Biophysical Feedbacks Research Articles

Elevated urban energy risks due to climate-driven biophysical feedbacks

Elevated urban energy risks due to climate-driven biophysical feedbacks

Phenological control of vegetation biophysical feedbacks to the regional climate

Phenological control of vegetation biophysical feedbacks to the regional climate

Examining the role of biophysical feedbacks on simulated temperature extremes during the Tinderbox Drought and Black Summer bushfires in southeast Australia

The Tinderbox Drought (2017–2019) was one of the most severe droughts recorded in Australia. The extreme summer air temperatures (>40 °C) combined with drought, contributed to the unprecedented Black Summer bushfires in 2019–20 over southeast Australia. Whilst the temperature extremes were largely driven by synoptic processes, it is important to understand to what extent interactions between land and atmosphere played a role. In this study, we use the WRF-LIS-CABLE land-atmosphere coupled model to examine the impacts of changes in leaf area index (LAI) and albedo by contrasting simulations with climatological and time-varying LAI and albedo. We analyse the impact of these biophysical feedbacks on temperature extremes and fire risk during the Tinderbox Drought and the Black Summer bushfires. Remote-sensing data showed a decrease in LAI (0.1–4.0 m2 m−2) over the three years of the drought along the southeast coast of Australia relative to the long-term climatology, while albedo increased inland (0.02–0.14). These changes in LAI and albedo were accompanied by an overall decrease in daily maximum temperature (Tmax) in the vast majority of interior regions (by ∼0.5 °C) and, in the 2019–20 summer, by a clear increase in Tmax in the coastal regions of up to ∼1 °C. Increased albedo explained most of the decreases in Tmax inland, whereas increases in Tmax along the coasts were mostly associated with LAI declines. The magnitude of the impact of biophysical changes on temperature demonstrates the potential impact that would be missed in simulations that assumed fixed vegetation properties. Finally, we only found a small impact from LAI and albedo changes on the fire risk (as measured by the fuel moisture index) preceding the Black Summer bushfires, suggesting these biophysical feedbacks did not significantly modulate fire risk. Our results have implications for coupled simulations relying on climatological LAI and albedo, including operation weather and seasonal climate predictions.

Foredune initiation and early development through biophysical interactions

Coastal dunes result from complex interactions between sand transport, topography and vegetation. However, uncertainty still persists due to limited quantitative analyses, integrating plant distribution and morphologic changes. This study aims to assess the initiation and maintenance of feedback processes by analysing the early development stages of incipient foredunes, combining data on the evolution of the plant cover and communities and dune morphology. Over three years, the monitoring of a newly formed dune (1 ha plot) reveals the progressive plant colonisation and the episodic accumulation of sand around vegetated areas controlled by sediment availability. Distinct colonisation rates were observed, influenced by inherited marine conditions, namely topography and presence of beach wrack. Berm-ridges provided elevations above the critical threshold for plant colonisation and surface roughness, aiding sediment accumulation. Beach wrack above this threshold led to rapid expansion and higher plant concentration. In the initial stages, vegetation cover significantly influenced sediment accumulation patterns, with higher accumulation around areas with high plant cover and low slopes or around areas with sparse vegetation but milder slopes. As the dune system matured and complexity grew, the link between vegetation cover and accumulation became nonlinear. Mid to low coverages (5–30 %) retained most of the observed accumulation, especially when coupled with steep slopes, resulting from positive feedbacks between vegetation, topography and sand transport. As foredune developed, vegetation cover and diversity increased while inherited morphologies grew vertically, explaining the emergence of dune ridge morphological types. Flat surfaces lacking wrack materials experienced a three-year delay in colonisation and sand accumulation, leading to the formation of terrace-type incipient foredunes. These observations underline feedback processes during the early stages of dune formation, with physical feedbacks primarily driving initiation and biophysical feedbacks prevailing in subsequent colonisation stages.

