1
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Ngeve MN, Engelhardt KAM, Gray M, Neel MC. Calm after the storm? Similar patterns of genetic variation in a riverine foundation species before and after severe disturbance. Ecol Evol 2023; 13:e10670. [PMID: 37920773 PMCID: PMC10618894 DOI: 10.1002/ece3.10670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/28/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023] Open
Abstract
In summer 2011, Tropical storms Lee and Irene caused an estimated 90% decline of the submersed aquatic plant Vallisneria americana Michx. (Hydrocharitaceae) in the Hudson River of New York (USA). To understand the genetic impact of such large-scale demographic losses, we compared diversity at 10 microsatellite loci in 135 samples collected from five sites just before the storms with 239 shoots collected from nine sites 4 years after. Although 80% of beds sampled in 2011 lacked V. americana in 2015, we found similar genotypic and genetic diversity and effective population sizes in pre-storm versus post-storm sites. These similarities suggest that despite local extirpations concentrated at the upstream end of the sampling area, V. americana was regionally resistant to genetic losses. Similar geographically based structure among sites in both sampling periods suggested that cryptic local refugia at previously occupied sites facilitated re-expansion after the storms. However, this apparent resistance to disturbance may lead to a false sense of security. Low effective population sizes and high clonality in both time periods suggest that V. americana beds were already small and had high frequency of asexual reproduction before the storms. Dispersal was not sufficient to recolonize more isolated sites that had been extirpated. Chronic low diversity and reliance on asexual reproduction for persistence can be risky when more frequent and intense storms are paired with ongoing anthropogenic stressors. Monitoring genetic diversity along with extent and abundance of V. americana will give a more complete picture of long-term potential for resilience.
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Affiliation(s)
- Magdalene N. Ngeve
- Department of Plant Science and Landscape ArchitectureUniversity of MarylandCollege ParkMarylandUSA
- Department of EntomologyUniversity of MarylandCollege ParkMarylandUSA
| | | | - Michelle Gray
- Department of Plant Science and Landscape ArchitectureUniversity of MarylandCollege ParkMarylandUSA
- Department of EntomologyUniversity of MarylandCollege ParkMarylandUSA
| | - Maile C. Neel
- Department of Plant Science and Landscape ArchitectureUniversity of MarylandCollege ParkMarylandUSA
- Department of EntomologyUniversity of MarylandCollege ParkMarylandUSA
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2
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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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3
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Kollars NM, Stachowicz JJ. Disturbance decreases genotypic diversity by reducing colonization: Implications for disturbance-diversity feedbacks. Ecology 2022; 103:e3710. [PMID: 35362174 DOI: 10.1002/ecy.3710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 01/06/2022] [Accepted: 02/07/2022] [Indexed: 11/09/2022]
Abstract
One objective of eco-evolutionary dynamics is to understand how the interplay between ecology and evolution on contemporary timescales contributes to the maintenance of biodiversity. Disturbance is an ecological process that can alter species diversity through both ecological and evolutionary effects on colonization and extinction dynamics. While analogous mechanisms likely operate among genotypes within a population, empirical evidence demonstrating the relationship between disturbance and genotypic diversity remains limited. We experimentally tested how disturbance altered the colonization (gain) and extinction (loss) of genets within a population of the marine angiosperm Zostera marina (eelgrass). In a 2-year field experiment conducted in northern California, we mimicked grazing disturbance by migratory geese by clipping leaves at varying frequencies during the winter months. Surprisingly, we found the greatest rates of new colonization in the absence of disturbance and that clipping had negligible effects on extinction. We hypothesize that genet extinction was not driven by selective mortality from clipping or from any stochastic loss resulting from the reduced shoot densities in clipped plots. We also hypothesize that increased flowering effort and facilitation within and among clones drove the increased colonization of new genets in the undisturbed treatment. This balance between colonization and extinction resulted in a negative relationship between clipping frequency and net changes in genotypic richness. We interpret our results in light of prior work showing that genotypic diversity increased resistance to grazing disturbance. We suggest that both directions of a feedback between disturbance and diversity occur in this system with consequences for the maintenance of eelgrass genotypic diversity.
