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Sgambelluri LR, Jarvis JC, Kamel SJ. Multiple paternity, fertilization success, and male quality: Mating system variation in the eelgrass, Zostera marina. Ecol Evol 2024; 14:e11608. [PMID: 38919644 PMCID: PMC11197038 DOI: 10.1002/ece3.11608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 06/27/2024] Open
Abstract
Genetic diversity can modulate a population's response to a changing environment and plays a critical role in its ecological function. While multiple processes act to maintain genetic diversity, sexual reproduction remains the primary driving force. Eelgrass (Zostera marina) is an important habitat-forming species found in temperate coastal ecosystems across the globe. Recent increases in sea surface temperatures have resulted in shifts to a mixed-annual life-history strategy (i.e., displaying characteristics of both annual and perennial meadows) at its southern edge-of-range. Given that mating systems are intimately linked to standing levels of genetic variation, understanding the scope of sexual reproduction can illuminate the processes that shape genetic diversity. To characterize edge-of-range eelgrass mating systems, developing seeds on flowering Z. marina shoots were genotyped from three meadows in Topsail, North Carolina. In all meadows, levels of multiple mating were high, with shoots pollinated by an average of eight sires (range: 3-16). The number of fertilized seeds (i.e., reproductive success) varied significantly across sires (range: 1-25) and was positively correlated with both individual heterozygosity and self-fertilization. Outcrossing rates were high (approx. 70%) and varied across spathes. No clones were detected, and kinship among sampled flowering shoots was low, supporting observed patterns of reproductive output. Given the role that genetic diversity plays in enhancing resistance to and resilience from ecological disturbance, disentangling the links between life history, sexual reproduction, and genetic variation will aid in informing the management and conservation of this key foundation species.
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Affiliation(s)
- Lauren R. Sgambelluri
- Department of Biology and Marine Biology, Center for Marine ScienceUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
| | - Jessie C. Jarvis
- Department of Biology and Marine Biology, Center for Marine ScienceUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
| | - Stephanie J. Kamel
- Department of Biology and Marine Biology, Center for Marine ScienceUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
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2
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The evolutionary past and the uncertain future of foundational species. Proc Natl Acad Sci U S A 2022; 119:e2211134119. [PMID: 35939678 PMCID: PMC9388067 DOI: 10.1073/pnas.2211134119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
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3
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DuBois K, Pollard KN, Kauffman BJ, Williams SL, Stachowicz JJ. Local adaptation in a marine foundation species: Implications for resilience to future global change. GLOBAL CHANGE BIOLOGY 2022; 28:2596-2610. [PMID: 35007376 DOI: 10.1111/gcb.16080] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 12/31/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Environmental change is multidimensional, with local anthropogenic stressors and global climate change interacting to differentially impact populations throughout a species' geographic range. Within species, the spatial distribution of phenotypic variation and its causes (i.e., local adaptation or plasticity) will determine species' adaptive capacity to respond to a changing environment. However, comparatively less is known about the spatial scale of adaptive differentiation among populations and how patterns of local adaptation might drive vulnerability to global change stressors. To test whether fine-scale (2-12 km) mosaics of environmental stress can cause adaptive differentiation in a marine foundation species, eelgrass (Zostera marina), we conducted a three-way reciprocal transplant experiment spanning the length of Tomales Bay, CA. Our results revealed strong home-site advantage in growth and survival for all three populations. In subsequent common garden experiments and feeding assays, we showed that countergradients in temperature, light availability, and grazing pressure from an introduced herbivore contribute to differential performance among populations consistent with local adaptation. Our findings highlight how local-scale mosaics in environmental stressors can increase phenotypic variation among neighboring populations, potentially increasing species resilience to future global change. More specifically, we identified a range-center eelgrass population that is pre-adapted to extremely warm temperatures similar to those experienced by low-latitude range-edge populations of eelgrass, demonstrating how reservoirs of heat-tolerant phenotypes may already exist throughout a species range. Future work on predicting species resilience to global change should incorporate potential buffering effects of local-scale population differentiation and promote a phenotypic management approach to species conservation.
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Affiliation(s)
- Katherine DuBois
- Department of Evolution and Ecology, University of California, Davis, California, USA
- Bodega Marine Laboratory, University of California Davis, Bodega Bay, California, USA
| | - Kenzie N Pollard
- Department of Evolution and Ecology, University of California, Davis, California, USA
| | - Brian J Kauffman
- Bodega Marine Laboratory, University of California Davis, Bodega Bay, California, USA
| | - Susan L Williams
- Department of Evolution and Ecology, University of California, Davis, California, USA
- Bodega Marine Laboratory, University of California Davis, Bodega Bay, California, USA
| | - John J Stachowicz
- Department of Evolution and Ecology, University of California, Davis, California, USA
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Hays CG, Hanley TC, Hughes AR, Truskey SB, Zerebecki RA, Sotka EE. Local Adaptation in Marine Foundation Species at Microgeographic Scales. THE BIOLOGICAL BULLETIN 2021; 241:16-29. [PMID: 34436968 DOI: 10.1086/714821] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
AbstractNearshore foundation species in coastal and estuarine systems (e.g., salt marsh grasses, mangroves, seagrasses, corals) drive the ecological functions of ecosystems and entire biomes by creating physical structure that alters local abiotic conditions and influences species interactions and composition. The resilience of foundation species and the ecosystem functions they provide depends on their phenotypic and genetic responses to spatial and temporal shifts in environmental conditions. In this review, we explore what is known about the causes and consequences of adaptive genetic differentiation in marine foundation species over spatial scales shorter than dispersal capabilities (i.e., microgeographic scales). We describe the strength of coupling field and laboratory experiments with population genetic techniques to illuminate patterns of local adaptation, and we illustrate this approach by using several foundation species. Among the major themes that emerge from our review include (1) adaptive differentiation of marine foundation species repeatedly evolves along vertical (i.e., elevation or depth) gradients, and (2) mating system and phenology may facilitate this differentiation. Microgeographic adaptation is an understudied mechanism potentially underpinning the resilience of many sessile marine species, and this evolutionary mechanism likely has particularly important consequences for the ecosystem functions provided by foundation species.
