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Kristopher G. Benson - One of the best experts on this subject based on the ideXlab platform.
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Meta-analysis of Nekton Recovery Following Marsh Restoration in the Northern Gulf of Mexico
Estuaries and Coasts, 2019Co-Authors: Terill A. Hollweg, Mary T. Huisenga, Joshua Lipton, Mary C. Christman, Diana R. Lane, Bryan P. Wallace, Kristopher G. BensonAbstract: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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Meta-analysis of Nekton Utilization of Coastal Habitats in the Northern Gulf of Mexico
Estuaries and Coasts, 2019Co-Authors: Terill A. Hollweg, Heather R. Ballestero, Mary T. Huisenga, Mary C. Christman, Just Cebrian, Bryan P. Wallace, Scott L. Friedman, Kristopher G. BensonAbstract: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.
Terill A. Hollweg - One of the best experts on this subject based on the ideXlab platform.
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Meta-analysis of Nekton Recovery Following Marsh Restoration in the Northern Gulf of Mexico
Estuaries and Coasts, 2019Co-Authors: Terill A. Hollweg, Mary T. Huisenga, Joshua Lipton, Mary C. Christman, Diana R. Lane, Bryan P. Wallace, Kristopher G. BensonAbstract: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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Meta-analysis of Nekton Utilization of Coastal Habitats in the Northern Gulf of Mexico
Estuaries and Coasts, 2019Co-Authors: Terill A. Hollweg, Heather R. Ballestero, Mary T. Huisenga, Mary C. Christman, Just Cebrian, Bryan P. Wallace, Scott L. Friedman, Kristopher G. BensonAbstract: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.
Carole C. Mcivor - One of the best experts on this subject based on the ideXlab platform.
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Assessing the Link Between Coastal Urbanization and the Quality of Nekton Habitat in Mangrove Tidal Tributaries
Estuaries and Coasts, 2014Co-Authors: Justin M. Krebs, Susan S. Bell, Carole C. McivorAbstract:To assess the potential influence of coastal development on habitat quality for estuarine Nekton, we characterized body condition and reproduction for common Nekton from tidal tributaries classified as undeveloped, industrial, urban or man-made (i.e., mosquito-control ditches). We then evaluated these metrics of Nekton performance, along with several abundance-based metrics and community structure from a companion paper (Krebs et al. 2013 ) to determine which metrics best reflected variation in land-use and in-stream habitat among tributaries. Body condition was not significantly different among undeveloped, industrial, and man-made tidal tributaries for six of nine taxa; however, three of those taxa were in significantly better condition in urban compared to undeveloped tributaries. Palaemonetes shrimp were the only taxon in significantly poorer condition in urban tributaries. For Poecilia latipinna , there was no difference in body condition (length–weight) between undeveloped and urban tributaries, but energetic condition was significantly better in urban tributaries. Reproductive output was reduced for both P . latipinna (i.e., fecundity) and grass shrimp (i.e., very low densities, few ovigerous females) in urban tributaries; however a tradeoff between fecundity and offspring size confounded meaningful interpretation of reproduction among land-use classes for P . latipinna . Reproductive allotment by P . latipinna did not differ significantly among land-use classes. Canonical correspondence analysis differentiated urban and non-urban tributaries based on greater impervious surface, less natural mangrove shoreline, higher frequency of hypoxia and lower, more variable salinities in urban tributaries. These characteristics explained 36 % of the variation in Nekton performance, including high densities of poeciliid fishes, greater energetic condition of sailfin mollies, and low densities of several common Nekton and economically important taxa from urban tributaries. While variation among tributaries in our study can be largely explained by impervious surface beyond the shorelines of the tributary, variation in Nekton metrics among non-urban tributaries was better explained by habitat factors within the tributary and along the shorelines. Our results support the paradigm that urban development in coastal areas has the potential to alter habitat quality in small tidal tributaries as reflected by variation in Nekton performance among tributaries from representative land-use classes.
