Marine Metapopulations
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Marine Metapopulations
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Author : Jacob P. Kritzer
language : en
Publisher: Elsevier
Release Date : 2010-07-20
Marine Metapopulations written by Jacob P. Kritzer and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-07-20 with Science categories.
Technological improvements have greatly increased the ability of marine scientists to collect and analyze data over large spatial scales, and the resultant insights attainable from interpreting those data vastly increase understanding of poplation dynamics, evolution and biogeography. Marine Metapopulations provides a synthesis of existing information and understanding, and frames the most important future directions and issues. First book to systematically apply metapopulation theory directly to marine systems Contributions from leading international ecologists and fisheries biologists Perspectives on a broad array of marine organisms and ecosystems, from coastal estuaries to shallow reefs to deep-sea hydrothermal vents Critical science for improved management of marine resources Paves the way for future research on large-scale spatial ecology of marine systems
Marine Protected Areas Mpas Metapopulations
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Author : Ridouan Bani
language : en
Publisher:
Release Date : 2020
Marine Protected Areas Mpas Metapopulations written by Ridouan Bani and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
"Conservation of coastal ecosystems, from the prediction of their response to climate change, to the design of effective marine reserve networks, requires that we understand the role of complex oceanic transport patterns as a major driver of connectivity among marine populations that disperse though a pelagic larval phase. Metapopulation theories have provided many insights on the role of dispersal for population persistence and stability, but few studies have integrated spatiotemporal variability in ocean currents and connectivity. In marine systems, the fate of propagules (egg or larvae) depends on ocean currents and on biological traits associated with dispersal such as spawning time and pelagic larval duration, which in turn can be affected by changing environmental conditions such as temperature. My thesis introduces a new theory of marine metapopulations under fluctuating connectivity and makes it applicable to predicting metapopulation response to climate change and to the design of marine reserve networks. I first develop a new theory that explains how spatiotemporal patterns of larval dispersal affect marine metapopulation growth and stability (Chapter 2). I then study the different pathways throughout which climate change is expected to affect metapopulation stability, by considering its effects on both biological traits associated with dispersal and on ocean currents (Chapter 3). I finally extended current reserve network theories and derived the contributions of both within- and between-reserve fluctuations in connectivity to the stability of whole MPA networks in relation to MPA size and spacing. I explain how spatiotemporal patterns of larval dispersal can create nested network within individual MPAs with important impacts on MPA network persistence. The three chapters combine theoretical approaches with application to specific case study (Northeast Pacific coastal system). The dynamic connectivity theory contained in this thesis captures the temporal as well as the spatial variation of larval dispersal between habitats, and helped reveal the complex relationship between pelagic traits (pelagic larval duration and spawning time), the statistical moments of dynamic connectivity. and metapopulation growth and stability. These complex relationships, once resolved, can explain non-monotonic and counterintuitive relationship between larval duration and climate change effects on marine metapopulations. Applying dynamic connectivity theory to the design of marine reserve networks shows how within-reserve connectivity can be as important as between-reserve connectivity for optimizing reserve size and spacing"--
Spatial Heterogeneity And The Importance Of Patchiness In Marine Metapopulations
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Author : Jeffery Aaron Rank
language : en
Publisher:
Release Date : 2001
Spatial Heterogeneity And The Importance Of Patchiness In Marine Metapopulations written by Jeffery Aaron Rank and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
Implications Of Complex Connectivity Patterns Disturbance Allee Effects And Fisheries In The Dynamics Of Marine Metapopulations
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Author : Tania Sarith Peña-Baca
language : en
Publisher:
Release Date : 2014
Implications Of Complex Connectivity Patterns Disturbance Allee Effects And Fisheries In The Dynamics Of Marine Metapopulations written by Tania Sarith Peña-Baca and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
