Download or read book H7 A Review of Biophysical Models of Marine Larval Dispersal written by Stephen E. Swearer and published by . This book was released on 2019 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Larval dispersal is arguably the most important but least understood demographic process in the sea. The likelihood of a larva dispersing from its birthplace to successfully recruit in another location is the culmination of many intrinsic and extrinsic factors that operate in early life. Empirically estimating the resulting population connectivity has been immensely difficult because of the challenges of studying and quantifying dispersal in the sea. Consequently, most estimates are based on predictions from biophysical models. Although there is a long history of dispersal modelling, there has been no comprehensive review of this literature. We conducted a systematic quantitative review to address the following questions: (1) Is there any bias in the distribution of research effort based on geographical or taxonomic coverage? (2) Are hydrodynamic models resolving ocean circulation at spatial scales (resolution and extent) relevant to the dispersal process under study? (3) Where, when and how many particles are being tracked, and is this effort sufficient to capture the spatiotemporal variability in dispersal? (4) How is biological and/or behavioural complexity incorporated into Lagrangian particle tracking models. (i.e. are key attributes of the dispersal process well captured.)? Our review confirms strong taxonomic and geographic biases in published work to date. We found that computational 'effort' (i.e. model resolution and particle number) has not kept pace with dramatic increases in computer processor speed. We also identified a number of shortcomings in the incorporation of biology, and behaviour specifically into models. Collectively, these findings highlight some important gaps and key areas for improvement of biophysical models that aspire to inform larval dispersal processes. In particular, we suggest the need for greater emphasis on validation of model assumptions, as well as testing of dispersal predictions with empirically derived data.
Download or read book The Bio physics of Marine Larval Dispersal written by Paul William Sammarco and published by . This book was released on 1994 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Trait based Modeling of Larval Dispersal in the Gulf of Maine written by Benjamin Thomas Jones and published by . This book was released on 2017 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: Population connectivity is a fundamental process that governs the spatial and temporal dynamics of marine ecosystems. For many marine species, population connectivity is driven by dispersal during a planktonic larval phase. The ability to obtain accurate, affordable, and meaningful estimates of larval dispersal patterns is therefore a key aspect of understanding marine ecosystems. Although field observations provide insight into dispersal processes, they do not provide a comprehensive assessment. Individual-based models (IBMs) that couple ocean circulation and particle-tracking models provide a unique ability to examine larval dispersal patterns with high spatial and temporal resolution. Obtaining accurate results with IBMs requires simulating a sufficient number of particles, and the sequential Bayesian procedure presented in chapter 2 identifies when the number of particles is adequate to address predefined research objectives. In addition, this method optimizes the particle release locations to minimize the requisite number of particles. Even after applying this method, the computational expense of IBM studies is still large. The model in chapter 3 seeks to increase the affordability of IBM studies by transferring some of the calculations to graphics processing units. Chapter 4 describes three algorithms that assist in interpreting IBM output by identifying coherent geographic clusters from population connectivity data. The first two algorithms have existed for nearly a decade and recently been applied separately to marine ecology, and we provide a direct comparison of the results from each. Additionally, we develop and present a new algorithm that simultaneously considers multiple species. Finally, in chapter 5, we apply these tools and a trait-based modeling framework to assess which species traits are most likely to impact dispersal success and patterns in the Gulf of Maine. We conclude that the traits influencing spawning distributions and habitat requirements for settlement are most likely to influence dispersal.
Download or read book Ecology of Marine Invertebrate Larvae written by Larry McEdward and published by CRC Press. This book was released on 2020-04-08 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book to provide a detailed treatment of the field of larval ecology. The 13 chapters use state-of-the-art reviews and critiques of nearly all of the major topics in this diverse and rapidly growing field. Topics include: patterns of larval diversity, reproductive energetics, spawning ecology, life history theory, larval feeding and nutrition, larval mortality, behavior and locomotion, larval transport, dispersal, population genetics, recruitment dynamics and larval evolution. Written by the leading new scientists in the field, chapters define the current state of larval ecology and outline the important questions for future research.
