Showing papers by "Jonathan H. Grabowski published in 2018"

Investing in Natural and Nature-Based Infrastructure: Building Better Along Our Coasts

Abstract: Much of the United States’ critical infrastructure is either aging or requires significant repair, leaving U.S. communities and the economy vulnerable. Outdated and dilapidated infrastructure places coastal communities, in particular, at risk from the increasingly frequent and intense coastal storm events and rising sea levels. Therefore, investments in coastal infrastructure are urgently needed to ensure community safety and prosperity; however, these investments should not jeopardize the ecosystems and natural resources that underlie economic wealth and human well-being. Over the past 50 years, efforts have been made to integrate built infrastructure with natural landscape features, often termed “green” infrastructure, in order to sustain and restore valuable ecosystem functions and services. For example, significant advances have been made in implementing green infrastructure approaches for stormwater management, wastewater treatment, and drinking water conservation and delivery. However, the implementation of natural and nature-based infrastructure (NNBI) aimed at flood prevention and coastal erosion protection is lagging. There is an opportunity now, as the U.S. government reacts to the recent, unprecedented flooding and hurricane damage and considers greater infrastructure investments, to incorporate NNBI into coastal infrastructure projects. Doing so will increase resilience and provide critical services to local communities in a cost-effective manner and thereby help to sustain a growing economy.

Ecosystem-Based Fisheries Management for Social–Ecological Systems: Renewing the Focus in the United States with Next Generation Fishery Ecosystem Plans

Abstract: Resource managers and policy makers have long recognized the importance of considering fisheries in the context of ecosystems; yet, movement towards widespread Ecosystem-based Fisheries Management (EBFM) has been slow. A conceptual reframing of fisheries management is occurring globally, which envisions fisheries as systems with interacting biophysical and human subsystems. This broader view, along with a process for decision making, can facilitate implementation of EBFM. A pathway to achieve these broadened objectives of EBFM in the United States is a Fishery Ecosystem Plan (FEP). The first generation of FEPs was conceived in the late 1990s as voluntary guidance documents that Regional Fishery Management Councils could adopt to develop and guide their ecosystem-based fisheries management decisions, but few of these FEPs took concrete steps to implement EBFM. Here, we emphasize the need for a new generation of FEPs that provide practical mechanisms for putting EBFM into practice in the United States. We argue that next-generation FEPs can balance environmental, economic, and social objectives—the triple bottom line—to improve long-term planning for fishery systems.

Maximizing the benefits of oyster reef restoration for finfish and their fisheries

Abstract: Global declines in oyster reefs have resulted in reduced habitat heterogeneity, extent and quality for some coastal finfish, potentially reducing fish populations and catches. It is well established that habitat restoration results in higher finfish biomass and diversity where oyster reefs replace bare substrata. Therefore, restoring oyster reefs with a view to also improving fish stocks is often a key goal of oyster restoration. However, the principles of habitat quality, ecological connectivity and broader ecosystem management are poorly integrated within oyster reef restoration ecology, but such principles may be instructive in enhancing the benefits of projects on fish populations throughout estuarine seascapes. This manuscript presents a framework for projects seeking to restore both oyster reef habitat and finfish communities. Structurally and biologically complex oyster reefs, comprising both oysters and other invertebrates, are required to provide shelter, food and nursery services to fish. By carefully considering site selection at seascape scales (km to 10s of km), restoration can enhance the network of habitat available to fish and potentially increase the overall carrying capacity of the estuary. Managers of estuaries that now include restored oyster reefs should implement fisheries management plans and consider the effects of management actions broadly throughout catchments; failing to do so may jeopardize gains in fish yields. Management decisions must be adaptable, responding to key criteria in thorough monitoring programs. Integrating these ecological and coastal management concepts into oyster reef restoration will enhance outcomes for fishes and increase stakeholder engagement and cost‐effectiveness.

Inclusion of Biodiversity in Habitat Restoration Policy to Facilitate Ecosystem Recovery

Abstract: Maintaining biodiversity is a central tenet of conservation, in part because biodiversity influences ecosystem functions across terrestrial, freshwater, and marine systems. Biodiversity-ecosystem function relationships have clear relevance for the design of habitat restoration efforts, yet the degree to which biodiversity has been incorporated into restoration practice is unclear. We conducted a review of the published literature on habitat restoration to evaluate this potential science-practice gap. The number of published restoration studies including the term biodiversity has increased slightly from 1990 to 2015 relative to the broader restoration literature. A greater percentage of empirical restorations, and a higher percentage of those with a biodiversity component, were from terrestrial than freshwater or marine ecosystems. The majority of studies considered biodiversity as a response to restoration rather than incorporating it in the restoration design. In fact, nearly half of the studies in our database that actively transplanted species manipulated only a single target species. Little consideration was given to genetic or trophic diversity despite their documented importance for ecosystem function. Given the limited resources available for and high economic costs associated with habitat restoration projects, we recommend policies that account for biodiversity to bridge this gap and maximize ecosystem function and restoration success. This article is protected by copyright. All rights reserved