Nearshore populations have been depleted and some have not yet recovered. Therefore, theoretical studies focus on improving fisheries management and designing marine protected areas (MPAs). Depleted populations may be undergoing an Allee effect, i.e. a decrease in fitness at low densities. Here, I constructed a marine metapopulation model that included pre- and post-dispersal Allee effects using a network theory approach. Networks represent metapopulations as groups of nodes connected by dispersal paths. With this model I answered four questions: What is the role of Allee effects on habitat occupancy? Are MPAs effective in recovering exploited populations? What is the importance of larval dispersal patterns in preventing local extinctions due to exploitation and Allee effects? Can exploitation fragment nearshore metapopulations? When weak Allee effects are included, habitat occupancy drops as larval retention decreases because more larvae are lost to unsuitable habitat. With strong Allee effects habitat occupancy also drops at high larval retention because more larvae are needed to overcome the Allee effect. Post-dispersal Allee effects seem more detrimental for nearshore metapopulations. MPA effectiveness seems also lower in a post-dispersal Allee effect scenario. In overexploited systems, local populations that go extinct are also less likely to recover even after protecting the whole coastline. In exploited nearshore metapopulations with Allee effects, local occupancy or the recovery of local populations depends not only on larval inflow from neighbor populations, but also on larval inflow for these neighbors. Nearshore metapopulations with intense fishing mortality and Allee effects may also suffer a decrease in dispersal strength and fragmentation. Population fragmentation occurs when large populations are split into smaller groups. A tool for detecting partitioning in a network is modularity. The modularity analysis performed for red abalone in the Southern California Bight showed that exploitation increases partitioning through time before the entire metapopulation collapses. These findings call for research effort in estimating the strength of potential Allee effects to prevent stock collapse and assess MPA effectiveness, evaluating the predictability of local occupancy by centrality metrics to help identify important sites for conservation, and using modularity analysis to quantify the health of exploited metapopulations to prevent their collapse.
Spatial Modelling For Monitoring And Management Of Marine Metapopulations
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Author : Gavin Fay
language : en
Publisher:
Release Date : 2012
Spatial Modelling For Monitoring And Management Of Marine Metapopulations written by Gavin Fay and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Bluenose warehou categories.
Accounting for spatial complexity provides a diversity of challenges for natural resource management. Challenges arise from uncertainties in spatial stock structure, heterogeneity in environmental and ecological constraints, and from spatial differences in exploitation and management actions. Simulation frameworks were used to analyse methods that account for spatial heterogeneity when (1) identifying spatial population trends, (2) evaluating the performance of monitoring designs among multiple sites, (3) estimating spatial distribution of sea lion prey, (4) examining energetic implications of foraging strategies given uncertainty, and (5) determining how spatial dynamics of exploited populations and fishing fleets affects performance of harvest strategies. Linear state-space models using the Kalman filter were developed to estimate trends in pup production for Steller sea lions (Eumetopias jubatus). Models assuming spatial correlation in trend among rookeries were more robust to stock structure assumptions, and estimated trends and abundance even given missing data. Relative gains in performance when optimising monitoring designs for pup production were evaluated using Canonical Correspondence Analysis and by assessing how frequently optimal designs out-performed random designs. Optimal allocation of monitoring effort depended on the metric of interest. Poorest performance occurred with suboptimal designs for current trend and individual rookery numbers. Bayesian hierarchical models were used to characterise the spatial distribution of fish species in the Gulf of Alaska. Spatial autocorrelation was prevalent in all species, with estimates of abundance generally lower than those obtained using models ignoring spatial correlation. Individual-based modelling of sea lion foraging examined how spatial persistence of prey and the choice of foraging strategy impacted the ability of foragers to meet energetic requirements. Tradeoffs and interactions were observed among model components, successful strategies involved either low uncertainty about prey distribution, or placed substantial emphasis on previous experience. The performance of harvest strategies for the blue eye trevalla (Hyperoglyphe antarctica) fishery in southeast Australia was evaluated using Management Strategy Evaluation. Appropriate weighting of spatial data was required to meet management objectives, although uncertainties regarding natural mortality and stock-recruitment steepness dominated variation in performance. In summary, spatial variability ought to be considered when modelling and managing marine resources, however appropriate scales of response are necessary.
