Coastal Ecosystem Resiliency after Major Disturbances

Disturbances are a common occurrence in coastal ecosystems and can provide opportunity for adaptation and renewal in healthy systems; hurricanes bring mineral accretion to a marsh, floods provide a pulse of freshwater and nutrients to estuaries, and fires increase species diversity and abundance in forests. Humans, however, have depleted the resiliency of many coastal systems via top down and bottom up mechanisms, leaving these ecosystems more vulnerable to both natural and anthropogenic disturbances. Louisiana’s wetlands have been modified for centuries via canals, levees, agricultural impoundments, etc., leading to a decreased resiliency to land loss. The Deepwater Horizon (DWH) oil spill had the potential to further reduce marsh resiliency, potentially precipitating a “regime shift” where natural disturbances that were once a subsidy to the system are now a stress. The DWH oil spill released 4.9 million barrels of oil into the northern Gulf of Mexico, covering 2,000 km of shoreline from Florida to Texas in the world’s largest accidental marine oil spill. I examined the direct and indirect impacts of the oil spill on salt marsh erosion rates in southeastern Louisiana on varying spatial (from cm to km) and temporal scales (from hours to years). I chronicled the effects using multiple techniques of documentation including field data collection of the marsh edge for 5 years, GIS analysis spanning 15 years, and time-lapse photography for one year. The DWH oil spill directly increased erosion rates for 2 years and also left a continuing land loss legacy of cascading erosional effects lasting for 3+ years. The salt marsh shoreline eroded unevenly, leaving behind micro-headlands that eroded at an accelerated rate, leading to cascading heightened land loss along the study area. The shoreline erosion rates immediately after the DWH oil spill that included Hurricane Isaac were higher than any time period in the last 15 years, including after the hurricane seasons of 2004 and 2005. The oil depleted the resiliency of the marsh, making it more susceptible to erosion precipitated by natural disturbances, and leaving a land loss legacy much greater than the initial impacts

Reversing Wetland Death From 35,000 Cuts: Opportunities To Restore Louisiana\u27S Dredged Canals

We determined the number of permits for oil and gas activities in 14 coastal Louisiana parishes from 1900 to 2017, compared them to land loss on this coast, and estimated their restoration potential. A total of 76,247 oil and gas recovery wells were permitted, of which 35,163 (46%) were on land (as of 2010) and 27,483 of which are officially abandoned. There is a direct spatial and temporal relationship between the number of these permits and land loss, attributable to the above and belowground changes in hydrology resulting from the dredged material levees placed parallel to the canal (spoil banks). These hydrologic modifications cause various direct and indirect compromises to plants and soils resulting in wetland collapse. Although oil and gas recovery beneath southern Louisiana wetlands has dramatically declined since its peak in the early 1960s, it has left behind spoil banks with a total length sufficient to cross coastal Louisiana 79 times from east to west. Dragging down the remaining material in the spoil bank back into the canal is a successful restoration technique that is rarely applied in Louisiana, but could be a dramatically cost-effective and proven long-term strategy if political will prevails. The absence of a State or Federal backfilling program is a huge missed opportunity to: 1) conduct cost-effective restoration at a relatively low cost, and, 2) conduct systematic restoration monitoring and hypothesis testing that advances knowledge and improves the efficacy of future attempts. The price of backfilling all canals is about $335 million dollars, or 0.67% of the State\u27s Master Plan for restoration and a pittance of the economic value gained from extracting the oil and gas beneath over the last 100 years

Missing the Boat? Measuring and Evaluating Local Groundfish Purchases by New England Institutions

The development of local food markets has provided a critical economic opportunity for small farms in New England. The collapse of Gulf of Maine groundfish stocks has motivated an interest in developing similar marketing opportunities for wild-caught, locally abundant seafood. Institutions, particularly schools and colleges, have been identified as a strategic entry point in the supply chain for such products. However, there has been a dearth of research on this topic. We undertake a case study that evaluates purchases of local groundfish by schools and colleges in New England. First, we analyze recently developed secondary data to assess the propensity and frequency of local seafood purchases. We find that local seafood purchases by schools in New England are not widespread even among the subset of schools that are undertaking farm to school activities, and that schools that are purchasing local seafood are doing so infrequently. We also find that colleges have been more proactive in sourcing local seafood products. There is a high degree of state-level variation within New England, as institutions in states with relatively more prominent commercial fishing sectors are sourcing local seafood products to a relatively greater degree. Further, colleges explicitly expressed that technical assistance in sourcing sustainable seafood products would be most beneficial in regions where there was less available supply. Second, to draw further inferences about the sustainability of local seafood purchases, we report the results of seafood procurement procedures from New England colleges. We find that these colleges source a wide variety of local groundfish principally for on-campus dining and that they place high value on seafood certification schemes as guidance for making sustainable purchases. We conclude by reviewing how data collection methods for local agricultural markets could be modified with regard to seafood distribution systems