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5
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DuBois K, Williams SL, Stachowicz JJ. Previous exposure mediates the response of eelgrass to future warming via clonal transgenerational plasticity. Ecology 2020; 101:e03169. [DOI: 10.1002/ecy.3169] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 04/08/2020] [Accepted: 06/18/2020] [Indexed: 01/18/2023]
Affiliation(s)
- Katherine DuBois
- Department of Evolution and Ecology University of California One Shields Avenue Davis California95616USA
- Bodega Marine Laboratory, University of California Davis Bodega Bay California94923USA
| | - Susan L. Williams
- Department of Evolution and Ecology University of California One Shields Avenue Davis California95616USA
- Bodega Marine Laboratory, University of California Davis Bodega Bay California94923USA
| | - John J. Stachowicz
- Department of Evolution and Ecology University of California One Shields Avenue Davis California95616USA
- Bodega Marine Laboratory, University of California Davis Bodega Bay California94923USA
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6
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Castorani MCN, Baskett ML. Disturbance size and frequency mediate the coexistence of benthic spatial competitors. Ecology 2019; 101:e02904. [PMID: 31562771 DOI: 10.1002/ecy.2904] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 09/11/2019] [Indexed: 11/07/2022]
Abstract
Disturbance plays a key role in structuring community dynamics and is central to conservation and natural resource management. However, ecologists continue to debate the importance of disturbance for species coexistence and biodiversity. Such disagreements may arise in part because few studies have examined variation across multiple dimensions of disturbance (e.g., size, frequency) and how the effects of disturbance may depend on species attributes (e.g., competitiveness, dispersal ability). In light of this gap in understanding and accelerating changes to disturbance regimes worldwide, we used spatial population models to explore how disturbance size and frequency interact with species attributes to affect coexistence between seagrass (Zostera marina) and colonial burrowing shrimp (Neotrypaea californiensis) that compete for benthic space in estuaries throughout the west coast of North America. By simulating population dynamics under a range of ecologically relevant disturbance regimes, we discovered that intermediate disturbance (approximately 9-23% of landscape area per year) to short-dispersing, competitively dominant seagrass can foster long-term stable coexistence with broad-dispersing, competitively inferior burrowing shrimp via the spatial storage effect. When holding the total extent of disturbance constant, the individual size and annual frequency of disturbance altered landscape spatial patterns and mediated the dominance and evenness of competitors. Many small disturbances favored short-dispersing seagrass by hastening recolonization, whereas fewer large disturbances benefited rapidly colonizing burrowing shrimp by creating temporary refugia from competition. As a result, large, infrequent disturbances generally improved the strength and stability of coexistence relative to small, frequent disturbances. Regardless of disturbance size or frequency, the dispersal ability of the superior competitor (seagrass), the competitive ability of the inferior competitor (burrowing shrimp), and the reproduction and survival of both species strongly influenced population abundances and coexistence. Our results show that disturbance size and frequency can promote or constrain coexistence by altering the duration of time over which inferior competitors can escape competitive exclusion, particularly when colonization depends on the spatial pattern of disturbance due to dispersal traits. For coastal managers and conservation practitioners, our findings indicate that reducing particularly large disturbances may help conserve globally imperiled seagrass meadows and control burrowing shrimp colonies that can threaten the viability of oyster aquaculture.
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Affiliation(s)
- Max C N Castorani
- Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia, 22904, USA
| | - Marissa L Baskett
- Department of Environmental Science and Policy, University of California, Davis, California, 95616, USA
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7
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Alvarez A. Secondary dispersal of seagrass seeds in complex microtopographies. J Theor Biol 2019; 473:28-37. [PMID: 31026446 DOI: 10.1016/j.jtbi.2019.04.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 03/15/2019] [Accepted: 04/22/2019] [Indexed: 11/19/2022]
Abstract
Motivated by observational and experimental evidence, a theoretical model is proposed to relate the secondary dispersal of seagrass seeds with the complexity of microtopography in natural environments. Complexity is encoded in terms of the Hurst exponent of a fractal description of the microtopographical geometry. The percentage of a seafloor transect where secondary dispersal of seagrass seeds occurs, is quantified in terms of the mainstream velocity, bottom complexity and properties of the seeds. Theoretical expressions are validated considering the cases of Zostera marina and Posidonia oceanica seeds and using computational fluid dynamics (CFD). A total of 200 CFD simulations with different bottom complexities and flow conditions, were done for each seagrass genus to validate the theoretical model. Numerical results agree with theoretical predictions. This finding provides a management tool to assess the degree of seed retention in seed-based restoration areas.
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Affiliation(s)
- A Alvarez
- Department of Marine Ecology (MARE), Instituto Mediterraneo de Estudios Avanzados-IMEDEA (CSIC-UIB), C/ Miquel Marques 21, 07190 Esporlas, Spain.
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8
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Lloyd MW, Tumas HR, Neel MC. Limited pollen dispersal, small genetic neighborhoods, and biparental inbreeding in Vallisneria americana. AMERICAN JOURNAL OF BOTANY 2018; 105:227-240. [PMID: 29578290 DOI: 10.1002/ajb2.1031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/08/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Pollen dispersal is a key process that influences ecological and evolutionary dynamics of plant populations by facilitating sexual reproduction and gene flow. Habitat loss and fragmentation have the potential to reduce pollen dispersal within and among habitat patches. We assessed aquatic pollen dispersal and mating system characteristics in Vallisneria americana-a water-pollinated plant with a distribution that has been reduced from historic levels. METHODS We examined pollen neighborhood size, biparental inbreeding, and pollen dispersal, based on seed paternity using the indirect paternity method KinDist, from samples of 18-39 mothers and 14-20 progeny per mother from three sites across 2 years. KEY RESULTS On average, fruits contained seeds sired by seven fathers. We found significant biparental inbreeding and limited pollen dispersal distances (0.8-4.34 m). However, in a number of cases, correlated paternity did not decline with distance, and dispersal could not be reliably estimated. CONCLUSIONS Frequent pollen dispersal is not expected among patches, and even within patches, gene flow via pollen will be limited. Limited pollen dispersal establishes genetic neighborhoods, which, unless overcome by seed and propagule dispersal, will lead to genetic differentiation even in a continuous population. Unless loss and fragmentation drive populations to extreme sex bias, local pollen dispersal is likely to be unaffected by habitat loss and fragmentation per se because the spatial scale of patch isolation already exceeds pollen dispersal distances. Therefore, managing specifically for pollen connectivity is only relevant over very short distances.