The Role Of Disturbance Cycles In Marine Mussel Metapopulations
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Author : Tarik Claude Gouhier
language : en
Publisher:
Release Date : 2005
The Role Of Disturbance Cycles In Marine Mussel Metapopulations written by Tarik Claude Gouhier and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Intertidal ecology categories.
"In marine environments, the open system (OS) theory, whereby populations are assumed to be well connected through large-scale dispersal, is currently being challenged by studies demonstrating limited dispersal. Using a novel metapopulation framework featuring nonequilibrium within-site disturbance cycles and limited dispersal, I investigate the large-scale response of marine mussel populations to changes in oceanographic productivity. By altering the fecundity parameter, I am able to shift from open to dynamically-coupled systems (DCS), thereby generating predictions that can be used to test the connectivity of marine populations. Within-site disturbance cycles scale-up and drive regional dynamics in both OS and DCS. Fast disturbance cycles induce synchronized oscillations that promote regional extinction risk in response to changes in oceanographic productivity for DCS but not OS. Slow disturbance cycles maintain spatial variability and temporal stability in both OS and DCS. These predictions can be used to test the applicability of OS theories to natural coastal ecosystems." --
Dispersal Fishing And The Conservation Of Marine Species
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Author : Malin La Farge Pinsky
language : en
Publisher: Stanford University
Release Date : 2011
Dispersal Fishing And The Conservation Of Marine Species written by Malin La Farge Pinsky and has been published by Stanford University this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
A central goal of ecology is to understand the forces driving the distribution and abundance of organisms. However, understanding the population dynamics of high-dispersal species, their conservation, and the connections between population dynamics and evolution remains difficult. It is in this context that marine organisms provide a particularly intriguing and challenging study system. Their population dynamics are often highly stochastic, most species have a great ability to disperse, and as the last group of wild species exploited commercially, their ecology and evolution can be strongly influenced by human behavior. By using population genetics, modeling, and meta-analysis, this thesis investigates the spatial ecology of reef fish and the causes and evolutionary consequences of global fisheries collapse. One of the first challenges in understanding spatial population dynamics is obtaining accurate measurements of dispersal abilities. This has been especially difficult for marine species with pelagic larvae. In Chapter 1, I apply a new approach to measuring single-generation dispersal kernels in Clark's anemonefish (Amphiprion clarkii) in the central Philippines. After developing two methods for measuring the strength of local genetic drift, my results suggest that larval dispersal kernels in A. clarkii had a spread near 11 km (4-27 km). This study shows that ecologically relevant larval dispersal can be estimated with widely available genetic methods when effective density is measured carefully through cohort sampling and ecological censuses. In Chapter 2, I use dispersal kernels to develop a model for population openness. Openness refers to the degree to which populations are replenished by immigrants or by local production, a factor that has strong implications for population dynamics, species interactions, and response to exploitation. It is also a population trait that has been increasingly measured empirically, though we have until now lacked theory for predicting population openness. I show that considering habitat isolation elegantly explains the existence of surprisingly closed populations in high dispersal species, and that relatively closed populations are expected when patch spacing is more than twice the standard deviation of a species' dispersal kernel. In addition, empirical scales of habitat patchiness on coral reefs are sufficient to create both largely open and largely closed populations. We predict that habitat patchiness has strong control over population replenishment pathways for a wide range of marine and terrestrial species with a highly dispersive life stage. While the first tow chapters have strong implications for the design of regional marine protected areas, I turn to global conservation questions in Chapters 3 and 4. I first ask which marine fishes are most vulnerable to human impacts. Surveys of terrestrial species have suggested that large-bodied species and top predators are the most at risk, but there has been no global test of this hypothesis in the sea. Contrary to expectations, two datasets compiled from around the world suggest that up to twice as many fisheries for small, low trophic level species have collapsed as compared to those for large predators. I then show that collapsed and overfished species have lower genetic diversity than their close relatives. While the ecological and ecosystem impacts of harvesting wild populations have long been recognized, it has been controversial how widespread evolutionary impacts are. Using a meta-analytical approach across 37 taxonomically paired comparisons, I find on average 19% fewer alleles per locus in overfished species, but little difference in heterozygosity. I confirm with simulations that these results are consistent with a recent population bottleneck. These results suggest that the genetic impacts of overharvest are widespread, even among abundant species. A loss of allelic richness has implications for the long-term evolutionary potential of species.
