Fish assemblage structure on a drowned barrier island in the northwestern Gulf of Mexico

We investigated the assemblage structure of fishes associated with different habitats (inshore mud, shell bank, and offshore mud) over a drowned barrier island, Freeport Rocks Bathymetric High, on the inner continental shelf of the northwestern Gulf of Mexico (NW Gulf). Density data from otter trawls were used to examine spatial (habitat and site) and temporal differences in fish assemblage structure using multi- and univariate procedures. Eight species accounted for 69% of the total composition and in order of decreasing abundance included shoal flounder (Syacium gunteri), dwarf sand perch (Diplectrum bivittatum), red snapper (Lutjanus campechanus), least puffer (Sphoeroides parvus), silver seatrout (Cynoscion nothus), largescale lizardfish (Saurida brasiliensis), silver jenny (Eucinostomus gula), and sand seatrout (Cynoscion arenarius). Multivariate results indicated fish assemblage structure differed among habitats (ANOSIM; Global R = 0.190, P < 0.001) and survey dates (ANOSIM; Global R = 0.541, P < 0.001); however, differences among sites were negligible (ANOSIM; Global R = −0.015, P = 0.749). Highest densities of dwarf sand perch and least puffer were found on the shell bank, while densities of shoal flounder, largescale lizardfish, and silver jenny were highest on offshore mud. In addition, smallest sizes and highest densities of six of the eight abundant species were found in July, suggesting an important period for juvenile fishes. Diversity indices also varied relative to habitat with highest Shannon diversity (H′) and species richness (S) values for fishes associated with the shell bank. Results of this study highlight the importance of a mosaic of habitat types to fish assemblages on a drowned barrier island in the NW Gulf. Handling editor: I. Nagelkerken     

Development of a biotic index using stream macroinvertebrates to assess stress from deposited fine sediment

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Fossilized intestine casts located within closed bivalve shells: implications for palaeoecological and sedimentological studies

Marine organisms inhabiting soft‐bottom sediment are particularly susceptible to rapid sedimentation and erosion events. This article presents a novel example of fossilized intestine casts located within closed bivalve shells in relation to rapid sedimentation event from the Pleistocene sediment of the Oga Peninsula, Akita Prefecture, northern Japan. The mollusc shells were loosely packed in well‐sorted medium‐grained to coarse‐grained sandstone associated with low‐angle trough cross‐stratification. The closed shells of Glycymeris yessoensis were present in the shell concentration. The internal parts of the shells were almost hollow, being partially filled with yellow fine‐grained clay minerals (median grain size = 30.63 μm). The characteristic material within the shells clearly differed from the surrounding sediment, which consisted of coarse‐grained felsic minerals (median grain size = 449.73 μm). Furthermore, the yellow fine‐grained clay minerals within the shells were tube‐shaped, and located near the posterior adductor scar. On the basis of anatomical observation of living Glycymeris, we confirmed that part of the intestine and the anus are also placed near the posterior adductor muscle. Therefore, the yellow fine‐grained clay minerals within the shells represent the fossil remains of particles ingested by the G. yessoensis individual through suspension‐feeding, and the tube‐shaped material is interpreted as being fossilized intestine cast. These results suggest that G. yessoensis individuals were buried alive, as rapid sedimentation prevented ejection and destruction of the filling material of intestine. The presence of intestine cast within the mollusc fossils can be used for recognizing rapid sedimentation.     

Cross‐scale variation in species richness–environment associations

Aim The scale dependence of many ecological patterns and processes implies that general inference is reliant on obtaining scale‐response curves over a large range of grains. Although environmental correlates of richness have been widely studied, comparisons among groups have usually been applied at single grains. Moreover, the relevance of environment–richness associations to fine‐grain assemblages has remained surprisingly unclear. We present a first global cross‐scale assessment of environment–richness associations for birds, mammals and amphibians from 2000 km down to c. 20 km. Location World‐wide. Methods We performed an extensive survey of the literature for well‐sampled terrestrial vertebrate inventories over clearly defined small extents. Coarser grain richness was estimated from the intersection of extent‐of‐occurrence range maps with concentric equal‐distance circles around fine‐grain assemblage location centroids. General linear and simultaneous autoregressive models were used to relate richness at the different grains to environmental correlates. Results The ability of environmental variables to explain species richness decreases markedly toward finer grains and is lowest for fine‐grained assemblages. A prominent transition in importance occurs between productivity and temperature at increased grains, which is consistent with the role of energy affecting regional, but not local, richness. Variation in fine‐grained predictability across groups is associated with their purported grain of space use, i.e. highest for amphibians and narrow‐ranged and small‐bodied species. Main conclusions We extend the global documentation of environment–richness associations to fine‐grained assemblages. The relationship between fine‐grained predictability of a group and its ecological characteristics lends empirical support to the idea that variation in species fine‐grained space use may scale up to explain coarse‐grained diversity patterns. Our study exposes a dramatic and taxonomically variable scale dependence of environment–richness associations and suggests that environmental correlates of richness may hold limited information at the level of communities.     