Effects Of Oil On The Rate And Trajectory Of Louisiana Marsh Shoreline Erosion

Oil can have long-term detrimental effects on marsh plant health, both above-and belowground. However, there are few data available that quantify the accelerated rate of erosion that oil may cause to marshes and the trajectory of change. Between November 2010 and August 2012, we collected data on shoreline erosion, soil strength, per cent cover of Spartina alterniflora, and marsh edge overhang at 30 closely spaced low oil and high oil sites in Bay Batiste, Louisiana. Surface oil samples were taken one meter into the marsh in February 2011. All high oiled sites in Bay Batiste were contaminated with Macondo 252 oil (oil from the Deepwater Horizon oil spill, 20 April-15 July 2010). The results suggest that there is a threshold where soil parameters change dramatically with a relatively small increase in oil concentration in the soil. Heavy oiling weakens the soil, creating a deeper undercut of the upper 50 cm of the marsh edge, and causing an accelerated rate of erosion that cascades along the shoreline. Our results demonstrate that it could take at least 2 yr to document the effects heavy oiling has had on the marsh shoreline. The presence of aboveground vegetation alone may not be an appropriate indicator of recovery

Islands In The Oil: Quantifying Salt Marsh Shoreline Erosion After The Deepwater Horizon Oiling

Qualitative inferences and sparse bay-wide measurements suggest that shoreline erosion increased after the 2010 BP Deepwater Horizon (DWH) disaster, but quantifying the impacts has been elusive at the landscape scale. We quantified the shoreline erosion of 46 islands for before and after the DWH oil spill to determine how much shoreline was lost, if the losses were temporary, and if recovery/restoration occurred. The erosion rates at the oiled islands increased to 275% in the first six months after the oiling, were 200% of that of the unoiled islands for the first 2.5 years after the oiling, and twelve times the average land loss in the deltaic plain of 0.4%y(-1) from 1988 to 2011. These results support the hypothesis that oiling compromised the belowground biomass of the emergent vegetation. The islands are, in effect, sentinels of marsh stability already in decline before the oil spill. (C) 2016 The Authors. Published by Elsevier Ltd

Historical Reconstruction Reveals Recovery in Hawaiian Coral Reefs

Coral reef ecosystems are declining worldwide, yet regional differences in the trajectories, timing and extent of degradation highlight the need for in-depth regional case studies to understand the factors that contribute to either ecosystem sustainability or decline. We reconstructed social-ecological interactions in Hawaiian coral reef environments over 700 years using detailed datasets on ecological conditions, proximate anthropogenic stressor regimes and social change. Here we report previously undetected recovery periods in Hawaiian coral reefs, including a historical recovery in the MHI (~AD 1400–1820) and an ongoing recovery in the NWHI (~AD 1950–2009+). These recovery periods appear to be attributed to a complex set of changes in underlying social systems, which served to release reefs from direct anthropogenic stressor regimes. Recovery at the ecosystem level is associated with reductions in stressors over long time periods (decades+) and large spatial scales (>103 km2). Our results challenge conventional assumptions and reported findings that human impacts to ecosystems are cumulative and lead only to long-term trajectories of environmental decline. In contrast, recovery periods reveal that human societies have interacted sustainably with coral reef environments over long time periods, and that degraded ecosystems may still retain the adaptive capacity and resilience to recover from human impacts

Extinction Risk and Bottlenecks in the Conservation of Charismatic Marine Species

The oceans face a biodiversity crisis, but the degree and scale of extinction risk remains poorly characterized. Charismatic species are most likely to gar- ner greatest support for conservation and thus provide a best-case scenario of the status of marine biodiversity. We summarize extinction risk and diagnose impediments to successful conservation for 1,568 species in 16 families of marine animals in the movie Finding Nemo. Sixteen percent (12–34%) of those that have been evaluated are threatened, ranging from 9% (7–28%) of bony fishes to 100% (83–100%) of marine turtles. A lack of scientific knowledge impedes analysis of threat status for invertebrates, which have 1,000 times fewer conservation papers than do turtles. Legal protection is severely deficient for sharks and rays; only 8% of threatened species in our analysis are protected. Extinction risk among wide-ranging taxa is higher thanmost terrestrial groups, suggesting a different conservation focus is required in the sea

Developing a Shoreline Restoration Suitability Model for North Indian River and Mosquito Lagoon, Phase II

