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Abstract:
Non-vascular vegetation has been shown to capture considerable quantities of rainfall, which may affect the hydrological cycle
and climate at continental scales. However, direct measurements of rainfall interception by non-vascular vegetation are confined
to the local scale, which makes extrapolation to the global effects difficult. Here we use a process-based numerical simulation
model to show that non-vascular vegetation contributes substantially to global rainfall interception. Inferred average
global water storage capacity including non-vascular vegetation was 2.7 mm, which is consistent with field observations and
markedly exceeds the values used in land surface models, which average around 0.4 mm. Consequently, we find that the total
evaporation of free water from the forest canopy and soil surface increases by 61% when non-vascular vegetation is included,
resulting in a global rainfall interception flux that is 22% of the terrestrial evaporative flux (compared with only 12% for simulations
where interception excludes non-vascular vegetation). We thus conclude that non-vascular vegetation is likely to significantly
influence global rainfall interception and evaporation with consequences for regional- to continental-scale hydrologic
cycling and climate.
