Edith's and Quino Checkerspot Butterflies
Quino Checkerspot. Image courtesy
of Dr. Gordon Pratt,
www.quinocheckerspot.com.Visitors to California's Yosemite National Park might keep an eye out for a medium-sized butterfly
with black, orange, and white patches on its wings flitting among the mountain wildflowers. What
makes this species, known as the Edith's checkerspot butterfly, special is its extreme sensitivity to
weather and climate, a quality that has turned it into an early warning indicator of climate change
in North America.
For more than 40 years, researchers have been tracking Edith's checkerspot butterflies, even dusting
off old museum records to determine where the species lived long ago. These investigations
have revealed a large-scale shift of the butterfly's range both northward and upward in elevation—
in concert with increasing temperature associated with climate change. Although the individual
butterflies aren't migrating (they tend to stay
in a small area their entire lives), the species' range
has shifted as separate populations, one by one, go
extinct—four times faster on the southern boundary
of their range (Baja, Mexico) than on the northern
boundary (in Canada), and nearly three times faster
at lower elevations than at higher elevations.
The butterfly's sensitivity to climate is also threatening
its survival. A subspecies, the Quino checkerspot,
is a federally listed endangered species.
Although the primary cause of its decline is habitat
destruction, climate change poses problems for
its recovery. The southern edge of its range, in
Mexico, has the least amount of human development
and would offer the best habitat for its recovery,
but as a result of climate change, the area is becoming too hot and dry. The Quino checkerspot
is the first endangered species for which climate change is officially listed as both a current
threat and a factor to be considered in the plan for its recovery.
Pacific Fisheries
Seafood is the primary source of protein for more than 1 billion people worldwide. With demand
for seafood growing dramatically, the future of the world's fisheries is of critical importance.
Currently, however, there is very limited understanding of how global climate change might affect
whole ocean ecosystems.
One effect that has already been observed is a shift in the types of species that are found in certain
locations. Among the creatures that inhabit the rocky shorelines of central California, for
example, formerly "southern" species have become more abundant since the mid-20th century,
while many "northern" species have decreased as the shoreline warms.
Scientists retrieve a water sample
for
research on the dead
zone. Image
courtesy of Oregon State University.Another abnormality that has been linked to climate change is a new "dead
zone"—an area of seawater with insufficient oxygen to support most marine
life—that has appeared off the coasts of Washington and Oregon. Dead
zones suffocate and kill marine organisms that cannot swim or scuttle away
fast enough. This dead zone, which has appeared every summer since 2002,
is different from most of the other ones around the world because it is not
caused by excess nutrients from fertilizer runoff or sewage discharges. Its ultimate
cause is still under investigation, but several potential causes are linked
to climate change. One possibility is that warmer ocean waters have directly
affected the water's ability to hold oxygen at the surface and resupply oxygen
to deeper waters. Climate-related changes in coastal winds and ocean circulation
may also be responsible.
Wine Quality in California
Some know California as the "Land of Wine and Food," but its premium
vineyards could be facing a difficult future. Climate change affects managed
ecosystems like vineyards just as it affects natural ecosystems, with corresponding
major economic and social implications.
Wine is one of California's most important agricultural products: The industry earns billions of
dollars per year and is a critical part of the state's cultural fabric. Wine grapes can grow in a wide
range of climates, but the quality of each crop depends on a subtle balance of climate, soils, and
landforms. Climate changes during the second half of the 20th century generally improved conditions
in California's premium wine regions as the incidence of frost decreased and the growing
season began earlier. Further warming, however, would be unlikely to help wine growers in this
area. One study concluded that if current greenhouse gas emissions continued, the projected
warming would degrade the state's premium wine regions from "optimal" to "marginal" by the
end of the 21st century. Another study concluded that the area with the potential to produce premium
wines could decrease by up to 81 percent.
This web page is based on the National Academies' educational booklet
Ecological Impacts of Climate Change.
