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Gloucester Point, VA, United States

The Virginia Institute of Marine Science is one of the oldest and largest schools of oceanography focused on coastal ocean and estuarine science in the United States. Founded in 1938, VIMS operates three campuses, has 57 faculty members and a total student body ranging from 100 - 125 students, and is a part of the College of William & Mary. It is funded by the Commonwealth of Virginia and includes four academic departments: Biological science, Environmental and Aquatic Animal Health, Fisheries Science, and Physical science, and offers both M.S. and Ph.D. degrees in marine science.The main campus is located in Gloucester Point, Virginia. Wikipedia.

Lefcheck J.S.,Virginia Institute of Marine Science
Methods in Ecology and Evolution | Year: 2015

Ecologists and evolutionary biologists rely on an increasingly sophisticated set of statistical tools to describe complex natural systems. One such tool that has gained significant traction in the biological sciences is structural equation models (SEM), a form of path analysis that resolves complex multivariate relationships among a suite of interrelated variables. Evaluation of SEMs has historically relied on covariances among variables, rather than the values of the data points themselves. While this approach permits a wide variety of model forms, it limits the incorporation of detailed specifications. Recent developments have allowed for the simultaneous implementation of non-normal distributions, random effects and different correlation structures using local estimation, but this process is not yet automated and consequently, evaluation can be prohibitive with complex models. Here, I present a fully documented, open-source package piecewiseSEM, a practical implementation of confirmatory path analysis for the r programming language. The package extends this method to all current (generalized) linear, (phylogenetic) least-square, and mixed effects models, relying on familiar r syntax. I also provide two worked examples: one involving random effects and temporal autocorrelation, and a second involving phylogenetically independent contrasts. My goal is to provide a user-friendly and tractable implementation of SEM that also reflects the ecological and methodological processes generating data. © 2015 British Ecological Society. Source

Shields J.D.,Virginia Institute of Marine Science
Journal of Invertebrate Pathology | Year: 2011

Spiny lobsters have few reported pathogens, parasites and symbionts. However, they do have a diverse fauna comprised of a pathogenic virus, several bacteria, protozoans, helminths and even symbiotic crustaceans. A few idiopathic syndromes have also been reported, but these appear correlated with lobsters held in poor conditions. Fungal and bacterial pathogens present significant threats for rearing spiny lobsters in aquaculture settings, but only one pathogen, Panulirus argus virus 1, is thought to have damaged a fishery for a spiny lobster. No doubt others will emerge as lobsters are brought into aquaculture setting and as fishing pressure intensifies with stocks become more susceptible to anthropogenic stressors. © 2010 Elsevier Inc. Source

Shields J.D.,Virginia Institute of Marine Science
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2013

Several diseases have recently emerged in lobsters (Homarus americanus) from Long Island Sound (LIS). Various stressors have been implicated as contributory factors, including increased bottom temperatures, extensive eutrophication with commensurate hypoxia, storm-induced thermal destratification, possible exposures to pesticides and metals, and fishery-induced stressors. Such stressors increase host susceptibility by weakening the host immune defenses and act to increase the transmission and severity of pathogens. The lobster mortality in western LIS in 1999 was linked to Neoparamoeba pemaquidensis, but a complex of stressors resulted in outright mortality from hypoxia or consequent immune suppression that increased susceptibility to the ameba. Similar stressors have been implicated in the etiology of epizootic shell disease and calcinosis. The role of environmental stressors has been hard to delineate, but recent declines in landings indicate that epizootic shell disease has had a negative impact on the lobster population in LIS. Calcinosis, blindness, and hepatopancreatitis are indicators of continued exposure to anthropogenic stressors, but their etiologies remain undetermined. More research is needed to understand emerging diseases, their complex etiologies, and their effects on the lobster population. Source

Hultgren K.M.,Smithsonian Institution | Duffy J.E.,Virginia Institute of Marine Science
Ecology Letters | Year: 2012

When functional traits are evolutionarily conserved, phylogenetic relatedness can serve as a proxy for ecological similarity to examine whether functional differences among species mediate community assembly. Using phylogenetic- and trait-based analyses, we demonstrate that sponge-dwelling shrimp (Synalpheus) assemblages are structured by size-based habitat filtering, interacting with competitive exclusion mediated by social system. Most shrimp communities were more closely related and/or more similar in size than randomized communities, consistent with habitat filtering facilitated by phylogenetically conserved body size. Those sponges with greater space heterogeneity hosted shrimp communities with greater size diversity, corroborating the importance of size in niche use. However, communities containing eusocial shrimp - which cooperatively defend territories - were less phylogenetically related and less similar in size, suggesting that eusociality enhances competitive ability and drives competitive exclusion. Our analyses demonstrate that community assembly in this diverse system occurs via traits mediating niche use and differential competitive ability. © 2012 Blackwell Publishing Ltd/CNRS. Source

Naeem S.,Columbia University | Duffy J.E.,Virginia Institute of Marine Science | Zavaleta E.,University of California at Santa Cruz
Science | Year: 2012

Ecosystems worldwide are rapidly losing taxonomic, phylogenetic, genetic, and functional diversity as a result of human appropriation of natural resources, modification of habitats and climate, and the spread of pathogenic, exotic, and domestic plants and animals. Twenty years of intense theoretical and empirical research have shown that such biotic impoverishment can markedly alter the biogeochemical and dynamic properties of ecosystems, but frontiers remain in linking this research to the complexity of wild nature, and in applying it to pressing environmental issues such as food, water, energy, and biosecurity. The question before us is whether these advances can take us beyond merely invoking the precautionary principle of conserving biodiversity to a predictive science that informs practical and specific solutions to mitigate and adapt to its loss. Source

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