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Affiliation(s)
- Michael W Lloyd
- Department of Plant Science and Landscape Architecture and Department of Entomology, University of Maryland-College Park, 2116 Plant Sciences Building, College Park, Maryland, 20742-4452, USA
| | - Hayley R Tumas
- Department of Plant Science and Landscape Architecture and Department of Entomology, University of Maryland-College Park, 2116 Plant Sciences Building, College Park, Maryland, 20742-4452, USA
| | - Maile C Neel
- Department of Plant Science and Landscape Architecture and Department of Entomology, University of Maryland-College Park, 2116 Plant Sciences Building, College Park, Maryland, 20742-4452, USA
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Ruckelshaus MH. SPATIAL SCALE OF GENETIC STRUCTURE AND AN INDIRECT ESTIMATE OF GENE FLOW IN EELGRASS,
ZOSTERA MARINA. Evolution 2017; 52:330-343. [DOI: 10.1111/j.1558-5646.1998.tb01635.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/1997] [Accepted: 09/20/1997] [Indexed: 12/01/2022]
Affiliation(s)
- Mary H. Ruckelshaus
- University of Washington Department of Botany Seattle Washington 98195
- Department of Biological Science Florida State University Tallahassee Florida 32306
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10
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Latta RG, Linhart YB, Fleck D, Elliot M. DIRECT AND INDIRECT ESTIMATES OF SEED VERSUS POLLEN MOVEMENT WITHIN A POPULATION OF PONDEROSA PINE. Evolution 2017; 52:61-67. [DOI: 10.1111/j.1558-5646.1998.tb05138.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/1997] [Accepted: 08/27/1997] [Indexed: 11/29/2022]
Affiliation(s)
- Robert G. Latta
- Department of Environmental, Population and Organismic Biology University of Colorado Boulder Colorado 80309‐0334
| | - Yan B. Linhart
- Department of Environmental, Population and Organismic Biology University of Colorado Boulder Colorado 80309‐0334
| | - David Fleck
- Department of Environmental, Population and Organismic Biology University of Colorado Boulder Colorado 80309‐0334
| | - Michael Elliot
- Department of Environmental, Population and Organismic Biology University of Colorado Boulder Colorado 80309‐0334
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11
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Van Tussenbroek BI, Valdivia‐Carrillo T, Rodríguez‐Virgen IT, Sanabria‐Alcaraz SNM, Jiménez‐Durán K, Van Dijk KJ, Marquez‐Guzmán GJ. Coping with potential bi-parental inbreeding: limited pollen and seed dispersal and large genets in the dioecious marine angiosperm Thalassia testudinum. Ecol Evol 2016; 6:5542-5556. [PMID: 27942375 PMCID: PMC5127610 DOI: 10.1002/ece3.2309] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 05/31/2016] [Accepted: 06/23/2016] [Indexed: 12/02/2022] Open
Abstract
The high prevalence of dioecy in marine angiosperms or seagrasses (>50% of all species) is thought to enforce cross-fertilization. However, seagrasses are clonal plants, and they may still be subject to sibling-mating or bi-parental inbreeding if the genetic neighborhood is smaller than the size of the genets. We tested this by determining the genetic neighborhoods of the dioecious seagrass Thalassia testudinum at two sites (Back-Reef and Mid-Lagoon) in Puerto Morelos Reef Lagoon, Mexico, by measuring dispersal of pollen and seeds in situ, and by fine-scale spatial autocorrelation analysis with eight polymorphic microsatellite DNA markers. Prevalence of inbreeding was verified by estimating pairwise kinship coefficients; and by analysing the genotypes of seedlings grown from seeds in mesocosms. Average dispersal of pollen was 0.3-1.6 m (max. 4.8 m) and of seeds was 0.3-0.4 m (max. 1.8 m), resulting in a neighborhood area of 7.4 m2 (range 3.4-11.4 m2) at Back-Reef and 1.9 (range 1.87-1.92 m2) at Mid-Lagoon. Neighborhood area (Na) derived from spatial autocorrelation was 0.1-20.5 m2 at Back-Reef and 0.1-16.9 m2 at Mid-Lagoon. Maximal extensions of the genets, in 19 × 30 m plots, were 19.2 m (median 7.5 m) and 10.8 m (median 4.8 m) at Back-Reef and Mid-Lagoon. There was no indication of deficit or excess of heterozygotes nor were coefficients of inbreeding (FIS) significant. The seedlings did not show statistically significant deficit of heterozygotes (except for 1 locus at Back-Reef). Contrary to our expectations, we did not find evidence of bi-parental inbreeding in this dioecious seagrass with large genets but small genetic neighborhoods. Proposed mechanisms to avoid bi-parental inbreeding are possible selection against homozygotes during fecundation or ovule development. Additionally, the genets grew highly dispersed (aggregation index Ac was 0.09 and 0.10 for Back-Reef and Mid-Lagoon, respectively); such highly dispersed guerrilla-like clonal growth form likely increases the probability of crossing between different potentially unrelated genets.
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Affiliation(s)
- Brigitta Ine Van Tussenbroek
- Instituto de Ciencias del Mar y LimnologíaUnidad Académica Sistemas Arrecifales‐Puerto MorelosUniversidad Nacional Autónoma de MéxicoProlongación Niños Héroes S/NPuerto MorelosQuintana RooMéxico
| | - Tania Valdivia‐Carrillo
- Instituto de Ciencias del Mar y LimnologíaUnidad Académica Sistemas Arrecifales‐Puerto MorelosUniversidad Nacional Autónoma de MéxicoProlongación Niños Héroes S/NPuerto MorelosQuintana RooMéxico
| | - Irene Teresa Rodríguez‐Virgen
- Instituto de Ciencias del Mar y LimnologíaUnidad Académica Sistemas Arrecifales‐Puerto MorelosUniversidad Nacional Autónoma de MéxicoProlongación Niños Héroes S/NPuerto MorelosQuintana RooMéxico
- Present address: Department of Life and Health SciencesUniversity of North Texas at DallasDallasTexas
| | - Sylvia Nashieli Marisela Sanabria‐Alcaraz
- Instituto de Ciencias del Mar y LimnologíaUnidad Académica Sistemas Arrecifales‐Puerto MorelosUniversidad Nacional Autónoma de MéxicoProlongación Niños Héroes S/NPuerto MorelosQuintana RooMéxico
| | - Karina Jiménez‐Durán
- Instituto de Ciencias del Mar y LimnologíaUnidad Académica Sistemas Arrecifales‐Puerto MorelosUniversidad Nacional Autónoma de MéxicoProlongación Niños Héroes S/NPuerto MorelosQuintana RooMéxico
- Facultad de CienciasLaboratorio de Desarrollo de PlantasCiudad UniversitariaUniversidad Nacional Autónoma de MéxicoCoyoacanDistrito FederalMéxico
| | - Kor Jent Van Dijk
- Instituto de Ciencias del Mar y LimnologíaUnidad Académica Sistemas Arrecifales‐Puerto MorelosUniversidad Nacional Autónoma de MéxicoProlongación Niños Héroes S/NPuerto MorelosQuintana RooMéxico
- Present address: School of Biological ScienceUniversity of AdelaideAdelaideSouth Australia5005Australia
| | - Guadalupe Judith Marquez‐Guzmán
- Facultad de CienciasLaboratorio de Desarrollo de PlantasCiudad UniversitariaUniversidad Nacional Autónoma de MéxicoCoyoacanDistrito FederalMéxico
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12
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Talbot SL, Sage GK, Rearick JR, Fowler MC, Muñiz-Salazar R, Baibak B, Wyllie-Echeverria S, Cabello-Pasini A, Ward DH. The Structure of Genetic Diversity in Eelgrass (Zostera marina L.) along the North Pacific and Bering Sea Coasts of Alaska. PLoS One 2016; 11:e0152701. [PMID: 27104836 PMCID: PMC4841600 DOI: 10.1371/journal.pone.0152701] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/17/2016] [Indexed: 11/25/2022] Open
Abstract
Eelgrass (Zostera marina) populations occupying coastal waters of Alaska are separated by a peninsula and island archipelago into two Large Marine Ecosystems (LMEs). From populations in both LMEs, we characterize genetic diversity, population structure, and polarity in gene flow using nuclear microsatellite fragment and chloroplast and nuclear sequence data. An inverse relationship between genetic diversity and latitude was observed (heterozygosity: R2 = 0.738, P < 0.001; allelic richness: R2 = 0.327, P = 0.047), as was significant genetic partitioning across most sampling sites (θ = 0.302, P < 0.0001). Variance in allele frequency was significantly partitioned by region only in cases when a population geographically in the Gulf of Alaska LME (Kinzarof Lagoon) was instead included with populations in the Eastern Bering Sea LME (θp = 0.128-0.172; P < 0.003), suggesting gene flow between the two LMEs in this region. Gene flow among locales was rarely symmetrical, with notable exceptions generally following net coastal ocean current direction. Genetic data failed to support recent proposals that multiple Zostera species (i.e. Z. japonica and Z. angustifolia) are codistributed with Z. marina in Alaska. Comparative analyses also failed to support the hypothesis that eelgrass populations in the North Atlantic derived from eelgrass retained in northeastern Pacific Last Glacial Maximum refugia. These data suggest northeastern Pacific populations are derived from populations expanding northward from temperate populations following climate amelioration at the terminus of the last Pleistocene glaciation.