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Nekton community structure varies in response to coastal urbanization near mangrove tidal tributaries
Estuaries and Coasts, 2014Co-Authors: Justin M. Krebs, Carole C. Mcivor, Susan S. BellAbstract:To assess the potential influence of coastal development on estuarine-habitat quality, we characterized land use and the intensity of land development surrounding small tidal tributaries in Tampa Bay. Based on this characterization, we classified tributaries as undeveloped, industrial, urban, or man-made (i.e., mosquito-control ditches). Over one third (37 %) of the tributaries have been heavily developed based on landscape development intensity (LDI) index values >5.0, while fewer than one third (28 %) remain relatively undeveloped (LDI < 3.0). We then examined the Nekton community from 11 tributaries in watersheds representing the four defined land-use classes. Whereas mean Nekton density was independent of land use, species richness and Nekton-community structure were significantly different between urban and non-urban (i.e., undeveloped, industrial, man-made) tributaries. In urban creeks, the community was species-poor and dominated by high densities of poeciliid fishes, Poecilia latipinna and Gambusia holbrooki, while typically dominant estuarine taxa including Menidia spp., Fundulus grandis, and Adinia xenica were in low abundance and palaemonid grass shrimp were nearly absent. Densities of economically important taxa in urban creeks were only half that observed in five of the six undeveloped or industrial creeks, but were similar to those observed in mosquito ditches suggesting that habitat quality in urban and mosquito-ditch tributaries is suboptimal compared to undeveloped tidal creeks. Furthermore, five of nine common taxa were rarely collected in urban creeks. Our results suggest that urban development in coastal areas has the potential to alter the quality of habitat for Nekton in small tidal tributaries as reflected by variation in the Nekton community.
Susan S. Bell - One of the best experts on this subject based on the ideXlab platform.
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Assessing the Link Between Coastal Urbanization and the Quality of Nekton Habitat in Mangrove Tidal Tributaries
Estuaries and Coasts, 2014Co-Authors: Justin M. Krebs, Susan S. Bell, Carole C. McivorAbstract:To assess the potential influence of coastal development on habitat quality for estuarine Nekton, we characterized body condition and reproduction for common Nekton from tidal tributaries classified as undeveloped, industrial, urban or man-made (i.e., mosquito-control ditches). We then evaluated these metrics of Nekton performance, along with several abundance-based metrics and community structure from a companion paper (Krebs et al. 2013 ) to determine which metrics best reflected variation in land-use and in-stream habitat among tributaries. Body condition was not significantly different among undeveloped, industrial, and man-made tidal tributaries for six of nine taxa; however, three of those taxa were in significantly better condition in urban compared to undeveloped tributaries. Palaemonetes shrimp were the only taxon in significantly poorer condition in urban tributaries. For Poecilia latipinna , there was no difference in body condition (length–weight) between undeveloped and urban tributaries, but energetic condition was significantly better in urban tributaries. Reproductive output was reduced for both P . latipinna (i.e., fecundity) and grass shrimp (i.e., very low densities, few ovigerous females) in urban tributaries; however a tradeoff between fecundity and offspring size confounded meaningful interpretation of reproduction among land-use classes for P . latipinna . Reproductive allotment by P . latipinna did not differ significantly among land-use classes. Canonical correspondence analysis differentiated urban and non-urban tributaries based on greater impervious surface, less natural mangrove shoreline, higher frequency of hypoxia and lower, more variable salinities in urban tributaries. These characteristics explained 36 % of the variation in Nekton performance, including high densities of poeciliid fishes, greater energetic condition of sailfin mollies, and low densities of several common Nekton and economically important taxa from urban tributaries. While variation among tributaries in our study can be largely explained by impervious surface beyond the shorelines of the tributary, variation in Nekton metrics among non-urban tributaries was better explained by habitat factors within the tributary and along the shorelines. Our results support the paradigm that urban development in coastal areas has the potential to alter habitat quality in small tidal tributaries as reflected by variation in Nekton performance among tributaries from representative land-use classes.
