What does the term "potential ET" signify in desert ecosystems?

The term "potential ET," or potential evapotranspiration, refers to the maximum rate at which water could be lost from an ecosystem due to the processes of evaporation from the soil and transpiration from plants, under optimal conditions. In desert ecosystems, where water availability is limited, understanding potential ET is crucial for assessing how much moisture could theoretically be lost if water were not a limiting factor. It helps researchers and ecologists evaluate the water balance in these environments and how different plant species might adapt to high rates of potential water loss.

In contrast, actual measured water loss is often lower than potential ET due to limitations in water supply and environmental conditions. Average rainfall does not directly relate to potential ET as it indicates precipitation rather than evapotranspiration processes. Soil erosion relates to the physical loss of soil rather than the water loss through evaporation or transpiration, making it unrelated to the concept of potential ET.