Download or read book Quantifying Population Connectivity of Marine Larvae written by Craig Norrie and published by . This book was released on 2019 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Behavioural Approach to Larval Dispersal in the Ocean written by Irisson-J and published by Omn.Univ.Europ.. This book was released on 2010 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most marine organisms that live near the coast broadcast their eggs and larvae into the vast expanses of the ocean. In many species, this pelagic episode is the sole opportunity for dispersal. As such, it structures the connections between populations which, in turn, determine the demography and genetic composition of coastal communities. Contrary to common belief, these "larvae" are not just drafts of the adults, passively roaming the ocean; they are very specialised organisms, often tightly adapted to their environment. In this book, I strive to evaluate the consequences of the behaviour of fish larvae during their pelagic life. I present experimental approaches to quantify larval orientation and swimming in situ. I detail the analysis of data collected during an oceanographic cruise to characterise the distribution of larvae in three dimensions and understand physical-biological interactions in the ocean. Finally, I introduce a novel modelling framework, drawing from cost minimisation techniques traditionally used in economics or in the optimal foraging theory, which allows to integrate larval behaviour into Lagrangian models of larval dispersal.
Download or read book Larval Dispersal in Marine Fishes written by Mark R. Christie and published by . This book was released on 2010 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Traveling Into the Unknown written by Heather Michelle Galindo and published by . This book was released on 2008 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding patterns of pelagic larval dispersal as a primary means of biological connectivity among populations is one of the great challenges in marine ecology. This dissertation developed novel approaches using population genetic tools to describe larval connections across different spatial and temporal scales. Chapter 1 presents a coupled oceanographic-genetic simulation model that predicts the genetic patterns expected to build up over evolutionary time if larval dispersal is directed by ocean currents. An application of this model in the Caribbean Sea successfully predicted regional-scale genetic patterns based on comparisons to empirical datasets. Chapters 2 and 3 used empirical approaches to estimate larval dispersal in ecological timeframes for the intertidal barnacle, Balanus glandula, living along the central California coast. The first of these chapters used a cohort genetics approach to detect potential changes in the genetic signature of larval cohorts settling in southern Monterey Bay across three settlement seasons (2004-2006). The genetic signature of the cohorts remained relatively stable across the three seasons and we were able to define the geographic scale from which most of the larvae in a cohort settling in southern Monterey Bay were drawn. Chapter 3 took an even closer look at the relative contributions of potential larval sources to B. glandula cohorts settling in Monterey Bay by using individual, multi-locus genotype analyses. The results of these analyses allowed us to create "arrival kernels" that provide the first direct evidence for long-distance larval dispersal from both north and south of Monterey Bay, in addition to a signature of local retention. Chapter 4 describes a pilot study using a survey-based approach to assess the conceptual models of marine population connectivity held by members of the public and how these models might relate to their opinions about marine policies. The results of this study indicate that most people do not have a readily formed model about this topic, but can create one given a few key pieces of information. Together, these chapters present new tools for using population genetics to study marine larval dispersal and guidelines about how to effectively communicate related research results outside the scientific community.
Download or read book Spreadsheet Exercises in Ecology and Evolution written by Therese Marie Donovan and published by Sinauer Associates Incorporated. This book was released on 2002 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: The exercises in this unique book allow students to use spreadsheet programs such as Microsoftr Excel to create working population models. The book contains basic spreadsheet exercises that explicate the concepts of statistical distributions, hypothesis testing and power, sampling techniques, and Leslie matrices. It contains exercises for modeling such crucial factors as population growth, life histories, reproductive success, demographic stochasticity, Hardy-Weinberg equilibrium, metapopulation dynamics, predator-prey interactions (Lotka-Volterra models), and many others. Building models using these exercises gives students "hands-on" information about what parameters are important in each model, how different parameters relate to each other, and how changing the parameters affects outcomes. The "mystery" of the mathematics dissolves as the spreadsheets produce tangible graphic results. Each exercise grew from hands-on use in the authors' classrooms. Each begins with a list of objectives, background information that includes standard mathematical formulae, and annotated step-by-step instructions for using this information to create a working model. Students then examine how changing the parameters affects model outcomes and, through a set of guided questions, are challenged to develop their models further. In the process, they become proficient with many of the functions available on spreadsheet programs and learn to write and use complex but useful macros. Spreadsheet Exercises in Ecology and Evolution can be used independently as the basis of a course in quantitative ecology and its applications or as an invaluable supplement to undergraduate textbooks in ecology, population biology, evolution, and population genetics.
