Ecohydrology of Salt-Affected Ecosystems: From the Plant-hydraulics- to
the Catchment-scale
Abstract
Soil salinization represents one of the most widespread forms of land
degradation worldwide, posing an enormous threat to food security,
sustainable development, and ecosystem resilience across a wide range of
climatic, hydrological, and socio-economic conditions. Globally, it
already affects an area about the size of Continental United States
(circa 1.1 Gha) and is expected to further intensify in response to
climate change, sea-level rise (SLR), and increasing demand for crop
production. Salt-affected soils are prevalent in arid regions, which are
naturally prone to salt accumulation due to elevated evaporative demand
and low precipitation input. However, salinity also plays a crucial role
in regulating vegetation-climate interactions in highly carbon-intense
tidal ecosystems - now threatened by SLR and coastal salinization. This
contribution explores the hydrological controls of soil salinization
across a wide range of temporal and spatial scales - ranging from the
plant to the catchment scale. We focus, in particular, on how salinity
affects the bi-directional interaction between vegetation and climate in
both the dry land and tidal critical zone. Using both process-based
models and observations, we unveil the central role of plant-salt
tolerance in regulating soil-plant-atmosphere interactions and show how
salinity acts as an aridity enhancer, able to exert major controls on
vegetation-climate interactions in the critical zone.