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Phenology
is generally described as the art of observing life cycle phases or
activities of plants and animals in their temporal occurrence throughout the
year (Lieth 1974). The onset of
phenological phases
is very closely related
to climate.
Thus,
global change
has
impacts
on phenology
and related
fields. In this context, phenology
has gained new importance
as a bio-indicator for
climate change or as a proxy for temperatures. The
value of phenology ranges from ground truth for satellites, education
and public awareness,
bio-indicator allowing
compelling observations of climate change impacts and their
cautious extrapolation,
to processes in vegetation-climate feedback.
Below, there
are some prominent examples out of my publications.
 | A
500 year pheno-climatological view on the 2003 heatwave in Europe
assessed by grape harvest dates -
In
2003, Europe was affected by a record-breaking heatwave in summer,
which is statistically extremely unlikely. However, there are
indications that comparably anomalous warm summers might have
occurred in the more distant historical past, for instance in
1540. Dates of grape harvesting in Western Europe, starting in
1484, allow a concise assessment of growing season temperatures.
The maturity of grapes strongly depends on growing season
temperatures, and 84% of the year-to-year variability is explained
by April to August temperature. When reconstructing the growing
season temperatures by these historical grape harvest dates, the
heatwave of 2003 stands out as an extreme, not only for the
instrumental period, but also during the preceding 500 years.
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after Menzel A, (in press)
A
500 year pheno-climatological view on the 2003 heatwave in Europe
assessed by grape harvest dates ( Meteorol Z) |
| Cherry flowering at the Royal Court at
Kyoto -
Phenology
has taken on a new importance since its value as one the oldest written biological record has been recognised. This
links the oldest records, observations of cherry flowering at the
Royal Court in Kyoto dating back to 705 AC, to the most recent Kyoto
Protocol efforts.
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after Menzel A, Dose V (2004) Analysis
of long-term time-series of beginning of flowering by Bayesian function
estimation (submittel to Meteorol Z) |
| Phenology as air temperature proxy -
In
temperate zones
the
timing of spring phenological phases is mainly regulated by temperature:
chilling temperatures break winter dormancy and subsequent warm
temperatures induce budburst.
Thus,
the phenological onset of spring correlates very well with air
temperature of the preceding months. In addition, the North Atlantic
Oscillation index has been shown to explain up to 50 % of the
interannual variability
of the length of the growing
season in
Germany.
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Ecological responses to recent climate change -Phenology
as the
timing of seasonal activities of animals and plants is perhaps the
simplest process in which to track changes in the ecology of species
in response to climate change.
Changes in the timing of spring
activities include earlier shooting and flowering of plants,
earlier
breeding or first singing of birds, earlier arrival of migrant birds,
earlier appearance of butterflies,
..
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after
WaltherGR, Post E,
Convey P, Menzel A, Parmesan C, Beebee TJC, Fromentin JM, Hoegh-Guldberg
O & Bairlein F (2002) Ecological responses to recent climate
change. Nature 416, 389-395. |
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