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Affiliation(s)
- Nicole M Kollars
- Center for Population Biology and the Department of Evolution and Ecology, University of California Davis, One Shields Ave, Davis, CA, USA
| | - John J Stachowicz
- Center for Population Biology and the Department of Evolution and Ecology, University of California Davis, One Shields Ave, Davis, CA, USA
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4
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Triest L, Dierick J, Phan TTH, Luong QD, Huy NQ, Sierens T. Low Genetic Connectivity of Strongly Inbred Ruppia brevipedunculata in Aquaculture Dominated Lagoons (Viet Nam). FRONTIERS IN CONSERVATION SCIENCE 2021. [DOI: 10.3389/fcosc.2021.723376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lagoonal environments exhibit high levels of instability depending on hydrological, climatic and ecological factors, thereby influencing the distribution and structure of submerged plant communities. Conditions typically fluctuate widely due to the interaction of freshwater from rivers with saltwater from the sea, as well as from aquaculture activities that together influence submerged hydrophyte community spatial and temporal variability depending on plant survival strategies. Ruppia species feature either underwater pollination mediated by an air bubble or by the release of pollen floating at the water surface, the former promoting self-pollination. Tropical Asian Ruppia brevipedunculata Yu and den Hartog was assumed to pollinate below the water surface and identified as a separate lineage among selfed Ruppia taxa. We used nine nuclear microsatellites to estimate inbreeding levels and connectivity of R. brevipedunculata within a large SE Asian lagoon complex. Ruppia brevipedunculata meadows were strongly inbred as could be derived from the many monomorphic or totally fixed loci for unique alleles in different parts of the lagoon, which appears consistent with selfing behavior. Those from aquaculture ponds were highly inbred (FIS = 0.620), though less than open lagoon sites that showed nearly total inbreeding (FIS = 0.942). Ruppia brevipedunculata from two major lagoon parts were highly differentiated with spatially structured gene pools and a strong barrier between parts of the lagoon over a 30 km distance. Migration-n analysis indicated unidirectional though limited gene flow and following potential hydrological connectivity. Overall, private alleles under homozygote conditions explained a stronger genetic differentiation of populations situated inside aquaculture ponds than of open lagoon populations. Kinship values were only relevant up to 5 km distance in the open lagoon. Within a confined area of aquaculture ponds featuring dense vegetation in stagnant water, there would be opportunity for mixed pollination, thereby explaining the higher diversity of unique multilocus genotypes of aquaculture pond habitats. Low connectivity prevents gene pools to homogenize however promoted sites with private alleles across the lagoon. Complex hydrodynamic systems and human-made habitats enclosed by physical structures impose barriers for propagule dispersal though may create refugia and contribute to conserving regional genetic diversity.
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5
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Dierick J, Phan TTH, Luong QD, Triest L. Persistent Clones and Local Seed Recruitment Contribute to the Resilience of Enhalus acoroides Populations Under Disturbance. FRONTIERS IN PLANT SCIENCE 2021; 12:658213. [PMID: 34220884 PMCID: PMC8248806 DOI: 10.3389/fpls.2021.658213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/10/2021] [Indexed: 06/13/2023]
Abstract
Human-induced land use in coastal areas is one of the main threats for seagrass meadows globally causing eutrophication and sedimentation. These environmental stressors induce sudden ecosystem shifts toward new alternative stable states defined by lower seagrass richness and abundance. Enhalus acoroides, a large-sized tropical seagrass species, appears to be more resistant toward environmental change compared to coexisting seagrass species. We hypothesize that reproductive strategy and the extent of seedling recruitment of E. acoroides are altered under disturbance and contribute to the persistence and resilience of E. acoroides meadows. In this research, we studied eight populations of E. acoroides in four lagoons along the South Central Coast of Vietnam using 11 polymorphic microsatellite loci. We classified land use in 6 classes based on Sentinel-2 L2A images and determined the effect of human-induced land use at different spatial scales on clonal richness and structure, fine-scale genetic structure and genetic diversity. No evidence of population size reductions due to disturbance was found, however, lagoons were strongly differentiated and may act as barriers to gene flow. The proportion and size of clones were significantly higher in populations of surrounding catchments with larger areas of agriculture, urbanization and aquaculture. We postulate that large resistant genets contribute to the resilience of E. acoroides meadows under high levels of disturbance. Although the importance of clonal growth increases with disturbance, sexual reproduction and the subsequent recruitment of seedlings remains an essential strategy for the persistence of populations of E. acoroides and should be prioritized in conservation measures to ensure broad-scale and long-term resilience toward future environmental change.
