River basin salinization as a form of aridity.

Area of Science:

• Hydrology
• Soil Science
• Ecology

Background:

• Soil salinization affects over one-third of global river basins, particularly arid, degraded, and climate-vulnerable systems.
• Salinization restricts plant water uptake and evapotranspiration, reducing soil moisture and fertility, similar to aridity.
• Long-term impacts of salinization on terrestrial water balance remain largely unquantified.

Purpose of the Study:

• To develop and apply a modified Budyko's framework that accounts for catchment-scale salinization and plant salt tolerance.
• To quantify the influence of salinization on hydrological partitioning and water availability in salt-affected watersheds.
• To assess the role of vegetation salt tolerance in regulating water budgets in these basins.

Main Methods:

• Introduction of a modified Budyko's framework incorporating catchment salinization and species-specific plant salt tolerance.
• Application of the framework to analyze water budget data from 237 Australian catchments using the Australian Water Availability Project (AWAP) data.
• Utilizing theoretical and experimental evidence to validate the framework's findings.

Main Results:

• Salinization significantly influences hydrological partitioning in salt-affected watersheds, constraining water availability and increasing aridity.
• The modified framework successfully estimates salinization levels and vegetation salt tolerance at the basin scale.
• Plant salt tolerance plays a crucial role in regulating vegetation feedback on soil water budgets in salt-affected basins.

Conclusions:

• Salinization is a significant factor altering hydrological processes and water availability in river basins.
• The developed framework offers a novel approach to assess salinization impacts and vegetation responses at the basin scale.
• Understanding plant salt tolerance is essential for managing water resources in salt-affected ecosystems.