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Affiliation(s)
- Sandra L. Talbot
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
| | - George K Sage
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
| | - Jolene R. Rearick
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Meg C. Fowler
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
| | - Raquel Muñiz-Salazar
- Escuela de Ciencias de la Salud, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico
| | - Bethany Baibak
- Biological Sciences, Humboldt State University, Arcata, California, United States of America
| | - Sandy Wyllie-Echeverria
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, United States of America
- Center for Marine and Environmental Studies, University of Virgin Islands, St. Thomas, Virgin Islands, United States of America
| | - Alejandro Cabello-Pasini
- Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, California, Mexico
| | - David H. Ward
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
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Kendrick GA, Orth RJ, Statton J, Hovey R, Ruiz Montoya L, Lowe RJ, Krauss SL, Sinclair EA. Demographic and genetic connectivity: the role and consequences of reproduction, dispersal and recruitment in seagrasses. Biol Rev Camb Philos Soc 2016; 92:921-938. [DOI: 10.1111/brv.12261] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 02/12/2016] [Accepted: 02/16/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Gary A. Kendrick
- School of Plant Biology, Faculty of Science; University of Western Australia; Crawley Western Australia 6009 Australia
- UWA Oceans Institute; University of Western Australia; Crawley Western Australia 6009 Australia
| | - Robert J. Orth
- Virginia Institute of Marine Science; College of William and Mary; Gloucester Point VA 23062 U.S.A
| | - John Statton
- School of Plant Biology, Faculty of Science; University of Western Australia; Crawley Western Australia 6009 Australia
- UWA Oceans Institute; University of Western Australia; Crawley Western Australia 6009 Australia
| | - Renae Hovey
- School of Plant Biology, Faculty of Science; University of Western Australia; Crawley Western Australia 6009 Australia
- UWA Oceans Institute; University of Western Australia; Crawley Western Australia 6009 Australia
| | - Leonardo Ruiz Montoya
- School of Plant Biology, Faculty of Science; University of Western Australia; Crawley Western Australia 6009 Australia
- UWA Oceans Institute; University of Western Australia; Crawley Western Australia 6009 Australia
| | - Ryan J. Lowe
- UWA Oceans Institute; University of Western Australia; Crawley Western Australia 6009 Australia
- School of Earth and Environment; University of Western Australia; Crawley Western Australia 6009 Australia
- ARC Centre of Excellence for Coral Reef Studies; James Cook University Townsville; Queensland 4811 Australia
| | - Siegfried L. Krauss
- School of Plant Biology, Faculty of Science; University of Western Australia; Crawley Western Australia 6009 Australia
- Kings Park and Botanic Garden; West Perth Western Australia 6005 Australia
| | - Elizabeth A. Sinclair
- School of Plant Biology, Faculty of Science; University of Western Australia; Crawley Western Australia 6009 Australia
- UWA Oceans Institute; University of Western Australia; Crawley Western Australia 6009 Australia
- Kings Park and Botanic Garden; West Perth Western Australia 6005 Australia
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14
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Warner PA, Willis BL, Oppen MJH. Sperm dispersal distances estimated by parentage analysis in a brooding scleractinian coral. Mol Ecol 2016; 25:1398-415. [DOI: 10.1111/mec.13553] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 12/27/2015] [Accepted: 01/04/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Patricia A. Warner
- AIMS@JCU and Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- College of Marine and Environmental Sciences James Cook University Townsville Qld 4811 Australia
| | - Bette L. Willis
- AIMS@JCU and Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- College of Marine and Environmental Sciences James Cook University Townsville Qld 4811 Australia
| | - Madeleine J. H. Oppen
- AIMS@JCU and Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld 4811 Australia
- Australian Institute of Marine Science PMB3, Townsville MC Townsville Qld 4810 Australia
- School of BioSciences The University of Melbourne Parkville Vic. 23010 Australia
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McMahon K, van Dijk KJ, Ruiz-Montoya L, Kendrick GA, Krauss SL, Waycott M, Verduin J, Lowe R, Statton J, Brown E, Duarte C. The movement ecology of seagrasses. Proc Biol Sci 2015; 281:rspb.2014.0878. [PMID: 25297859 PMCID: PMC4213608 DOI: 10.1098/rspb.2014.0878] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
A movement ecology framework is applied to enhance our understanding of the causes, mechanisms and consequences of movement in seagrasses: marine, clonal, flowering plants. Four life-history stages of seagrasses can move: pollen, sexual propagules, vegetative fragments and the spread of individuals through clonal growth. Movement occurs on the water surface, in the water column, on or in the sediment, via animal vectors and through spreading clones. A capacity for long-distance dispersal and demographic connectivity over multiple timeframes is the novel feature of the movement ecology of seagrasses with significant evolutionary and ecological consequences. The space–time movement footprint of different life-history stages varies. For example, the distance moved by reproductive propagules and vegetative expansion via clonal growth is similar, but the timescales range exponentially, from hours to months or centuries to millennia, respectively. Consequently, environmental factors and key traits that interact to influence movement also operate on vastly different spatial and temporal scales. Six key future research areas have been identified.
