Nine Possible Reasons the Monarch Population is Changing and Why We Have New Butterfly Species in the Southwest
- The National Arbor Day Foundation has assigned a range of zones to different tree and perennial species that reflect where they can thrive. Much of coastal Southern California from Santa Barbara to San Diego has gained a zone, changing from 9 to 10. From 1990 to 2006, the zones have moved north, with some areas shifting by as much as two zones.Butterflies and other insects shift with the climate zones.
- These shifts of zones affect plant life and the animals that use the plants as a food source.An example is forests expanding into higher Rocky Mountain elevations due to global warming threaten to wipe out the meadow habitats of a high-mountain butterfly, including the apollo butterfly (Parnassius).Research by biologist Jens Roland (University of Alberta) shows that as colonies of Parnassius become isolated from each other by the new forests, the gene pool is depleted.One particularly cold winter or summer may be enough to wipe out an entire colony of Parnassius, Roland writes in the “Proceedings of the National Academy of Sciences.”
- The California Department of Forestry and Fire Protection conducts a survey of plant moisture content every year.The survey showed that vegetation during the summer of 2007 in the Southwest was the driest in 90 years.This type of prolonged dryness has a great effect on insects.
- A new ten year climate prediction model indicates that global warming will not increase significantly during the next two years, but will set in with a vengeance after 2009.This prediction is from the U.K.’s Hadley Center for Climate Research and Prediction.This prediction was based on a ten year climate outlook made possible by plugging current weather and ocean data into well established long term climate algorithms.
- The Fahrenheit temperature in Southern California is 2.2 degrees higher since 1950.San Diego County was the fourth driest year, and Riverside and San Bernardino Counties were the driest ever in 2007. The study WeatherBill found that 57 percent of cities in the United States showed significant warming trends in the winter.
- “After eight very dry years on the Colorado River watershed and a record breaking dry winter in Southern California in 2006-2007, the situation in the American Southwest is dangerously dry,” said oceanographer and forecaster Bill Patzert at the Jet Propulsion Laboratory in Pasadena, CA (JPL).
- La Niña, the oceanic phenomenon that almost always brings a dry winter in Southern California, now appears inevitable.Long-range forecasters at JPL say the La Niña brewing in the central Pacific Ocean is intensifying — more evidence that the Southwest could face another dry year.However, San Diego had an average rainfall byJanuary 1st 2008.
- Southern California wildfires in late October of 2003 and late October of 2007 have had major effects on plants and wildlife, including monarchs.Thousands of migrant monarchs that entered the Southwest during this time were probably killed by flames and smoke.The fires may have influenced the low overwintering populations by early November during these seasons because the butterflies usually enter the area by late October, based on a study of 20 years by Monarch Program volunteers.
- Climate experts claim that global warming is intensifying nature’s cycles by lengthening fire seasons and prolonging droughts in parts of the the west.However, “The connection between global warming, Santa Ana winds, and extremely low Southern California precipitation last winter are not known with sufficient certainty to conclusively link global warming with this disaster,” said researchers at the University of California, Merced, and the University of Arizona.Another study from 2006 in Geophysical Research Letters, the publication of the American Geophysical Union, suggests that Santa Ana winds may occur more frequently in November and December as Southern California’s climate becomes warmer.In turn, that would heighten the risk of deadly blazes.