Bivalve facilitation mediates seagrass recovery from physical disturbance in a temperate estuary

Rapid global degradation of coastal habitats can be attributed to anthropogenic activities associated with coastal development, aquaculture, and recreational surface water use. Restoration of degraded habitats has proven challenging and costly, and there is a clear need to develop novel approaches that promote resilience to human-caused disturbances. Positive interactions between species can mitigate environmental stress and recent work suggests that incorporating positive interactions into restoration efforts may improve restoration outcomes. We hypothesized that the addition of a potential facultative mutualist, the native hard clam (Mercenaria mercenaria), could enhance seagrass bed recovery from disturbance. We conducted two experiments to examine the independent and interacting effects of hard clam addition and physical disturbance mimicking propeller scarring on mixed community Zostera marina and Halodule wrightii seagrass beds in North Carolina. Adding clams to seagrass beds exposed to experimental disturbance generally enhanced seagrass summer growth rates and autumn shoot densities. In contrast, clam addition to non-disturbed seagrass beds did not result in any increase in seagrass growth rates or shoot densities. Clam enhancement of autumn percent cover relative to areas without clam addition was most prominent after Hurricane Dorian, suggesting that clams may also enhance seagrass resilience to repeated disturbances. By June of the next growing season, disturbed areas with clam additions had greater percent cover of seagrass than disturbed areas without clam additions. Beds that were disturbed in April had higher percent cover than areas disturbed in June of the previous growing season. Our results suggest that the timing and occurrence of physical disturbances may modify the ability of clams to facilitate seagrass resiliency and productivity. Understanding when and how to utilize positive, interspecific interactions in coastal restoration is key for improving restoration success rates.ECU Open Access Publishing Support Fun

Fish and Invertebrate Use of Restored vs. Natural Oyster Reefs in a Shallow Temperate Latitude Estuary

Coastal marine habitats continue to be degraded, thereby compelling largescale restoration in many parts of the world. Whether restored habitats function similarly to natural habitats and fully recover lost ecosystem services is unclear. In estuaries, oyster reefs have been degraded by multiple anthropogenic activities including destructive fishing practices and reduced water quality, motivating restoration to maintain oyster fisheries and other ecosystem services, often at relatively high cost. We compared fish and invertebrate communities on recently restored (0–1 year post-restoration), older restored (3–4 years post-restoration), and natural oyster reefs to determine if and when restored reefs support functionally similar faunal communities. To test the influence of landscape setting on the faunal communities, the restored and natural reefs, as well as a control without reef present, were distributed among three landscapes (on the edge of salt marsh away from seagrass [salt marsh landscape], on mudflats [mudflat landscape], and near to seagrass and salt marsh [seagrass landscape]). Oyster density and biomass were greatest on restored reef habitat, as were those of non-oyster bivalve species. Total abundance of invertebrates was much greater on oyster reefs than in control plots, regardless of reef or landscape type, yet were frequently highest on older restored reefs. Meanwhile, juvenile fish densities were greatest on natural reefs, at intermediate densities on older restored reefs, and least abundant on controls. When comparing the effects of reef age and landscape setting, juvenile fish densities were greatest on younger reefs within the mudflat landscape. Collectively, these results indicate that oyster reefs harbor higher densities of resident invertebrate prey, which may explain why reef habitat is also important for juvenile fish. Laboratory and field experiments supported the notion that gag grouper (a predatory demersal fish) forage more effectively on oyster reefs than on unstructured mud bottom, whereas our experiments suggest that flounders that utilize oyster reefs likely forage on adjacent mud bottom. Because landscape setting influenced fish and invertebrate communities on restored reefs, the ecological consequences of landscape setting should be incorporated into restoration decision making and site selection to enhance the recovery of ecosystem goods and services

