the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 16 Jul 2026
Modelling dynamic coastal vegetation establishment and ecosystem engineering in hydro-morphodynamic models with DYCOVE
Abstract. Coastal areas are complex environments with diverse hydrodynamic, morphological, sedimentological, and biological contexts. Vegetation is increasingly recognized as a crucial agent that shapes the geomorphology and hydrology of coastal and riverine systems by inducing a hydraulic roughness that influences flow velocities, inundation, erosion, and deposition. At the same time, vegetation growth depends on the environmental habitat conditions, which it modifies continuously, resulting in a biophysical feedback-loop. This loop between plant growth and the physical environment is inherently dynamic, meaning they both vary spatiotemporally through their interactions; however, these dynamics are currently excluded from most hydro-morphodynamic models that predict long-term coastal change. We present the DYnamic COastal VEgetation model DYCOVE: an open-source, process-based vegetation model that simulates dynamic coastal marsh vegetation by representing key ecological processes such as seed dispersal, establishment criteria, growth curves, and mortality rules. Vegetation dynamics are governed by species-specific thresholds for inundation, desiccation, bed level change, and flow conditions while age-dependent stress tolerance enables realistic transitions from seedlings to mature plants of multiple species. Based on literature-derived parameterizations of ecological thresholds, DYCOVE reproduces realistic vegetation distributions and zonations both in tidally- and fluvially-impacted coastal environments with an F1 score above 0.8 and species distribution with a total accuracy of 70 %. DYCOVE’s flexible, species-agnostic framework allows exploration of how various vegetation types influence coastal hydrodynamics, sediment transport, and land-building, representing a crucial advancement in process-based eco-hydro(morpho)dynamic modelling.
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CEC1: 'Comment on egusphere-2026-3337 - No compliance with the policy of the journal', Juan Antonio Añel, 07 Aug 2026
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AC1: 'Reply on CEC1', Muriel Brückner, 17 Aug 2026
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Dear Dr. Años,
Thank you. We added all model files in the repository and added a reference with identifier to our code. See below our new Code and data availability statement and the two references:
The DYCOVE code used for this manuscript is archived at https://doi.org/10.5281/zenodo.20703854 (Tull and Brückner, 2026a). Development of DYCOVE is ongoing (https://github.com/Ecomomo-lab/dycove-model). The applied codes, model files and results, and other relevant files used for reproducibility are archived at https://doi.org/10.5281/zenodo.21905037 (Tull and Brückner, 2026b).
Tull, N. and Brückner, M. Z. M.: Ecomomo-lab/dycove-model: DYCOVE Version 0.2.0, Zenodo, https://doi.org/10.5281/ zenodo.21905037, 2026a.
Tull, N. and Brückner, M. Z. M.: Model files for "Modelling dynamic coastal vegetation establishment and ecosystem engineering in hydro-morphodynamic models with DYCOVE", Zenodo, https://doi.org/10.5281/zenodo.21905037, 2026b.
Citation: https://doi.org/10.5194/egusphere-2026-3337-AC1 -
CEC2: 'Reply on AC1', Juan Antonio Añel, 18 Aug 2026
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Dear authors,
Thanks for addressing this issue. I have checked the repositories and we can consider now the current version of your manuscript in compliance with the code policy of the journal.
Juan A. Añel
Geosci. Model Dev. Executive Editor
Citation: https://doi.org/10.5194/egusphere-2026-3337-CEC2
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CEC2: 'Reply on AC1', Juan Antonio Añel, 18 Aug 2026
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AC1: 'Reply on CEC1', Muriel Brückner, 17 Aug 2026
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RC1: 'Comment on egusphere-2026-3337', Anonymous Referee #1, 31 Oct 2026
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General comments
The manuscript presents DYCOVE, an open-source model developed to simulate dynamic coastal vegetation establishment, growth, and mortality, and its interactions with hydro-morphodynamic processes. The model incorporates species-specific ecological characteristics and is coupled with two existing numerical models, Delft3D Flexible Mesh and ANUGA. Its capabilities are illustrated through two applications: an idealized macrotidal flat inspired by the Western Scheldt Estuary and a microtidal, river-dominated environment in Wax Lake Delta.