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Affiliation(s)
- Jasper Dierick
- Ecology and Biodiversity Research Group, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Thi Thuy Hang Phan
- Biology Department, University of Sciences, Hue University, Hue, Vietnam
| | - Quang Doc Luong
- Biology Department, University of Sciences, Hue University, Hue, Vietnam
| | - Ludwig Triest
- Ecology and Biodiversity Research Group, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
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6
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Evans RD, McMahon KM, van Dijk KJ, Dawkins K, Nilsson Jacobi M, Vikrant A. Identification of dispersal barriers for a colonising seagrass using seascape genetic analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 763:143052. [PMID: 33189383 DOI: 10.1016/j.scitotenv.2020.143052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/30/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Seagrasses are important habitats providing many ecological services. Most species have broad distributions with maximum dispersal distances of 100's of kms, however there is limited understanding of dispersal distances of colonising species like Halodule uninervis. It commonly grows in disturbed environments and could disperse to other meadows via clonal fragments. Effective conservation management requires greater understanding of genetic structure, dispersal barriers, and connectivity timescales to predict recovery following disturbance. Despite fragment viability of up to 28 days in a congenera, this theory remains untested in situ. Using 80 neutral single nucleotide polymorphisms, we investigated genetic diversity, gene flow patterns and structure among 15 populations of H. uninervis along 2000 km of Western Australian coastline. These data were combined with a multi-generational oceanographic dispersal model and a barrier dispersal analysis to identify dispersal barriers and determine which fragment dispersal duration (FDD) and timescale over which stepping-stone connectivity occurred, best matched the observed genetic structure. The 2-7 day FDD best matched the genetic structure with 4-12 clusters, with barriers to dispersal that persisted for up to 100 years. Modelling suggested greater fragmentation of metapopulations towards the southern edge of the species distribution, but genetic diversity did not decline. Several long-term boundaries were identified even with fragment viability of up to 28 days. This suggests H. uninervis dispersal is spatially limited by factors like oceanographic features and habitat continuity which may limit dispersal of this species. This study reiterates that potential dispersal does not equal realised dispersal, and management scales of 10's of kilometers are required to maintain existing meadows. Recruitment from distances further than this scale are unlikely to aid recovery after extreme disturbance events, particularly towards the range edge of H. uninervis distribution.
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Affiliation(s)
- R D Evans
- Department of Biodiversity, Conservation and Attractions, 17 Dick Perry Ave, Kensington 6151, Australia; Oceans Institute, the University of Western Australia, Perth, WA 6009, Australia.
| | - K M McMahon
- School of Science, Edith Cowan University, 270 Joondalup Drive, Joondalup 6027, Australia; Centre for Marine Ecosystems Research, Edith Cowan University, 270 Joondalup Drive, Joondalup 6027, Australia
| | - K-J van Dijk
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - K Dawkins
- School of Science, Edith Cowan University, 270 Joondalup Drive, Joondalup 6027, Australia; Centre for Ecosystem Management, Edith Cowan University, 270 Joondalup Drive, Joondalup 6027, Australia
| | - M Nilsson Jacobi
- Department of Space, Earth and Environment, Chalmers University of Technology, Maskingränd 2, 412 58 Gothenburg, Sweden
| | - A Vikrant
- Department of Space, Earth and Environment, Chalmers University of Technology, Maskingränd 2, 412 58 Gothenburg, Sweden
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7
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Stoeckel S, Porro B, Arnaud-Haond S. The discernible and hidden effects of clonality on the genotypic and genetic states of populations: Improving our estimation of clonal rates. Mol Ecol Resour 2021; 21:1068-1084. [PMID: 33386695 DOI: 10.1111/1755-0998.13316] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 11/05/2020] [Accepted: 12/21/2020] [Indexed: 11/29/2022]
Abstract
Partial clonality is widespread across the tree of life, but most population genetic models are designed for exclusively clonal or sexual organisms. This gap hampers our understanding of the influence of clonality on evolutionary trajectories and the interpretation of population genetic data. We performed forward simulations of diploid populations at increasing rates of clonality (c), analysed their relationships with genotypic (clonal richness, R, and distribution of clonal sizes, Pareto β) and genetic (FIS and linkage disequilibrium) indices, and tested predictions of c from population genetic data through supervised machine learning. Two complementary behaviours emerged from the probability distributions of genotypic and genetic indices with increasing c. While the impact of c on R and Pareto β was easily described by simple mathematical equations, its effects on genetic indices were noticeable only at the highest levels (c > 0.95). Consequently, genotypic indices allowed reliable estimates of c, while genetic descriptors led to poorer performances when c < 0.95. These results provide clear baseline expectations for genotypic and genetic diversity and dynamics under partial clonality. Worryingly, however, the use of realistic sample sizes to acquire empirical data systematically led to gross underestimates (often of one to two orders of magnitude) of c, suggesting that many interpretations hitherto proposed in the literature, mostly based on genotypic richness, should be reappraised. We propose future avenues to derive realistic confidence intervals for c and show that, although still approximate, a supervised learning method would greatly improve the estimation of c from population genetic data.
