Understanding ecosystem water dynamics with a new theoretical framework
A recent FORGENIUS-funded study introduces a novel framework for quantifying how ecosystems manage water by linking two key measures: water potential and water content.
Water potential measures the energy status of water in plants and is crucial for understanding processes like water movement, stomatal function, and even plant mortality. On the other hand, water content represents how much water is stored in vegetation. Connecting these two concepts is vital for predicting how ecosystems respond to environmental changes, particularly with advancements in remote sensing that can detect vegetation water content from space.
This study builds on a biophysical principle called pressure-volume (PV) relationships, commonly used to describe how plants store and use water. By scaling this concept up to ecosystems, the research explores how short-term changes in water availability and long-term structural changes in vegetation interact to influence water dynamics.
As a proof of concept, researchers measured water potential and water content in diverse ecosystems, including tropical rainforests, savannas, and temperate forests. They found that:
- Ecosystems with more biomass stored more water and had greater water "capacitance" (the ability to buffer water availability).
- Surprisingly, the relative capacity for plants to access this stored water did not systematically vary with biomass.
These insights reveal that understanding how water is distributed across plant tissues at the community level is essential for predicting ecosystem water dynamics.
This theoretical framework bridges the gap between small-scale plant water processes and larger-scale models that inform climate science. By linking on-the-ground measurements to remote sensing technologies, it opens exciting possibilities for monitoring and managing water in ecosystems around the world.
