Transcript + Evidence of Climate Change Glaciers, geographic ranges, flower bursts, migratory patterns, and mating seasons.

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Evidence of Climate
Change
Glaciers, geographic ranges, flower bursts,
migratory patterns, and mating seasons
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Global temperature change has
affected ecosystems in the past
and present
 “Bleaching” of
 Shift
reef building corals
of species geographic ranges
 Migratory
birds arrive earlier at their
summer breeding grounds
 Insects
 Not
and amphibians breed earlier
a new occurrence
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If climate change is real…
 So
are the problems
 Rate
of warming increasing greater than other
warming events in geologic time?
 Evolutionary adaptations for species survival may not
have time to occur
 Natural areas no longer cover the whole landscape
 Species that shift to higher altitudes may have
reached the peak of the mountain
 Species’ habitat disappears entirely
 Species disappear entirely
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Climate plays a major role in
defining the niche of all species
 Temperatures
too hot or too cold, too much
moisture or too little, all determine where
plants can grow and where animals can
survive.
 The
niche space in which species can
survive is determined in large part by
suitable climatic conditions.
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Species’ ranges shift over time to
track suitable climate.
 When
climate changes in a location, some
species may find themselves in suddenly
hostile conditions.
 Others
will find that previously unsuitable
climates have changed in their favor.
 Individuals
in unsuitable conditions will die or
fail to reproduce, gradually disappearing from
the location, whereas individuals near newly
suitable habitat will gradually occupy areas in
which they have not occurred previously.
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First Sign of Change: Coral
Bleaching
 Corals
harbor microscopic algae called
zooxanthellae within their tissues.
 Zooxanthellae
provide products of
photosynthesis to the coral, while the coral in
turn provides a physical reef structure that
keeps the zooxanthellae near the surface,
where light for photosynthesis is abundant.
 When
this symbiotic relationship breaks down
due to high water temperature, corals expel
their zooxanthellae, causing them to appear
white or “bleached.”
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Coral head in St. Croix bleached in
1995
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Bleaching is directly related to
temperature
 Bleaching
occurs when SST rises more than 1 or
2°C above normal summer maximal temperatures
for periods longer than 3–5 weeks.
 Thus, both
temperature and duration of exposure
are important determinants of whether bleaching
occurs and its severity once it happens.
 Coral
bleaching was undescribed in the scientific
literature 50 years ago, yet it is so common and
widespread today that almost all coral reefs in the
world have been affected at one time or another.
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Evidence of coral bleaching
 In
the central lagoon of Belize, staghorn coral
(Acropora cervicornis) was the dominant species
until the 1980s, when it was wiped out by a
combination of disease and rising water
temperatures. The scroll-like coral Agaricia
tenuifolia took over as the dominant coral, only to
be wiped out in the high water temperatures of the
1998 El Niño event.
 These
massive mortalities were the worst in at least
3000 years, resulting in range changes over large
areas of the Caribbean for staghorn and other
corals.
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Evidence of coral bleaching
 There
were seven major coral bleaching
events, affecting reefs in all areas of the world,
between 1979 and 2002.
 There
have been several pan-global mass
bleaching events since.
 All
of these events are associated with El Niño
conditions. The 1997–1998 El Niño was the
worst of the last century for coral bleaching. In
that event, reefs throughout the world were
affected.
 More
than 10% of all the world's corals died in
that event, with mortality in some regions, such
as the Indian Ocean, as high as 46%.
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A terrestrial sign of change:
Butterfly distribution
 Checkerspot
butterflies (genus Euphydras)
had been known to be vulnerable to
population crashes or booms due to weather
conditions for some time.
A
1996 study showed that Edith's checkerspot
butterfly (Euphydras editha) was undergoing a
major range shift. Populations of Edith's
checkerspot are found from Mexico to Canada,
and populations in the south and in the
lowlands were found to be disappearing faster
than populations in the north and in the
uplands.
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Butterflies & birds have moved
north in Europe
 In
Europe, a study of 35
butterfly species found that
63% had undergone
northward range shifts
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Only 3% had shifted
southward.
 Range
shifts were large—
between 35 and 240 km.
 Of
59 species of birds in
Great Britain, a mean
northward range shift of
nearly 20 km was observed
over 20 years.
Speckled wood butterfly
1970-1997: blue
1915-1939: black
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More shifts recorded in last 100
years in Europe
 Dragonflies
in Great Britain have expanded
northward; 23 of 24 well-documented species
haves hown a northward shift, with a mean shift of
88 km.
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A total of 77 lichen species have expanded their
ranges northward into The Netherlands.
 Alpine
plants have been moving upslope in Swiss
mountains.
 These
results are all for relatively well-known
species for which good historical records exist.
+ The number of documented cases of
invasions of non-native species is
rising steadily
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Shift seen in arctic animal ranges
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Reduction in algae in Antarctic and
phytoplankton in N Atlantic
 The
freshwater input to the North Atlantic
increased stratification in shelf waters off
Canada and Europe in the 1990s. When dense
waters of the Gulf Stream hit the lighter
freshwater, they were less likely to sink,
meaning that phytoplankton stayed closer to
the surface and photosynthesized more.
 The
rise in phytoplankton caused autumn
spikes in the zooplankton that fed on them and,
ultimately, increases in commercially valuable
species such as herring.
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Reduction in algae in Antarctic and
phytoplankton in N Atlantic
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Decline in the
abundance of algae that
grows on the underside
of the ice
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Resultant declines and
range retractions in krill
that feed on the algae