The development of an open-source model capable of representing dynamic vegetation establishment in coastal environments is certainly of interest to the scientific community. However, I have substantial concerns regarding the completeness of the model description and, consequently, the manuscript's compliance with the journal's publication requirements.
The stated aim of the paper is to present the DYCOVE model (L59). I therefore assume that the manuscript falls under the “Model description papers” category of Geoscientific Model Development. According to the journal's manuscript-type guidelines: “The main paper should describe both the underlying scientific basis and purpose of the model and overview the numerical solutions employed. The scientific goal is reproducibility: ideally, the description should be sufficiently detailed to in principle allow for the re-implementation of the model by others, so all technical details which could substantially affect the numerical output should be described.”
Although the model code is made publicly available, I believe that the manuscript falls considerably short of these requirements. The description of the model is largely conceptual, while the mathematical formulation and numerical implementation of several fundamental processes are missing. In particular, the equations governing vegetation establishment, growth, and mortality, as well as the algorithms used to implement these processes, are not presented in sufficient detail. These elements are not provided in the Supplementary Information either.
Code availability is undoubtedly valuable, but it does not replace the need for a comprehensive and self-contained scientific description of the model. In its current form, the manuscript does not provide sufficient information to understand precisely how several processes are represented or, in principle, to reproduce the model implementation independently.
Even if the manuscript were intended to fall under a different category, such as “Development and technical papers”, I believe that too many fundamental elements of the model description are missing to meet the journal's requirements.
Addressing these shortcomings would require a substantial restructuring and expansion of the manuscript, rather than revisions to individual sections. In my opinion, the extent of the necessary changes goes beyond what can reasonably be accommodated within a standard revision process. For this reason, my recommendation is to reject the manuscript in its present form, while encouraging the authors to thoroughly revise and resubmit their work as a new submission.
Beyond this fundamental structural issue, I have identified two additional concerns that I believe should be considered when rethinking the manuscript.
- Representation of ecosystem engineering effects
As stated in the title and throughout the manuscript, DYCOVE is intended to represent not only vegetation establishment and dynamics but also the ecosystem engineering effects of coastal vegetation. However, from the model description, it appears that the effects of vegetation on hydro-morphodynamic processes are represented primarily through changes in hydraulic roughness (L208).
Several other important ecosystem engineering processes are not explicitly represented. These include, for example, sediment trapping by vegetation and, perhaps more importantly, the contribution of organic matter production and accumulation to vertical marsh accretion. The latter is particularly relevant because vegetation is completely removed from the model once its maximum lifespan is reached (L181), without an apparent representation of the contribution of dead biomass to soil formation.
These processes can play a fundamental role in the long-term morphological evolution of coastal wetlands. Their omission therefore raises questions about the extent to which the model can represent the broader ecosystem engineering effects claimed in the manuscript.
If the authors do not intend to incorporate these processes within the present framework, I believe that the scope and claims of the manuscript should be revised accordingly. In particular, “vegetation colonization and dynamics” would more accurately describe the model's primary contribution than the broader term “ecosystem engineering”.
- Representation of ecological processes and the definition of a process-based model
Several fundamental ecological processes are not explicitly incorporated into the model, including seed banks and rhizomatous growth (L465). Instead, their effects appear to be represented indirectly through simplified colonization rules.
While such simplifications may be entirely reasonable, depending on the intended applications, they raise questions about the extent to which DYCOVE can be described as a “process-based” vegetation model.
In my view, the authors should more clearly distinguish between processes that are explicitly represented and those whose effects are only parameterized or approximated through empirical rules.
There are two possible ways to address this issue. The first would be to explicitly incorporate the missing mechanisms into the model. Alternatively, if the authors intend to retain the current simplified formulation, I believe that the selection of the case studies should be reconsidered. In particular, applications involving species such as Nelumbo lutea and Colocasia esculenta, for which vegetative reproduction and rhizomatous growth can be important, may not be the most appropriate examples to demonstrate the model's process-based capabilities unless these limitations are carefully addressed.