Winter cover cropping increases albedo and latent heat flux in a Texas High Plains agroecosystem

AbstractWinter cover crops represent a land cover change that may sequester carbon in the soil and improve agricultural sustainability. Their adoption may also change the Earth's radiative balance and result in biophysical feedbacks to climate through alterations in albedo and latent heat fluxes. Understanding the mechanisms underlying these alterations to the radiative balance is important for making reliable future climate projections. However, data on cover crop biophysics are limited, requiring models to rely on data from summer plants for parameterization, likely biasing predictions. To address this gap, we measured the albedo and stomatal conductance of two summer crops and three winter crops on farms in the High Plains region of Texas. We also established a winter cover crop field experiment with two cover crops and fallow fields to estimate the change in albedo and latent heat flux that results from a switch to winter cover cropping. We found that albedo was significantly higher in winter‐like conditions than in summer‐like conditions due to an increase in plant albedo and a reduction in leaf area index. The albedo of winter cover crops was higher than the soil albedo, resulting in an increase in top‐of‐atmosphere reflected radiation of 7%–14% when converting from fallow fields to winter cover cropped fields. There was an additional cooling effect through doubling of the estimated latent heat flux caused by the presence of cover crops. The combined changes in albedo and latent heat resulted in a change in the surface energy balance that is associated with an overall cooling effect of winter cover crops on surface atmospheric temperatures. While this effect is likely to be region‐specific, these results strongly indicate that winter cover crops alter the surface albedo and latent heat flux of agricultural fields and provide a direct cooling effect in the High Plains region of Texas.

Observing coastal wetland transitions using national land cover products

Over the coming century, climate change and sea-level rise are predicted to cause widespread change to coastal wetlands. Estuarine vegetated wetlands can adapt to sea-level rise through both vertical development (i.e., biophysical feedbacks and sedimentation) and upslope/horizontal migration. Quantifying changes to estuarine vegetated wetlands over time can help to inform current and future decisions regarding land management and resource stewardship. In this study, we show how coastal land cover maps readily available in the US can be used to assess and understand estuarine vegetated wetland changes. This assessment involves two steps: (1) identifying the net gain/loss of estuarine vegetated wetlands and (2) determining which land cover types contribute to the net gain/loss. From this information, we developed estuarine vegetated wetland change scenarios that evaluate whether estuarine vegetated wetland gain kept up with loss and whether the contribution was from: (1) estuarine vegetated wetland migration or tidal restoration; (2) land building (i.e., development); or (3) both. We assessed changes from 1996 to 2016 for: (1) the conterminous US; (2) each major US coastline; and (3) focal estuaries with the most change per coast. We found that the change scenario (1, 2, or 3) varied across coastlines. Moving forward, national coastal land cover programs can be informed by utilizing methodologies that leverage contemporary information for delineating the estuarine zone from upslope/adjacent wetlands. We highlight approaches that could be used to address this challenge and provide complementary information related to wetland condition changes.

Discrepant trends in global land-surface and air temperatures controlled by vegetation biophysical feedbacks

Satellite-based land surface temperature (Ts) with continuous global coverage is increasingly used as a complementary measure for air temperature (Ta), yet whether they observe similar temporal trends remains unknown. Here, we systematically analyzed the trend of the difference between satellite-based Ts and station-based Ta (Ts–Ta) over 2003–2022. We found the global land warming rate inffered from Ts was on average 42.6% slower than that from Ta (Ts–Ta trend: −0.011 °C yr−1, p = 0.06) during daytime of summer. This slower Ts-based warming was attributed to recent Earth greening, which effectively cooled canopy surface through enhancing evapotranspiration and turbulent heat transfer. However, Ts showed faster warming than Ta during summer nighttime (0.015 °C yr−1, p < 0.01), winter daytime (0.0069 °C yr−1, p = 0.08) and winter nighttime (0.0042 °C yr−1, p = 0.16), when vegetation activity is limited by temperature and solar radiation. Our results indicate potential biases in assessments of atmospheric warming and the vegetation-air temperature feedbacks using satellite-observed surface temperature proxies.

Biophysical Effects of Land Cover Changes on Land Surface Temperature on the Sichuan Basin and Surrounding Regions

The biophysical effect of land cover changes (LCC) on local temperature is currently a hot topic. This work selects one of the nine agricultural divisions in China, the Sichuan Basin and surrounding regions, as the study area. By combining long-term series satellite remote sensing products with the space-and-time method, the spatial and temporal variations of the actual biophysical effects of LCC on land surface temperature (LST) are obtained. The results show that: (1) From 2001 to 2020, LCCs from Savannas to Cropland, from Cropland to Savannas, and from Savannas to Mixed Forest occurred frequently within the study area, and their area proportions of the total conversions are 21.7%, 18.5%, and 17.6%, respectively. (2) The biophysical feedback of LCC in the study area led to a LST increase of 0.01 ± 0.004 K at annual scale, which presents a seasonal pattern of “strong warming in summer and autumn yet weak cooling in winter”. It can exacerbate 14.3% or alleviate 8.3% of the background climate warming effect, illustrating the importance of biophysical effects on local climate change. The interaction between savannas and cropland or mixed forest and urbanizations formed the main driver for the above patterns. (3) Both the occurrence area of LCC and the warming effects at annual or seasonal scale show a trend of “first rising and then declining”, whereas the cooling effect in winter exhibits continuous enhancement over time. The monodirectional or mutual conversion between cropland and savannas is the dominant conversion responsible for these temporal patterns. The findings can provide realistic scientific guidance for informing rational policies on land management and targeted strategies for climate change response in the study area.