The effects of sediment type on growth rate and shell allometry in the soft shelled clam Mya arenaria L

Hatchery-reared juvenile Mya arenaria L. were grown for 11 wk in replicated gravel, sand, mud, and pearl net treatments under flow-through sea-water conditions in Maine. Analyses of variance showed significant differences between sediment treatments for final shell length, dry meat weight, chondrophore growth increment, and percent shell weight. Growth of juvenile M. arenaria was more rapid in fine sediments than in coarse sediments or nets.Regression slopes of shell length-shell height and shell length-shell depth varied significantly between sediment treatments. Slower-growing clams from nets and gravel were more globose than clams from sand or mud treatments. Clams grown in sand were longer and narrower than those from mud. Differences in growth rates and shell form were attributed primarily to the physical properties of the substrata, and their effects on the scope for growth of M. arenaria.     

The role of fine sediment characteristics and body size on the vertical movement of a freshwater amphipod

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eDNA metabarcoding survey reveals fine‐scale coral reef community variation across a remote,tropical island ecosystem

Environmental DNA (eDNA) metabarcoding, a technique for retrieving multispecies DNA from environmental samples, can detect a diverse array of marine species from filtered seawater samples. There is a growing potential to integrate eDNA alongside existing monitoring methods in order to establish or improve the assessment of species diversity. Remote island reefs are increasingly vulnerable to climate‐related threats and as such there is a pressing need for cost‐effective whole‐ecosystem surveying to baseline biodiversity, study assemblage changes and ultimately develop sustainable management plans. We investigated the utility of eDNA metabarcoding as a high‐resolution, multitrophic biomonitoring tool at the Cocos (Keeling) Islands, Australia (CKI)—a remote tropical coral reef atoll situated within the eastern Indian Ocean. Metabarcoding assays targeting the mitochondrial 16S rRNA and CO1 genes, as well as the 18S rRNA nuclear gene, were applied to 252 surface seawater samples collected from 42 sites within a 140 km² area. Our assays successfully detected a wide range of bony fish and elasmobranchs (244 taxa), crustaceans (88), molluscs (37) and echinoderms (7). Assemblage composition varied significantly between sites, reflecting habitat partitioning across the island ecosystem and demonstrating the localisation of eDNA signals, despite extensive tidal and oceanic movements. In addition, we document putative new occurrence records for 46 taxa and compare the efficiency of our eDNA approach to visual survey techniques at CKI. Our study demonstrates the utility of a multimarker metabarcoding approach in capturing multitrophic biodiversity across an entire coral reef atoll and sets an important baseline for ongoing monitoring and management.     

Variability in spatial and temporal occurrence of presettlement and settlement‐stage fishes associated with shallow reefs

Presettlement and settlement‐stage fishes were studied in a large, log‐spiral bay in temperate South Africa. The aim was to describe the assemblage composition, density and distribution associated with four types of habitats common to the bay: high profile reef, low profile reef, reef‐associated sand and open sand spatially separated from reef. Samples were collected with both a plankton ring net and a light trap at each habitat type as part of a mixed‐method approach. A total of 4084 presettlement and settlement‐stage fishes belonging to 31 teleost families and 84 species were captured. Reef‐associated sand and open sand habitats yielded higher species richness and diversity than the high and low‐profile reef habitats. Engraulidae, Gobiidae, Clupeidae and Cynoglossidae were the dominant fish families captured with the ring net, while Engraulidae, Clupeidae, Carangidae and Clinidae were captured with the light trap. A temporal difference in the abundance of presettlement fishes occurred between the sampling periods with highest values recorded during the summer settlement period. Habitat type together with associated physico‐chemical variables played a pivotal role in determining presettlement fish species composition, density and distribution across habitat types.     