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Affiliation(s)
- Kathryn McMahon
- School of Natural Sciences and Centre for Marine Ecosystems Research, Edith Cowan University, Joondalup, 6027 Western Australia, Australia
| | - Kor-Jent van Dijk
- School of Earth and Environmental Sciences, Australian Centre for Evolutionary Biology and Biodiversity, The University of Adelaide, Adelaide, 5001 South Australia, Australia
| | - Leonardo Ruiz-Montoya
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - Gary A Kendrick
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - Siegfried L Krauss
- School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia Kings Park and Botanic Garden, Botanic Gardens and Parks Authority, West Perth, 6005 Western Australia, Australia
| | - Michelle Waycott
- School of Earth and Environmental Sciences, Australian Centre for Evolutionary Biology and Biodiversity, The University of Adelaide, Adelaide, 5001 South Australia, Australia
| | | | - Ryan Lowe
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Earth and Environment, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - John Statton
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - Eloise Brown
- School of Environmental Systems and Engineering, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - Carlos Duarte
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia Mediterranean Institute for Advanced Studies, IMEDA (UIB-CSIC), 07190 Esporles, Islas Baleares, Spain
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16
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Furman BT, Peterson BJ. Sexual Recruitment in Zostera marina: Progress toward a Predictive Model. PLoS One 2015; 10:e0138206. [PMID: 26368792 PMCID: PMC4569585 DOI: 10.1371/journal.pone.0138206] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 08/27/2015] [Indexed: 11/18/2022] Open
Abstract
Ecophysiological stress and physical disturbance are capable of structuring meadows through a combination of direct biomass removal and recruitment limitation; however, predicting these effects at landscape scales has rarely been successful. To model environmental influence on sexual recruitment in perennial Zostera marina, we selected a sub-tidal, light-replete study site with seasonal extremes in temperature and wave energy. During an 8-year observation period, areal coverage increased from 4.8 to 42.7%. Gains were stepwise in pattern, attributable to annual recruitment of patches followed by centrifugal growth and coalescence. Recruitment varied from 13 to 4,894 patches per year. Using a multiple linear regression approach, we examined the association between patch appearance and relative wave energy, atmospheric condition and water temperature. Two models were developed, one appropriate for the dispersal of naked seeds, and another for rafted flowers. Results indicated that both modes of sexual recruitment varied as functions of wind, temperature, rainfall and wave energy, with a regime shift in wind-wave energy corresponding to periods of rapid colonization within our site. Temporal correlations between sexual recruitment and time-lagged climatic summaries highlighted floral induction, seed bank and small patch development as periods of vulnerability. Given global losses in seagrass coverage, regions of recovery and re-colonization will become increasingly important. Lacking landscape-scale process models for seagrass recruitment, temporally explicit statistical approaches presented here could be used to forecast colonization trajectories and to provide managers with real-time estimates of future meadow performance; i.e., when to expect a good year in terms of seagrass expansion. To facilitate use as forecasting tools, we did not use statistical composites or normalized variables as our predictors. This study, therefore, represents a first step toward linking remotely acquired environmental data to sexual recruitment, an important measure of seagrass performance that translates directly into landscape-scale coverage change.
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Affiliation(s)
- Bradley T Furman
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Bradley J Peterson
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, United States of America
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McMahon K, van Dijk KJ, Ruiz-Montoya L, Kendrick GA, Krauss SL, Waycott M, Verduin J, Lowe R, Statton J, Brown E, Duarte C. The movement ecology of seagrasses. Proc Biol Sci 2014. [PMID: 25297859 DOI: 10.1098/rspb.2014.0878.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A movement ecology framework is applied to enhance our understanding of the causes, mechanisms and consequences of movement in seagrasses: marine, clonal, flowering plants. Four life-history stages of seagrasses can move: pollen, sexual propagules, vegetative fragments and the spread of individuals through clonal growth. Movement occurs on the water surface, in the water column, on or in the sediment, via animal vectors and through spreading clones. A capacity for long-distance dispersal and demographic connectivity over multiple timeframes is the novel feature of the movement ecology of seagrasses with significant evolutionary and ecological consequences. The space-time movement footprint of different life-history stages varies. For example, the distance moved by reproductive propagules and vegetative expansion via clonal growth is similar, but the timescales range exponentially, from hours to months or centuries to millennia, respectively. Consequently, environmental factors and key traits that interact to influence movement also operate on vastly different spatial and temporal scales. Six key future research areas have been identified.
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Affiliation(s)
- Kathryn McMahon
- School of Natural Sciences and Centre for Marine Ecosystems Research, Edith Cowan University, Joondalup, 6027 Western Australia, Australia
| | - Kor-Jent van Dijk
- School of Earth and Environmental Sciences, Australian Centre for Evolutionary Biology and Biodiversity, The University of Adelaide, Adelaide, 5001 South Australia, Australia
| | - Leonardo Ruiz-Montoya
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - Gary A Kendrick
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - Siegfried L Krauss
- School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia Kings Park and Botanic Garden, Botanic Gardens and Parks Authority, West Perth, 6005 Western Australia, Australia
| | - Michelle Waycott
- School of Earth and Environmental Sciences, Australian Centre for Evolutionary Biology and Biodiversity, The University of Adelaide, Adelaide, 5001 South Australia, Australia
| | | | - Ryan Lowe
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Earth and Environment, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - John Statton
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - Eloise Brown
- School of Environmental Systems and Engineering, The University of Western Australia, Crawley, 6009 Western Australia, Australia
| | - Carlos Duarte
- The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia Mediterranean Institute for Advanced Studies, IMEDA (UIB-CSIC), 07190 Esporles, Islas Baleares, Spain
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18
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Zipperle AM, Coyer JA, Reise K, Gitz E, Stam WT, Olsen JL. Clonal architecture in an intertidal bed of the dwarf eelgrass Zostera noltii in the Northern Wadden Sea: persistence through extreme physical perturbation and the importance of a seed bank. MARINE BIOLOGY 2009; 156:2139-2148. [PMID: 24391236 PMCID: PMC3873049 DOI: 10.1007/s00227-009-1244-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Accepted: 06/18/2009] [Indexed: 05/20/2023]
Abstract
Genotypic structure and temporal dynamics of the dwarf seagrass, Zostera noltii, were studied in an intertidal meadow that has persisted since prior to 1936 near the Wadden Sea island of Sylt. Samples were collected from two 10 × 10 m plots separated by 250 m from May 2002 to June 2005 and from four 1 × 1 m plots from June 2003 to September 2004. All the samples were genotyped with nine microsatellite loci. No genotypes were shared between the plots separated by 250 m. Genetic diversity was higher in the Wadden Sea than in the other regions of its geographic range. The average clone size (genets) (SD) in the two plots was 1.38 (0.26) and 1.46 (0.4) m², respectively, with a range up to 9 m² and <20% persisted for >4 years. A high genetic and genotypic diversity was maintained by annual recruitment of seedlings despite a dramatic decrease in ramet density that coincided with the severe heat stress event of 2003. Fine-scale (1 m²) analysis suggested that extensive loss of seagrass cover precluded space competition among the genets, while a persistent seed bank prevented local extinction. Long-term persistence of Z. noltii meadows in the intertidal Wadden Sea was achieved by high genet turnover and frequent seedling recruitment from a seed bank, in contrast to the low diversity observed in large and long-living clones of Z. noltii and other seagrasses in subtidal habitats.
