Download 2.6.4a Biodiversity and Climate Change

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2.6.4a Climate Change and Biodiversity
Findings from the US Climate Change Science Program
• Climate change is already affecting U.S. water resources, agriculture, land resources, and biodiversity, and will
continue to do so.
Findings: Crops
•
crops will mature more rapidly,
– But increasing temperatures will increase the risk of crop
, particularly if
decreases or becomes more variable.
•
crops (such as tomato, onion, and fruit) are more sensitive to climate change than grains
and oilseed crops.
Findings: Livestock
• Higher temperatures will
affect livestock.
– Warmer winters will reduce
but this will be more than offset by greater mortality in
summers.
– Hotter temperatures will also result in reduced
of livestock and dairy animals.
Findings: Productivity
• Young forests on
soils will achieve higher productivity from
atmospheric
concentrations.
–
deposition and warmer temperatures will
productivity in other types of
forests where
is available.
• The growing season has
by 10 to 14 days over the last 19 years across the temperate latitudes.
• Species’
have also shifted.
Findings: Fire and Invasive Species
• Forests in the interior West, the Southwest, and Alaska are already being affected by climate change with
–
in the size and frequency of forest fires,
–
outbreaks and
– Tree
.
•
grow more rapidly under elevated atmospheric CO2.
– Under projections reported in the assessment, weeds migrate
and are less sensitive to
herbicide applications.
• Invasion by exotic grass species into arid lands will result from climate change, causing an increase fire
frequency.
– Rivers and riparian systems in arid lands will be negatively impacted.
Findings: Water
• Much of the United States has experienced
precipitation and stream-flow, with
drought severity and duration, over the 20th century.
• The
and Southwest, however, are notable exceptions, and increased drought conditions have occurred
in these regions.
• A continuation of the trend toward increased water use
could help mitigate the impacts of
climate change on water resources.
Findings: Snow
•
•
There is a trend toward reduced mountain snowpack and earlier spring snowmelt runoff in the Western United
States.
The
rates of warming in the Arctic observed in recent decades, and projected for at least the next
century, are dramatically reducing the snow and ice covers that provide
habitat for polar bears.
Birds and Climate Change
• More is known about them
– not too many ‘fish-watchers’
– ‘canaries in the coal mine’
• 9787 known living species
– 21% (2,055 species) are extinction prone (for a variety of reasons)
• Habitat destruction/fragmentation impacts
• Climate change is quickly emerging as a
factor
• Being out of ecological
–
is tied to seasonal events: flowering, seeds, insect emergence, etc.
– Being out of step with
supplies may mean the early bird doesn’t get the
– Species may be driven by different cues:
• birds by photoperiod (
)
Draw a diagram detailing how climate change affects
• insects by
biodiversity:
What makes a species extinction prone?
•
(vs Generalist)
–
– food
– nesting requirements
– restricted
• Importance to humans
• Predators, diseases, etc.
Can’t they just
?
• Many species rich areas are already protected, e.g.,
national parks, nature preserves, etc.
– If vegetation changes, habitats are lost
– Where can they move to?
• Ecological communities will be
• As species move they may have to deal with changes in
–
– predators
–
– parasites
– diseases
–
that are less than ideal
• Case Study: Hawaiian Honeycreepers
• Once 29 species, now
due to habitat
loss, disease, predators
• Avian
, one agent, pushed
their distribution to altitudes where the
was rare
•
ºC increase will reduce habitat by 50%, 96%,
and 100% in their three established refuges
Your turn:
What benefits can come from climate change?
How could we save species that might be affected from climate change?