Effects of current speed, shell length and type of sediment on the erosion and transport of juvenile softshell clams (Mya arenaria)

The erosion and transport of juvenile softshell clams (Mya arenaria) was studied in a laboratory flume in relation to free-stream velocity (0, 7, 16, 29 and 35 cm s^− 1), shell length (0-5, 5-10, 10-15, 15-20 mm) and type of sediment (mud, sandy-mud, sand and gravel). Our results showed that these factors interact together on the erosion of clams from the sediment. Juveniles were eroded in great numbers in sand while mud retained them more easily. Bedload transport was initiated at speeds of 16 cm s^− 1. Most of the clams were eroded in sandy sediments at speeds of 29 and 35 cm s^− 1. The smallest individuals were highly vulnerable to erosion compared to the other size classes studied. A results-based model using the logistic regression statistics was proposed. This allowed the estimation of erosion probabilities for a given hydrosedimentary environment. A field validation of the model was then carried out. Field results confirmed the importance of free-stream velocity, shell length and type of sediment on the erosion rate of clams. The differences observed between predicted and field results suggest that the model underestimated the erosion rate in the field. Results are discussed in the context of hydrosedimentary environments found off the eastern coast of Canada.     

Mollusken-Gemeinschaften der Bahía de Nenguange (Karibik,Kolumbien)

The Bahía de Nenguange is one of the largest bays (5 km²) east of Santa Marta. The shore of the U-shaped bay is made up of steep slate rocks, interrupted by sandy beaches. The waters within the bay are rather shallow but get deeper to the north; in the western part, which is 10–12 m deep, a platform is situated. The western shore is subject to strong exposure of waves; the eastern half is calmer. On the eastern beach a small stand of mangroves is located. Altogether, 491 species of molluscs were found, belonging to 100 families and 259 genera. 12 molluscan assemblages have been documented: 4 distributed in the intertidal, and 8 in the sublittoral zone. The distribution of the sublittoral coenoses depends on the distribution of the substrates. Numerous microgastropods occur in coarse-grained sediments. Highest diversity was observed on fine and mixed sands. Variations documented in the diversity of theThalassia-coenosis and of the fine sand-mixed sand coenoses are due to changes in numbers of species, whereas the diversity on ooze is due likewise to modifications in the number of species and to evenness.     

A high‐stress shelly fauna associated with sponge mud‐mounds in the Coniacian Arnager Limestone of Bornholm,Denmark

The benthic macrofaunas of the Upper Cretaceous chalk of NW Europe show characteristically high species‐richnesses and commonly high densities. They are predominated by bivalves, brachiopods, polychaetes, echinoids, crinoids, asteroids, sponges and towards the end of the Cretaceous also by bryozoans. The mound‐bedded chalk of the Coniacian Arnager Limestone on the island of Bornholm in the Baltic Sea, Denmark, differs from this general picture. It was deposited on a small fault block adjacent to the main Bornholm block, which was emerged during much of the Mesozoic and thus occupied a much more proximal position than most other Upper Cretaceous chalks in NW Europe. The Arnager Limestone contains a unique, exceptionally rich and well‐preserved fauna of mainly hexactinellid, lyssacinosan sponges. The low mud‐mounds are interpreted as formed by baffling and trapping of fine sediment particles by the dense sponge thickets. In contrast, the associated shelly fauna is unusually sparse, of very low richness and extremely low density, except for inoceramid bivalves. It represents a strongly depauparated version of the shelly faunas of contemporaneous chalks in NW Europe. The rare specimens of non‐inoceramid shelly species are interpreted to represent occasional successful spatfalls of benthic species from the deeper‐water chalk farther offshore in the Baltic area. The sponge mud‐mounds of the Arnager Limestone show remarkable resemblances with modern sponge mounds recently discovered on the continental shelf of western Canada. They form an important link between the well‐known older Mesozoic sponge mud‐mounds or ‘reefs’ and the modern mounds and are among the youngest examples of Mesozoic sponge mounds.     

Sediment dispersion: part 2, characterisation by size of sand fraction and percent mud

In part 2 of this contribution, examples are drawn from the River Mersey and Liverpool Bay illustrating the use of simple statistical parameters to describe dispersion of sands and muddy sediments. The River Mersey and Liverpool Bay, eastern Irish Sea, were sites of intensive studies on the dispersal of dumped harbour mud and sewage sludge during the mid 1960's–70's. The combined effects of strong tidal scour, wave action and shoreward near-bed residual drift result in shoreward transport of large volumes of sand in the bay. Large amounts of mud (silt/clay mixtures) oscillate in the river estuary, and naturally derived and dumped muds also move shoreward in the bay. Unpublished historic geochemical data have been combined with reprocessed particle size data and both have been used to reassess sedimentological techniques for defining transport and dispersal pathways. River and bay muds have similar size compositions, but river muds have excess Cd > V > U > As = Zn relative to bay muds. The lower relative concentrations of heavy metals in the bay are thought to reflect desorption and degradation of organic matter from the river. Trends in sediment distribution data based on the means of the sand size fraction, alone, provide sensitivities comparable to those of higher order moment measures and are usually easier to interpret than full size spectrum analyses.     

