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Jonathan H. Grabowski

Bio: Jonathan H. Grabowski is an academic researcher from Northeastern University. The author has contributed to research in topics: Oyster & Reef. The author has an hindex of 39, co-authored 120 publications receiving 5874 citations. Previous affiliations of Jonathan H. Grabowski include National Ocean Service & Gulf of Maine Research Institute.
Topics: Oyster, Reef, Predation, Habitat, Fisheries management


Papers
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Journal ArticleDOI
TL;DR: In this paper, the economic value of oyster reef services, excluding oyster harvesting, is estimated to be between $5500 and $99,000 per hectare per year and reefs recover their median restoration costs in 2-14 years.
Abstract: Valuation of ecosystem services can provide evidence of the importance of sustaining and enhancing those resources and the ecosystems that provide them. Long appreciated only as a commercial source of oysters, oyster reefs are now acknowledged for the other services they provide, such as enhancing water quality and stabilizing shorelines. We develop a framework to assess the value of these services. We conservatively estimate that the economic value of oyster reef services, excluding oyster harvesting, is between $5500 and $99,000 per hectare per year and that reefs recover their median restoration costs in 2–14 years. In contrast, when oyster reefs are subjected to destructive oyster harvesting, they do not recover the costs of restoration. Shoreline stabilization is the most valuable potential service, although this value varies greatly by reef location. Quantifying the economic values of ecosystem services provides guidance about when oyster reef restoration is a good use of funds.

450 citations

Journal ArticleDOI
01 Sep 2008-Ecology
TL;DR: It is argued that both consumption and intimidation contribute to the total effects of keystone predators, and that characteristics ofKeystone consumers may differ from those of predators having predominantly NCE, defined as changes in prey traits measured on an ecological time scale.
Abstract: Predator effects on prey dynamics are conventionally studied by measuring changes in prey abundance attributed to consumption by predators. We revisit four classic examples of predator-prey systems often cited in textbooks and incorporate subsequent studies of nonconsumptive effects of predators (NCE), defined as changes in prey traits (e.g., behavior, growth, development) measured on an ecological time scale. Our review revealed that NCE were integral to explaining lynx-hare population dynamics in boreal forests, cascading effects of top predators in Wisconsin lakes, and cascading effects of killer whales and sea otters on kelp forests in nearshore marine habitats. The relative roles of consumption and NCE of wolves on moose and consequent indirect effects on plant communities of Isle Royale depended on climate oscillations. Nonconsumptive effects have not been explicitly tested to explain the link between planktonic alewives and the size structure of the zooplankton, nor have they been invoked to attribute keystone predator status in intertidal communities or elsewhere. We argue that both consumption and intimidation contribute to the total effects of keystone predators, and that characteristics of keystone consumers may differ from those of predators having predominantly NCE. Nonconsumptive effects are often considered as an afterthought to explain observations inconsistent with consumption-based theory. Consequently, NCE with the same sign as consumptive effects may be overlooked, even though they can affect the magnitude, rate, or scale of a prey response to predation and can have important management or conservation implications. Nonconsumptive effects may underlie other classic paradigms in ecology, such as delayed density dependence and predator-mediated prey coexistence. Revisiting classic studies enriches our understanding of predator-prey dynamics and provides compelling rationale for ramping up efforts to consider how NCE affect traditional predator-prey models based on consumption, and to compare the relative magnitude of consumptive and NCE of predators.

