Threshold Conditions for the Shift Between Vegetated and Barebed Rivers

Calvani, Giulio; Carbonari, Costanza; Solari, Luca

doi:10.1029/2021gl096393

Cited by 9 publications

(12 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this case, incision into aggraded surfaces limited the lateral migration of the channel and prevented a return to the pre‐invasion state (Reynolds et al, 2021). Recently, Calvani et al (2022) mathematically predicted a threshold velocity above which rivers switch between vegetated and bare‐bed conditions, which was tested in real systems.…”

Section: Discussionmentioning

confidence: 99%

“…Recently,Calvani et al (2022) mathematically predicted a threshold velocity above which rivers switch between vegetated and bare-bed conditions, which was tested in real systems.Awareness of the growth habits and traits of vegetation allows for prediction of how invasion may influence rivers currently undergoing, or likely to undergo, exotic species invasions or changes in vegetation dynamics from climate change, as was suggested by Calvani et al (2022) as well. Future efforts should couple measurements of plant traits and community structure with the additional physical parameters on the Green New Balance pendulum to test the efficacy of the model and add more nuance to it.…”

mentioning

confidence: 99%

See 1 more Smart Citation

A Green New Balance: Interactions among riparian vegetation plant traits and morphodynamics in alluvial rivers

Bywater‐Reyes

Diehl

Wilcox

et al. 2022

Earth Surf Processes Landf

View full text Add to dashboard Cite

The strength of interactions between plants and river processes is mediated by plant traits and fluvial conditions, including above-ground biomass, stem density and flexibility, channel and bed-material properties, and flow and sediment regimes. In many rivers, concurrent changes in (1) the composition of riparian vegetation communities as a result of exotic species invasion and (2) shifts in hydrology have altered physical and ecological conditions in a manner that has been mediated by feedbacks between vegetation and morphodynamic processes. We review how Tamarix, which has invaded many southwestern US waterways, and Populus species, woody pioneer trees that are native to the region, differentially affect hydraulics, sediment transport, and river morphology. We draw on flume, field, and modelling approaches spanning the individual seedling to river-corridor scales. In a flume study, we found that differences in the crown morphology, stem density, and flexibility of Tamarix compared to Populus influenced near-bed flow velocities in a manner that favoured aggradation associated with Tamarix. Similarly, at the patch and corridor scales, observations confirmed increased aggradation with increased vegetation density. Furthermore, longterm channel adjustments were different for Tamarix-versus Populus-dominated reaches, with faster and greater geomorphic adjustments for Tamarix. Collectively, our studies show how plant-trait differences between Tamarix and Populus, from individual seedlings to larger spatial and temporal scales, influence the co-adjustment of rivers and riparian plant communities. These findings provide a basis for predicting changes in alluvial riverine systems which we conceptualize as a Green New Balance model that considers how channels may adjust to changes in plant traits and community structure, in addition to alterations in flow and sediment supply. We offer suggestions regarding how the Green New Balance can be used in management and invasive species management.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

A Green New Balance: Interactions among riparian vegetation plant traits and morphodynamics in alluvial rivers

Bywater‐Reyes

Diehl

Wilcox

et al. 2022

Earth Surf Processes Landf

View full text Add to dashboard Cite

show abstract

“…Indeed, we decide not to include a sediment transport equation in the model in order to focus on the vegetation dynamics, with the aim of addressing the eco-morphodynamic problem in a further step. Finally, the non-erodible bed presents favourable condition for plant colonization [9], and at equilibrium it is covered by submerged aquatic vegetation with a uniform density. The set composed by the fluid mass density , the uniform depthaveraged flow velocity U * 0 and depth Y * 0 , the river width W * =2B * (with B * the half-width of the river), and the carrying capacity * m is used for the non-dimensionalization of the equations.…”

Section: Formulation Of the Problemmentioning

confidence: 99%

“…These rates mainly depend on ( 5) the vegetation species and on the hydraulic conditions. For a detailed analysis of these vegetation parameters and coefficients the reader is referred to Calvani et al [9] and Calvani et al [8].…”

Section: The Vegetation Dynamics Modelmentioning

confidence: 99%

“…Recently, Calvani et al [9], for a given vegetation species, formulated an analytical approach to define the threshold conditions between vegetated and sediment-covered river beds. In the case of Froude numbers below the critical value for removal of vegetation, Calvani et al [8] extended the approach by Bärenbold et al [3] and Crouzy et al [18] to mathematically disclose the mutual interactions between flow field and vegetation evolution through a linear stability analysis.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Explaining multiple patches of aquatic vegetation through linear stability analysis

2022

Self Cite

View full text Add to dashboard Cite

Aquatic vegetation is ubiquitous in lowland rivers, and it is typically present in the shape of spatial self-organized patches of biomass. In this work, we mathematically define the threshold conditions for the incipient formation of self-organized vegetated patterns in the shape of central or multiple row patches. The analysis is carried out through a linear stability analysis whereby the 2D eco-hydrodynamic model is linearized and the growth rate of small-scale perturbations is evaluated considering a basic state represented by an initially uniformly vegetated and straight channel having a certain aspect ratio and Froude number. Results illustrate that, for given vegetation properties, instability arises when both the Froude number and the aspect ratio are higher than a given threshold; in this case, self-organization occurs, and spatial patterns of patches will develop according to the wavelength associated to the maximum growth rate. Moreover, instability and self-organization take place when the undisturbed vegetation density is lower than upper bound; this suggests that densely vegetated channels, as in the case of rivers populated by invasive species, will not experience the formation of any spatial patterns.

show abstract

Plants and river morphodynamics: The emergence of fluvial biogeomorphology

Gurnell,

Bertoldi

2024

River Research & Apps

View full text Add to dashboard Cite

In this article, we track the evolution of fluvial biogeomorphology from the middle of the 20th century to the present. We consider the emergence of fluvial biogeomorphology as an interdisciplinary research area that integrates knowledge drawn primarily from fluvial geomorphology and plant ecology, but with inputs from hydrology and landscape ecology. We start by assembling evidence for the emergence of the field of fluvial biogeomorphology with a keyword search of the Web of Science and a detailed analysis of papers published in two scientific journals: a geomorphology journal—Earth Surface Processes and Landforms; a multidisciplinary river science journal—River Research and Applications. Based on this evidence, we identify three distinct time periods in the development of fluvial biogeomorphology: the ‘early years’ before 1990; the transitional decade of the 1990s; and the period of rapid expansion and diversification in themes, methods and investigation scales since 2000. Because the literature is vast, we can only summarize developments in each of these time periods, but we refer to recent in‐depth reviews and conceptual perspectives on relevant topics. Thus, rather than a full and deep review, we present an annotated bibliographic overview of the development of fluvial biogeomorphology, whereby the text describes broad trends but is supported by tables of citations that can deliver greater detail. We end with a brief consideration of likely future developments.

show abstract

Threshold Conditions for the Shift Between Vegetated and Barebed Rivers

Abstract: Formulations for the threshold conditions between vegetated and barebed channel are derived • Threshold conditions are mainly related to species-dependent characteristics • Submerged plants are more vulnerable to removal than emergent as relative emergence reduces the threshold value

Cited by 9 publications

References 35 publications

A Green New Balance: Interactions among riparian vegetation plant traits and morphodynamics in alluvial rivers

A Green New Balance: Interactions among riparian vegetation plant traits and morphodynamics in alluvial rivers

Explaining multiple patches of aquatic vegetation through linear stability analysis

Plants and river morphodynamics: The emergence of fluvial biogeomorphology

Contact Info

Product

Resources

About