Using Meta-Analysis to Develop Evidence-Based Recovery Trajectories of Vegetation and Soils in Restored Wetlands in the Northern Gulf of Mexico

Abstract This collection of papers provides insights into methods and data currently available to quantify the benefits associated with estuarine habitat restoration projects in the northern Gulf of Mexico, USA, with potential applicability to other coastal systems. Extensive habitat restoration is expected to occur in the northern Gulf of Mexico region over the next several decades through funding associated with the 2010 Deepwater Horizon oil spill. Papers in this section examine the development of vegetation, soil properties, invertebrate fauna, and nekton communities in restored coastal marshes and provide a conceptual framework for applying these findings to quantify the benefits associated with compensatory marsh restoration. Extensive meta-analysis of existing data for Gulf of Mexico coastal habitats further confirms that structured habitats such as marsh, submerged aquatic vegetation, and oyster reefs support greater nekton densities than nonvegetated bottom habitat, with oyster reefs supporting different species assemblages than marsh and submerged aquatic vegetation. Other papers demonstrate that while vegetation cover can establish rapidly within the first 5 years of restoration, belowground parameters such as root biomass and soil organic matter remain 44% to 92% lower at restored marshes than reference marshes 15 years after restoration. On average, amphipod and nekton densities are also not fully restored until at least 20 and 13 years following restoration, respectively. Additional papers present methods to estimate the benefits associated with marsh restoration projects, nekton productivity associated with coastal and estuarine habitats, and the benefits associated with the removal of derelict crab traps in Gulf of Mexico estuaries.

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Meta-analysis of Nekton Utilization of Coastal Habitats in the Northern Gulf of Mexico

Estuaries and Coasts ◽

10.1007/s12237-019-00633-y ◽

2019 ◽

Vol 43 (7) ◽

pp. 1722-1745 ◽

Cited By ~ 3

Author(s):

Terill A. Hollweg ◽

Mary C. Christman ◽

Just Cebrian ◽

Bryan P. Wallace ◽

Scott L. Friedman ◽

...

Keyword(s):

Gulf Of Mexico ◽

Analytical Approach ◽

Meta Analysis ◽

Regional Scale ◽

Open Water ◽

Oyster Reefs ◽

Habitat Types ◽

Coastal Habitats ◽

Northern Gulf Of Mexico ◽

Community Assemblages

Abstract Estuaries in the northern Gulf of Mexico (GOM) provide habitat for many ecologically, commercially, and recreationally important fish and crustacean species (i.e., nekton), but patterns of nekton abundance and community assemblages across habitat types, salinity zones, and seasons have not been described region-wide. Recognizing the wealth of information collected from previous and ongoing field sampling efforts, we developed a meta-analytical approach to aggregate nekton density data from separate studies (using different gear types) that can be used to answer key research questions. We then applied this meta-analytical approach to separate nekton datasets from studies conducted in the Gulf of Mexico to summarize patterns in nekton density across and within several estuarine habitat types, including marsh, oyster reefs, submerged aquatic vegetation (SAV), and open-water non-vegetated bottom (NVB). The results of the meta-analysis highlighted several important patterns of nekton use associated with these habitat types. Nekton densities were higher in structured estuarine habitats (i.e., marsh, oyster reefs, SAV) than in open-water NVB habitat. Marsh and SAV community assemblages were relatively similar to each other, but different from those associated with open-water NVB and oyster habitats. Densities of commercially and recreationally important crustacean and fish species were highest in saline marshes, thus demonstrating the importance of this habitat in the northern GOM. The results of our meta-analysis are generally consistent with previous site-specific studies in the region (many of which were included in the meta-analysis) and provide further evidence for these patterns at a regional scale. This meta-analytical approach is easy to implement for diverse research and management purposes, and provides the opportunity to advance understanding of the value and role of coastal habitats to nekton communities.

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Meta-analysis of Nekton Recovery Following Marsh Restoration in the Northern Gulf of Mexico

Estuaries and Coasts ◽

10.1007/s12237-019-00630-1 ◽

2019 ◽

Vol 43 (7) ◽

pp. 1746-1763 ◽

Cited By ~ 4

Author(s):

Terill A. Hollweg ◽

Mary C. Christman ◽

Joshua Lipton ◽

Bryan P. Wallace ◽

Mary T. Huisenga ◽

...

Keyword(s):

Confidence Interval ◽

Gulf Of Mexico ◽

Meta Analysis ◽

Ecosystem Processes ◽

Reference Sites ◽

Regional Patterns ◽

Marsh Restoration ◽

Northern Gulf Of Mexico ◽

Increasing Trend ◽

Reference Marsh

Abstract To investigate regional patterns in marsh recovery following restoration, a meta-analysis of nekton densities at restored and reference marshes in the northern Gulf of Mexico (GOM) was conducted. Results were variable at both restored and reference sites, but general trends with respect to the age of the restored site were observed. Pooled together, mean total nekton density in restored marshes during the first 5 years following restoration was approximately 50% of reference marsh densities [95% confidence interval (CI): 26.6–93.0%]. Mean total nekton density in restored marshes in subsequent years (age of restored sites: 6 to 30 years) was approximately 73% of reference marsh densities (95% CI: 46.1–116.1%). Relative densities of crustaceans in restored marshes tended to be lower than in reference marshes during both the initial 5 years following restoration (mean = 36%; 95% CI: 16.6–76.7%) and in subsequent years (mean = 71%; 95% CI: 42.7–119.2%). Mean densities of fish species also tended to be somewhat lower in restored marshes than in reference marshes, but relative densities were highly variable during both the initial 5-year period (mean = 85%; 95% CI: 33.5–215.3%) and in subsequent years (mean = 77%; 95% CI: 39.3–152.7%). A generally increasing trend in total nekton and total crustacean densities was observed over the first 15 years following restoration; mean densities at restored sites were comparable to paired reference locations by approximately year 13. Findings from this study indicate that marsh restoration may not consistently result in nekton production similar to that of natural sites, particularly in the earlier years following restoration when baseline ecosystem processes are developing.

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