Abstract
Tropical montane cloud forests (TMCF) are recognized for their capacity
to maintain high dry-season baseflow, and a host of other, ecosystem
services. Despite their importance, they are endangered with a
multidirectional array of land use changes, including conversion to
pasture and crops such as coffee, while there are places where forest is
being recovered. However, little is known about the effects of this
complex dynamic on catchment hydrology. We investigated the effect of
land use on rainfall-runoff response in five neighboring headwater
micro-catchments in central Veracruz, Mexico, by comparing primary TMCF
(PF), young (20 yr-old) and intermediate (40 yr-old) naturally
regenerating TMCF (YF and IF, respectively), shaded coffee (SC), and an
intensively grazed pasture (IP). We used a 4-year record of
high-resolution rainfall and streamflow (10 min) data, collected from
2015 to 2019. These data were analyzed via hydrologic metrics and
statistical tests. Results showed no statistical difference in the
regulation capacity of high flows after 20 years of natural
regeneration, compared to the PF. In terms of baseflow sustenance, our
results suggested that PF and IF better promote this hydrological
service than the other land uses, although all the catchments showed
high mean annual low flows. SC exhibited a high capacity to modulate
peak flows comparable to that of PF, and an intermediate capacity to
sustain baseflow, suggesting that the integrated functioning of this
catchment was largely preserved. Finally, we found that 40 years of
pasture management can decrease the soil hydraulic properties in the
area, causing a fivefold increase in the peak discharge response, and a
much lower baseflow maintenance compared to PF.
Keywords: hydrological function, peak flow, baseflow, cloud forest, land
use change, deforestation, natural regeneration