Spatial Models Of Metapopulations And Benthic Communities In Patchy Environments
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Author : Mark Forrest Hill
language : en
Publisher:
Release Date : 2000
Spatial Models Of Metapopulations And Benthic Communities In Patchy Environments written by Mark Forrest Hill and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Benthos categories.
The distribution of organisms in space has important consequences for the function and structure of ecological systems. Such distributions are often referred to as patchy, and a patch-based approach to modeling ecosystem dynamics has become a major research focus. These models have been used to explore a wide range of questions concerning population, metapopulation, community, and landscape ecology, in both terrestrial and aquatic systems. In this dissertation I develop and analyze a series of spatial models to study the dynamics of metapopulations and marine benthic communities in patchy environments. All the models have the form of a discrete-time Markov chain, and assume that the landscape is composed of discrete patches, each of which is in one of a number of possible states. The state of a patch is determined by the presence of an individual of a given species, a local population, or a group of species, depending on the spatial scale of the model. The research is organized into two main parts as follows. In the first part, I present an analysis of the effects of habitat destruction on metapopulation persistence. Theoretical studies have already shown that a metapopulation goes extinct when the fraction of suitable patches in the landscape falls below a critical threshold (the so called extinction threshold). This result has become a paradigm in conservation biology and several models have been developed to calculate extinction thresholds for endangered species. These models, however, generally do not take into account the spatial arrangement of habitat destruction, or the actual size of the landscape. To investigate how the spatial structure of habitat destruction affects persistence, I compare the behavior of two models: a spatially implicit patch-occupancy model (which recreates the extinction patterns found in other models) and a spatially explicit cellular automaton (CA) model. In the CA, I use fractal arrangements of suitable and unsuitable patches to simulate habitat destruction and show that the extinction threshold depends on the fractal dimension of the landscape. To investigate how habitat destruction affects persistence in finite landscapes, I develop and analyze a chain-binomial metapopulation (CBM) model. This model predicts the expected extinction time of a metapopulation as a function of the number of patches in the landscape and the number of those patches that are suitable for the population. The CBM model shows that the expected time to extinction decreases greater than exponentially as suitable patches are destroyed. I also describe a statistical method for estimating parameters for the CBM model in order to evaluate metapopulation viability in real landscapes. In the second part, I develop and analyze a series of Markov chain models for a rocky subtidal community in the Gulf of Maine. Data for the model comes from ten permanent quadrats (located on Ammen Rock Pinnacle at 30 meters depth) monitored over an 8-year period (1986-1994). I first parameterize a linear (homogenous) Markov chain model from the data set and analyze it using an array of novel techniques, including a compression algorithm to classify species into functional groups, a set of measures from stochastic process theory to characterize successional patterns, sensitivity analyses to predict how changes in various ecological processes effect community composition, and a method for simulating species removal to identify keystone species. I then explore the effects of time and space on successional patterns using log-linear analysis, and show that transition probabilities vary significantly across small spatial scales and over yearly time intervals. I examine the implications of these findings for predicting equilibrium species abundances and for characterizing the transient dynamics of the community. Finally, I develop a nonlinear Markov chain for the rocky subtidal community. The model is parameterized using maximum likelihood methods to estimate density-dependent transition probabilities. I analyze the best fitting models to study the effects of nonlinear species interactions on community dynamics, and to identify multiple stable states in the subtidal system.