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Nekton community structure varies in response to coastal urbanization near mangrove tidal tributaries
Estuaries and Coasts, 2014Co-Authors: Justin M. Krebs, Carole C. Mcivor, Susan S. BellAbstract:To assess the potential influence of coastal development on estuarine-habitat quality, we characterized land use and the intensity of land development surrounding small tidal tributaries in Tampa Bay. Based on this characterization, we classified tributaries as undeveloped, industrial, urban, or man-made (i.e., mosquito-control ditches). Over one third (37 %) of the tributaries have been heavily developed based on landscape development intensity (LDI) index values >5.0, while fewer than one third (28 %) remain relatively undeveloped (LDI < 3.0). We then examined the Nekton community from 11 tributaries in watersheds representing the four defined land-use classes. Whereas mean Nekton density was independent of land use, species richness and Nekton-community structure were significantly different between urban and non-urban (i.e., undeveloped, industrial, man-made) tributaries. In urban creeks, the community was species-poor and dominated by high densities of poeciliid fishes, Poecilia latipinna and Gambusia holbrooki, while typically dominant estuarine taxa including Menidia spp., Fundulus grandis, and Adinia xenica were in low abundance and palaemonid grass shrimp were nearly absent. Densities of economically important taxa in urban creeks were only half that observed in five of the six undeveloped or industrial creeks, but were similar to those observed in mosquito ditches suggesting that habitat quality in urban and mosquito-ditch tributaries is suboptimal compared to undeveloped tidal creeks. Furthermore, five of nine common taxa were rarely collected in urban creeks. Our results suggest that urban development in coastal areas has the potential to alter the quality of habitat for Nekton in small tidal tributaries as reflected by variation in the Nekton community.
Lawrence P. Rozas - One of the best experts on this subject based on the ideXlab platform.
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effects of slotted water control structures on Nekton movement within salt marshes
Marine and Coastal Fisheries: Dynamics Management and Ecosystem Science, 2015Co-Authors: Matthew E. Kimball, Lawrence P. Rozas, Kevin M Boswell, James H CowanAbstract:AbstractWater control structures (WCSs) restrict hydrological connectivity in salt marshes and thereby impede Nekton movement within the greater habitat mosaic. Transient fishery species, which spawn outside salt marshes and must get past these barriers to reach spawning areas or salt-marsh nurseries, are especially vulnerable to these structures. Water control structures incorporating slots (narrow vertical openings spanning most of the water column) are thought to improve Nekton passage; however, few studies have directly examined Nekton passage through WCS slots. Dual-frequency identification sonar (DIDSON) acoustic imaging was used monthly (April–September 2010) on diurnal flood tides to examine Nekton movement through 15-cm-wide slots at two identical WCSs located in Louisiana tidal marsh channels. Nekton behavior was compared between these WCSs and a nearby natural salt-marsh creek. Examination of 12 h of subsampled acoustic data revealed large concentrations of salt-marsh Nekton at the WCSs (n = 2,...
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hydrodynamic regulation of salt marsh contributions to aquatic food webs
Marine Ecology Progress Series, 2013Co-Authors: Ronald Baker, Lawrence P. Rozas, Brian Fry, Thomas J MinelloAbstract:Vegetated salt marsh habitats are widely considered critical for supporting many species of Nekton, yet direct evidence of the processes controlling marsh habitat use for most species remains elusive. We related salt marsh flooding patterns and Nekton trophic dynamics among 14 sites spanning 2500 km across the northern Gulf of Mexico (GoM) and southern Atlantic coasts of the USA. Functional access for Nekton to marsh vegetation (edge flooded to ≥5 cm depth) ranged from 90% access in the western GoM and Pamlico Sound. Food web mixing models based on stable isotope analysis show that the impor- tance of Spartina trophic support for common Nekton may be regulated by the duration of marsh surface flooding. In particular, the potential contribution of Spartina production was positively related to indices of marsh surface flooding for brown shrimp Farfantepenaeus aztecus, white shrimp Litopenaeus setiferus, small (≤60 mm carapace width) blue crabs Callinectes sapidus, grass shrimp Palaemonetes pugio, and killifish Fundulus heteroclitus/grandis. The value of Spartina salt marsh production to several common species of Nekton appears to depend, at least in part, on direct access to the vegetated marsh surface, which is regulated by hydrodynamics. Hence, the substantial geographic and temporal variability in marsh flooding regulates the func- tional roles and value of these tidal wetlands for aquatic organisms.