Populations of krillsupported fish, birds,
and mammals higher in
the food chain decrease
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Tree lines have shifted poleward
and upslope in wide variety of
settings and regions
 Upslope
migration of tree line is mediated
by a number of factors, which in many
instances has made it difficult to
demonstrate a tree line effect of climate
change alone.
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Evidence of range shifts from
several areas of the tropics
 In
the Monteverde cloud forest
of Costa Rica, toucans and
other birds are moving
upslope in synch with
warming.
 Mountaintop
amphibians at
Monteverde have declined or
disappeared.
 Butterflies
from North Africa
are expanding their ranges
into southern Europe.
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Phenologic changes are occurring
 Changes
 Bud
in timing of biological events
burst, flowering, arrival of migratory
birds, nesting patterns, length of growing
season are all timed events
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A six-century-long record of
cherry blossom in Japan indicates
earlier bloom during past 200 yrs.
 Timing
begins to advance at approximately the
same time that human fossil fuel use intensifies,
becoming statistically significant after 1900.
 The
rate of acceleration in advancement
increases after 1950, tracking the acceleration
in the use of fossil fuels in the latter half of the
previous century.
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By the end of the record, timing of the
Japanese cherry bloom was several days
earlier than at the start of the record in 1400.
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Similar patterns recorded in other
species, not just plants
 Lilac
& honeysuckle
 Ecologist
Aldo Leopold recorded spring events for
55 species during the 1930s and 1940s.
 When
these species were resampled in the 1990s,
33% showed earlier spring timing.
A
study of spring vocalization in six frog species
from the early 1900s was compared with similar
measurements taken almost 100 years later,
revealing an advancement of almost 2 weeks
during the course of the century.
 Directly
related to earlier mating season
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Different species respond to
warming at different rates, leading
to possible mismatches in timing
between species
 Predator–prey, herbivore–food
plant,
pollinator–plant, and other species–
species interactions may be affected
 In
the Netherlands, leaf emergence in
trees is advancing, resulting in earlier
peak insect abundances.
 Blue
tit bird populations are responding to this
change in food supply & laying eggs earlier.
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Glacial evidence is mounting
 Ice
free seasons are 2.5 wks longer
 Glaciers
 Directly
decreasing in size
affects snow-dependent
ecosystems within the cryosphere
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Worldwide, glaciers are receding
and disappearing
 On
Mount Kenya in eastern Africa, of 18
glaciers present in 1900, only 11 remained
by 1986.
 During
the same period, 75% of the glacier
cover of the mountain was lost (from 1.6 to
0.4 km2).
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Worldwide, glaciers are receding
and disappearing
 The
Qori Kalis glacier in Peru, the main
outlet glacier of the biggest tropical ice cap
in the world, is retreating at a rate of more
than 1 km per decade.
1970s / 2004
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Disappearing glaciers on Mt.
Kilimanjaro
1970
2000
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Past terrestrial response is that
things move
 Our
record of climate change and
biological responses is best for the past
500,000 years.

The movement of the continents & plates is
always occurring and changes in climate
conditions follows
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The result was a constant shifting
of species associations
 Species
found together at the height of the
glaciation might not be found together at
the advancing edge of vegetation
occupying the habitats newly vacated by
the ice.
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Several species might be found together in
one region, only to have one or more of the
group be absent in another region.
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Bottom line, climate change isn’t
new, but human influences are
 The
affinity of northern floras in North America
and Eurasia and in southern floras and faunas from
South America to Australia results from geographic
and climatic connections dating back 50 million to
100 million years.
 Response
to more recent, rapid climate changes
indicates that vegetation has been able to respond
even to very rapid climate flickers of 100–1000
years.
 Whether
this response capacity will be fast enough
to keep pace with human activity remains to be
seen.