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Titel |
Impacts of forest changes on hydrology: a case study of large watersheds in the upper reaches of Minjiang River watershed in China |
VerfasserIn |
X. Cui, S. Liu, X. Wei |
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 ; 16, no. 11 ; Nr. 16, no. 11 (2012-11-20), S.4279-4290 |
Datensatznummer |
250013574
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Publikation (Nr.) |
copernicus.org/hess-16-4279-2012.pdf |
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Zusammenfassung |
Quantifying the effects of forest changes on hydrology in large watersheds
is important for designing forest or land management and adaptation
strategies for watershed ecosystem sustainability. Minjiang River watershed,
located in the upper reach of the Yangtze River basin, plays a strategic role
in the environmental protection and economic and social well-being for both the
watershed and the entire Yangtze River basin. The watershed lies in the
transition zone from Sichuan Basin to Qinghai-Tibet Plateau with a size of
24 000 km2. Due to its strategic significance, severe historic
deforestation and high sensitivity to climate change, the watershed has long
been recognized as one of the highest priority watersheds in China for
scientific research and resource management. The purpose of this review
paper is to provide a state-of-the-art summary on what we have learned from
several recently completed research programs (one of them known as "973 of
the China National Major Fundamental Science" from 2002 to 2008). This
summary paper focused on how land cover or forest change affected hydrology
at both forest stand and watershed scales in this large watershed. Inclusion
of two different spatial scales is useful, because the results from a small
spatial scale (e.g. forest stand level) can help interpret the findings on
a large spatial scale. Our review suggests that historic forest harvesting
or land cover change has caused significant water yield increase due to
reduction of forest canopy interception and evapotranspiration caused by
removal of forest vegetation on both spatial scales. The impact magnitude
caused by forest harvesting indicates that the hydrological effects of
forest or land cover changes can be as important as those caused by climate
change, while the opposite impact directions suggest their offsetting
effects on water yield in the Minjiang River watershed. In addition,
different types of forests have different magnitudes of evapotranspiration
(ET), with the lowest in old-growth natural coniferous forests (Abies faxoniana Rehd. et Wils.)
and the highest in coniferous plantations (e.g. Picea asperata Mast.) among major
forest types in the study watershed. This suggests that selection of
different types of forests can have an important role in ET and consequently
water yield. Our synthesis indicates that future reforestation and climate
change would likely produce the hydrological effects in the same direction
and thus place double the pressure on water resource as both key drivers
may lead to water yield reduction. The findings can support designing
management strategies for protection of watershed ecological functions in
the context of future land cover and climate changes. |
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