Sources Sinks And Sea Lice
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Author : Peter David Harrington
language : en
Publisher:
Release Date : 2022
Sources Sinks And Sea Lice written by Peter David Harrington and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with Branchiura (Crustacea) categories.
Sea lice are a threat to the health of both wild and farmed salmon and an economic burden for salmon farms. Open-net salmon farms act as reservoirs for sea lice in near coastal areas, which can lead to elevated sea louse levels on wild salmon. With a free living larval stage, sea lice can disperse tens of kilometers in the ocean, both from salmon farms onto wild salmon and between salmon farms. This larval dispersal connects local sea louse populations on salmon farms and thus modelling the collection of salmon farms as a metapopulation can lead to a better understanding of which salmon farms are driving the overall growth of sea lice in a salmon farming region. In this thesis I use metapopulation models to specifically study sea lice on salmon farms in the Broughton Archipelago, BC, and more broadly to better understand the transient and asymptotic dynamics of marine metapopulations. I begin in Chapter 1 by presenting a brief background on the mathematical concepts used in this thesis and on the biological systems on which it is focused. In Chapter 2 I create a stage-structured metapopulation model for sea lice on salmon farms using age-density equations to capture the complexities of the sea louse life cycle. To identify which salmon farms are acting as sources or sinks of sea lice in a salmon farming region I create a next-generation matrix which distills the essential elements of sea louse dispersal and demography into a single operator. Using the next-generation matrix I investigate the effect of interfarm spacing and environmental variables on the source-sink distribution of salmon farms and show that on the generational scale it is possible for transient dynamics to be different than the long term dynamics of this metapopulation. In Chapter 3 I further explore the transient dynamics which can occur in general marine and other birth-jump metapopulations. I demonstrate that even in simple linear metapopulation models the transient dynamics can be very different from the asymptotic dynamics of these populations. I show how to connect reactivity and attenuation, measures of the maximum and minimum growth rates that can occur following perturbations, to the source-sink distribution of habitat patches and how reactivity and attenuation can differ from the actual population growth rates when measured in the commonly used l2 norm. I then demonstrate how to meaningfully measure reactivity in marine metapopulations, where adults typically produce a large number of offspring and thus most would be considered reactive under the classical definition. In Chapter 4 I use the next-generation matrix developed in Chapter 2 to calculate which salmon farms are acting as the largest source of sea lice in the Broughton Archipelago, BC. The Broughton Archipelago has been ground zero for studying the effects of sea lice on wild salmon and several of the farms are currently being removed in an agreement between the provincial government and local First Nations. I find that several of the farms that are not slated to be removed are acting as the largest sources of sea lice in this region and occur in two distinct clusters. I also find that warming temperatures coupled with high salinities could lead to increased sea louse growth in the Broughton. In Chapter 5 I calculate the distribution of arrival times for sea lice dispersing between salmon farms in the Broughton Archipelago to disentangle the factors affecting dispersal and cross-infection of sea lice in this region. First, I calculate the arrival time distribution directly using a hydrodynamic model of the Broughton to which I then parameterize a simple advection diffusion model of the arrival time distribution. I use the simple model to show that there an intermediate distance between farms can maximize cross infection, and the specific distance which maximizes cross infection depends on the magnitude of the current and temperature of the ocean. I conclude the thesis in Chapter 6 by contextualizaing the results within the broader literature and discussing limitations, potential for future work, and management implications of sea lice on salmon farms.
Metapopulation Dynamics Of A Marine Reserve Network
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Author : Brandon Joel Puckett
language : en
Publisher:
Release Date : 2013
Metapopulation Dynamics Of A Marine Reserve Network written by Brandon Joel Puckett and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.