Macromolecular condensation buffers intracellular water potential

Optimum protein function and biochemical activity critically depends on water availability because solvent thermodynamics drive protein folding and macromolecular interactions1. Reciprocally, macromolecules restrict the movement of ‘structured’ water molecules within their hydration layers, reducing the available ‘free’ bulk solvent and therefore the total thermodynamic potential energy of water, or water potential. Here, within concentrated macromolecular solutions such as the cytosol, we found that modest changes in temperature greatly affect the water potential, and are counteracted by opposing changes in osmotic strength. This duality of temperature and osmotic strength enables simple manipulations of solvent thermodynamics to prevent cell death after extreme cold or heat shock. Physiologically, cells must sustain their activity against fluctuating temperature, pressure and osmotic strength, which impact water availability within seconds. Yet, established mechanisms of water homeostasis act over much slower timescales2,3; we therefore postulated the existence of a rapid compensatory response. We find that this function is performed by water potential-driven changes in macromolecular assembly, particularly biomolecular condensation of intrinsically disordered proteins. The formation and dissolution of biomolecular condensates liberates and captures free water, respectively, quickly counteracting thermal or osmotic perturbations of water potential, which is consequently robustly buffered in the cytoplasm. Our results indicate that biomolecular condensation constitutes an intrinsic biophysical feedback response that rapidly compensates for intracellular osmotic and thermal fluctuations. We suggest that preserving water availability within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function.

Enhanced Mid‐Holocene Vegetation Growth and Its Biophysical Feedbacks in China

AbstractProxy‐based reconstructions show that the climate during the mid‐Holocene (MH) was warmer and wetter than the present day in most regions of China, characterized by a northwestward extension of the East Asian summer monsoon and an increase in woody cover. However, climate simulations that neglect vegetation shifts yield cooler climates than proxy‐based reconstructions for the MH. Here, we simulate MH vegetation cover, productivity, and terrestrial parameters in China using a state‐of‐the‐art land surface model forced with realistic proxy‐based climate data. Our simulations corroborate MH vegetation cover inferred from 246 pollen sites, and indicate a higher vegetation productivity in China, despite the lower CO2 concentration during the MH compared to the present day. Enhanced vegetation growth during the MH could have affected land surface energy and hydrological budgets through biophysical feedbacks. Our findings highlight the impact of vegetation dynamics on the terrestrial carbon cycle and regional climate in China.

Biophysical Impact of Multiple Surface Forcings on Land Surface Temperature Over Eastern China

AbstractOver the past decades, human activities have directly or indirectly driven the land surface changes in eastern China. These anthropogenic forcings could trigger biochemical feedback and alter the surface biophysical properties, thus affecting local temperature. However, the latter is recognized as the “noise” and ignored when assessing historical or future climate. Here, we adopt the “observation minus reanalysis” (OMR) method to isolate the biophysical temperature footprint of multiple surface changes in eastern China over 2001–2018, using remote sensing land surface temperature and reanalysis skin temperature. A spatial regression model was used to separate the contributions from different processes. We find the biophysical feedbacks of surface changes have an annual cooling effect of −0.072 K/decade in eastern China, and the contributions from urban expansion, agricultural development, and natural vegetation greening are 0.042, −0.042, and −0.072 K/decade, correspondingly. The Northeast Plain shows agricultural activities induced cooling of −0.040 K/decade; the Loess Plateau shows natural vegetation recovery dominated cooling of −0.145 K/decade; the Huang‐Huai‐Hai Plain demonstrates a predominant urbanization warming effect of 0.124 K/decade; the Middle‐lower Yangtze shows natural vegetation greening related cooling of −0.106 K/decade. Both the intensity of the land surface changes and the temperature sensitivities drive the large spatial variability of the temperature effect. Overall, the temperature effects of surface changes are spatially heterogeneous and show considerable magnitudes. We emphasize that vegetation changes in eastern China show a strong surface cooling effect, and may contribute to the regional climate mitigation in the context of global warming.

