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Titel |
Treeline dynamics with climate change at the central Nepal Himalaya |
VerfasserIn |
N. P. Gaire, M. Koirala, D. R. Bhuju, H. P. Borgaonkar |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1814-9324
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Digitales Dokument |
URL |
Erschienen |
In: Climate of the Past ; 10, no. 4 ; Nr. 10, no. 4 (2014-07-04), S.1277-1290 |
Datensatznummer |
250117011
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Publikation (Nr.) |
copernicus.org/cp-10-1277-2014.pdf |
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Zusammenfassung |
Treeline shifting in tandem with climate change has widely been reported from
various parts of the world. In Nepal, several impacts of climate change on the
physical environment have been observed, but study on the biological impacts
is lacking. This dendrochronological study was carried out at the treeline in
the high mountain slope of Kalchuman Lake (3750–4003 m a.s.l.) area
of Manaslu Conservation Area in the central Nepal Himalaya to explore the
impact of climate change on the treeline dynamic. Two belt transect plots
(size: 20 m wide, > 250 m long) were laid which included treeline as well
as tree species limit. Ecological mapping of all individuals of dominant
trees Abies spectabilis and Betula utilis was done and
their tree cores were collected. Stand character and age distribution
revealed an occurrence of more matured B. utilis (max. age
198 years) compared to A. spectabilis (max. age
160 years). A. spectabilis contained an overwhelmingly high
population (89%) of younger plants (< 50 years) indicating its
high recruitment rate. Population age structure along the elevation gradient
revealed an upward shifting of A. spectabilis at the rate of
2.61 m year-1 since AD 1850. The upper distribution limit of
B. utilis was found to be stagnant in the past few decades. An increment
in plant density as well as upward shifting in the studied treeline ecotones
was observed. The temporal growth of A. spectabilis was correlated
negatively with the monthly mean and minimum temperature of June to September
of the current and previous year. The regeneration of
A. spectabilis, on the other hand, was positively correlated with
August precipitation and monthly maximum temperature of the month of the
current year. The growth and regeneration of A. spectabilis was more
sensitive to maximum and minimum temperature rather than average temperature.
The growth of the B. utilis was mainly limited by moisture stress
during the pre-monsoon season. As these two species presented species-specific
responses to climate change with differential pattern in regeneration
condition, much wider differences are anticipated in their population status
as climate continues to change throughout the century. |
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