Vulnerability of terrestrial island vertebrates to projected sea‐level rise

Sea‐level rise (SLR) from global warming may have severe consequences for biodiversity; however, a baseline, broad‐scale assessment of the potential consequences of SLR for island biodiversity is lacking. Here, we quantify area loss for over 12 900 islands and over 3000 terrestrial vertebrates in the Pacific and Southeast Asia under three different SLR scenarios (1 m, 3 m and 6 m). We used very fine‐grained elevation information, which offered >100 times greater spatial detail than previous analyses and allowed us to evaluate thousands of hitherto not assessed small islands. Depending on the SLR scenario, we estimate that 15–62% of islands in our study region will be completely inundated and 19–24% will lose 50–99% of their area. Overall, we project that between 1% and 9% of the total island area in our study region may be lost. We find that Pacific species are 2–3 times more vulnerable than those in the Indomalayan or Australasian region and risk losing 4–22% of range area (1–6 m SLR). Species already listed as threatened by IUCN are particularly vulnerable compared with non‐threatened species. Under a simple area loss–species loss proportionality assumption, we estimate that 37 island group endemic species in this region risk complete inundation of their current global distribution in the 1 m SLR scenario that is widely anticipated for this century (and 118 species under 3 m SLR). Our analysis provides a first, broad‐scale estimate of the potential consequences of SLR for island biodiversity and our findings confirm that islands are extremely vulnerable to sea‐level rise even within this century.     

Sediment‐phosphorus dynamics can shift aquatic ecology and cause downstream legacy effects after wildfire in large river systems

Global increases in the occurrence of large, severe wildfires in forested watersheds threaten drinking water supplies and aquatic ecology. Wildfire effects on water quality, particularly nutrient levels and forms, can be significant. The longevity and downstream propagation of these effects as well as the geochemical mechanisms regulating them remain largely undocumented at larger river basin scales. Here, phosphorus (P) speciation and sorption behavior of suspended sediment were examined in two river basins impacted by a severe wildfire in southern Alberta, Canada. Fine‐grained suspended sediments (<125 μm) were sampled continuously during ice‐free conditions over a two‐year period (2009–2010), 6 and 7 years after the wildfire. Suspended sediment samples were collected from upstream reference (unburned) river reaches, multiple tributaries within the burned areas, and from reaches downstream of the burned areas, in the Crowsnest and Castle River basins. Total particulate phosphorus (TPP) and particulate phosphorus forms (nonapatite inorganic P, apatite P, organic P), and the equilibrium phosphorus concentration (EPC₀) of suspended sediment were assessed. Concentrations of TPP and the EPC₀ were significantly higher downstream of wildfire‐impacted areas compared to reference (unburned) upstream river reaches. Sediments from the burned tributary inputs contained higher levels of bioavailable particulate P (NAIP) – these effects were also observed downstream at larger river basin scales. The release of bioavailable P from postfire, P‐enriched fine sediment is a key mechanism causing these effects in gravel‐bed rivers at larger basin scales. Wildfire‐associated increases in NAIP and the EPC₀ persisted 6 and 7 years after wildfire. Accordingly, this work demonstrated that fine sediment in gravel‐bed rivers is a significant, long‐term source of in‐stream bioavailable P that contributes to a legacy of wildfire impacts on downstream water quality, aquatic ecology, and drinking water treatability.     