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Testing the effect of habitat structure and complexity on Nekton assemblages using experimental oyster reefs
Journal of Experimental Marine Biology and Ecology, 2011Co-Authors: Austin T Humphries, Megan K. La Peyre, Matthew E. Kimball, Lawrence P. RozasAbstract:article i nfo Structurally complex habitats are often associated with more diverse and abundant species assemblages in both aquatic and terrestrial ecosystems. Biogenic reefs formed by the eastern oyster (Crassostrea virginica) are complex in nature and are recognized for their potential habitat value in estuarine systems along the US Atlantic and Gulf of Mexico coasts. Few studies, however, have examined the response of Nekton to structural complexity within oyster reefs. We used a quantitative sampling technique to examine how the presence and complexity of experimental oyster reefs influence the abundance, biomass, and distribution of Nekton by sampling reefs 4 months and 16 months post-construction. Experimental oyster reefs were colonized immediately by resident fishes and decapod crustaceans, and reefs supported a distinct Nekton assemblage compared to mud-bottom habitat. Neither increased reef complexity, nor age of the experimental reef resulted in further changes in Nekton assemblages or increases in Nekton abundance or diversity. The presence of oyster reefs per se was the most important factor determining Nekton usage.
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evaluating the effect of slot size and environmental variables on the passage of estuarine Nekton through a water control structure
Journal of Experimental Marine Biology and Ecology, 2010Co-Authors: Matthew E. Kimball, Lawrence P. Rozas, Kevin M Boswell, James H CowanAbstract:Abstract Water control structures (WCSs) installed to regulate water levels can alter both the hydrology and ecology of salt marshes. WCSs are thought to limit Nekton ingress into, and egress from, managed marshes. Slots (vertical openings that span most of the water column) incorporated into WCSs are thought to facilitate Nekton passage through structures, but little research has directly examined how slot size affects passage rates. We used dual-frequency identification sonar (DIDSON) acoustic imaging to examine the effect of slot width (10, 15, 30, or 60 cm), tidal cycle, diel period, and season on Nekton passage at a WCS located in a tidal salt marsh canal. Few individuals (total numbers and relative percentages) used the slots for passage through the structure during any stage of the tidal cycle, day or night, or seasonally. The number and size of migrants were similar for all four slot sizes examined. Nekton used the slots most often on flood tides to access the managed marsh (i.e., swim inside), primarily at night. Individuals entering the managed marsh were larger than those observed leaving the managed marsh. Whereas the majority of migrants were observed during winter months, season did not affect Nekton passage in our study. Acoustic imaging allowed a unique and comprehensive evaluation of Nekton passage by permitting an examination of factors such as swimming direction and proportion of migrants that are unobservable with other sampling techniques.
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Nekton Density Patterns in Tidal Ponds and Adjacent Wetlands Related to Pond Size and Salinity
Estuaries and Coasts, 2010Co-Authors: Lawrence P. Rozas, Thomas J MinelloAbstract:We examined the distribution of Nekton across the marsh landscape using a 1-m^2 drop sampler to compare Nekton densities across three different salinity zones (intermediate, brackish, saline), three pond sizes (diameter 750 m = large), and two habitat types (pond, adjacent marsh) in the Barataria Bay Estuary, Louisiana. Nekton assemblages of ponds and the adjacent marsh appeared to be structured by the responses of individual species to the estuarine salinity gradient at the landscape scale and to pond habitat attributes locally. Our results indicate that ponds in the brackish and saline zones are more important nursery areas for most fishery species than ponds in the intermediate zone. Medium and large ponds supported higher densities of most species than small ponds. Most species of Nekton were associated with vegetation structure, and individuals of these species were either concentrated among plant stems at the marsh edge or within submerged aquatic vegetation in ponds.