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Affiliation(s)
- Solenn Stoeckel
- Institute for Genetics, Environment and Plant Protection, INRAE, Le Rheu, France
| | - Barbara Porro
- Institute for Research on Cancer and Aging (IRCAN), Université Côte d'Azur, Nice, France.,MARBEC - Marine Biodiversity Exploitation and Conservation, University of Montpellier, CNRS, Ifremer, IRD, MARBEC, Sète, France
| | - Sophie Arnaud-Haond
- MARBEC - Marine Biodiversity Exploitation and Conservation, University of Montpellier, CNRS, Ifremer, IRD, MARBEC, Sète, France
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8
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Kollars NM, DuBois K, Stachowicz JJ. Sequential disturbances alter the outcome of inter‐genotypic interactions in a clonal plant. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Nicole M. Kollars
- Center for Population Biology University of California Davis CA USA
- Department of Evolution and Ecology University of California Davis CA USA
| | - Katherine DuBois
- Department of Evolution and Ecology University of California Davis CA USA
- Bodega Marine Laboratory Bodega Bay CA USA
| | - John J. Stachowicz
- Center for Population Biology University of California Davis CA USA
- Department of Evolution and Ecology University of California Davis CA USA
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9
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Arnaud-Haond S, Stoeckel S, Bailleul D. New insights into the population genetics of partially clonal organisms: When seagrass data meet theoretical expectations. Mol Ecol 2020; 29:3248-3260. [PMID: 32613610 DOI: 10.1111/mec.15532] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/30/2020] [Accepted: 06/11/2020] [Indexed: 01/23/2023]
Abstract
Seagrass meadows are among the most important coastal ecosystems in terms of both spatial extent and ecosystem services, but they are also declining worldwide. Understanding the drivers of seagrass meadow dynamics is essential for designing sound management, conservation and restoration strategies. However, poor knowledge of the effect of clonality on the population genetics of natural populations severely limits our understanding of the dynamics and connectivity of meadows. Recent modelling approaches have described the expected distributions of genotypic and genetic descriptors under increasing clonal rates, which may help us better understand and interpret population genetics data obtained for partial asexuals. Here, in the light of these recent theoretical developments, we revisited population genetics data for 165 meadows of four seagrass species. Contrasting shoot lifespan and rhizome turnover led to the prediction that the influence of asexual reproduction would increase along a gradient from Zostera noltii to Zostera marina, Cymodocea nodosa and Posidonia oceanica, with increasing departure from Hardy-Weinberg equilibrium (Fis ), mostly towards heterozygote excess, and decreasing genotypic richness (R). This meta-analysis provides a nested validation of this hypothesis at both the species and meadow scales through a significant relationship between Fis and R within each species. By empirically demonstrating the theoretical expectations derived from recent modelling approaches, this work calls for the use of Hardy-Weinberg equilibrium (Fis ) rather than only the strongly sampling-sensitive R to assess the importance of clonal reproduction (c), at least when the impact of selfing on Fis can be neglected. The results also emphasize the need to revise our appraisal of the extent of clonality and its influence on the dynamics, connectivity and evolutionary trajectory of partial asexuals in general, including in seagrass meadows, to develop the most accurate management strategies.
