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When Camille Parmesan and Gary
Yohe published evidence in 2003—
based on an analysis of more than
1,700 species—they demonstrated
that change was very real. Their
data showed that spring change
was indeed taking place earlier—by
an average of 2.3 days per decade.
Studies by other scientists in recent
years have supported their findings.
Many of the changes that take
place in plants are governed by
temperature, including growth
spurts; the appearance of leaves,
flowers, and fruit; and leaves dying
in fall. Most food chains start with
plants, so these changes affect
grazers and browsers, from rabbits
to deer, and pollinators, including
bees and butterflies. All of these
are at the bottom of the food chain
(primary consumers). If they
struggle to find food, those that prey
on them (secondary consumers) also
suffer from the absence of prey.Effects of climate change
A warmer Earth produces many
effects. In most cooler parts of the
world, the frost-free season is longerthan before, providing a longer
growing season for plants. As
some regions become drier and
some wetter, bouts of extremely
heavy rainfall and flooding have
become more common. Toxic algal
blooms in lakes are occurring more
frequently. Ice cover in polar regions
is also decreasing. All these changes
have affected and will continue to
affect animal and plant behavior.
Since 1993, the European
Environmental Agency (EEA) has
worked in earnest to pull together
data from thousands of studies—
dating back to at least 1943—to
create a picture of spring creep in
Europe. The EEA’s evidence shows
earlier dates for plants producing
pollen, frogs spawning, and birds
nesting. According to their data,
many insects whose life cycles
are governed by air temperature
(thermophilic insects, such as
butterflies and bark beetles) now
have a longer breeding season,
enabling them to produce extra
generations each year. For example,
some butterflies that previously had
two generations now have three.See also: Animal ecology 106–113 ■ Animal behavior 116–117 ■ The foundations of plant ecology 167 ■ Global warming
202–203 ■ Endangered habitats 236–239 ■ Halting climate change 316–321THE HUMAN FACTOR
The leaves of some oak species
turn red shortly before they fall in fall.
Comparing the date on which this
occurs from year to year can provide
evidence for climate change.Camille Parmesan Born in 1961, Professor Camille
Parmesan is an American
academic who has established
a reputation as one of the leading
climate change scientists. She
received her Ph.D. in biological
sciences from the University of
Texas at Austin in 1995 and her
early research concerned the
evolution of insect–plant
interactions. For the best part of
20 years, she has focused on
documenting the shifting
geographical ranges of butterflies
across North America and Europe,
linking these to climate change.
Parmesan has been a leadingfigure in the IPCC and her work
has won her many accolades
and has been cited in hundreds
of academic papers. She is
professor in Integrative Biology
at the University of Texas at
Austin and advises international
conservation bodies.Key works2003 “A globally coherent
fingerprint of climate change
impacts,” Nature
2015 “Plants and climate
change: complexities and
sur pr ises,” Annals of BotanyIn Spain, botanists studied data for
29 species of plants. They found
that in 2003, leaves first appeared
4.8 days earlier on average than
in 1943; flowers first bloomed
5.9 days earlier; trees produced
fruit 3.2 days earlier; and leaves
died 1.2 days later. In the UK, the ❯❯US_274-279_Spring_creep.indd 277 17/12/2018 14:34