IntCal09 and Marine09 radiocarbon age calibration curves, 0-50,000 years cal BP

The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14C and calendar timescales as established in 2002. No change was made to the curves from 0-12 cal kBP. The curves were constructed using a Markov chain Monte Carlo (MCMC) implementation of the random walk model used for IntCal04 and Marine04. The new curves were ratified at the 20th International Radiocarbon Conference in June 2009 and are available in the Supplemental Material at www.radiocarbon.org.Additional co-authors: TJ Heaton, AG Hogg, KA Hughen, KF Kaiser, B Kromer, SW Manning, RW Reimer, DA Richards, JR Southon, S Talamo, CSM Turney, J van der Plicht, CE Weyhenmeye

Reversing a Tyranny of Cascading Shoreline-Protection Decisions Driving Coastal Habitat Loss

Abstract Shoreline hardening is a major driver of biodiversity and habitat loss in coastal ecosystems yet remains a common approach to coastal management globally. Using surveys of waterfront residents in North Carolina, USA, we sought to identify factors influencing individual shore‐protection decisions and ultimately impacting coastal ecosystems, particularly coastal wetlands. We found that neighboring shore condition was the best predictor of respondent shore condition. Respondents with hardened shorelines were more likely to have neighbors with hardened shorelines, and to report that neighbors influenced their shore‐protection choices than respondents with natural shorelines. Further, respondents who expressed climate‐change skepticism and preference for shoreline hardening were opposed to shoreline‐hardening restrictions. Despite preferring hardening, respondents ranked wetlands as highly valuable for storm protection and other ecosystem services, suggesting a disconnect between the ecological knowledge of individuals and social norms of shore‐protection decisions. However, our results also suggest that efforts to increase the installation of living shorelines have the potential to conserve and restore important coastal habitats and support biodiversity along shorelines that may otherwise be degraded by hardening. Further, encouraging waterfront‐property owners who have adopted living shorelines to recommend them to neighbors may be an effective strategy to initiate and reinforce pro‐conservation social norms

NotCal04; comparison/ calibration 14C records 26-50 cal kyr BP

Author Posting. © Arizona Board of Regents on behalf of the University of Arizona, 2004. This article is posted here by permission of Dept. of Geosciences, University of Arizona for personal use, not for redistribution. The definitive version was published in Radiocarbon 46 (2004): 1225-1238.The radiocarbon calibration curve IntCal04 extends back to 26 cal kyr BP. While several high-resolution records exist beyond this limit, these data sets exhibit discrepancies of up to several millennia. As a result, no calibration curve for the time range 26–50 cal kyr BP can be recommended as yet, but in this paper the IntCal04 working group compares the available data sets and offers a discussion of the information that they hold

Oxygen isotope dendrochronology of Llwyn Celyn; One of the oldest houses in Wales

We report the application of oxygen isotope dendrochronology to date a high-status and remarkably unaltered late medieval hall house on the eastern border of South Wales. The oak timbers have either short and complacent ring series, or very strong growth disturbance, and none were suitable for ring-width dendrochronology. By using stable oxygen isotopes from the latewood cellulose, rather than ring widths, it was possible to cross-match and date all 14 timber samples and to provide felling dates related to several phases of building. The hall and solar cross-wing were constructed shortly after 1420CE, which is remarkably early. The house was upgraded using timbers felled in the winter of 1695/6CE by ceiling over of the hall and inserting a chimney. A separate small domestic building was added at the same time and the addition of the kitchen is likely to be contemporaneous. A substantial beast house was added a few years before the house was refurbished, emphasising the importance of cattle as the main source of wealth. A small barn with timbers felled in spring 1843 CE was added later. Llwyn Celyn is one of the most important domestic buildings in Wales, but without the new approach none of the phases of its evolution could have been dated precisely. Oxygen isotope dendrochronology has enormous potential for dating timbers that have small numbers of rings and/or show severe growth disturbance and it works well in regions where tree growth is not strongly constrained by climate. The research was generously supported by the Leverhulme Trust, Natural Environment Research Council, Landmark Trust and the UK National Lottery Heritage Fund