Marine Population Connectivity
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Marine Population Connectivity
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Author :
language : en
Publisher:
Release Date : 2007
Marine Population Connectivity written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with categories.
Special Issue On Marine Population Connectivity
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Author :
language : en
Publisher:
Release Date : 2007
Special Issue On Marine Population Connectivity written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Marine animals categories.
Population Connectivity In Marine Systems
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Author : Robert K. Cowen
language : en
Publisher:
Release Date : 2003
Population Connectivity In Marine Systems written by Robert K. Cowen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Fish populations categories.
A central goal of marine ecology is to achieve a mechanistic understanding of the factors regulating the abundance and distribution of marine populations. One critical component of the goal is to quantify rates of exchange, or connectivity, among sub-populations of marine organisms via larval dispersal. Theoretical studies suggest that these linkages play a fundamental role in local and meta-population dynamics, community structure, genetic diversity, and the resiliency of populations to human exploitation. Understanding population connectivity is also key in efforts to develop spatial management methods for marine-capture fisheries, including the design of networks of marine reserves. There are considerable advances in understanding of the biology of juvenile and adult life history stages through experimental marine ecology.
Population Connectivity And Its Application To Marine Protected Area Effectiveness In A Sub Arctic Coastal Ecosystem
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Author : Corey John Morris
language : en
Publisher:
Release Date : 2013
Population Connectivity And Its Application To Marine Protected Area Effectiveness In A Sub Arctic Coastal Ecosystem written by Corey John Morris and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Atlantic cod categories.
Connectivity Fecundity And Larval Abundance Along An Upwelling Coast
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Author : Sarah Olverson Hameed
language : en
Publisher:
Release Date : 2016
Connectivity Fecundity And Larval Abundance Along An Upwelling Coast written by Sarah Olverson Hameed and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
A better understanding of the processes that regulate marine metapopulations is needed for effective conservation management planning. Ecosystem level protections in the form of marine protected areas (MPAs) may be the most effective strategy to minimize the risk of population collapse, community disruption, and biodiversity loss because intact communities appear to be more resilient to natural and anthropogenic disturbances. The effectiveness of MPAs as a tool for conserving marine populations, however, hinges on understanding the processes that regulate marine populations. This dissertation focuses on three connected processes that play large roles in regulating marine metapopulations - population connectivity, fecundity, and larval distribution. I investigate these processes in decapod populations along an open coast characterized by strong seasonal upwelling that drives high primary production and rich marine biodiversity and supports a plethora of fisheries. In Chapter 1, I used extensive field measurements of fecundity, population size, and settlement and a Bayesian modeling approach to determine demographic connectivity among invertebrate populations along the California coastline. This study provides the first evidence of high local retention and limited connectivity among populations spanning 700 km along an open coast in an upwelling system with larvae that spend approximately six weeks in the plankton. The Bayesian modeling approach employed to estimate larval dispersal revealed the importance of employing demographic data in these estimates. The approach provides a tractable framework for addressing these questions for species occurring in discrete coastal populations. Latitudinal variation in upwelling affecting larval supply via advection offshore is widely considered to regulate populations and communities in upwelling regimes. In Chapter 2, I investigated an alternative explanation for differences in recruitment along the west coast of the U.S. - whether variation in fecundity could explain differences in recruitment across the two upwelling regimes that occur between Washington and California. Fecundity varied between upwelling regions, likely due to previously documented differences in primary productivity, and locally, depending on habitat type and surfzone hydrodynamics, both of which likely affect access to food. Larval distributions provide us with the clues to determine larval transport and survival. In Chapter 3, I determined the degree to which decapod larval abundance and spatial distribution are affected by local, regional, and basin-scale oceanographic conditions interannually. This investigation revealed that environmental variability, predominantly related to upwelling and primary production, explained 5% - 20% of the variability in the larval distributions, and the spatial distributions found in previous temporally constrained studies remained generally consistent across 8 years. The findings indicate that larval behaviors and demographic variables likely play a more important role in larval distributions than physical forcing. Effective spatial conservation management relies on understanding population persistence, which requires knowledge of population connectivity, fecundity, and the drivers of larval abundance through time. Taken together, these investigations into processes that regulate marine populations along a productive upwelling coast advance our fundamental understanding of the ecology and evolution of life in the sea and provide insights to improve management and conservation of its resources and ecosystems.