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Affiliation(s)
- Andreas M. Zipperle
- Department of Marine Benthic Ecology and Evolution, Centre for Ecological and Evolutionary Studies, Biological Centre, University of Groningen, Kerklaan 30, 9750 AA Haren, The Netherlands
| | - James A. Coyer
- Department of Marine Benthic Ecology and Evolution, Centre for Ecological and Evolutionary Studies, Biological Centre, University of Groningen, Kerklaan 30, 9750 AA Haren, The Netherlands
| | - Karsten Reise
- Alfred Wegener Institute for Polar and Marine Research, Wadden Sea Station Sylt, 25992 List, Germany
| | - Eelo Gitz
- Department of Marine Benthic Ecology and Evolution, Centre for Ecological and Evolutionary Studies, Biological Centre, University of Groningen, Kerklaan 30, 9750 AA Haren, The Netherlands
| | - Wytze T. Stam
- Department of Marine Benthic Ecology and Evolution, Centre for Ecological and Evolutionary Studies, Biological Centre, University of Groningen, Kerklaan 30, 9750 AA Haren, The Netherlands
| | - Jeanine L. Olsen
- Department of Marine Benthic Ecology and Evolution, Centre for Ecological and Evolutionary Studies, Biological Centre, University of Groningen, Kerklaan 30, 9750 AA Haren, The Netherlands
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19
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Shelton AO. SKEWED SEX RATIOS, POLLEN LIMITATION, AND REPRODUCTIVE FAILURE IN THE DIOECIOUS SEAGRASS PHYLLOSPADIX. Ecology 2008; 89:3020-3029. [PMID: 31766794 DOI: 10.1890/07-1835.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 03/04/2008] [Accepted: 03/17/2008] [Indexed: 11/18/2022]
Abstract
Dioecious mating systems in angiosperms, in which individuals are unisexual, require that pollen disperses between male and female individuals and may cause dioecious species to be vulnerable to reduced reproductive success via pollen limitation. This potential cost has rarely been documented, in part because of a dearth of studies investigating abiotic pollen dispersal, which tends to be associated with dioecy. I document widespread variation in reproductive success in an ecologically important, habitat-forming group, the seagrasses (marine angiosperms), using two species of the dioecious genus Phyllospadix. At multiple sites in the state of Washington, USA, I demonstrate pervasive male rarity (all sites <24% male by area). Male abundance is shown to predict female reproductive success at two scales. Within sites, the ratio of maturing seeds to total ovules declines rapidly with increasing distance to the nearest male, while among sites, mean seed : ovule ratios scale positively with male abundance. At some sites, less than 1 in 100 ovules mature into seeds. A field experiment conducted at a high pollen availability site shows that manipulating pollen availability could produce the range of seed sets observed across sites, but pollen limitation was not definitively demonstrated. Overall my results are consistent with pollen limitation in Phyllospadix and comprise the first strong evidence of this phenomenon in seagrass populations. In addition, seed production rates predicted local seedling recruitment, demonstrating a measurable demographic consequence of low pollen availability.
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Affiliation(s)
- Andrew Olaf Shelton
- Department of Ecology and Evolution, University of Chicago, 1101 E. 57th Street, Chicago, Illinois 60637 USA
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20
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Neville HM, Isaak DJ, Dunham JB, Thurow RF, Rieman BE. Fine-scale natal homing and localized movement as shaped by sex and spawning habitat in Chinook salmon: insights from spatial autocorrelation analysis of individual genotypes. Mol Ecol 2006; 15:4589-602. [PMID: 17107485 DOI: 10.1111/j.1365-294x.2006.03082.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Natal homing is a hallmark of the life history of salmonid fishes, but the spatial scale of homing within local, naturally reproducing salmon populations is still poorly understood. Accurate homing (paired with restricted movement) should lead to the existence of fine-scale genetic structuring due to the spatial clustering of related individuals on spawning grounds. Thus, we explored the spatial resolution of natal homing using genetic associations among individual Chinook salmon (Oncorhynchus tshawytscha) in an interconnected stream network. We also investigated the relationship between genetic patterns and two factors hypothesized to influence natal homing and localized movements at finer scales in this species, localized patterns in the distribution of spawning gravels and sex. Spatial autocorrelation analyses showed that spawning locations in both sub-basins of our study site were spatially clumped, but the upper sub-basin generally had a larger spatial extent and continuity of redd locations than the lower sub-basin, where the distribution of redds and associated habitat conditions were more patchy. Male genotypes were not autocorrelated at any spatial scale in either sub-basin. Female genotypes showed significant spatial autocorrelation and genetic patterns for females varied in the direction predicted between the two sub-basins, with much stronger autocorrelation in the sub-basin with less continuity in spawning gravels. The patterns observed here support predictions about differential constraints and breeding tactics between the two sexes and the potential for fine-scale habitat structure to influence the precision of natal homing and localized movements of individual Chinook salmon on their breeding grounds.
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Affiliation(s)
- H M Neville
- Department of Biology/314, University of Nevada, Reno, NV 89557, USA.
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Ravigné V, Olivieri I, González-Martínez SC, Rousset F. SELECTIVE INTERACTIONS BETWEEN SHORT-DISTANCE POLLEN AND SEED DISPERSAL IN SELF-COMPATIBLE SPECIES. Evolution 2006. [DOI: 10.1554/05-352.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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Muñiz-Salazar R, Talbot SL, Sage GK, Ward DH, Cabello-Pasini A. Population genetic structure of annual and perennial populations of Zostera marina L. along the Pacific coast of Baja California and the Gulf of California. Mol Ecol 2005; 14:711-22. [PMID: 15723663 DOI: 10.1111/j.1365-294x.2005.02454.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Baja California peninsula represents a biogeographical boundary contributing to regional differentiation among populations of marine animals. We investigated the genetic characteristics of perennial and annual populations of the marine angiosperm, Zostera marina, along the Pacific coast of Baja California and in the Gulf of California, respectively. Populations of Z. marina from five coastal lagoons along the Pacific coast and four sites in the Gulf of California were studied using nine microsatellite loci. Analyses of variance revealed significant interregional differentiation, but no subregional differentiation. Significant spatial differentiation, assessed using theta(ST) values, was observed among all populations within the two regions. Z. marina populations along the Pacific coast are separated by more than 220 km and had the greatest theta(ST) (0.13-0.28) values, suggesting restricted gene flow. In contrast, lower but still significant genetic differentiation was observed among populations within the Gulf of California (theta(ST) = 0.04-0.18), even though populations are separated by more than 250 km. This suggests higher levels of gene flow among Gulf of California populations relative to Pacific coast populations. Direction of gene flow was predominantly southward among Pacific coast populations, whereas no dominant polarity in the Gulf of California populations was observed. The test for isolation by distance (IBD) showed a significant correlation between genetic and geographical distances in Gulf of California populations, but not in Pacific coast populations, perhaps because of shifts in currents during El Niño Southern Oscillation (ENSO) events along the Pacific coast.