Download or read book Seagrasses Biology Ecology and Conservation written by Anthony Larkum and published by Springer Science & Business Media. This book was released on 2007-02-22 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seagrasses are unique plants; the only group of flowering plants to recolonise the sea. They occur on every continental margin, except Antarctica, and form ecosystems which have important roles in fisheries, fish nursery grounds, prawn fisheries, habitat diversity and sediment stabilisation. Over the last two decades there has been an explosion of research and information on all aspects of seagrass biology. However the compilation of all this work into one book has not been attempted previously. In this book experts in 26 areas of seagrass biology present their work in chapters which are state-of–the-art and designed to be useful to students and researchers alike. The book not only focuses on what has been discovered but what exciting areas are left to discover. The book is divided into sections on taxonomy, anatomy, reproduction, ecology, physiology, fisheries, management, conservation and landscape ecology. It is destined to become the chosen text on seagrasses for any marine biology course.
Download or read book The Social Biology of Microbial Communities written by Institute of Medicine and published by National Academies Press. This book was released on 2013-01-10 with total page 633 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with the germ theory of disease in the 19th century and extending through most of the 20th century, microbes were believed to live their lives as solitary, unicellular, disease-causing organisms . This perception stemmed from the focus of most investigators on organisms that could be grown in the laboratory as cellular monocultures, often dispersed in liquid, and under ambient conditions of temperature, lighting, and humidity. Most such inquiries were designed to identify microbial pathogens by satisfying Koch's postulates.3 This pathogen-centric approach to the study of microorganisms produced a metaphorical "war" against these microbial invaders waged with antibiotic therapies, while simultaneously obscuring the dynamic relationships that exist among and between host organisms and their associated microorganisms-only a tiny fraction of which act as pathogens. Despite their obvious importance, very little is actually known about the processes and factors that influence the assembly, function, and stability of microbial communities. Gaining this knowledge will require a seismic shift away from the study of individual microbes in isolation to inquiries into the nature of diverse and often complex microbial communities, the forces that shape them, and their relationships with other communities and organisms, including their multicellular hosts. On March 6 and 7, 2012, the Institute of Medicine's (IOM's) Forum on Microbial Threats hosted a public workshop to explore the emerging science of the "social biology" of microbial communities. Workshop presentations and discussions embraced a wide spectrum of topics, experimental systems, and theoretical perspectives representative of the current, multifaceted exploration of the microbial frontier. Participants discussed ecological, evolutionary, and genetic factors contributing to the assembly, function, and stability of microbial communities; how microbial communities adapt and respond to environmental stimuli; theoretical and experimental approaches to advance this nascent field; and potential applications of knowledge gained from the study of microbial communities for the improvement of human, animal, plant, and ecosystem health and toward a deeper understanding of microbial diversity and evolution. The Social Biology of Microbial Communities: Workshop Summary further explains the happenings of the workshop.
Download or read book The Wetland Book written by C. Max Finlayson and published by Springer. This book was released on 2018-06-07 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Wetland Book is a comprehensive resource aimed at supporting the trans- and multidisciplinary research and practice which is inherent to this field. Aware both that wetlands research is on the rise and that researchers and students are often working or learning across several disciplines, The Wetland Book is a readily accessible online and print reference which will be the first port of call on key concepts in wetlands science and management. This easy-to-follow reference will allow multidisciplinary teams and transdisciplinary individuals to look up terms, access further details, read overviews on key issues and navigate to key articles selected by experts.
