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Metapopulation portfolio effects. Long-term mean metapopulation density across all four estuaries (full), two northern estuaries (AB and CK combined), and two southern estuaries (TB and CH combined). The coefficient of variation portfolio effect (CVPE) values are reported for each metapopulation. https://doi.org/10.1371/journal.pone.0221131.g005
Source publication
Forage fishes play an important role in marine ecosystems by transferring energy and nutrients through the food web. The population dynamics of forage species can therefore have cascading effects across multiple trophic levels. Here, we analyzed a 19-year dataset on Pinfish (Lagodon rhomboides) across four eastern Gulf of Mexico estuaries to invest...
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Context 1
... magnitude of portfolio effects varied among metapopulations. The full, four-estuary portfolio effect was 42% more stable than a single homogenous population (CVPE = 1.42; Fig 5). The portfolio effects differed between the northern (CVPE = 1.35) and southern (CVPE = 1.05) metapopulations (Fig 5). ...
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Citations
... Seagrass restoration may be particularly beneficial to juvenile fishes because meadows commonly function as nursery habitat (Heck et al., 2003;Lefcheck et al., 2019) that offer shelter from predation (Hindell et al., 2002;Smith et al., 2011) and enhance food availability (Nakamura & Sano, 2005;Alfaro, 2006). Numerous coastal fishes recruit to seagrass meadows as larvae and remain in or near meadows until maturity (Rooker et al., 1998;ASMFC, 2010;Faletti et al., 2019). Seasonal recruitment results in distinct assemblages of juvenile fishes inhabiting meadows throughout the year (Rooker et al., 1998;Sobocinski et al., 2013). ...
... For example, pinfish (L. rhomboides) recruit to seagrass meadows from offshore spawning grounds in the winter and spring months (Faletti et al., 2019). Likewise, the most abundant taxa in our collections, pipefish (Syngnathus spp.), migrate from offshore into estuaries during the spring and summer where spawning and brooding of eggs occurs (Campbell & Able, 1998). ...
Restoration is accelerating to reverse global declines of key habitats and recover lost ecosystem functions, particularly in coastal ecosystems. However, there is high uncertainty about the long‐term capacity of restored ecosystems to provide habitat and increase biodiversity and the degree to which these ecosystem services are mediated by spatial and temporal environmental variability. We addressed these gaps by sampling fishes biannually for 5–7 years (2012–2018) at 16 sites inside and outside a rapidly expanding restored seagrass meadow in coastal Virginia (USA). Despite substantial among‐year variation in abundance and species composition, seine catches in restored seagrass beds were consistently larger (6.4 times more fish, p < 0.001) and more speciose (2.6 times greater species richness, p < 0.001; 3.1 times greater Hill–Shannon diversity, p = 0.03) than seine catches in adjacent unvegetated areas. Catches were particularly larger during summer than autumn (p < 0.01). Structural equation modeling revealed that depth and water residence time interacted to control seagrass presence, leading to higher fish abundance and richness in shallow, well‐flushed areas that supported seagrass. Together, our results indicate that seagrass restoration yields large and consistent benefits for many coastal fishes, but that restoration and its benefits are sensitive to the dynamic seascapes in which restoration is conducted. Consideration of how seascape‐scale environmental variability affects the success of habitat restoration and subsequent ecosystem function will improve restoration outcomes and the provisioning of ecosystem services.
... The core distribution of seagrass habitats used by juvenile gag is in the eastern Gulf of Mexico, spanning two biogeographic provinces and two ecoregions from warm temperate to subtropical latitudes (Spalding et al. 2007), where the composition and abundance of decapods and fishes (i.e., likely prey) have been shown to vary spatially (e.g., Schrandt et al. 2018;Faletti et al. 2019). Regional heterogeneity in species that are likely to be prey for gag may also reflect a gradient in basal-resource dependence from more phytoplankton-based food webs at higher, eutrophic latitudes to greater dependence on benthic food webs at lower, oligotrophic latitudes (Radabaugh et al. 2013;Lesser et al. 2020;Peake et al. 2022). ...
... These seven seagrass systems span from the Warm Temperate Northwest Atlantic province (Northern Gulf of Mexico ecoregion) in the north to the Tropical Northwestern Atlantic province (Floridian ecoregion) in the south (Spalding et al. 2007). Coinciding with the large biogeographic expanse of these focal seagrass systems, the composition and abundance of species that are observed prey of gag vary substantially ( Schrandt et al. 2018;Faletti et al. 2019). As generalist predators, we expected this variation in prey availability to be reflected in the diets of gag. ...
