Riparian evapotranspiration modelling: model description and implementation for predicting vegetation spatial distribution in semi‐arid environments

Abstract

Biotic and abiotic interactions between the riparian zone and the river determine relevant hydrological processes and exert control over riparian and bordering upland vegetation types. Vegetation growth and development are mainly controlled by water availability on semi-arid regions so the closeness to the river yields a moisture gradient which clearly determines the boundaries between exuberant riparian zone and semi-arid upland. A mathematical model named RibAV is presented. Its conceptualization is based on the main worldwide ecosystem modelling approaches and field expertise. The implementation of RibAV that is proposed in this paper allows the simulation of the vegetation functional types distribution in riparian zones. An evapotranspiration index (E idx ) obtained through RibAV is used as criterion for long-term plant absence/presence prediction. Two permanent river reaches of semi-arid Mediterranean basins, the Terde reach (Mijares River, Spain) and the Lorcha reach (Serpis River, Spain), have been selected as case studies for the evaluation of the model performance. Several criteria based on the confusion matrix were used to analyze the efficiency of RibAV on the prediction of plant distribution. The model outstanding performance to establish riparian vegetation types distribution and the limit between this zone and the bordering upland is demonstrated in this paper; the strength of the E idx to classify plant functional types in riparian semi-arid environments is additionally proved. This is a pre-copyedited, author-produced PDF version following peer review of the article: García-Arias A., Francés F., Morales-de la Cruz M., Real J., Vallés-Morán F., Martínez-Capel F., Garófano-Gómez V. 2014. Riparian evapotranspiration modelling: model description and implementation for predicting vegetation spatial distribution in semi-arid environments. Ecohydrology, 7: 659-677.

Riparian evapotranspiration shapes stream flow dynamics and water budgets in a Mediterranean catchment

“…The small effect predicted by the model was likely because warming also induced higher ET from upland forests (4 ± 11%). However, our hydrological model does not account for changes in vegetation community induced by warming, a phenomenon that is expected to occur in areas experiencing increases in water stress 385 (Benito-Garzón et al, 2008;García-Arias et al, 2014;Peñuelas andBoada, 2003, Walther et al, 2002).…”

The RVDM: modelling impacts, evolution and competition processes to determine riparian vegetation dynamics

“…Through a daily time step and a fine spatial resolution [usually between 0.5 and 2 m as explained in García‐Arias et al . ()], this distributed model allows analysing in detail the vegetation dynamics in riverine areas of semi‐arid environments. The cell size has to be a compromise between the vegetation patch and elevation spatial variabilities.…”

“…In riparian areas, it is also important to consider the accessibility to the water table and the plant capacities to use the water from the saturated zone of the soil. Taking this into account, through balance equations similar to those used in the riparian evapotranspiration model (RibAV) (García‐Arias et al ., ), the capillary water in the upper soil at the end of the day ( H ) and the actual transpiration ( T ) can be estimated. Comparing the daily values of these two variables with several vegetation parameters, the RVDM modules establish the changes on the SPFTs and biomass state variables.…”

Floodplain forest succession reveals fluvial processes: A hydrogeomorphic model for temperate riparian woodlands

“…Conversely, flood events remove vegetation through erosive scour (Bendix, 1999;Bendix and Hupp, 2000;Asaeda and Rashid, 2012). River flows recharge alluvial groundwater, especially in semi-arid climates, thus avoiding drought-induced mortality (García-Arias et al, 2013a). However, extended inundation produces root anoxia and mortality (Glenz et al, 2006).…”