446 citations

Journal ArticleDOI
TL;DR: In this paper, the authors compared density by size (age) class on oyster reefs and sedimentary bottom as a means of estimating the degree to which restoration of oyster reef could augment abundances.
Abstract: We reviewed studies providing quantitative measurements of abundance of fishes and large mobile crustaceans on oyster reefs and on nearby sedimentary habitat in the southeast United States. For each species, we compared density by size (age) class on oyster reefs and sedimentary bottom as a means of estimating the degree to which restoration of oyster reef on sedimentary bottom could augment abundances. By applying published information on growth rates of each species and a combination of empirical data and published information on age-specific survivorship, we calcu- lated the per-unit-area enhancement of production of fishes and large mobile crustaceans expected from the addition of oyster reef habitat. For this calculation, we gave the reef habitat full credit for the expected lifetime production of species whose recruitment was judged to be limited by the area of oyster reefs based on nearly exclusive association of recruits to reefs. For species that were only mod- estly enhanced in abundance by oyster reefs, we gave the reef credit for the fraction of production that is derived from consumption of reef-associated prey, using a combination of gut content data and natural history information. This combination of analyses and calculations revealed that 10 m 2 of restored oyster reef in the southeast United States is expected to yield an additional 2.6 kg yr -1 of pro- duction of fish and large mobile crustaceans for the functional lifetime of the reef. Because the reef is biogenic and self-sustaining, the lifetime of a reef protected from bottom-disturbing fishing gear is limited by intense storms or sedimentation. A reef lasting 20 to 30 yr would be expected to augment fish and large mobile crustacean production by a cumulative amount of 38 to 50 kg 10 m -2 , discounted to present-day value. This set of calculations assumes that oyster reef habitat now limits production of reef-associated fish and crustaceans in the southeast United States. This assumption seems reasonable based on the tight associations of so many fishes with reef-dependent prey, and the depletion of reef habitat over the past century.

415 citations

Journal ArticleDOI
01 Apr 2004-Ecology
TL;DR: Experimental manipulations of the abundance of the two predators in an oyster-reef trophic cascade, and the structural complexity provided by reefs of living oysters, demonstrated that enhanced habitat complexity weakened the strengths of Trophic interactions.
Abstract: Despite recognition of the significance of both food web interactions and habitat complexity in community dynamics, current ecological theory rarely couples these two processes Experimental manipulations of the abundance of the two predators in an oyster-reef trophic cascade, and the structural complexity provided by reefs of living oysters, demonstrated that enhanced habitat complexity weakened the strengths of trophic interactions The system of tri-trophic interactions included oyster toadfish (Opsanus tau) as the top predator that consumed the mud crab (Panopeus herbstii), which preys upon juvenile oysters (Crassostrea virginica) On reefs of low complexity, toadfish controlled mud crab abundances and indirectly determined the level of mortality of juvenile oysters The indirect effects of toadfish on oysters emerged through their influence on how intensely mud crabs preyed on oysters Augmentation of habitat complexity by substituting vertically oriented, living oysters for the flat shells of dead o

370 citations

Book ChapterDOI
01 Jan 2007
TL;DR: In this article, the authors quantify the economic value of each of the ecosystem services provided by oyster reefs and provide quantitative estimates of the value of some specific functions (i.e., oyster harvests, water quality improvements, and recreational and commercial fishery benefits).
Abstract: This chapter discusses how to quantify the economic value of each of the ecosystem services provided by oyster reefs. The chapter also provides quantitative estimates of the value of some specific functions (i.e., oyster harvests, water quality improvements, and recreational and commercial fishery benefits) where data are available to compare the value of harvesting oysters in a traditional fishery to the monetary value of providing other oyster reef services. Placing oyster reefs in the greater context of the estuary requires landscape-scale data with simultaneous evaluation of each habitat across multiple trophic levels, which is difficult to obtain. However, larger-scale restoration efforts to assess the recovery of ecosystem services are currently being conducted in the Gulf of Mexico and in several estuaries along the East Coast of the United States. These studies will greatly enhance one's ability to develop more holistic economic models that account for spatial variability in the provision of ecosystem goods and services by oyster reefs.

338 citations


Cited by
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Journal ArticleDOI
23 Jun 2006-Science
TL;DR: Reconstructed time lines, causes, and consequences of change in 12 once diverse and productive estuaries and coastal seas worldwide show similar patterns: Human impacts have depleted >90% of formerly important species, destroyed >65% of seagrass and wetland habitat, degraded water quality, and accelerated species invasions.
Abstract: Estuarine and coastal transformation is as old as civilization yet has dramatically accelerated over the past 150 to 300 years. Reconstructed time lines, causes, and consequences of change in 12 once diverse and productive estuaries and coastal seas worldwide show similar patterns: Human impacts have depleted >90% of formerly important species, destroyed >65% of seagrass and wetland habitat, degraded water quality, and accelerated species invasions. Twentieth-century conservation efforts achieved partial recovery of upper trophic levels but have so far failed to restore former ecosystem structure and function. Our results provide detailed historical baselines and quantitative targets for ecosystem-based management and marine conservation.