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Affiliation(s)
| | - Solenn Stoeckel
- IGEPP INRAE, Institut Agro, University of Rennes, Le Rheu, France
| | - Diane Bailleul
- Université de Montpellier, Ifremer, CNRS, IRD, MARBEC, Sète, France
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10
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Strydom S, Murray K, Wilson S, Huntley B, Rule M, Heithaus M, Bessey C, Kendrick GA, Burkholder D, Fraser MW, Zdunic K. Too hot to handle: Unprecedented seagrass death driven by marine heatwave in a World Heritage Area. GLOBAL CHANGE BIOLOGY 2020; 26:3525-3538. [PMID: 32129909 DOI: 10.1111/gcb.15065] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/12/2020] [Accepted: 02/23/2020] [Indexed: 05/12/2023]
Abstract
The increased occurrence of extreme climate events, such as marine heatwaves (MHWs), has resulted in substantial ecological impacts worldwide. To date, metrics of thermal stress within marine systems have focussed on coral communities, and less is known about measuring stress relevant to other primary producers, such as seagrasses. An extreme MHW occurred across the Western Australian coastline in the austral summer of 2010-2011, exposing marine communities to summer seawater temperatures 2-5°C warmer than average. Using a combination of satellite imagery and in situ assessments, we provide detailed maps of seagrass coverage across the entire Shark Bay World Heritage Area (ca. 13,000 km2 ) before (2002 and 2010) and after the MHW (2014 and 2016). Our temporal analysis of these maps documents the single largest loss in dense seagrass extent globally (1,310 km2 ) following an acute disturbance. Total change in seagrass extent was spatially heterogeneous, with the most extensive declines occurring in the Western Gulf, Wooramel Bank and Faure Sill. Spatial variation in seagrass loss was best explained by a model that included an interaction between two heat stress metrics, the most substantial loss occurring when degree heating weeks (DHWm) was ≥10 and the number of days exposed to extreme sea surface temperature during the MHW (DaysOver) was ≥94. Ground truthing at 622 points indicated that change in seagrass cover was predominantly due to loss of Amphibolis antarctica rather than Posidonia australis, the other prominent seagrass at Shark Bay. As seawater temperatures continue to rise and the incidence of MHWs increase globally, this work will provide a basis for identifying areas of meadow degradation, or stability and recovery, and potential areas of resilience.
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Affiliation(s)
- Simone Strydom
- Marine Science Program, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, WA, Australia
- Centre for Marine Ecosystems Research and School of Science, Edith Cowan University, Joondalup, WA, Australia
| | - Kathy Murray
- Remote Sensing and Spatial Analysis Program, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, WA, Australia
| | - Shaun Wilson
- Marine Science Program, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, WA, Australia
- School of Biological Sciences and the Oceans Institute, The University of Western Australia, Crawley, WA, Australia
| | - Bart Huntley
- Remote Sensing and Spatial Analysis Program, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, WA, Australia
| | - Michael Rule
- Marine Science Program, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, WA, Australia
| | - Michael Heithaus
- Center for Coastal Oceans Research, Department of Biological Sciences, Florida International University, Miami, FL, USA
| | - Cindy Bessey
- CSIRO, Oceans and Atmosphere, Indian Ocean Marine Research Centre, Crawley, WA, Australia
| | - Gary A Kendrick
- School of Biological Sciences and the Oceans Institute, The University of Western Australia, Crawley, WA, Australia
| | - Derek Burkholder
- Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Dania Beach, FL, USA
| | - Matthew W Fraser
- School of Biological Sciences and the Oceans Institute, The University of Western Australia, Crawley, WA, Australia
| | - Katherine Zdunic
- Remote Sensing and Spatial Analysis Program, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Kensington, WA, Australia
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11
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Ceccarelli DM, Evans RD, Logan M, Mantel P, Puotinen M, Petus C, Russ GR, Williamson DH. Long-term dynamics and drivers of coral and macroalgal cover on inshore reefs of the Great Barrier Reef Marine Park. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02008. [PMID: 31550393 DOI: 10.1002/eap.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/20/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
Quantifying the role of biophysical and anthropogenic drivers of coral reef ecosystem processes can inform management strategies that aim to maintain or restore ecosystem structure and productivity. However, few studies have examined the combined effects of multiple drivers, partitioned their impacts, or established threshold values that may trigger shifts in benthic cover. Inshore fringing reefs of the Great Barrier Reef Marine Park (GBRMP) occur in high-sediment, high-nutrient environments and are under increasing pressure from multiple acute and chronic stressors. Despite world-leading management, including networks of no-take marine reserves, relative declines in hard coral cover of 40-50% have occurred in recent years, with localized but persistent shifts from coral to macroalgal dominance on some reefs. Here we use boosted regression tree analyses to test the relative importance of multiple biophysical drivers on coral and macroalgal cover using a long-term (12-18 yr) data set collected from reefs at four island groups. Coral and macroalgal cover were negatively correlated at all island groups, and particularly when macroalgal cover was above 20%. Although reefs at each island group had different disturbance-and-recovery histories, degree heating weeks (DHW) and routine wave exposure consistently emerged as common drivers of coral and macroalgal cover. In addition, different combinations of sea-surface temperature, nutrient and turbidity parameters, exposure to high turbidity (primary) floodwater, depth, grazing fish density, farming damselfish density, and management zoning variously contributed to changes in coral and macroalgal cover at each island group. Clear threshold values were apparent for multiple drivers including wave exposure, depth, and degree heating weeks for coral cover, and depth, degree heating weeks, chlorophyll a, and cyclone exposure for macroalgal cover, however, all threshold values were variable among island groups. Our findings demonstrate that inshore coral reef communities are typically structured by broadscale climatic perturbations, superimposed upon unique sets of local-scale drivers. Although rapidly escalating climate change impacts are the largest threat to coral reefs of the GBRMP and globally, our findings suggest that proactive management actions that effectively reduce chronic stressors at local scales should contribute to improved reef resistance and recovery potential following acute climatic disturbances.
