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| Titel |
Land use change effects on runoff generation in a humid tropical montane cloud forest region |
| VerfasserIn |
L. E. Muñoz-Villers, J. J. McDonnell |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 17, no. 9 ; Nr. 17, no. 9 (2013-09-16), S.3543-3560 |
| Datensatznummer |
250085931
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| Publikation (Nr.) |
 copernicus.org/hess-17-3543-2013.pdf |
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| Zusammenfassung |
| While tropical montane cloud forests (TMCF) provide critical hydrological
services to downstream regions throughout much of the humid tropics,
catchment hydrology and impacts associated with forest conversion in these
ecosystems remain poorly understood. Here, we compare the annual, seasonal
and event-scale streamflow patterns and runoff generation processes of three
neighbouring headwater catchments in central Veracruz (eastern Mexico) with
similar pedological and geological characteristics, but different land
cover: old-growth TMCF, 20 yr-old naturally regenerating TMCF and a
heavily grazed pasture. We used a 2 yr record of high resolution rainfall
and stream flow data (2008–2010) in combination with stable isotope and
chemical tracer data collected for a series of storms during a 6-week period
of increasing antecedent wetness (wetting-up cycle). Our results showed that
annual and seasonal streamflow patterns in the mature and secondary forest
were similar. In contrast, the pasture showed a 10% higher mean annual
streamflow, most likely because of a lower rainfall interception. During the
wetting-up cycle, storm runoff ratios increased at all three catchments
(from 11 to 54% for the mature forest, 7 to 52% for the secondary
forest and 3 to 59% for the pasture). With the increasing antecedent
wetness, hydrograph separation analysis showed progressive increases of
pre-event water contributions to total stormflow (from 35 to 99% in the
mature forest, 26 to 92% in the secondary forest and 64 to 97% in the
pasture). At all three sites, rainfall-runoff responses were dominated by
subsurface flow generation processes for the majority of storms. However,
for the largest and most intense storm (typically occurring once every 2 yr),
sampled under wet antecedent conditions, the event water
contribution in the pasture (34% on average) was much higher than in the
forests (5% on average), indicating that rainfall infiltration capacity
of the pasture was exceeded. This result suggests that despite the high
permeability of the volcanic soils and underlying substrate in this TMCF
environment, the conversion of forest to pasture may lead to important
changes in runoff generation processes during large and high intensity
storms. On the other hand, our results also showed that 20 yr of natural
regeneration may be enough to largely restore the original hydrological
conditions of this TMCF. |
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