Download or read book World Atlas of Seagrasses written by Frederick T. Short and published by Univ of California Press. This book was released on 2003 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seagrasses are a vital and widespread but often overlooked coastal marine habitat. This volume provides a global survey of their distribution and conservation status.
Download or read book Livestock s Long Shadow written by Henning Steinfeld and published by Food & Agriculture Org.. This book was released on 2006 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The assessment builds on the work of the Livestock, Environment and Development (LEAD) Initiative"--Pref.
Download or read book Toward Sustainable Agricultural Systems in the 21st Century written by National Research Council and published by National Academies Press. This book was released on 2010-07-25 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last 20 years, there has been a remarkable emergence of innovations and technological advances that are generating promising changes and opportunities for sustainable agriculture, yet at the same time the agricultural sector worldwide faces numerous daunting challenges. Not only is the agricultural sector expected to produce adequate food, fiber, and feed, and contribute to biofuels to meet the needs of a rising global population, it is expected to do so under increasingly scarce natural resources and climate change. Growing awareness of the unintended impacts associated with some agricultural production practices has led to heightened societal expectations for improved environmental, community, labor, and animal welfare standards in agriculture. Toward Sustainable Agricultural Systems in the 21st Century assesses the scientific evidence for the strengths and weaknesses of different production, marketing, and policy approaches for improving and reducing the costs and unintended consequences of agricultural production. It discusses the principles underlying farming systems and practices that could improve the sustainability. It also explores how those lessons learned could be applied to agriculture in different regional and international settings, with an emphasis on sub-Saharan Africa. By focusing on a systems approach to improving the sustainability of U.S. agriculture, this book can have a profound impact on the development and implementation of sustainable farming systems. Toward Sustainable Agricultural Systems in the 21st Century serves as a valuable resource for policy makers, farmers, experts in food production and agribusiness, and federal regulatory agencies.
Download or read book Seagrass Ecology written by Marten A. Hemminga and published by Cambridge University Press. This book was released on 2000-10-19 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seagrasses occur in coastal zones throughout the world, in the part of the marine habitat that is most heavily influenced by humans. Decisions about coastal management therefore often involve seagrasses, but a full appreciation of the role of seagrasses in coastal ecosystems has yet to be reached. This book provides an entry point for those wishing to learn about the ecology of this fascinating group of plants, and gives a broad overview of current knowledge, complemented by extensive literature references to guide the reader to more detailed studies.
Download or read book Climate Change Implications for Fisheries and Aquaculture written by K. L. Cochrane and published by Food & Agriculture Organization of the UN (FAO). This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the current scientific knowledge available on climate change implications for fisheries and aquaculture is provided through three technical papers that were presented and discussed during the Expert Workshop on Climate Change Implications for Fisheries and Aquaculture (Rome, 7-9 April 2008). A summary of the workshop outcomes as well as key messages on impacts of climate change on aquatic ecosystems and on fisheries- and aquaculture-based livelihoods are provided in the introduction of this Technical Paper. The first paper reviews the physical and ecological impacts of climate change relevant to marine and inland capture fisheries and aquaculture. The paper begins with a review of the physical impacts of climate change on marine and freshwater systems and then connects these changes with observed effects on fish production processes. It also outlines a series of scenarios of climate change impacts on fish production and ecosystems through case studies in different regions and ecosystems. The second paper tackles the consequences of climate change impacts on fisheries and their dependent communities. It analyses the exposure, sensitivity and vulnerability of fisheries to climate change and presents examples of adaptive mechanisms currently used in the sector. The contribution of fisheries to greenhouse gas emissions is addressed and examples of mitigation strategies are given. The role of public policy and institutions in promoting climate change adaptation and mitigation is also explored. Finally, the third paper addresses the impacts of climate change on aquaculture. It provides an overview of the current food fish and aquaculture production and a synthesis of existing studies on climate change effects on aquaculture and fisheries. The paper focuses on the direct and indirect impacts of climate change on aquaculture, in terms of biodiversity, fish disease and fishmeal. Contribution of aquaculture to climate change is addressed (carbon emission and carbon sequestration), as well as possible adaptation and mitigation measures that could be implemented.