Consumers can influence ecological patterns and processes through their trophic roles and contributions to the flow of energy through ecosystems. However, the diet and associated trophic roles of consumers commonly change during ontogeny. Despite the prevalence of ontogenetic variation in trophic roles of most animals, we lack an understanding of whether they change consistently across local populations and broad geographic gradients. We examined how the diet and trophic position of a generalist marine predator varied with ontogeny across seven broadly separated locations (~ 750 km). We observed a high degree of heterogeneity in prey consumed without evidence of spatial structuring in this variability. However, compound-specific isotope analysis of amino acids revealed remarkably consistent patterns of increasing trophic position through ontogeny across local populations, suggesting that the roles of this generalist predator scaled with its body size across space. Given the high degree of diet heterogeneity we observed, this finding suggests that even though the dietary patterns differed, the underlying food web architecture transcended variation in prey species across locations for this generalist consumer. Our research addresses a gap in empirical field work regarding the interplay between stage-structured populations and food webs, and suggests ontogenetic changes in trophic position can be consistent in generalist consumers.
... Forage fish populations can be influenced by spatiotemporal variability in habitat and climatic conditions, which can affect community structure and dynamics (Burghart et al., 2013;Faletti et al., 2019;Lubbers et al., 1990;Simonis & Merz, 2019). For example, latitudinal gradients in community composition and species diversity are quite common in marine and estuarine environments (Hillebrand, 2004;Pease, 1999). ...
... Seasonal periodicity may be related to differing life history strategies among forage fish taxa. For example, Faletti et al. (2019) and found that Pinfish in the eGOM were most abundant in late winter and early spring due to postspawning recruitment, while Godefroid et al. (2001) found that juvenile abundance of Eucinostomus mojarras peaked in summer and early fall following early-summer spawning. Both of these patterns are reflected in eGOM forage fish community seasonal associations shown in this study. ...
Forage fishes are an important component of marine, estuarine, and aquatic food webs that facilitate the transfer of energy and nutrients from primary producers to upper trophic levels. Previous studies of forage fishes have focused primarily on pelagic planktivorous species in pelagic environments. However, benthically associated taxa can be just as important as planktivorous species, particularly in highly productive estuarine environments that provide critical habitat for many predators. In this study, we analyzed a 20‐year forage fish community composition and abundance dataset across four eastern Gulf of Mexico estuaries spanning a broad latitudinal gradient to investigate spatiotemporal variability in community structure and quantify associations with habitat. Our analyses revealed significant regional structuring of forage fish communities, coupled with a strong association with habitat characteristics related to latitudinal effects and basal resource regime. Communities in the two northern estuaries and two southern estuaries were associated primarily with planktonically reliant and benthically reliant taxa, respectively. Despite regional differences, we uncovered a coherent annual cycle in forage fish communities across all estuaries related to seasonal shifts in abundances of several abundant and ubiquitous species. We additionally revealed significant subdecadal periodicity potentially associated with bottom‐up effects of global climatic cycles. The significant association of forage fish communities with habitat regime shown in this study underlies the importance of continued monitoring of these communities. This study represents a novel approach to assess this critical ecosystem component in diverse estuarine systems globally.
... Random sampling of the system was modeled after the Florida Fish and Wildlife Conservation commission's fishery-independent monitoring program (see Faletti et al. 2019) and spatially stratified to equally sample 2 regions within the system: the Apalachicola Bay (APB) region, which includes Apalachicla Bay proper, East Bay, and St. Vincent Sound areas (304.6 km 2 ), and the St. George Sound (SGS) region (305.9 km 2 ; Livingston 1984) (Fig. 1). ...
Coastal areas serve as vital habitat for many marine fishes and often host broad gradients of environmental conditions that result in diverse species assemblages. Understanding the influence of environmental variables on the distribution and abundance of fishes is especially important for devising appropriate management strategies. We documented large fish community structure in the Apalachicola Bay system from 2018 to 2021 using fishery-independent longline and gillnet surveys. Spatiotemporal variation in fish assemblages was evaluated with permutational multivariate ANOVA, while community- and species-level habitat relationships were described across gradients of environmental variables with non-metric multidimensional scaling and generalized additive models. We captured 5085 fishes from 17 elasmobranch and 33 bony fish species, with gafftopsail catfish Bagre marinus, blacktip shark Carcharhinus limbatus, Atlantic sharpnose shark Rhizoprionodon terraenovae, and hardhead catfish Ariopsis felis comprising 82.1% of the total catch. Fish communities varied spatially throughout the system, and changes in these communities were most strongly correlated with gradients in salinity, clarity, and depth. We documented higher species richness and density of young elasmobranchs in our surveys compared to adjacent systems, supporting past suggestions that this area serves as important juvenile shark habitat. We suggest that flow from the Apalachicola River, transporting nutrients to the system and supporting numerous environmental niches across spatiotemporal scales, plays an influential role in maintaining the elevated diversity and density of elasmobranchs observed in this study.
