Abstract
In tropical rainforests, large-scale deforestation is considered one of
the biggest threats to the environment. This threat has been shown to
contribute to a loss of biodiversity, carbon storage, and hydrological
services such as erosion control, streamflow regulation, and water
quality. Interception losses are a much higher proportion of the water
budget in areas such as moist tropical forests, where precipitation can
exceed 3000 mm per year. Given interception is higher in forests with
large canopy storage capacity than low stature vegetation, we aimed to
identify the relative differences in leaf wetness duration in Costa
Rican premontane forest and adjoining cropland. Biomass alone determines
maximum interception storage, but does not determine interception loss,
since storage can saturate with relatively small rain events. We aimed
to determine if leaf wetness duration (LWD) is positively correlated
with interception. Forest leaves stayed wet five times longer than the
crop fields, 487 ± 41 minutes compared to 94 ± 37 minutes. Within crop
species, papaya took twice the time to dry than taro and sweet potato
(137 ± 51 in contrast to 73 ± 23 minutes). Crop heights were well
correlated with dry-down rates (r2 = 0.98). These
results suggest the possibility of higher runoff and alteration of
rainfall recycling in the humid tropics, following tropical forest
conversion to cropland.