Dispersal Connectivity And Population Genetic Structure In The Sea
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Author : Amanda Xuereb
language : en
Publisher:
Release Date : 2018
Dispersal Connectivity And Population Genetic Structure In The Sea written by Amanda Xuereb and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
The spatial distribution of genetic variation across landscapes is influenced by physical features that facilitate or restrict movement and natural selection driven by environmental heterogeneity. Many marine organisms undergo a pelagic larval stage, during which time ocean currents influence dispersal and the degree of gene flow. Furthermore, gradients in temperature, salinity, and other environmental conditions produce spatially varying selection pressures across species ranges. In the first part of my thesis, I offer a novel perspective for marine conservation that emphasizes the importance of considering both connectivity (where connectivity is maintained by dispersal) and the potential for marine populations to adapt to their environment. To do so, I highlight how genomic data can be used to infer population connectivity (i.e. based on neutral genetic variation) and environmental selection (i.e. based on putatively adaptive genetic variation) in the context of marine reserve networks. Next, using a genomic dataset derived from restriction-site associated DNA sequencing (RADseq), I investigated the impact of ocean currents and environmental variables on spatial patterns of neutral and adaptive genetic variation in the commercially harvested giant California sea cucumber (P. californicus) along the northeastern Pacific coast. The results showed evidence for population structure despite the potential for widespread gene flow, and demonstrated that accounting for directionality of ocean currents explained genetic variation better than between-site geographic distances. Strong associations between sea bottom temperature and putatively adaptive loci were identified at a broad spatial scale, as well as moderate evidence that surface salinity and bottom current velocities contribute to regional patterns of adaptive differentiation. In a study using simulations of larval dispersal coupled with demo-genetic simulations, I found that potential dispersal was spatially restricted with shorter pelagic larval duration (PLD), but there was no difference between a model of diffusive (isotropic) larval transport and oceanographic (anisotropic) transport. However, several important caveats were highlighted that should be addressed in future work. Collectively, my thesis integrates genomic, environmental, and oceanographic data to understand the role of seascape features on connectivity and adaptation, with implications for marine conservation plans that aim to connect marine populations and support adaptive responses to environmental change.
Spationtemporal Population Genomics Of Marine Species
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Author : Eleanor Kathleen Bors
language : en
Publisher:
Release Date : 2017
Spationtemporal Population Genomics Of Marine Species written by Eleanor Kathleen Bors and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with DNA. categories.
Every genome tells a story. This dissertation contains four such stories, focused on shared themes of marine population dynamics and rapid change, with an emphasis on invasive marine species. Biological invasions are often characterized by a range expansion, during which strong genetic drift is hypothesized to result in decreased genetic diversity with increased distance from the center of the historic range, or the point of invasion. In this dissertation, population genetic and genomic tools are used to approach complex and previously intractable fundamental questions pertaining to the non-equilibrium dynamics of species invasions and rapid range expansions in two invasive marine species: the lionfish, Pterois volitans; and the shrimp, Palaemon macrodactylus. Using thousands of loci sequenced with restriction enzyme associated DNA sequencing in these two systems, this research tests theoretical predictions of the genomic signatures of range expansions. Additionally, the first chapter elucidates patterns of population genetic connectivity for deep-sea invertebrates in the New Zealand region demonstrating intimate relationships between genetics, oceanographic currents, and life history traits. Invasive shrimp results extend our understanding of marine population connectivity to suggest that human-mediated dispersal may be as important - if not more important - than oceanographic and life history considerations in determining genetic connectivity during specific phases of marine invasions. In invasive populations of lionfish, measures of genomic diversity, including a difference between observed and expected heterozygosity, were found to correlate with distance from the point of introduction, even in the absence of spatial metapopulation genetic structure. These results indicate a signal of rapid range expansion. The final study in this dissertation uses an innovative temporal approach to explore observed genomic patterns in the lionfish. In all, this dissertation provides a broad perspective through the study of multiple species undergoing superficially parallel processes that, under more intense scrutiny, are found to be mechanistically unique. It is only through comparative approaches that predictable patterns of population dynamics will emerge.
Quantifying Population Connectivity Of Marine Larvae
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Author : Craig Norrie
language : en
Publisher:
Release Date : 2019
Quantifying Population Connectivity Of Marine Larvae written by Craig Norrie and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Animal population genetics categories.
Population connectivity plays an important role in population dynamics. In the marine environment many species have a biphasic life history which consists of a pelagic larval phase followed by a relatively sedentary adult phase. Larval dispersal therefore plays an important role in population connectivity. Bivalve aquaculture is expanding worldwide while simultaneously many wild bivalve reefs are being degraded. There is interest in the restoration of these degraded bivalve reefs to which aquaculture may provide a larval subsidy through larval spill-over. The aim of this thesis was therefore to examine larval dispersal of the bivalve mussel Perna canaliculus (mussels). The Firth of Thames (FoT) in Northern New Zealand once supported dense mussel reefs, however currently the largest known populations in the area are in aquaculture. This thesis used a combination of trace elemental fingerprinting (TEF) and biophysical modelling to examine larval dispersal. TEF is based on the trace elemental composition of bivalve shell reflecting the environmental conditions under which it formed. Prior to the application of TEF in the FoT I investigated the role played by pH and the genetic history of an individual on the elemental composition of shell material. I demonstrated that while the genetic history of an individual will affect the composition of shell material, this will not affect the ability to determine the location at which it formed. I then demonstrated that despite pH changes TEF will remain a viable technique to track the dispersal of larvae under possible future conditions of ocean acidification. Both these results are novel findings. In the biophysical modelling study, virtual larval were continually released over a 10 year period and tracked until settlement. This study demonstrated that larvae from aquaculture are capable of settling throughout the FoT. TEF then demonstrated that the larval pool in the FoT is well mixed with larvae predicted to have originated throughout the FoT found at all locations monitored. These results showed that larval spill-over from aquaculture has the potential to contribute to the restoration of bivalve reefs through a larval subsidy. Restoration programmes should therefore carefully consider potential population subsidies from aquaculture and apply a network approach.