... Here, M i is the midpoint of class I and f i is frequency, including cells with the same number of layers i. Coverage levels of seagrass as described by English et al. are described in Table 1 (English et al. 1997). The classification of seagrasses is based on their external morphological characteristics, as described by Den Hartog (1970) and Phillips and Menez (1988), who were the first scientists to classify seagrasses. ...
... The seagrass community at Nam Yet Island is mostly distributed on the sandy bottom and among coral debris, dead coral, consistent with a previous study of seagrasses in Truong Sa archipelago (Luong et al. 2019). However, the distribution of seagrasses depends on environmental factors such as temperature, pH, dissolved oxygen, annual cycle, and human impact (Faletti et al. 2019). This explains the difference in structure of the two research areas, Nam Yet-1 and Nam Yet-2, between which there is a relatively large difference in human impact. ...
Seagrasses are among the most important ecosystems of continental and island coastal waters globally. Analyses of the species diversity, structure, and distribution mapping of seagrass communities provide a scientific basis for seagrass conservation and development and protection of the marine environment. The application of remote sensing, especially using very high-resolution remote sensing data, in mapping seagrass distribution confers high accuracy and detailed results. The distribution of seagrass communities and benthic biomes typical of Nam Yet Island, Truong Sa Archipelago, Vietnam was mapped using object-based classification of Pléiades satellite imagery with four spectral bands (red, blue, green, and near-infrared) and the Green–Blue Normalized Difference Vegetation Index, combined with handheld positioning devices (total field samples 100, overall accuracy 91%, kappa coefficient = 0.88). Besides, by sampling and measurement in the field, two seagrass species, Thalassia hemprichii and Halophila ovalis were identified with the same structure, density, and biomass in the northern and southern parts of the island. The application of high-resolution remote sensing images combined with field surveys contributes to improving the accuracy of seagrass distribution maps as well as benthic biome ones for shallow sea areas. Establishing a seagrass distribution map and assessing the diversity of seagrass is the basis for the conservation and development of the current seagrass community at Nam Yet Island.
... It is acknowledged that pinfish are routinely used because of their abundance and ease of capture, and although Stoner (1980) indicate these fish only ingest minor amounts of fish prey in their diet, more recent authors, i.e. Beck & Rooker (2012), suggest pinfish are natural predators known to feed on red drum larvae and juveniles (Fuiman, 1994;Rooker et al., 1998); juvenile pinfish are considered piscivorous when no other food items are available (Anonymous, 2021 (Faletti et al., 2019) showing preference to feeding on barnacles, shrimp, fish eggs, amphipods, insect larvae, and polychate worms. Juvenile Sergeant major fish were caught using dip nets on the Port Aransas, Texas south jetty from water depths ranging from 0 to 1 m. ...
Many fish species use intercoastal jetties throughout their life cycle to migrate to and from the ocean into bays and estuaries. During migration, fish may encounter rock, algae, sand, sea-grass, and coral. Anecdotal information indicates that some migrating fish of intercoastal jetties preferentially select colonies of gorgonian coral (Leptogorgia spp.) vs. any other habitat when encountering a predator. Since very little information exists regarding Leptogorgia, we focused our study in determining the importance of such coral as fish habitat. Stationary field sampling was conducted seasonally to determine the abundance of these coral, the type of migrating fish, and the habitat they associated with. Mesocosm studies were then conducted to determine whether Leptogorgia habitats are important to fish in the presence or absence of a predator. Five different habitats were compared (rock, algae, sand, Leptogorgia, and seagrass) and 6 species of fish (sergeant major, pinfish, mangrove snapper, spotfin mojarra, pigfish, and red drum). In the field study component, more than 600 colonies of Leptogorgia were observed and 17 different fish species. The most commonly observed fish were sergeant major, pinfish, mangrove snapper, and spotfin mojarra, however, sergeant majors were the most abundant species using coral as habitat. The use of mesocosms showed that all fish species significantly selected for structured habitat over non-structured habitat (e.g. sand), but that the fish commonly called ‘sergeant major’ significantly (ANOVA; p ≤ 0.001) selected for Leptogorgia.