Stochastic resonance in a single autapse–coupled neuron

The signal detection ability of nervous system is highly associated with nonlinear and collective behaviors in neuronal medium. Neuronal noise, which occurs as natural endogenous fluctuations in brain activity, is the most salient factor influencing this ability. Experimental and theoretical research suggests that noise is beneficial, not detrimental, for regular functioning of nervous system. In this regard, there is a general agreement that noise at an adequate intensity can engage rhythmic activity in brain and noise-induced oscillations enhances performance of the weak signal processing, especially when frequency of the signal is around that of the noise-induced rhythmic oscillation. This behavior in biological neural systems is explained by the notion of “stochastic resonance”. Another factor that plays a key role in regulating neuronal behaviors, including motor and cognitive tasks by maintaining signaling between cells, is characteristics of synapses different in structure and functioning. Here, we study stochastic resonance in Hodgkin–Huxley neuron that has a peculiar synaptic connection called autapse, known as a biophysical feedback mechanism, under presynaptic noise originating from superposition of inhibitory and excitatory Poisson bombardment. Our results show that, under certain conditions, autapse dynamics are able to improve the weak signal detection performance of Hodgkin–Huxley neuron via stochastic resonance. This study provides novel insights into functional role of autapse in neural information processing by revealing a biophysical aspect of stochastic resonance with numerical computations.

Widespread and complex drought effects on vegetation physiology inferred from space

The response of vegetation physiology to drought at large spatial scales is poorly understood due to a lack of direct observations. Here, we study vegetation drought responses related to photosynthesis, evaporation, and vegetation water content using remotely sensed data, and we isolate physiological responses using a machine learning technique. We find that vegetation functional decreases are largely driven by the downregulation of vegetation physiology such as stomatal conductance and light use efficiency, with the strongest downregulation in water-limited regions. Vegetation physiological decreases in wet regions also result in a discrepancy between functional and structural changes under severe drought. We find similar patterns of physiological drought response using simulations from a soil–plant–atmosphere continuum model coupled with a radiative transfer model. Observation-derived vegetation physiological responses to drought across space are mainly controlled by aridity and additionally modulated by abnormal hydro-meteorological conditions and vegetation types. Hence, isolating and quantifying vegetation physiological responses to drought enables a better understanding of ecosystem biogeochemical and biophysical feedback in modulating climate change.

Lagged feedback of peak season photosynthetic activities on local surface temperature in Inner Mongolia, China

Increased vegetation peak growth and phenological shifts toward spring have been observed in response to climate warming in the temperate regions. Such changes have the potential to modify warming by perturbing land‒atmosphere energy exchanges; however, the signs and magnitudes of biophysical feedback on surface temperature in different biomes are largely unknown. Here, we synthesized information from vegetation growth proxies, land surface temperature (LST), and surface energy balance factors (surface evapotranspiration (ET), albedo, and broadband emissivity (BBE)) to investigate the variations in timing (PPT) and productivity (PPmax) of seasonal peak photosynthesis and their time-lagged biophysical feedbacks to the post-season LST in Inner Mongolia (IM) during 2001–2020. We found that increased PPmax, rather than advanced PPT, exhibited a significant impact on LST, with divergent signs and magnitudes across diurnal periods and among different biomes. In the grassland biome, increased PPmax cooled both LST during daytime (LSTday) and nighttime (LSTnight) throughout the post-season period, with a more pronounced response during daytime and diminishing gradually from July to September. This cooling effect on LST was primarily attributed to enhanced ET, as evidenced by the greater effect of ET cooling than that of albedo warming and BBE cooling based on a structural equation model (SEM). In the forest biome, increased PPmax led to a symmetrical warming effect on LSTday and LSTnight, and none of the surface energy balance factors were identified as significant intermediate explanatory factors for the observed warming effect. Moreover, the responses of average LST (LSTmean) and diurnal temperature range of LST (LSTDTR) to variations in PPmax were consistent with those of LSTday at two biomes. The observations above elucidate the divergent feedback mechanisms of vegetation peak growth on LST among different biomes and diurnal cycles, which could facilitate the improvement of the realistic parameterization of surface processes in global climate models.