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Affiliation(s)
- Raquel Muñiz-Salazar
- Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California A.P. 453, Ensenada, Baja California 22800, México.
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23
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Olsen JL, Stam WT, Coyer JA, Reusch TBH, Billingham M, Boström C, Calvert E, Christie H, Granger S, la Lumière R, Milchakova N, Oudot-Le Secq MP, Procaccini G, Sanjabi B, Serrao E, Veldsink J, Widdicombe S, Wyllie-Echeverria S. North Atlantic phylogeography and large-scale population differentiation of the seagrass Zostera marina L. Mol Ecol 2005; 13:1923-41. [PMID: 15189214 DOI: 10.1111/j.1365-294x.2004.02205.x] [Citation(s) in RCA: 226] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
As the most widespread seagrass in temperate waters of the Northern Hemisphere, Zostera marina provides a unique opportunity to investigate the extent to which the historical legacy of the last glacial maximum (LGM18 000-10 000 years bp) is detectable in modern population genetic structure. We used sequences from the nuclear rDNA-internal transcribed spacer (ITS) and chloroplast matK-intron, and nine microsatellite loci to survey 49 populations (> 2000 individuals) from throughout the species' range. Minimal sequence variation between Pacific and Atlantic populations combined with biogeographical groupings derived from the microsatellite data, suggest that the trans-Arctic connection is currently open. The east Pacific and west Atlantic are more connected than either is to the east Atlantic. Allelic richness was almost two-fold higher in the Pacific. Populations from putative Atlantic refugia now represent the southern edges of the distribution and are not genetically diverse. Unexpectedly, the highest allelic diversity was observed in the North Sea-Wadden Sea-southwest Baltic region. Except for the Mediterranean and Black Seas, significant isolation-by-distance was found from ~150 to 5000 km. A transition from weak to strong isolation-by-distance occurred at ~150 km among northern European populations suggesting this scale as the natural limit for dispersal within the metapopulation. Links between historical and contemporary processes are discussed in terms of the projected effects of climate change on coastal marine plants. The identification of a high genetic diversity hotspot in Northern Europe provides a basis for restoration decisions.
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Affiliation(s)
- Jeanine L Olsen
- Department of Marine Biology, Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
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24
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Hämmerli A, Reusch TBH. Genetic neighbourhood of clone structures in eelgrass meadows quantified by spatial autocorrelation of microsatellite markers. Heredity (Edinb) 2004; 91:448-55. [PMID: 14576737 DOI: 10.1038/sj.hdy.6800310] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Limited dispersal distances in plant populations frequently cause local genetic structure, which can be quantified by spatial autocorrelation. In clonal plants, three levels of spatial organization can contribute to positive autocorrelation; namely, the neighbourhood of (a) ramets, (b) clone fragments and (c) entire clones. Here we use data from an exhaustive sampling scheme on a clonal plant to measure the contribution of the neighbourhoods of each distinct clonal structure to total spatial autocorrelation. Four plots (256 grid points each) within dense meadows of the marine clonal plant Zostera marina (eelgrass) were sampled for clone structure with nine microsatellite markers ( approximately 80 alleles). We found significant coancestry (f(ij)), at all three levels of spatial organization, even when not allowing for joins between samples of identical genets. In addition, absolute values of f(ij) and the maximum distance with significant positive f(ij) decreased with the progressive exclusion of joins between alike genotypes. The neighbourhood of this clonal plant thus consists of three levels of organization, which are reflected in different kinship structures. Each of these kinship structures may affect the level of biparental inbreeding and the physical distance between flowering shoots and their outcrossing neighbourhood. These results also emphasize the notion that spatial autocorrelation crucially depends on the scale and intensity of sampling.
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Affiliation(s)
- A Hämmerli
- 1Max Planck Institute for Limnology, August-Thienemann-Str. 2, D-24306 Plön, Germany.
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Rhode JM, Emmett Duffy J. Seed production from the mixed mating system of Chesapeake Bay (USA) eelgrass (Zostera marina; Zosteraceae). AMERICAN JOURNAL OF BOTANY 2004; 91:192-197. [PMID: 21653375 DOI: 10.3732/ajb.91.2.192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In monoecious plants, gametes can be exchanged in three ways: among unrelated genets (outbreeding), with close relatives (inbreeding), or within individuals (geitonogamous selfing). These different mating systems may have consequences for population demography and fitness. The experiment presented herein used artificial crosses to examine the mating system of Chesapeake Bay, Virginia, USA eelgrass (Zostera marina L; Zosteraceae), a bisexual submerged aquatic plant that can outbreed, inbreed, and self. Genetic data indicate severe heterozygosity deficiencies and patchy genotype distribution in these beds, suggesting that plants therein reproduce primarily by vegetative propagation, autogamy, or geitonogamy. To clarify eelgrass reproductive strategies, flowers from three genetically and geographically distinct beds were hand-pollinated in outbred, inbred, and selfed matings. Fertilization success and seed production, life history stages which contribute greatly to the numeric maintenance of populations, were monitored. We found no evidence that inbreeding had negative consequences for seed production. On the contrary, selfed matings produced seeds significantly more frequently than outcrossed matings and produced significantly larger numbers of seeds than either inbred or outbred matings. These results contrast with patterns for eelgrass in other regions but might be expected for similar populations in which pollen limitation or a short reproductive season renders selfing advantageous.
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Affiliation(s)
- Jennifer M Rhode
- College of William and Mary, School of Marine Science, P.O. Box 1346, Gloucester Point, Virginia 23062 USA
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26
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Rhode JM, Duffy JE. Relationships between bed age, bed size, and genetic structure in Chesapeake Bay (Virginia, USA) eelgrass (Zostera marina L.). CONSERV GENET 2004. [DOI: 10.1007/s10592-004-1856-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Hämmerli A, Reusch TBH. Flexible mating: cross-pollination affects sex-expression in a marine clonal plant. J Evol Biol 2003; 16:1096-105. [PMID: 14640401 DOI: 10.1046/j.1420-9101.2003.00626.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many functionally hermaphroditic plants have evolved mechanisms to reduce interference between the sex functions and to optimize reproductive output. In addition to physical mechanisms such as the spatial (herkogamy) and temporal (dichogamy) separation of male and female functions, plasticity in sex expression by means of mate-recognition (flexible mating) could be important in plants with variable access to cross-pollen. This applies particularly to clonal plants because of their modular growth form. We experimentally tested for the effects of pollen source and vegetative neighbourhood on instantaneous sex ratio and seed production in the self-compatible clonal marine angiosperm Zostera marina L. To this end, we exposed the (monoecious) flowering shoots to self and cross-pollen and to neighbourhoods of their own and a mix of foreign vegetative shoots. Flowering shoots that had been exposed to cross-pollen showed (1) a significantly lower female/male ratio at peak flowering, evidence for mate-recognition, and (2) a significantly higher seed set by the end of the season. Both effects were independent of the genetic composition of their vegetative neighbourhood. The results suggest that Z. marina maintains a cryptic self-incompatibility system not previously described for angiosperms with sub-aqueous pollination. In Z. marina, and possibly other self-compatible clonal plant species, mate-recognition could be a means of increasing the out-crossing probability for flowering shoots with central positions within their clone.
