Conserving and Restoring Critical Habitats II

Our work focused on 23 coastal habitat restoration projects in Alabama and Mississippi, most of which were constructed as a result of post-Deepwater Horizon funding. We organized projects into four categories: marsh creation, living shorelines, oyster cultch, and beach enhancement. We collected cost and benefit information for each project. Benefits were organized into nine categories: marsh habitat created, restored, or enhanced; marsh habitat protected; bottom reef habitat created; breakwater reef habitat created; oysters produced; benthic secondary production enhanced; beach/dune habitat created; recreational beach trips enhanced; and residential property values enhanced. Benefits were quantified based on data found in project documentation, including project summaries, monitoring reports, and other information obtained from project personnel. Benefits were monetized using benefit transfer, a method that takes existing benefit values from one or more existing studies and applies them to a new study. Fortunately, a handful of valuation projects have been completed in recent years specifically for our study area and habitat types, making benefit transfer relatively straightforward.
Median, lower-bound, and upper-bound benefit values were estimated and benefit-cost (B-C) ratios were calculated. Of the fifteen completed projects, ten of them have positive estimated median net benefits, that is, median total benefits generated by the project exceed project cost. All but two projects have positive estimated net benefits under the upper-bound benefit values. Only one project has positive estimated net benefits even under the lower-bound benefit values. Ten of the fifteen projects have median benefit-cost ratios greater than 1.0. Five projects have median benefit-cost ratios greater than 2.0, meaning that for every dollar invested, they yielded over $2 in benefits. Two projects have median ratios greater than 3.0. Projects with construction or monitoring ongoing had incomplete benefit information, making a complete analysis infeasible.

Three Mile Creek is a historic scenic streamway situated in the backyard of Mobile, AL, draining a watershed of 28 square miles within an urbanized and industrialized basin. This modification and channelization of the adjacent USACE bypass channel in the 1980s resulted in reduced flows, sedimentation, vegetation colonization and blockage which prohibited historic flow from occurring for over three decades through a segment of the historic streamway located within one of the few natural settings present within the surrounding urbanized area. 
The City of Mobile, as the local project sponsor, obtained a grant in 2018 to complete engineering, design, and construction. The design was completed considering both cost and flow enhancement and is estimated to enhance flows between 15% (minimum flow events) and 40% (high flow events), which will enhance habitat quality and diversity within the creek. Project construction started in June of 2023, when over 37,500 CY of sediment and vegetation were removed over several months, fully restoring the creek's flow and ecological functions and services. Sediment from within approximately 2,875 LF of the historic creek was removed to restore the area to its previous condition, and construction was completed in January 2024. 
Challenges included poor, variable soils within the project area, shallow water depths during site access, and dredged material handling. Significant sediment accretion occurred within the bypass channel and restoration area between design and construction, which required a swift permit modification and change order execution during construction to accomplish the primary goal of the project. Three Mile Creek is a hidden, natural gem that is unique to the City where one can travel a small distance to escape the feel of being in a larger city. It is once again behaving similar to how it once did years ago, and will hopefully be preserved for many years.

Urbanization along the Gulf of Mexico has increasingly encroached on critical coastal habitats, rendering many critical habitats functionally unfit to offer the full range of ecosystem services required for long-term resilience. This paper attempts to investigate and analyze bio-mimetic urban design – a set of nature-based solutions that imitate the form and function of natural ecosystems in developing a sustainable built environment. Although this approach has not been extensively adopted in the Gulf, if effectively executed, it can serve as a valuable instrument to reduce habitat loss and flood risk caused by urban growth, resulting in a net increase in biodiversity.
This paper assesses the applicability of bio-mimetic approaches derived from successful case studies across the globe to the Gulf of Mexico Region-based ecosystems. The main bio-mimetic approaches explored include urban infrastructure that emulates natural performance in safeguarding natural barriers like mangroves and oyster reefs, as well as green infrastructure that improves ecological functions like water filtration and flood abatement. 
This research aims to demonstrate the capacity of urban planners and designers to use the bio-mimetic design approach to develop habitats that replicate local ecosystems on the Gulf Coast. By restoring specific essential elements, this strategy can potentially restore and conserve critical habitats while fostering resilience in coastal cities. The paper further outlines a framework for applying these innovative design principles in future urban development to ensure the sustainable coexistence of natural and built environments in the face of climate change and continued population growth.

Salt marshes of the northern Gulf of Mexico provide a range of ecosystem services, including supporting some of the nation's most productive fisheries. Early work identified links between salt marsh area and commercial shrimp landings, while more recent research highlighted the importance of marsh edge. Many species appear to be restricted to the outer few meters of the vegetated marsh even when large areas are flooded for extended periods. We hypothesized that low dissolved oxygen (DO), driven by high rates of respiration, may limit more extensive use of the flooded marsh surface by fishery species. DO may limit the suitability of flooded marsh habitat either directly, by regularly falling to levels that are stressful for fish, shrimp, and crabs, or indirectly, by periodically reaching levels that prevent the persistence of benthic infauna that are important prey for many of these species. To evaluate this, we logged DO at 5 cm above the substrate along transects at 10, 5, and 1 m into open water adjacent to the marsh edge, and at 1, 5, and 10 m into the flooded marsh, for 48+ hour periods at multiple sites in Mississippi Sound, AL. We also collected cores at each logging location to quantify benthic infauna community composition, abundance, and biomass. DO levels 10 and 5 m into the flooded marsh regularly dropped to stressful levels (< 4 mg/L), often becoming hypoxic (< 2 mg/L) for periods of several hours. Analysis of the benthic cores and planned drop samples will identify relationships of infauna and nekton to DO in the flooded marsh, however the DO data alone indicate that much of the flooded marsh is a physiologically stressful environment for many aquatic species. Increasing temperatures and nutrient loads in our coastal waters will further exacerbate poor DO conditions in this essential fish habitat.

The Mesophotic and Deep Benthic Communities (MDBC) restoration portfolio is made up of four projects selected in the Deepwater Horizon oil spill Natural Resource Damage Assessment Open Ocean Trustee Implementation Group's Open Ocean Restoration Plan 2. The portfolio is intended to restore deep-sea benthic communities that were injured during the Deepwater Horizon oil spill. 
Four project teams are executing the MDBC portfolio and are tasked with several synergistic objectives to: inventory current knowledge, map and assess ecological communities, develop coral propagation and restoration techniques, and conduct active management activities to protect and reduce threats to deep-sea communities. The teams consist of members from three NOAA line offices (NESDIS, NMFS, NOS), BOEM, USGS, and over 30 external partner organizations. The effort includes the syntheses of diverse data volumes and data types including geophysical, hydrographic, high-resolution video, and genetic data.
In our third year of MDBC data collection, the MDBC cross-project data management team continues to address challenges related to data collection and storage, access, metadata, quality assurance, and long-term archiving for cross-line office and cross-agency data management. Here, we describe the sea-to-archive process in development for the MDBC portfolio of projects.