2,795 citations

Journal ArticleDOI
Tamar Frankel1
TL;DR: The Essay concludes that practitioners theorize, and theorists practice, use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ.
Abstract: Much has been written about theory and practice in the law, and the tension between practitioners and theorists. Judges do not cite theoretical articles often; they rarely "apply" theories to particular cases. These arguments are not revisited. Instead the Essay explores the working and interaction of theory and practice, practitioners and theorists. The Essay starts with a story about solving a legal issue using our intellectual tools - theory, practice, and their progenies: experience and "gut." Next the Essay elaborates on the nature of theory, practice, experience and "gut." The third part of the Essay discusses theories that are helpful to practitioners and those that are less helpful. The Essay concludes that practitioners theorize, and theorists practice. They use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ. Theory, practice, experience and "gut" help us think, remember, decide and create. They complement each other like the two sides of the same coin: distinct but inseparable.

2,077 citations

Journal ArticleDOI
01 Feb 2005-Ecology
TL;DR: The results suggest that the costs of intimidation, traditionally ignored in predator-prey ecology, may actually be the dominant facet of trophic interactions.
Abstract: Predation is a central feature of ecological communities. Most theoretical and empirical studies of predation focus on the consequences of predators consuming their prey. Predators reduce prey population densities through direct consumption (a density- mediated interaction, DMI), a process that may indirectly affect the prey's resources, com- petitors, and other predators. However, predators can also affect prey population density by stimulating costly defensive strategies. The costs of these defensive strategies can include reduced energy income, energetic investment in defensive structures, lower mating success, increased vulnerability to other predators, or emigration. Theoretical and empirical studies confirm the existence of these induced costs (trait-mediated interactions, TMIs); however, the relative importance of intimidation (TMI) and consumption (DMI) effects remains an open question. We conducted a meta-analysis assessing the magnitude of both TMIs and DMIs in predator-prey interactions. On average, the impact of intimidation on prey de- mographics was at least as strong as direct consumption (63% and 51% the size of the total predator effect, respectively). This contrast is even more pronounced when we consider the cascading effects of predators on their prey's resources: density effects attenuated through food chains, while TMIs remained strong, rising to 85% of the total predator effect. Predators can thus strongly influence resource density even if they consume few prey items. Finally, intimidation was more important in aquatic than terrestrial ecosystems. Our results suggest that the costs of intimidation, traditionally ignored in predator-prey ecology, may actually be the dominant facet of trophic interactions.

1,557 citations

Journal ArticleDOI
TL;DR: The consequences of marine predator declines are outlined and an integrated predictive framework that includes risk effects is proposed, which appear to be strongest for long-lived prey species and when resources are abundant.
Abstract: Recent studies document unprecedented declines in marine top predators that can initiate trophic cascades. Predicting the wider ecological consequences of these declines requires understanding how predators influence communities by inflicting mortality on prey and inducing behavioral modifications (risk effects). Both mechanisms are important in marine communities, and a sole focus on the effects of predator-inflicted mortality might severely underestimate the importance of predators. We outline direct and indirect consequences of marine predator declines and propose an integrated predictive framework that includes risk effects, which appear to be strongest for long-lived prey species and when resources are abundant. We conclude that marine predators should be managed for the maintenance of both density- and risk-driven ecological processes, and not demographic persistence alone.

1,175 citations

23 Mar 2010
TL;DR: In this article, the authors analyse les relations conceptuelles (imprecises) de la vulnerabilite, de la resilience and de la capacite d'adaptation aux changements climatiques selon le systeme socioecologique (socio-ecologigal systems -SES) afin de comprendre and anticiper le comportement des composantes sociales et ecologiques du systeme.
Abstract: Cet article analyse les relations conceptuelles (imprecises) de la vulnerabilite, de la resilience et de la capacite d’adaptation aux changements climatiques selon le systeme socio-ecologique (socio-ecologigal systems – SES) afin de comprendre et anticiper le comportement des composantes sociales et ecologiques du systeme. Une serie de questions est proposee par l’auteur sur la specification de ces termes afin de developper une structure conceptuelle qui inclut les dimensions naturelles et so...

1,133 citations