Eelgrass,Zostera marina,as essential fish habitat for young‐of‐the‐year winter flounder,Pseudopleuronectes americanus (Walbaum, 1792) in Maine estuaries

Distribution and density by habitat for age‐0, young‐of‐the‐year (YOY) winter flounder, Pseudopleuronectes americanus (Walbaum, 1792), were compared for two Maine estuaries to help define essential fish habitat for this life history stage. Two estuaries (Weskeag River and Penobscot Bay) along Mid‐coast Maine were sampled monthly with daytime 1.0 m² fixed‐frame throw traps around neap low tide, May–December over two consecutive years (2003–2004). Both eelgrass and adjacent sand/mud (20–60 cm deep) were randomly sampled with equal effort (4–12 samples per month) at two sites in both the Weskeag River and Penobscot Bay. Significantly higher densities of YOY winter flounder (2–9 cm TL) occurred in eelgrass relative to sand/mud. Density increased significantly in both habitats in 2004, and was higher in Penobscot Bay relative to the Weskeag River. YOY densities compared by eelgrass coverage within throw traps were found to be significantly higher in eelgrass that exceeded 30% coverage when compared with adjacent sand/mud areas and eelgrass coverage of 10–20%. YOY occurred in all months sampled (May–December); no density differences existed by month. These results indicate that very shallow (<0.6 m) eelgrass habitat is of key importance to YOY winter flounder in Maine estuaries and should be viewed as essential fish habitat (EFH) for this species and life stage.     

Palaeoenvironment and taphonomy of a Late Jurassic (Late Tithonian) Lagerstätte from central Poland

A rich assemblage of exceptionally preserved marine and terrestrial fossils occurs in fine‐grained limestones in the upper part of the Late Tithonian (Middle Volgian) shallowing upward carbonate sequence in Central Poland. The richest horizon, a deposit known locally as the Corbulomima horizon, is named after the shallow burrowing suspension feeding bivalve Corbulomima obscura, moulds of which occur in densities of up to 500 per square metre on some bedding planes. The fauna in this bed also includes organic and phosphatic remains of a wide range of other creatures including the exuviae of limulids and decapods, disarticulated fish skeletons and rare isolated pterosaur bones and teeth. There are also perfectly preserved dragonfly wings and beetle exoskeletons. The average stable carbon and oxygen isotope values for ostracod shells and fine‐grained sediment from this horizon suggest precipitation of the calcium carbonate from warm seawater of normal marine salinity. The carbonate sediments overlying the fossiliferous horizon have been interpreted as nearshore to shoreface facies. These pass abruptly into coarse reworked intraclastic sediments interpreted as possible tsunami or storm surge over‐wash deposits. The clasts in this deposit have more positive oxygen isotope values than those in the underlying limestone, which may indicate that they were lithified in a slightly more evaporative, perhaps intertidal, setting. The succession terminates with silicified fine‐grained limestones likely to have formed in extremely shallow lagoonal environments. In contrast with the Solnhofen limestones of Lower Tithonian age in south‐central Germany the Corbulomima horizon is interpreted as a transitional deposit formed in a shallow marine setting by rapid burial with elements of both Konservat‐ and Konzentrat‐Lagerstätte preservation. □Konzentrat and Konservat‐Lagerstätte, Taphonomy, Palaeoenvironment, Paleogeography, Late Jurassic, Poland.     

Land reclamation as a cause of fine-grained sediment depletion in backbarrier tidal flats (Southern North Sea)

Grain size distribution patterns along the East Frisian coast (German Wadden Sea) were evafuated with the aim of identifying potential effects of man-made structures (e.g. dikes) on the textural composition and sediment budget of the area. It was found that the distribution of various grain size fractions and settling velocities revealed a well-defined cross-shore energy gradient. Adjacent to the mainland dike the sediment is dominated by the 3.0–3.5 phi sand fraction (>70% by weight). In comparison to the sedimentary sequences normally observed in unobstructed backbarrier depositional environments, the sediments along the land-ward margin are in this case conspicuously depleted in grain sizes <3.5 phi, the corresponding size fractions contributing <20% by weight. This suggests that the dike interrupts the normal energy gradient, thereby inhibiting the deposition of sediments with settling velocities <0.5 cm s⁻¹. This interpretation is confirmed when comparing individual cross-shore transects. The shorter the transect between the barrier island shore and the dike, the greater the fine sediment depletion. Since many faunal assemblages are grain-size specific, it is further suggested that the backbarrier ecosystem must have undergone significant modifications as a result of the substantial reduction in mud flats since the onset of dike construction some 1000 years BP. It is predicted that in the wake of the persisting and possibly accelerating sealevel rise this process of fine sediment depletion will continue and also affect progressively coarser sediments.     

