Ecohydrological modelling of vegetation composition in semi-arid ecosystems with shallow saline groundwater systems

Soil salinity management is becoming increasingly urgent in view of a growing world population, demand in food production and increasing drought risk. Semi-arid soils are prone to salinization due to interactions with saline groundwater which also interacts with the vegetation distribution. Plant communities in those regions create heterogeneous, self-reinforcing spatial structures consisting of densely vegetated and less vegetated or bare patches. Vegetation influences groundwater recharge and salt dynamics and vice versa [1], hence it is necessary to meet the challenge of understanding salinity-vegetation interactions and determining stable system states. As an analogy, different patterns have been associated with changes of system states, which were warning signs of desertification [2]. Understanding and predicting these system changes can aid in adjusting land management measures to prevent catastrophic shifts. Groundwater-salt dynamics and the resulting vegetation response are not fully understood, and the role of salinity in interaction with vegetation dynamics and a changing climate has to be assessed. We present a modelling tool to analyze the influence of of environmental factors on vegetation pattern formation in semiarid ecosystems. This is an extension of an existing model [3] that bases pattern formation on increased infiltration under vegetated patches. Suitable parameterizations for the new extensions are demonstrated.