Photoperiod drives cessation of wood formation in northern conifers

AbstractAimsShifts in xylem phenology directly determine the forest capacity for carbon sequestration. However, a systematic understanding of the spatial patterns and the underpinning drivers in determining the cessation of wood formation (Ccw) is lacking at a pan‐continental scale. Here, we addressed this knowledge gap by compiling a new dataset of multiple xylem phenology timings for northern conifers.LocationsSixty‐two study sites, Northern Hemisphere (25–55° N).Time period2003–2018 (16 years).TaxaThirty‐three conifer species.MethodsA generalized additive model was fitted to characterize the latitudinal pattern in Ccw. Structural equation modelling and a linear mixed‐effects model were applied to determine the main drivers underlying the latitudinal pattern in Ccw.ResultsThe Ccw followed a flat S‐shaped pattern with increasing latitude. Photoperiod was the dominant determinant of the latitudinal pattern of Ccw, and a longer photoperiod was associated with an earlier Ccw. Both mean growing‐season temperature and total growing‐season precipitation exhibited significantly positive relationships to the cessation of cell elongation and thus the Ccw across all study sites. In arid regions, the pre‐growing‐season temperature had a significantly negative effect on Ccw. In humid regions, Ccw was positively affected by the mean growing‐season temperature. The onset of wood formation showed significantly positive coupling with Ccw at arid sites but not at humid sites. Early successional species were sensitive to hydrothermal variations during the pre‐growing season.Main conclusionsWe reveal the dominant role of photoperiod in determining the cessation of wood formation for northern conifers and highlight differentiated interactive effects between photoperiod and seasonal climatic factors and the preceding xylem phenophases in determining Ccw among ecoregions and tree species. These insights provide evidence to reduce uncertainty in prediction of the forest carbon uptake potential and the consequent biophysical feedbacks of northern forests.

Widespread spring phenology effects on drought recovery of Northern Hemisphere ecosystems

The time required for an ecosystem to recover from severe drought is a key component of ecological resilience. The phenology effects on drought recovery are, however, poorly understood. These effects centre on how phenology variations impact biophysical feedbacks, vegetation growth and, ultimately, recovery itself. Using multiple remotely sensed datasets, we found that more than half of ecosystems in mid- and high-latitudinal Northern Hemisphere failed to recover from extreme droughts within a single growing season. Earlier spring phenology in the drought year slowed drought recovery when extreme droughts occurred in mid-growing season. Delayed spring phenology in the subsequent year slowed drought recovery for all vegetation types (with importance of spring phenology ranging from 46% to 58%). The phenology effects on drought recovery were comparable to or larger than other well-known postdrought climatic factors. These results strongly suggest that the interactions between vegetation phenology and drought must be incorporated into Earth system models to accurately quantify ecosystem resilience.

Warming-Induced Growth Inhibition Weakens the Resilience of Low-Latitude Tidal Marshes to Sea-Level Rise

Sea-level rise (SLR) is expected to suppress the growth of tidal marshes due to prolonged inundation, but this can be compensated by increasing surface elevation with SLR. Warming-induced growth regulation could make it more complicated. We applied a spatially explicit individual-based model (IBM) with dynamic parameterization to predict the range expansion of Spartina alterniflora by 2100 over a low-latitude wetland, under one low-emission scenario (Shared Socioeconomic Pathway 1 [SSP1]: 0.28 m SLR and 0.55 °C warming) and one high-emission scenario (SSP5: 1.01 m and 3.55 °C). The results showed that (a) the simulations of an IBM with life-history-mediated biophysical feedbacks (IBM 1 ) better tracked the actual range expansion of S. alterniflora over 2014 to 2017 (90.1% accuracy) than that without the feedbacks (IBM 0 ) (83.0%); (b) under SSP1, most marshes were predicted to survive SLR by 2100 in both IBM 0 and IBM 1 , while, under SSP5, the marshes were predicted to disappear much more in IBM 0 (93.2% drowned) than IBM 1 (31.9%); and (c) warming-induced growth inhibition of S. alterniflora leads to exacerbated disappearance and even collapse of the marshes under SSP5 in IBM 1 . This study highlights the importance of life-history-mediated biophysical and physiological feedbacks in regulating the response of tidal marshes to climate change. Warming-induced growth inhibition weakens low-latitude tidal marsh resilience to SLR.