Detectability and visibility biases associated with using a consumer‐grade unmanned aircraft to survey nesting colonial waterbirds

Surveys of colonial‐nesting waterbirds are needed to assess population trends and gain insight into the health of wetland ecosystems. Use of unmanned aerial systems (UAS) for such surveys has increased over the past decade, but possible sources of bias in surveys conducted with UAS have not been examined. We examined possible visibility biases associated with using a UAS to survey waterbird colonies in cypress‐tupelo watersheds and coastal island habitats in Texas in 2016. We used known numbers of four waterbird decoy types, including Black Skimmers (Rynchops niger), terns, and white‐ and dark‐plumaged herons, to estimate their detectability in each habitat. Six observers independently counted decoys from aerial imagery mosaics taken with a consumer‐grade, off‐the‐shelf quadcopter drone. We used generalized linear mixed‐effects models to estimate detection probabilities of each decoy type. Black Skimmers at the coastal island had a detection probability of just 53%. Detectability of both white‐ and dark‐plumaged herons was lower in the canopied cypress‐tupelo habitat than the coastal island. In addition, cloud cover > 50% further reduced detectability of white heron decoys in cypress‐tupelo habitat. Use of the double‐count method yielded biased‐low abundance estimates for white‐ and dark‐plumaged herons in canopied sites, suggesting that habitat differences were a greater source of bias than observer error. Black Skimmers were the only decoy type to be imperfectly detected at the coastal island, a surprising result given the stark contrast of their plumage with their sand and shell nesting substrate. Our results indicate that UAS‐derived photographic surveys are prone to low detection probabilities at sites where vegetation occludes nests. In habitats without canopy, however, UAS surveys show promise for obtaining accurate counts of terns, white herons, and dark herons.     

Palaeontological and sedimentological effects of micro‐bioherms in the Middle Silurian Massie Formation of southeastern Indiana,USA

Small build‐ups composed primarily of micrite and benthic skeletal remains, termed ‘micro‐bioherms’, have been recognized within Silurian strata of eastern and midcontinental United States for well over 75 years; however, previous research has focused nearly entirely on such structures within the upper Wenlock (Homerian) Waldron Shale. An undolomitized section of the lower Wenlock (Sheinwoodian) Massie Formation in Ripley County, southeastern Indiana, was studied to assess the influence of micro‐bioherms on palaeoecological, taphonomical and sedimentological patterns. Increased baffling of fine‐grained material by organisms composing and/or encrusting build‐ups is evidenced by muddy sediment containing pascichnial traces surrounding micro‐bioherms. Pelmatozoan attachment structures densely encrust micro‐bioherms, but are swollen by secondary stereomic overgrowths reflecting some form of antagonistic interaction or investment in strong affixation to elevated substrates. Clusters of bumastine trilobite material occur in ‘pockets’ related to cavities within build‐ups, and otherwise rare spathacalymenid trilobites, often exceptionally preserved, are found in muds in the vicinity of partially buried micro‐bioherms. Coeval sections nearby are nearly unfossiliferous as result of dolomitization, but contain recognizable skeletal material in greatest abundance in micro‐bioherm flank beds. The occurrence of these bodies within the Massie Formation is genetically linked to a major transgressive episode, but also reflects a mid‐Silurian climatic/palaeoceanographic change.     

Connectivity in coastal systems: Barrier island vegetation influences upland migration in a changing climate

Due to their position at the land–sea interface, barrier islands are vulnerable to both oceanic and atmospheric climate change‐related drivers. In response to relative sea‐level rise, barrier islands tend to migrate landward via overwash processes which deposit sediment onto the backbarrier marsh, thus maintaining elevation above sea level. In this paper, we assess the importance of interior upland vegetation and sediment transport (from upland to marsh) on the movement of the marsh–upland boundary in a transgressive barrier system along the mid‐Atlantic Coast. We hypothesize that recent woody expansion is altering the rate of marsh to upland conversion. Using Landsat imagery over a 32 year time period (1984–2016), we quantify transitions between land cover (bare, grassland, woody vegetation, and marsh) and the marsh–upland boundary. We find that the Virginia Barrier Islands have both gains and losses in backbarrier marsh and upland, with 19% net loss from the system during the timeframe of the study and increased variance in marsh to upland conversion. This is consistent with recent work indicating a shift toward increasing rates of landward barrier island migration. Despite a net loss of upland area, macroclimatic winter warming resulted in 41% increase in woody vegetation in protected, low‐elevation areas, introducing new ecological scenarios that increase resistance to sediment movement from upland to marsh. Our analysis demonstrates how the interplay between elevation and interior island vegetative cover influences landward migration of the boundary between upland and marsh (a previously underappreciated indicator that an island is migrating), and thus, the importance of including ecological processes in the island interior into coastal modeling of barrier island migration and sediment movement across the barrier landscape.