential to allow organisms to outcompete their diploid progenitor(s) and occupy new environments. Shark Bay, Western Australia, is a World Heritage Area dominated by temperate seagrass meadows including Poseidon's ribbon weed, Posidonia australis. This seagrass is at the northern extent of its natural geographic range and experiences extremes in temperature and salinity. Our genomic and cytogenetic assessments of 10 meadows identified geographically restricted, diploid clones (2n = 20) in a single location, and a single widespread, high-heterozygosity, polyploid clone (2n = 40) in all other locations. The polyploid clone spanned at least 180 km, making it the largest known example of a clone in any environment on earth. Whole-genome duplication through polyploidy, combined with clonality, may have provided the mechanism for P. australis to expand into new habitats and adapt to new environments that became increasingly stressful for its diploid progenitor(s). The new polyploid clone probably formed in shallow waters after the inundation of Shark Bay less than 8500 years ago and subsequently expanded via vegetative growth into newly submerged habitats.
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Affiliation(s)
- Jane M. Edgeloe
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia,Oceans Institute, University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Anita A. Severn-Ellis
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Philipp E. Bayer
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Shaghayegh Mehravi
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Martin F. Breed
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Siegfried L. Krauss
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia,Kings Park Science, Department of Biodiversity Conservation and Attractions, 1 Kattidj Close, West Perth, Western Australia 6005, Australia
| | - Jacqueline Batley
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Gary A. Kendrick
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia,Oceans Institute, University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Elizabeth A. Sinclair
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia,Oceans Institute, University of Western Australia, Crawley, Western Australia, 6009, Australia,Kings Park Science, Department of Biodiversity Conservation and Attractions, 1 Kattidj Close, West Perth, Western Australia 6005, Australia
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The Genetic Component of Seagrass Restoration: What We Know and the Way Forwards. WATER 2021. [DOI: 10.3390/w13060829] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Seagrasses are marine flowering plants providing key ecological services and functions in coasts and estuaries across the globe. Increased environmental changes fueled by human activities are affecting their existence, compromising natural habitats and ecosystems’ biodiversity and functioning. In this context, restoration of disturbed seagrass environments has become a worldwide priority to reverse ecosystem degradation and to recover ecosystem functionality and associated services. Despite the proven importance of genetic research to perform successful restoration projects, this aspect has often been overlooked in seagrass restoration. Here, we aimed to provide a comprehensive perspective of genetic aspects related to seagrass restoration. To this end, we first reviewed the importance of studying the genetic diversity and population structure of target seagrass populations; then, we discussed the pros and cons of different approaches used to restore and/or reinforce degraded populations. In general, the collection of genetic information and the development of connectivity maps are critical steps for any seagrass restoration activity. Traditionally, the selection of donor population preferred the use of local gene pools, thought to be the best adapted to current conditions. However, in the face of rapid ocean changes, alternative approaches such as the use of climate-adjusted or admixture genotypes might provide more sustainable options to secure the survival of restored meadows. Also, we discussed different transplantation strategies applied in seagrasses and emphasized the importance of long-term seagrass monitoring in restoration. The newly developed information on epigenetics as well as the application of assisted evolution strategies were also explored. Finally, a view of legal and ethical issues related to national and international restoration management is included, highlighting improvements and potential new directions to integrate with the genetic assessment. We concluded that a good restoration effort should incorporate: (1) a good understanding of the genetic structure of both donors and populations being restored; (2) the analysis of local environmental conditions and disturbances that affect the site to be restored; (3) the analysis of local adaptation constraints influencing the performances of donor populations and native plants; (4) the integration of distribution/connectivity maps with genetic information and environmental factors relative to the target seagrass populations; (5) the planning of long-term monitoring programs to assess the performance of the restored populations. The inclusion of epigenetic knowledge and the development of assisted evolution programs are strongly hoped for the future.
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