Biophysical impacts of vegetation dynamics largely contribute to climate mitigation in High Mountain Asia

Satellite-driven and site observational data show that global warming has greatly enhanced vegetation activity (greening), with a broad upward trend in vegetation indices (VIs). However, the biophysical impact of vegetation on land surface temperature (Ts) is widely unknown, particularly in High Mountain Asia (HMA). In this study, we assessed vegetation dynamics in HMA from 2000 to 2020 and used intrinsic biophysical mechanism (IBM) models to quantify the biophysical feedback effects of vegetation on Ts. The results illustrate that, during the study period, HMA has undergone greening at a rate of 0.505 × 10−3 W m−2 μm−1 sr−1 yr−1 (solar-induced chlorophyll fluorescence: SIF) and 1.7 × 10−3 yr−1 (normalized vegetation index: NDVI), accounting for 52.75% and 47.24% of the total number of pixels, respectively. However, vegetation browning has occurred in areas such as the central Tien Shan and southeastern Tibet. Meanwhile, 64.22% (SIF) and 53.68% (NDVI) of the vegetation area in HMA showed a negative sensitivity of Ts to vegetation activity, particularly herbaceous and scrub vegetation in Inner Tibet and eastern Kun Lun. Additionally, the Bovine ratio and aerodynamic drag (ra) exhibited a negative sensitivity to vegetation activity. Most importantly, the vegetation activity-induced temperature changes were -0.278 K (ΔTNDVICIBM), -0.538 K (ΔTSIFCIBM), 0.028 K (ΔTNDVISIBM), and 0.024 K (ΔTSIFSIBM). Moreover, in the sensitivity method (ΔTVegSIBM), vegetation cooling was detected in more than half of the pixels in HMA and was even more pronounced with SIF, accounting for 64.22% compared to 53.68% with NDVI. Enhanced vegetation activity alters the original balance of latent and sensible heat fluxes (Le,H) and increases the turbulent heat transfer between land and atmosphere, particularly Le. Our findings have important implications for understanding the response and feedback of vegetation dynamics to climate change in arid alpine regions.

Soil temperature mitigation due to vegetation biophysical feedbacks

Understanding the interactions between temperature regimes and vegetation cover is one of the key scientific topics in global environmental change and land surface process research. Recently, the prominent global greening trend has inspired considerable interest in examining climate feedbacks to vegetation changes. However, the impacts of recent widespread vegetation cover changes on soil temperature have been less documented and have received insufficient attention. Here, a high-resolution regional climate model was used to examine the potential impact of vegetation cover changes over the past 37 years, obtained as satellite observational data, on regional air and soil temperatures across the Heilong-Amur River Basin. Our sensitivity experiments indicated that the 1.85% increase in the regional fractional vegetation cover (FVC) from 1982 to 2018 cooled the air temperature by 0.045 °C and the soil temperature by 0.19 °C and that this cooling effect would continue in the near future, from 2016 to 2053. We found that soil temperatures were more sensitive to vegetation cover changes than air temperatures, particularly in mid-high latitude forests; this finding helps to explain the nonsignificant decrease in soil temperatures in forests over the past 40 years detected in the ERA5-Land reanalysis. Our results also suggest that vegetation restoration in forest ecosystems could mitigate the effects of climate change on permafrost environments by increasing the number of soil freezing days.

Sand supply and dune grass species density affect foredune shape along the US Central Atlantic Coast

AbstractCoastal foredunes form via biophysical feedbacks between sand accretion and burial‐tolerant vegetation and can protect coastlines from hazards such as extreme storms and sea level rise. Predicting how coastal dunes, and the services they provide, will change in the future requires an understanding of the relative roles of the physical and ecological processes that shape their structure and function. Here we assess the relative roles of sand supply, beach morphology, and vegetation in determining foredune morphology, and its change, along a 300‐km stretch of the US Central Atlantic coast. In particular, we used the spatial variability inherent in beaches and dunes of this region to determine the relative importance of shoreline change rate (SCR; a proxy for sand supply to the beach), beach morphology, and grass density of four widespread dune grasses (Uniola paniculata, Ammophila breviligulata, Panicum amarum, and Spartina patens) to foredune morphology metrics (height, width, and aspect ratio) along the North Carolina Outer Banks barrier islands. Foredune morphology and change metrics are correlated with three main factors: multidecadal SCR (1997–2016), beach slope, and dune grass density and species identity. Multidecadal SCR and beach width explained the most variation in, and were positively correlated with, foredune height and width, and were negatively correlated with foredune aspect ratio (height divided by width). In addition, grass density and changes in grass density contributed significantly to foredune morphology change. We found a positive relationship between change in A. breviligulata density and foredune width, which aligns with previous studies on the US Atlantic and Pacific Northwest coasts. Our results demonstrate the interactive roles of beach sand supply and dune grass functional morphology in dune building processes on highly vulnerable coastlines.