... For example, the presence, abundance and species composition of seagrasses are linked to faunal richness and abundance patterns (McCloskey & Unsworth, 2015;Ray et al., 2014), but seagrass communities can vary considerably along environmental gradients of depth, nutrients, light availability, temperature and salinity (Duarte et al., 2007;Jayathilake & Costello, 2018;Uhrin & Turner, 2018). The spatial distribution and abundance of seagrass-associated fauna may also vary in response to environmental conditions (e.g., ocean temperature, phytoplankton production, pH and dissolved oxygen) that can fluctuate across space and over diel, seasonal, annual and inter-annual time-scales, especially for more mobile fauna like marine fishes (Faletti et al., 2019;Garwood et al., 2013;Unsworth et al., 2007). Additionally, seascape features like habitat connectivity and proximity to anthropogenic stressors can affect seagrass patterns and associated fauna at landscape scales (Bittner et al., 2020;Gilby et al., 2018). ...
Aim
Seagrass beds are declining globally and are increasingly vulnerable to sea level rise (SLR), which could have consequences for the rich biodiversity they support. Spatial variation in the role of seagrass beds in enhancing biodiversity is poorly resolved, limiting our ability to set priorities for conservation and restoration. We aimed to model the biodiversity enhancement value of seagrass beds.
Location
Florida Gulf Coast, USA.
Methods
We used generalized additive mixed models (GAMMs) to describe the distribution, total cover and species composition of seagrass beds and to estimate their effects on spatial patterns of faunal species richness under three scenarios. Specifically, we: (a) quantified the biodiversity enhancement value of current seagrass beds, (b) inferred the biodiversity value of potential restoration areas and (c) projected potential changes in the distribution and biodiversity enhancement value of seagrass beds due to SLR using low (+0.50 m) and high (+1.0 m) SLR forecasts for 2100.
Results
Current seagrass beds supported 43%–64% more species than unvegetated habitats, even when accounting for spatial variability in predicted faunal richness due to other environmental, seascape, temporal and geographic factors. Seagrass restoration in potential habitats would also increase biodiversity in the near-term (i.e., 43%–45% above unvegetated levels). However, model projections indicate that SLR could result in significant losses of current seagrass beds and potential restoration areas, causing contracted distributions and lower seagrass cover. Overall, these changes could result in significant reductions in the enhancement value provided by seagrasses. Although, there could also be many suitable locations for seagrasses by 2100, with some having either comparable or potentially increased enhancement value.
Main conclusions
Our findings highlight the importance of considering spatial variation in biodiversity benefits when planning for seagrass conservation and restoration and when managing the impacts of SLR.
... Orthopristis chrysoptera (pigfish) and Lagodon rhomboides (pinfish) individuals, as well as representative samples of all available primary production channels, were collected via the beam trawl protocol described above and subjected to stable isotope analysis. Orthopristis chrysoptera and L. rhomboides represent two omnivorous, ubiquitous species native to this ecosystem (Stallings et al. 2015a, Faletti et al. 2019, that undergo ontogenetic shifts in their diet (Stoner 1980, Darcy 1983), and use resources over similar, small home ranges (Potthoff and Allen 2003). Epiphytes, seagrass detrius and benthic microalgae are known to make up a large portion of the diet of both species (Hansen 1969, Adams 1976, Stoner and Livingston 1984, both via direct consumption and via the consumption of benthic invertebrates relying on those production channels (Carr andAdams 1973, Stoner 1980). ...
... Due to different numbers of the two species captured, a total of 88 O. chrysoptera samples and 186 L. rhomboides were used to understand how each species' niche varied over the seagrass productivity regime. All fish were young-of-year (meaning they had recruited to the seagrass system in the winter through spring of the year, Chacin et al. 2016, Faletti et al. 2019 and were between 5 and 7 cm total length. Samples of primary production sources (algae, seagrass and epiphytes) were collected haphazardly throughout sampling and averaged over the entire study area. ...
The production and transfer of biomass through trophic relationships is a core ecosystem function. The movement of energy through the food web is mediated by organisms operating in their niche space. For generalists, the size of this niche space is inherently plastic and changes in response to available food sources. Therefore, this relationship between ecosystem productivity and niche size is an important determinant of ecosystem function. Competing theories about the nature of this relationship predict that as productivity increases niche size will either increase as species capitalize on a general increase in resource availability or decrease as it becomes viable to focus on preferred production channels. Here, we test these two competing theoretical frameworks using a novel approach to determine trophic niche size using stable isotope analysis and hypervolume metrics. Resource use is quantified in two generalist fish species at three productivity levels in a seagrass ecosystem. Niche size of both species was inversely related to seagrass productivity, consistent with the hypothesis that increasing productivity allows species to focus on a narrower diet. This pattern describes the relationship between ecosystem production and niche size and provides an empirical ecological explanation for the resource maximization behaviors commonly observed in nature.
