Rapid population growth and coastal development are primary drivers of marine habitat degradation. Although shoreline hardening or armoring (the addition of concrete structures such as seawalls, jetties, and groins), a byproduct of development, can accelerate erosion and loss of beaches and tidal wetlands, it is a common practice globally. Here, we provide the first estimate of shoreline hardening along US Pacific, Atlantic, and Gulf of Mexico coasts and predict where future armoring may result in tidal wetland loss if coastal management practices remain unchanged. Our analysis indicates that 22 842 km of continental US shoreline -approximately 14% of the total US coastline -has been armored. We also consider how socioeconomic and physical factors relate to the pervasiveness of shoreline armoring and show that housing density, gross domestic product, storms, and wave height are positively correlated with hardening. Over 50% of South Atlantic and Gulf of Mexico coasts are fringed with tidal wetlands that could be threatened by future hardening, based on projected population growth, storm frequency, and an absence of coastal development restrictions.

Coastal ecosystems provide numerous services, such as nutrient cycling, climate change amelioration, and habitat provision for commercially valuable organisms. Ecosystem functions and processes are modified by human activities locally and globally, with degradation of coastal ecosystems by development and climate change occurring at unprecedented rates. The demand for coastal defense strategies against storms and sea-level rise has increased with human population growth and development along coastlines world-wide, even while that population growth has reduced natural buffering of shorelines. Shoreline hardening, a common coastal defense strategy that includes the use of seawalls and bulkheads (vertical walls constructed of concrete, wood, vinyl, or steel), is resulting in a "coastal squeeze" on estuarine habitats. In contrast to hardening, living shorelines, which range from vegetation plantings to a combination of hard structures and plantings, can be deployed to restore or enhance multiple ecosystem services normally delivered by naturally vegetated shores. Although hundreds of living shoreline projects have been implemented in the United States alone, few studies have evaluated their effectiveness in sustaining or enhancing ecosystem services relative to naturally vegetated shorelines and hardened shorelines. We quantified the effectiveness of (1) sills with landward marsh (a type of living shoreline that combines marsh plantings with an offshore low-profile breakwater), (2) natural salt marsh shorelines (control marshes), and (3) unvegetated bulkheaded shores in providing habitat for fish and crustaceans (nekton). Sills supported higher abundances and species diversity of fishes than unvegetated habitat adjacent to bulkheads, and even control marshes. Sills also supported higher cover of filter-feeding bivalves (a food resource and refuge habitat for nekton) than bulkheads or control marshes. These ecosystem-service enhancements were detected on shores with sills three or more years after construction, but not before. Sills provide added structure and may provide better refuges from predation and greater opportunity to use available food resources for nekton than unvegetated bulkheaded shores or control marshes. Our study shows that unlike shoreline hardening, living shorelines can enhance some ecosystem services provided by marshes, such as provision of nursery habitat.

The Indo-Pacific lionfish (Pterois volitans and P. miles complex) has become widely established along the United States Southeast coast and continues to colonize the Caribbean, yet its biology and ecology is only beginning to be understood. We used stomach contents and stable isotope analyses to determine the diet of lionfish in the warm-temperate hard bottom reef community in the Southeast US Atlantic Ocean. During June to August 2004 and 2006, we collected lionfish with SCUBA from 18 different locations in Onslow Bay, North Carolina, at depths of 30 to 45 m. In 2006, we also conducted visual surveys of small benthic fishes to estimate the abundances of potential prey. Analyses of stomach contents (n = 183) and stable isotopes (n = 115) suggest a generalist carnivorous diet, and prey categories were predominately fish (~99% of total volume) from 16 families. Major differences in the importance of prey occurred between years. Serranidae and Scaridae dominated the diet in 2004, while Haemulidae and Carangidae were important in 2006. Analyses of visual prey surveys did not reveal specialization on particular prey taxa but instead suggest that prey are consumed in relation to their local abundance. Given current theory pertaining to invasive species impacts, the expanding lionfish distribution, and observations that lionfish appear capable of settling to many different habitat types, the overall pattern of generalist piscivory emerging from these data indicates the potential for significant impacts to the invaded community.KEY WORDS: Marine invasion · Rocky reef · Scorpaenidae · Warm temperate · Continental shelf · Piscivory · Diet · Prey Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 432: [181][182][183][184][185][186][187][188][189][190][191][192][193] 2011 Along the United States Southeast Atlantic coast, and in Bermuda and the Bahamas, red lionfish Pterois volitans and devil firefish P. miles are now established and are continuing to expand their range in the Caribbean , Schofield 2009). These 2 species are nearly morphologically identical and 93% of specimens sampled from the Atlantic as well as North Carolina were P. volitans (Hamner et al. 2007), so hereafter we refer to invasive specimens collectively as lionfish or P. volitans. Native to the subtropical and tropical regions of the South Pacific, Indian Ocean, and the Red Sea, lionfish are venomous predators whose popularity in the aquarium trade may have contributed to their introduction to Atlantic waters (Whitfield et al. 2002, Semmens et al. 2004, Ruiz-Carus et al. 2006. Classified as demersal mesocarnivores together with groupers (Serranidae) and snappers (Lutjanidae) (Caillet et al. 1986), lionfish are believed to be opportunistic predators that consume fish, shrimp, and crabs in their native range (Hiatt & Strasburg 1960, Harmelin-Vivien & Bouchon 1976, Sano et al. 1984. However, until their recent invasion of the Atlantic and Caribbean, their biology and ecology were poorly understood bey...

We conducted a study to determine the trophic pathways leading to juvenile fish in 2 mesohaline tidal marshes bordering Delaware Bay. The relative roles of the major primary producers in supplying energy, ultimately, to the mummichog Fundulus heteroclitus were assessed by measuring the stable isotopic compositions of juveniles (21 to 56 mm total length, TL; most of which were young-of-the-year) and those of macrophyte vegetation, phytoplankton, and benthlc microalgae at each site. We collected samples of primary producers and F. heteroclitus, the dominant fish species in this and other marshes along the east coast of the USA, in June and August 1997, at 2 study sites (upstream and downstream) within Mad Horse Creek (a Spartina alterniflora-dominated site) and Alloway Creek (a Phragmites australis-dominated site), for a total of 4 study sites. Our results indicate that F. heteroclitus production is based on a mixture of primary producers, but the mixture depends on the relative abundance of macrophytes. In S. alterniflora-dominated marshes, C and S isotope ratios indicate that F. heteroclitus production is supported by S. alterniflora production (ca 39%, presumably via detritus), whde in P. australis-dominated marshes, secondary production is based upon P. australis (73%). To our knowledge, this finding provides the first evidence that P. australis may contribute to aquatic food webs in tidal marshes. Benthic microalgae also contribute to the food chain that leads to E heteroclitus in both marsh types, while phytoplankton may be of lesser importance. Benthic microalgal biomass was lower in the P. australis-dominated system, consistent with a greater effect of shading in P. australis-versus S. alterniflora-based creek systems. Based on the difference in nitrogen isotope values between F. heteroclitus and the primary producers, the trophic level of E heteroclitus appears to be similar in the 2 marsh types, despite the differing vegetation types. In summary, the relative roles of the primary producers in supplying energy to F. heteroclitus varies locally and, in particular, with respect to the type of marsh macrophyte vegetation.

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