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Affiliation(s)
- A Hämmerli
- Max Planck Institute for Limnology, Plön, Germany.
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28
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Abstract
Although inbreeding depression is a major genetic phenomena influencing individual fitness, it is difficult to measure in wild populations. An alternative approach is to correlate heterozygosity, measured using highly polymorphic markers, with a fitness-correlated trait. In clonal plants, genet size is predicted to be fitness correlated. Here we test the prediction that the genet size distribution of the marine clonal plant Zostera marina (eelgrass) is influenced by inbreeding depression. We used nine polymorphic microsatellite markers to access the fine scale clonal structure and to measure individual heterozygosity within 4 plots (each corresponds to 256 m2, sampled at 1-m intervals) in two populations along the German Baltic Coast. The same plots were also sampled for flowering and vegetative shoots to obtain estimates for sexual reproductive output at the level of the genetic individual. We found substantial differences in the genet size distribution between the two populations that may be explained by different disturbance frequency. In both populations, clone size was significantly positively correlated with the total number of flowering shoots, indicating that larger clones have a higher reproductive output. Individual heterozygosity was significantly positively associated with clone size. The effect was much stronger in Falkenstein (low disturbance) than in Maasholm (high disturbance). The results indicate that in a low disturbance population the relatively outbred clones occupy a higher proportion of the available space, possibly because they outcompete relatively inbred neighbours.
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Affiliation(s)
- A Hämmerli
- Max Planck Institute for Limnology, August-Thienemann-Str. 2, D-24306 Plön, Germany.
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29
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Reusch TBH. Fitness-consequences of geitonogamous selfing in a clonal marine angiosperm (Zostera marina). J Evol Biol 2001; 14:129-138. [DOI: 10.1046/j.1420-9101.2001.00257.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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30
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Reusch TB, Stam WT, Olsen JL. A microsatellite-based estimation of clonal diversity and population subdivision in Zostera marina, a marine flowering plant. Mol Ecol 2000; 9:127-40. [PMID: 10672157 DOI: 10.1046/j.1365-294x.2000.00839.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We examined the genetic population structure in eelgrass (Zostera marina L.), the dominant seagrass species of the northern hemisphere, over spatial scales from 12 km to 10 000 km using the polymorphism of DNA microsatellites. Twelve populations were genotyped for six loci representing a total of 67 alleles. Populations sampled included the North Sea (four), the Baltic Sea (three), the western Atlantic (two), the eastern Atlantic (one), the Mediterranean Sea (one) and the eastern Pacific (one). Microsatellites revealed substantial genetic variation in a plant group with low allozyme diversity. Average expected heterozygosities per population (monoclonal populations excluded) ranged from 0.32 to 0.61 (mean = 0. 48) and allele numbers varied between 3.3 and 6.7 (mean = 4.7). Using the expected frequency of multilocus genotypes within populations, we distinguished ramets from genetic individuals (i.e. equivalent to clones). Differences in clonal diversity among populations varied widely and ranged from maximal diversity (i.e. all ramets with different genotype) to near or total monoclonality (two populations). All multiple sampled ramets were excluded from further analysis of genetic differentiation within and between populations. All but one population were in Hardy-Weinberg equilibrium, indicating that Zostera marina is predominantly outcrossing. From a regression of the pairwise population differentiation with distance, we obtained an effective population size Ne of 2440-5000. The overall genetic differentiation among eelgrass populations, assessed as rho (a standardized estimate of Slatkin's RST) was 0.384 (95% CI 0.34-0.44, P < 0.001). Genetic differentiation was weak among three North Sea populations situated 12-42 km distant from one another, suggesting that tidal currents result in an efficient exchange of propagules. In the Baltic and in Nova Scotia, a small but statistically significant fraction of the genetic variance was distributed between populations (rho = 0.029-0. 053) at scales of 15-35 km. Pairwise genetic differentiation between European populations were correlated with distance between populations up to a distance of 4500 km (linear differentiation-by-distance model, R2 = 0.67). In contrast, both Nova Scotian populations were genetically much closer to North Sea and Baltic populations than expected from their geographical distance (pairwise rho = 0.03-0.08, P < 0.01). A biogeographical cluster of Canadian with Baltic/North Sea populations was also supported using a neighbour-joining tree based on Cavalli-Sforza's chord distance. Relatedness between populations may be very different from predictions based on geographical vicinity.
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Affiliation(s)
- T B Reusch
- Department of Marine Biology, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
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Reusch TB, Hukriede W, Stam WT, Olsen JL. Differentiating between clonal growth and limited gene flow using spatial autocorrelation of microsatellites. Heredity (Edinb) 1999; 83 (Pt 2):120-6. [PMID: 10469199 DOI: 10.1046/j.1365-2540.1999.00546.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In plant populations alleles often deviate from a random distribution and reveal positive autocorrelation at short distances. In species with both clonal and sexual reproduction, such clustering may be because ramets of the same genet were sampled at nearby locations. Alternatively, clustering may be the result of limited gene flow through pollen or seeds (isolation-by-distance). Here, we modify a conventional spatial autocorrelation analysis using the join-count statistic in order to differentiate between these two causes of genetic structure. We examined the distribution of seven microsatellite loci representing 37 alleles in a 20 x 80 m plot of a perennial population of eelgrass Zostera marina L. In analysing join-counts between all like genotypes we found significant genetic autocorrelation among ramets at distances between 1 and 7 m (P < 0. 001). We then excluded joins between clonemates which were identified from the expected likelihood of their seven-locus genotypes. Without joins within genets, no autocorrelation was evident, indicating that most of the significant genetic clustering was caused by clonal spread. At distances up to 27 m, alleles were distributed at random, indicating a panmictic population at this spatial scale. These results illustrate the need for an a priori estimation of genet-ramet structure in clonally reproducing plants in order to avoid erroneous inferences about putative gene flow at various spatial scales.
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Affiliation(s)
- TB Reusch
- Department of Marine Biology, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands
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Gornall RJ, Hollingsworth PM, Preston CD. Evidence for spatial structure and directional gene flow in a population of an aquatic plant, Potamogeton coloratus. Heredity (Edinb) 1998. [DOI: 10.1046/j.1365-2540.1998.00270.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Williams SL, Davis CA. Population Genetic Analyses of Transplanted Eelgrass (Zostera marina) Beds Reveal Reduced Genetic Diversity in Southern California. Restor Ecol 1996. [DOI: 10.1111/j.1526-100x.1996.tb00117.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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