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Matching ecohydrological processes and scales of banded vegetation patterns in semi-arid catchments

Matching ecohydrological processes and scales of banded vegetation patterns in semi-arid catchments
Matching ecohydrological processes and scales of banded vegetation patterns in semi-arid catchments
While the claim that water-carbon interactions result in spatially coherent vegetation patterning is rarely disputed in many arid and semi-arid regions, the significance of the detailed water pathways and other high frequency variability remain an open question. How the short temporal scale meteorological fluctuations form the long term spatial variability of available soil water in complex terrains due to the various hydrological, land surface and vegetation dynamic feedbacks, frames the scope of the work here. Knowledge of the detailed mechanistic feedbacks between soil, plants and the atmosphere will lead to advances in our understanding of plant water availability in arid and semi-arid ecosystems and will provide insights for future model development concerning vegetation pattern formation. In this study, quantitative estimates of water fluxes and vegetation productivity are provided for a semi-arid ecosystem with established vegetation bands on hillslopes using numerical simulations. A state-of-the-science process based ecohydrological model is used, which resolves hydrological and plant physiological processes at the relevant space and time scales, for relatively small periods (e.g. decades) of mature ecosystems (i.e. spatially static vegetation distribution). To unfold the mechanisms that shape the spatial distribution of soil moisture, plant productivity and the relevant surface/subsurface and atmospheric water fluxes, idealized hillslope numerical experiments are constructed, where the effects of soil-type, slope steepness and overland flow accumulation area are quantified. Those mechanisms are also simulated in the presence of complex topography features on landscapes. The main results are: (a) Short temporal scale meteorological variability and accurate representation of the scales at which each ecohydrological process operates are crucial for the estimation of the spatial variability of soil water availability to the plant root zone; (b) Water fluxes such as evapotranspiration, infiltration, runoff-runon and subsurface soil water movement have a dynamic short temporal scale behavior that determines the long term spatial organization of plant soil water availability in ecosystems with established vegetation patterns; (c) Hypotheses concerning the hydrological responses that can lead to vegetation pattern formation have to accommodate realistic and physically based representations of the fast dynamics of key ecohydrological fluxes.
banded vegetation, ecohydrological modeling, hillslope processes, meterological temporal variability, semiarid
0043-1397
2259-2278
Paschalis, Athanasios
e7626e9f-172b-4da2-882c-bddb219f3fb6
Katul, Gabriel G.
5f0cb2ab-2d91-4cc4-9ac2-e5c2eaf928f9
Fatichi, Simone
2a12468d-8094-495b-922d-4d00aa0afb11
Manoli, Gabriele
c09c8710-d3d7-4db7-909d-96b6777eb520
Molnar, Peter
99f2d15c-5348-4c80-bb35-fb54c133862d
Paschalis, Athanasios
e7626e9f-172b-4da2-882c-bddb219f3fb6
Katul, Gabriel G.
5f0cb2ab-2d91-4cc4-9ac2-e5c2eaf928f9
Fatichi, Simone
2a12468d-8094-495b-922d-4d00aa0afb11
Manoli, Gabriele
c09c8710-d3d7-4db7-909d-96b6777eb520
Molnar, Peter
99f2d15c-5348-4c80-bb35-fb54c133862d

Paschalis, Athanasios, Katul, Gabriel G., Fatichi, Simone, Manoli, Gabriele and Molnar, Peter (2016) Matching ecohydrological processes and scales of banded vegetation patterns in semi-arid catchments. Water Resources Research, 52 (3), 2259-2278. (doi:10.1002/2015WR017679).

Record type: Article

Abstract

While the claim that water-carbon interactions result in spatially coherent vegetation patterning is rarely disputed in many arid and semi-arid regions, the significance of the detailed water pathways and other high frequency variability remain an open question. How the short temporal scale meteorological fluctuations form the long term spatial variability of available soil water in complex terrains due to the various hydrological, land surface and vegetation dynamic feedbacks, frames the scope of the work here. Knowledge of the detailed mechanistic feedbacks between soil, plants and the atmosphere will lead to advances in our understanding of plant water availability in arid and semi-arid ecosystems and will provide insights for future model development concerning vegetation pattern formation. In this study, quantitative estimates of water fluxes and vegetation productivity are provided for a semi-arid ecosystem with established vegetation bands on hillslopes using numerical simulations. A state-of-the-science process based ecohydrological model is used, which resolves hydrological and plant physiological processes at the relevant space and time scales, for relatively small periods (e.g. decades) of mature ecosystems (i.e. spatially static vegetation distribution). To unfold the mechanisms that shape the spatial distribution of soil moisture, plant productivity and the relevant surface/subsurface and atmospheric water fluxes, idealized hillslope numerical experiments are constructed, where the effects of soil-type, slope steepness and overland flow accumulation area are quantified. Those mechanisms are also simulated in the presence of complex topography features on landscapes. The main results are: (a) Short temporal scale meteorological variability and accurate representation of the scales at which each ecohydrological process operates are crucial for the estimation of the spatial variability of soil water availability to the plant root zone; (b) Water fluxes such as evapotranspiration, infiltration, runoff-runon and subsurface soil water movement have a dynamic short temporal scale behavior that determines the long term spatial organization of plant soil water availability in ecosystems with established vegetation patterns; (c) Hypotheses concerning the hydrological responses that can lead to vegetation pattern formation have to accommodate realistic and physically based representations of the fast dynamics of key ecohydrological fluxes.

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Accepted/In Press date: 21 February 2016
e-pub ahead of print date: 25 February 2016
Keywords: banded vegetation, ecohydrological modeling, hillslope processes, meterological temporal variability, semiarid
Organisations: Water & Environmental Engineering Group

Identifiers

Local EPrints ID: 388485
URI: https://eprints.soton.ac.uk/id/eprint/388485
ISSN: 0043-1397
PURE UUID: d802b29a-370b-404e-8603-420c7ea8d2f1
ORCID for Athanasios Paschalis: ORCID iD orcid.org/0000-0003-4833-9962

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Date deposited: 26 Feb 2016 14:02
Last modified: 02 Dec 2019 20:22

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Contributors

Author: Athanasios Paschalis ORCID iD
Author: Gabriel G. Katul
Author: Simone Fatichi
Author: Gabriele Manoli
Author: Peter Molnar

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