The Declining Monarch Population
Monarch butterflies encounter many challenges during their life cycle and in their migration process. In the last 15 years, their population has declined greatly.
Monarchs used to cover about 44.5 acres of land when they came to Mexico in 1995. now the butterflies cover only about 1.65 acres as of 2014. This is used as a measure of their population size.
Note: the graph to the left shows this trend, but using hectares instead of acres.
Causes
The most important cause of the declining monarch population seems to be the loss of their larval food, milkweed.
Milkweed VS Round-up Ready
Milkweed populations are running low in the Midwestern states because of genetically altered crops that are being used in areas they grow. Because of the extensive use of herbicide on crops that have been genetically modified to resist it, the herbicide kills everything but the crops, leaving nothing for the creatures living around the crops.
The Mexican Connection
Monarchs from the Midwest spend the winter in specific mountain forests in Mexico. These places are becoming endangered due to illegal logging. As the forests become smaller, the monarchs have less protection from bad weather.
Other Challenges
Droughts
Urban development
Pollution
Monarch butterflies encounter many challenges during their life cycle and in their migration process. In the last 15 years, their population has declined greatly.
Monarchs used to cover about 44.5 acres of land when they came to Mexico in 1995. now the butterflies cover only about 1.65 acres as of 2014. This is used as a measure of their population size.
Note: the graph to the left shows this trend, but using hectares instead of acres.
Causes
The most important cause of the declining monarch population seems to be the loss of their larval food, milkweed.
Milkweed VS Round-up Ready
Milkweed populations are running low in the Midwestern states because of genetically altered crops that are being used in areas they grow. Because of the extensive use of herbicide on crops that have been genetically modified to resist it, the herbicide kills everything but the crops, leaving nothing for the creatures living around the crops.
The Mexican Connection
Monarchs from the Midwest spend the winter in specific mountain forests in Mexico. These places are becoming endangered due to illegal logging. As the forests become smaller, the monarchs have less protection from bad weather.
Other Challenges
Droughts
Urban development
Pollution