... Abiotic factors such as depth, physico-chemical conditions (dissolved oxygen and salinity), habitat disturbance, prevailing winds, and tidal regimes all influence both larval supply and subsequent recruitment of pinfish in seagrass meadows (Faletti et al. 2019). In addition to habitat characteristics, the spatial distribution of seagrass beds in an estuary can also have significant effects on abundance and density of juvenile fishes. ...
Seagrass meadows in far South Texas are dominated by turtle grass (Thalassia testudinum), and juvenile pinfish (Lagodon rhomboides) are abundant grazers of seagrass epifauna. As they grow, pinfish exhibit an ontogenetic dietary shift and begin consuming increasing amounts of plant material. In this study, contrasting environmental regimes in two seagrass meadows were examined to identify how they might affect pinfish diets, diet shifts, and growth across the growing season. The eastern site was sheltered from prevailing southeasterly winds by a barrier island, while the western site was shallower and subjected to higher wind energy and turbidity. Gut contents from 290 pinfish were quantified from May through October 2016 and multivariate analyses showed strong but overlapping separation of diets and temporal change in feeding habits. Although there were spatial and temporal differences between the two sites, a site by time interaction indicated different temporal trends. Nonetheless, ooze (amorphous detritus) and aquatic invertebrates (primarily amphipods) were the primary diet items consumed at both localities across time. Pinfish at both sites consumed seagrass, which increased in importance as the growing season progressed, although volume and consumption rate did not differ between sites. Growth rates of pinfish were similar at both sites, but pinfish from the western site were larger and fewer in number across the study. Although pinfish diets differed under different environmental regimes, they were generalist consumers in South Texas seagrass meadows with high diet variability that trended towards herbivory in late summer and fall.
... For example, 34% of the 2010 community similarity (i.e., the species typifying the 2010 community) was attributed to L. rhomboides, a forage fish that is present in all years and most samples, but with variable abundance. Its relatively large contribution (34%) to community similarity was likely a result of its highest abundance in this long-term dataset occurring in 2010 (Faletti et al. 2019). Other prey species, such as Leiostomus xanthurus, contributed more to the community similarity in 2010 than in other years. ...
... This higher contribution by prey species may be a result of reduced predation pressure from C. undecimalis, Estuaries and Coasts especially for Lagodon rhomboides, which can constitute more than half of C. undecimalis' diet by number and weight (Blewett et al. 2005). Indeed, a nearly threefold increase occurred in L. rhomboides abundance in small seine samples, which was also documented, along with a biomass increase, by Faletti et al. (2019) in Tampa Bay and Charlotte Harbor in 2010. The species contributing to community similarity in trawl samples shifted from Prionotus scitulus and Synodus foetens to P. scitulus and L. rhomboides. ...
Estuarine and coastal marine ecosystems can have significant intra- and interannual variability in faunal community structure, complicating management response to disturbances as disturbance effects must be detectable within normal variability and on timescales relevant to management entities. We examined a long-term, multi-gear dataset on estuarine faunal (fish and select invertebrate) communities to determine if community structure changes due to disturbances could be detected on management-relevant timescales (e.g., years), given that these communities have known seasonal and interannual variability. Results from multivariate, community-based analyses, and several univariate diversity indices for fauna of Tampa Bay, Florida, USA suggested general community stability over the long term, with the exceptions of 2005–2006 (prolonged red tide event) and 2010 (extreme cold event in winter). Community structure was notably outside the typical variability for both time periods. In 2005, species richness decreased by half for one gear type and was the lowest on record for the other two gear types. In 2010, when the relative abundance of a top predator decreased by 50% from cold-related mortality, Simpson’s diversity index was the lowest on record for one gear type. The red tide and extreme-cold events differed in duration and the number of taxa directly impacted (multispecies vs. single-species, respectively) but both multivariate and univariate analyses indicated significant deviation in the faunal community structure during these years. Within 1–3 years after these major events, however, the community seemed to have returned to a structure like that of previous years, suggesting long-term stability and resilience. Our results confirm that multivariate and univariate analyses can detect major disturbances to estuarine faunal communities, which gives management entities options for which analysis approach is appropriate for their needs. Since the Tampa Bay faunal communities recovered within 3 years, we suggest that where long-term monitoring exists, active restoration might be deferred while monitoring for signs of recovery following the removal of a perturbation. This is a fundamental part of sound adaptive management processes to promote sustainable ecosystems.