Habitat Associations of Juvenile Cod in Nearshore Waters

Abstract: Abiotic conditions greatly influence the distribution and abundance of marine organisms during early life-history phases. For instance, factors such as habitat heterogeneity often affect the dispersive phase of marine fishes, and then diminish in importance as species approach maturity and are influenced more so by biological processes. While recently settled fish are typically found in shallow, complex habitats such as seagrass beds, the degree to which juveniles associate with specific habitats as they grow and migrate into deeper water remains less clear. To better understand fish habitat preferences during early life-history phases, a literature review was conducted on habitat use by juvenile Atlantic cod (Gadus morhua), followed by an evaluation of the relationships between habitat characteristics and bottom trawl, video and hook-and-line data in the western Gulf of Maine. The review revealed that juvenile densities, survival, and growth rates were higher in structured than in less complex ha...

Threat of Predation Does Not Affect Crassostrea virginica Filtration

Abstract: Biotic interactions can structure ecological communities and influence ecosystem functioning. As ecosystem engineers and filter feeders, bivalves often have disproportionately large effects on ecosystem functioning. They also utilize numerous morphological and behavioral responses to reduce predation, which can include changes in their filtration rates. To test the response of Crassostrea virginica filtration rates to the presence of predators, juvenile and adult oysters were separately exposed to varying types of predation risk from Callinectes sapidus and Panopeus herbstii in outdoor mesocosms. Water column chlorophyll a concentrations and crab behavior were measured over the duration of the experiment. Predation risk had no effect on oyster reef drawdown of chlorophyll a, which suggests that this important ecosystem function of oyster reefs is not mediated by behaviorally induced predator effects. Therefore, efforts to model how oyster predators influence filtration rates and associated ecosystem services should focus primarily on the factors that influence oyster mortality rather than predator effects on oyster behavior.

Competitive and agonistic interactions between the invasive Asian shore crab and juvenile American lobster

Abstract: Invasive species can have profound ecological and evolutionary impacts on native fauna, particularly those from overlapping guilds. Intraguild predation and competition often occur simultaneously, and ontogenetic shifts in competitive strength can dictate the magnitude and direction of species interactions. The recent introduction of the Asian shore crab Hemigrapsus sanguineus to the Atlantic coast of North America has resulted in the potential for considerable intraguild interactions with juvenile American lobsters Homarus americanus, with which it now co-occupies rocky intertidal and shallow subtidal habitats. We present data from 5 yr of monthly (May-October) field sampling revealing a significant decline in lobster density as H. sanguineus density increased in the low intertidal. To investigate potential mechanisms behind this pattern, we conducted three mesocosm experiments designed to examine whether competitive interactions between H. americanus and H. sanguineus are size- or density-dependent. Larger early benthic phase lobsters (16-34 mm CL) outcompeted H. sanguineus for both food and shelter resources. These lobsters fed faster and more in the presence of H. sanguineus, effectively defended shelter, were responsible for the majority of agonistic interactions, and, in multiple instances, killed and consumed H. sanguineus. Effects on sheltering and agonstic interactions by these lobsters were independent of H. sanguineus density; however, prior shelter residency increased lobster agonistic behavior towards crabs. In contrast, H. sanguineus outcompeted smaller, early benthic phase lobsters (7.2-11.2 mm CL) for shelter, and these interactions were density dependent. Displacement of lobsters from shelter by crabs and cumulative agonistic interactions instigated by crabs towards lobsters scaled positively with H. sanguineus density. Given the similarity of the invasion documented here and others occurring globally, these experiments demonstrate the importance of considering how factors such as ontogeny, density-dependence, and primacy influence the outcomes of interactions between intraguild predators. Disentangling how these factors structure intraguild interactions between invasive and endemic species will both advance our fundamental understanding of community ecology and enhance efforts to conserve and manage natural resources.

Movement ecology of a mobile predatory fish reveals limited habitat linkages within a temperate estuarine seascape

Abstract: Large predatory fishes, capable of traveling great distances, can facilitate energy flow linkages among spatially separated habitat patches via extended foraging behaviors over expansive areas Her