Larval Dispersal In Marine Fishes
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Author : Mark R. Christie
language : en
Publisher:
Release Date : 2010
Larval Dispersal In Marine Fishes written by Mark R. Christie and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Pomacentridae categories.
Many marine fish populations are severely declining due to over-fishing, loss of both juvenile and adult habitats, and accelerating environmental degradation. Fisheries management and the implementation of marine protected areas (MPAs) and other conservation tools are currently hindered by large gaps in knowledge about larval dispersal and its subsequent effects on population dynamics and regulation. This lack of knowledge is due to the inherent difficulty associated with tracking miniscule marine fish larvae. Population genetics approaches are particularly promising, but current methods have been of limited use for inferring ecologically relevant rates of population connectivity because of the large population sizes and high amounts of gene flow present in most marine species. To address these issues, I developed novel genetic methods of identifying parent-offspring pairs to directly track the origin and settlement of larvae in natural populations. These parentage methods fully account for large numbers of pair-wise comparisons and do not require any demographic assumptions or observational data. Furthermore, these methods can be used when only a small proportion of candidate parents can be sampled, which is often the case in large marine populations. I also employed Bayes' theorem to take into account the frequencies of shared alleles in putative parent-offspring pairs, which can maximize statistical power when faced with fixed numbers of loci. I accounted for genotyping errors by introducing a quantitative method to determine the number of loci to allow to mismatch based upon study-specific error rates. These novel parentage methods were applied to yellow tang (Zebrasoma flavescens, Acanthuridae) sampled around the Island of Hawai'i (measuring 140 km by 129 km) during the summer of 2006. We identified four parent-offspring pairs, which documented dispersal distances ranging from 15 to 184 kilometers. Two of the parents were located within MPAs and their offspring dispersed to unprotected areas. This observation provided direct evidence that MPAs can successfully seed unprotected sites with larvae that survive to become established juveniles. All four offspring were found to the north of their parents and a detailed oceanographic analysis from relevant time periods demonstrated that passive transport initially explained the documented dispersal patterns. However, passive dispersal could not explain how larvae eventually settled on the same island from which they were spawned, indicating a role for larval behavior interacting with fine-scale oceanographic features. Two findings together suggested that sampled reefs did not contribute equally to successful recruitment: (1) low levels of genetic differentiation among all recruit samples, and (2) the fact that the 4 documented parents occurred at only 2 sites. These findings empirically demonstrated the effectiveness of MPAs as useful conservation and management tools and highlighted the value of identifying both the sources and successful settlement sites of marine larvae. I next examined patterns of larval dispersal in bicolor damselfish (Stegastes partitus, Pomacentridae) collected during the summers of 2004 and 2005 from reefs lining the Exuma Sound, Bahamas (measuring 205 km by 85 km). Parentage analysis directly documented two parent-offspring pairs located within the two northern-most sites, which indicated self-recruitment at these sites. Multivariate analyses of pair-wise relatedness values confirmed that self-recruitment was common at all sampled populations. I also found evidence of "sweepstakes events", whereby only a small proportion of mature adults contributed to subsequent generations. Independent sweepstakes events were indentified in both space and time, bolstering the direct observations of self-recruitment and suggesting a role for sweepstakes analyses to identify the scale of larval dispersal events. This dissertation provides insights into the patterns of larval dispersal in coral-reef fishes. The coupling of direct (e.g., parentage) and indirect (e.g., assignment methods, sweepstakes analyses) methods in conjunction with continued technological and methodological advances will soon provide large-scale, ecologically relevant, rates of larval exchange. By uncovering the dynamics of these enigmatic processes, the implementation of conservation and management strategies for marine fishes in general will undoubtedly experience greater success.
Population Genetics Larval Dispersal And Demographic Connectivity In Marine Systems
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Author : Kimberley A. Weersing
language : en
Publisher:
Release Date : 2007
Population Genetics Larval Dispersal And Demographic Connectivity In Marine Systems written by Kimberley A. Weersing and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Animal population genetics categories.