Specific comments
Title
As discussed in the general comments, I believe that the reference to “ecosystem engineering” should be reconsidered unless the authors can demonstrate that the model represents a sufficiently broad range of the processes through which vegetation influences coastal morphology.
Introduction
L41: “Marshes can be highly dynamic … colonize new sediments.” This sentence sounds somewhat odd. I am not sure that the authors mean that marshes themselves colonize new sediments. Perhaps they are referring to vegetation colonizing newly deposited sediments. This interpretation would also be more consistent with the following sentence (“Their distribution…”). Please clarify the intended meaning.
L52: “Most coastal models”. This statement is too broad, as it also includes models developed to simulate the evolution of sandy beaches and other coastal environments where vegetation is not that relevant. I believe that the statement would be more appropriate if restricted to models of tidal environments or coastal wetlands. Moreover, I find the use of “assess” somewhat inappropriate in this context. Given the limited availability of long-term observations of vegetation dynamics, I believe that “simulate” or “describe” would better reflect the purpose of these models.
L63: “Sophisticated”. The Merriam-Webster dictionary defines “sophisticated” as “highly complicated”. I do not believe that Delft3D, ANUGA, or other hydro-morphodynamic models should be described in these terms. Although these models may appear complicated, their complexity is generally justified by the physical processes they are designed to represent. I suggest using a more neutral and technically appropriate term, such as “established” or “widely used”.
Methodology
As discussed in the general comments, the mathematical formulation and detailed description of the numerical algorithms are largely missing. The authors should provide the governing equations and explain how the different ecological processes are implemented, including the sequence of operations and the treatment of vegetation fractions during each ecological timestep. These details are essential for understanding and reproducing the model.
L103: “fractions approach” → “fraction approach”.
Results
L271: It should be explicitly stated that this comparison is qualitative. The Introduction appears to suggest that the model is also quantitatively validated against observations in this case, which is not supported by the comparison presented here. Please clarify this distinction and ensure consistency throughout the manuscript.
Figure 4b: In the legend, the specific epithets “Lutea” and “Esculenta” should be written in lowercase, following the conventions of scientific nomenclature (Nelumbo lutea and Colocasia esculenta). The same correction should be made in the corresponding figure in the Supplementary Information.
Discussion
L379: “well-documented”. Since one of the main objectives of this manuscript is precisely to present and document DYCOVE, describing the model as already “well-documented” seems inappropriate, particularly given the shortcomings discussed above. I suggest removing this expression.
L465–468: The information presented here concerns fundamental aspects of the model formulation and implementation. A detailed explanation should therefore be included in the Methodology section rather than introduced only in the Discussion.
Citation: https://doi.org/10.5194/egusphere-2026-3337-RC1
Model code and software
dycove-model Nelson Tull and Muriel Z. M. Brückner https://github.com/Ecomomo-lab/dycove-model/
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Dear authors,
Unfortunately, after checking your manuscript, it has come to our attention that it does not comply with our "Code and Data Policy".
https://www.geoscientific-model-development.net/policies/code_and_data_policy.html
You have archived your code on GitHub. However, GitHub is not a suitable repository for scientific publication. GitHub itself instructs authors to use other long-term archival and publishing alternatives, such as Zenodo. In addition, in your manuscript you do not provide a repository for the data used to validate the model's results, nor for the ANUGA model also used in your work.
The GMD review and publication process depends on reviewers and community commentators being able to access, during the discussion phase, the code and data on which a manuscript depends, and on ensuring the provenance of replicability of the published papers for years after their publication. Please, therefore, publish your code and data in one of the appropriate repositories and reply to this comment with the relevant information (link and a permanent identifier for it (e.g. DOI)) as soon as possible. We cannot have manuscripts under discussion that do not comply with our policy.
Later, if the Topical Editor decides to continue with the review or publication process of your manuscript and you are requested to upload a new version of it, then The 'Code and Data Availability’ section of your manuscript must also be modified to cite the new repository locations, and corresponding references added to the bibliography.
I must note that if you do not fix this problem, we cannot continue with the peer-review process or accept your manuscript for publication in GMD.
Juan A. Añel
Geosci. Model Dev. Executive Editor