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Affiliation(s)
- Daniela M Ceccarelli
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
| | - Richard D Evans
- Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, 6151, Australia
- Oceans Institute, University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Murray Logan
- Australian Institute of Marine Science, PMB 3, Townsville, Queensland, 4810, Australia
| | - Philippa Mantel
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
| | - Marji Puotinen
- Australian Institute of Marine Science, PMB 3, Townsville, Queensland, 4810, Australia
| | - Caroline Petus
- TropWATER, James Cook University, Townsville, Queensland, 4811, Australia
| | - Garry R Russ
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
- College of Science and Engineering, James Cook University, Townsville, Queensland, 4811, Australia
| | - David H Williamson
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
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Alotaibi NM, Kenyon EJ, Cook KJ, Börger L, Bull JC. Low genotypic diversity and long-term ecological decline in a spatially structured seagrass population. Sci Rep 2019; 9:18387. [PMID: 31804557 PMCID: PMC6895181 DOI: 10.1038/s41598-019-54828-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 11/14/2019] [Indexed: 12/03/2022] Open
Abstract
In isolated or declining populations, viability may be compromised further by loss of genetic diversity. Therefore, it is important to understand the relationship between long-term ecological trajectories and population genetic structure. However, opportunities to combine these types of data are rare, especially in natural systems. Using an existing panel of 15 microsatellites, we estimated allelic diversity in seagrass, Zostera marina, at five sites around the Isles of Scilly Special Area of Conservation, UK, in 2010 and compared this to 23 years of annual ecological monitoring (1996–2018). We found low diversity and long-term declines in abundance in this relatively pristine but isolated location. Inclusion of the snapshot of genotypic, but less-so genetic, diversity improved prediction of abundance trajectories; however, this was spatial scale-dependent. Selection of the appropriate level of genetic organization and spatial scale for monitoring is, therefore, important to identify drivers of eco-evolutionary dynamics. This has implications for the use of population genetic information in conservation, management, and spatial planning.
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Affiliation(s)
- Nahaa M Alotaibi
- Department of Biosciences, Swansea University, Swansea, Wales, United Kingdom.,Princess Nourah bint Abdulrahman University, Riyadh, Kingdom of Saudi Arabia
| | - Emma J Kenyon
- School of Life Sciences, University of Sussex, Brighton, England, UK
| | | | - Luca Börger
- Department of Biosciences, Swansea University, Swansea, Wales, United Kingdom
| | - James C Bull
- Department of Biosciences, Swansea University, Swansea, Wales, United Kingdom.
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Xu NN, Jiang K, Biswas SR, Tong X, Wang R, Chen XY. Clone Configuration and Spatial Genetic Structure of Two Halophila ovalis Populations With Contrasting Internode Lengths. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00170] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Maxwell SL, Butt N, Maron M, McAlpine CA, Chapman S, Ullmann A, Segan DB, Watson JEM. Conservation implications of ecological responses to extreme weather and climate events. DIVERS DISTRIB 2018. [DOI: 10.1111/ddi.12878] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Sean L. Maxwell
- School of Earth and Environmental Sciences The University of Queensland Brisbane Queensland Australia
| | - Nathalie Butt
- School of Biological Sciences The University of Queensland Brisbane Queensland Australia
| | - Martine Maron
- School of Earth and Environmental Sciences The University of Queensland Brisbane Queensland Australia
| | - Clive A. McAlpine
- School of Earth and Environmental Sciences The University of Queensland Brisbane Queensland Australia
| | - Sarah Chapman
- School of Earth and Environmental Sciences The University of Queensland Brisbane Queensland Australia
| | - Ailish Ullmann
- Dana and David Dornsife College of Letters, Arts, and Sciences University of Southern California Los Angeles California
| | | | - James E. M. Watson
- School of Earth and Environmental Sciences The University of Queensland Brisbane Queensland Australia
- Wildlife Conservation Society Global Conservation Program Bronx New York
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