This project successfully created a living shoreline restoration prioritization model and a mangrove hydrodynamic habitat suitability model for 180 miles of estuarine shorelines in Mosquito Lagoon and northern Indian River. Shoreline model data are available for direct download as a spatial dataset (https://stars.library.ucf.edu/shorelines/), or for online viewing in a GIS storymap: (https://ucfonline.maps.arcgis.com/apps/MapSeries/index.html?appid=45caa29e80e6441c8bf6f75c542860af). New empirical wave data were created through hydrodynamic modeling. Frequency analysis was applied to characterize wave climate in study area shorelines. Wind-wave measurements observed in the field validated that actual wave heights above 2 cm were well represented by the model. Modelled hydrodynamic data were combined with shoreline data (collected in the field during the project Phase I) to develop fundamental knowledge regarding hydrodynamic habitat suitability of IRL shoreline species. Through this analysis, strong relationships between mangrove presence and wind wave hydrodynamics were illuminated, such that the probability of mangrove persistence was predicted at the project site scale based on wave climate. Additionally, the influential role of site intertidal slope and its interaction with site hydrodynamics was confirmed. This is a transformative source of information from the perspective of Planning, Design and Engineering (PD&E) of shoreline stabilization projects and regional-scale restoration planning. Mangroves were found on shorelines with overall lower incoming wave height distributions as compared to shorelines without mangrove vegetation. Mangrove presence became less likely as wave height increased, suggesting that there is a critical wave magnitude-frequency combination above which it is increasingly unlikely that mangrove vegetation will persist. Where wave heights exceeded 5 cm 20% of time, there was over an 80% chance of mangrove persistence. Where wave heights were 8 cm 20% of time, chance of mangrove persistence dropped to 50%. Where wave heights were over 15 cm 20% of time, there was less than 10% chance of mangrove persistence. While wave climate was found to explain the greatest variance within a generalized linear model of mangrove distribution, the influence of shoreline slope was also found to be significant. Low shoreline intertidal slopes were found to increase the threshold wave climate mangroves can survive. For example, the 80th percentile wave height associated with 50% probability of mangrove survival was 8 cm when slope was 0.2, increased to 9 cm when slope was lower than 0.2, and decreased to 4 cm when slope was greater. The presence of oysters or seagrasses at the shoreline were also correlated with wave height; however, conditions within the project area were insufficient to create robust hydrodynamic habitat thresholds for these important coastal ecosystem engineers. There are therefore future research opportunities to apply frameworks developed herein to broader study areas, which will potentially lead to discovery of flow-ecology relationships for a more diverse suite of coastal ecosystem engineers. All study shorelines were classified within a prioritization model according to need and urgency of stabilization. Shoreline sites classified in Urgent need (18% of study shoreline) should be triaged for immediate stabilization. Shoreline sites classified as Priority (10% of study shoreline) will eventually move to the Urgent category without intervention. Shorelines classified as Vulnerable (6% of study shorelines) are sites for pre-emptive restoration. Sites within the Wetland category (38% of study shorelines) do not need to be restored at this time and can serve as reference sites for living shoreline stabilization. Shorelines with hard armoring (28% of study shorelines) may represent opportunities to increase long-term shoreline resilience or restore shoreline ecotone functionality. Analysis of Hardened shorelines in context of local wave climate and slope indicate that many hardened shorelines in the project study area may not actually require armoring. Living shoreline containing mangrove forest could be expected to stabilize many currently hardened shorelines. All study shorelines were classified according to likelihood of mangrove persistence based on hydrodynamic habitat suitability. Within the study area, 68% of the shoreline was characterized by 50% or greater probability of mangrove persistence. At the site scale, likelihood of mangrove persistence can also be increased by design of an equilibrium shoreline slope, adding elasticity to stabilization site designs in areas that are on the borderline of mangrove hydrodynamic habitat suitability. Severe erosion was three times more likely to be observed on shorelines without mangrove vegetation, where over 60% of sites had escarpment heights greater than 30 cm. Similarly, shorelines with mangrove were more than two times as likely to be characterized by no to low levels of erosion. Managers and practitioners within and outside of the direct project area can benefit from this work. First, the actual hydrodynamic habitat thresholds for mangrove discovered in this study can be transferred to other locations within and outside of the Indian River Lagoon system. Locations throughout Florida that fit within the mangrove temperature, salinity and hydrology habitat zones may apply the hydrodynamic habitat knowledge developed herein to site-scale project planning. Second, the synergy between regional-scale project prioritization data and site-scale habitat suitability design tools demonstrated in this project can be a framework for future restoration planning efforts. Provision of information both at a broad geographic scale for use in regional planning, and making the information sufficiently detailed such that it can be applied at the site scale can help managers and practitioners understand when and where restoration is needed, and also the appropriateness of nature-based or green-grey hybrid designs on a site-by-site basis. Widespread investment in this type of information, and dedicated strategies to adopt such information in project PD&E may increase restoration success and impact on a regional scale

Filling historical data gaps to foster solutions in marine conservation

Ecological data sets rarely extend back more than a few decades, limiting our understanding of environmental change and its drivers. Marine historical ecology has played a critical role in filling these data gaps by illuminating the magnitude and rate of ongoing changes in marine ecosystems. Yet despite a growing body of knowledge, historical insights are rarely explicitly incorporated in mainstream conservation and management efforts. Failing to consider historical change can have major implications for conservation, such as the ratcheting down of expectations of ecosystem quality over time, leading to less ambitious targets for recovery or restoration. We discuss several unconventional sources used by historical ecologists to fill data gaps - including menus, newspaper articles, cookbooks, museum collections, artwork, benthic sediment cores - and novel techniques for their analysis. We specify opportunities for the integration of historical data into conservation and management, and highlight the important role that these data can play in filling conservation data gaps and motivating conservation actions. As historical marine ecology research continues to grow as a multidisciplinary enterprise, great opportunities remain to foster direct linkages to conservation and improve the outlook for marine ecosystems