TX CA MT AZ ID NV CO OR KS NM SD WY IL UT NE IA MN ND WA OK FL WI MO GA PA AL AR NY MI IN LA NC KY MS VA TN OH SC ME MI WV VT NJ NH MD MA CT DE RI MA RI DC Human Population and Monarch Butterfly Migration in the United States Human Population and Monarch Butterfly Migration in the United States Over the last ten years there has been a frightening trend in monarch butterfly population. The number of monarch butterflies in the U.S. has been in sharp decline. In 2003, 27.48 acres were inhabited by these insects (this measurement is a reflection of population). Just ten years later, the population is a fraction of that with the number of acres inhabited during seasonal hibernation at 1.65 acres, an all-time low. One of the largest threats facing monarch butterflies today is the destruction of their habitat and the loss of milkweed throughout the nation, a plant vital to the survival of the insect. Population Percent Change Along Migration Paths (Between 2000 and 2010) Population Decrease No Change 1 - 6 7 - 19 20 and over Data courtesy of ESRI, MonarchWatch, and the U.S. Census Bureau 0 150 300 450 600 75 Miles ± Unlike the dwindling monarch butterfly population the number of people living in the United States has risen from 290.1 million in 2003 to an estimated 313.9 million in 2013. This rising population has presumably been met with construction, more housing units, and ultimately more destruction of wildlife habitats. All of these factors are likely to affect monarch butterflies. This calls into question what the relationship between rising human population has on the fate of the monarch butterflies. This map was initially created by rectifying an image of monarch butterfly migration paths with a US census tracts map in ArcMap.The migration paths were than digitized within the census tracts map, making the migration paths a permanent feature. A ten mile buffer was put around this feature and a new layer was created with all census tracts within or intersecting the ten mile buffer around the migration paths. Using the field calculator the percent change of the population within those tracts from 2000 to 2010 was calculated and then displayed as a choropleth map. Some areas of the U.S. have seen a decline or no change in population over the time period examined, particularly those in the heartland and southwest regions. But the majority of areas saw at least a 7% increase in population. These areas are also home to some major cities such as Portland, Kansas City, Newark, and Riverside. With the decline in monarch butterfly population within the last ten years and the rise of the human population along their migration paths conclusions can be drawn on the negative effect humans have on the monarch population. If this trend continues and the U.S. population in these areas continues to grow, it is possible the monarchs will continue to disappear. As previously stated, the biggest threat to monarch butterflies is the destruction of their habitat. This map not only has implications in the relationship between human population and the monarch butterfly population but what can be done in order to counteract the downward trend in the population. Citizens and developers within these regions can take steps to help maintain the monarch butterfly population, such as planting milkweed and avoiding the destruction of milkweed on a local scale and educating communities on the effects of human impact on the butterflies. Monarch Butterflies in the United States Making of the Map Implications of the Project

Human Population and Monarch Butterfly Migration in the ... · Some areas of the U.S. have seen a decline or no change ... If this trend continues and the U.S. population in these

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Page 1: Human Population and Monarch Butterfly Migration in the ... · Some areas of the U.S. have seen a decline or no change ... If this trend continues and the U.S. population in these

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Human Population and Monarch Butterfly Migration in the United StatesHuman Population and Monarch Butterfly Migration in the United States

Over the last ten years there has been a frightening trend in monarch butterfly population. The number of monarch butterflies in the U.S. has been in sharp decline. In 2003, 27.48 acres were inhabited by these insects (this measurement is a reflection of population). Just ten years later, the population is a fraction of that with the number of acres inhabited during seasonal hibernation at1.65 acres, an all-time low. One of the largest threats facingmonarch butterflies today is the destruction of their habitat and the loss of milkweed throughout the nation, a plant vital to the survival of the insect.

Population Percent ChangeAlong Migration Paths(Between 2000 and 2010)

Population DecreaseNo Change1 - 67 - 1920 and over

Data courtesy of ESRI, MonarchWatch, and the U.S. Census Bureau

0 150 300 450 60075 Miles±Unlike the dwindling monarch butterfly population the number of people living in the United States has risen from 290.1 million in 2003 to an estimated 313.9 million in 2013. This rising population has presumably been met with construction, more housing units, and ultimately more destruction of wildlife habitats. All of these factors are likely to affect monarch butterflies. This calls into question what the relationship between rising human population has on the fate of the monarch butterflies.

This map was initially created by rectifying an imageof monarch butterfly migration paths with a US census tracts map in ArcMap.The migration paths were than digitized within the census tracts map, making the migration paths a permanent feature. A ten mile buffer was put around this feature and a new layer was created with all census tracts within or intersecting the ten mile buffer around the migration paths. Using the field calculator the percent change of the population within those tracts from 2000 to 2010 was calculated and then displayed as a choropleth map.

Some areas of the U.S. have seen a decline or no change in population over the time period examined, particularlythose in the heartland and southwest regions. But the majority of areas saw at least a 7% increase in population. These areas are also home to some major cities such as Portland, Kansas City, Newark, and Riverside. With the decline in monarch butterfly population within the last ten years and the rise of the human population along their migration paths conclusions can be drawn on the negative effect humans have on the monarch population. If this trend continues and the U.S. population in these areas continues to grow, it is possible the monarchs will continue to disappear.

As previously stated, the biggest threatto monarch butterflies is the destruction of their habitat. This map not only has implications in the relationship between human population and the monarch butterflypopulation but what can be done in order to counteract the downward trend in the population. Citizens and developers within these regions can take steps to help maintain the monarch butterfly population, such as planting milkweed and avoiding the destructionof milkweed on a local scale and educating communities on the effects of human impact on the butterflies.

Monarch Butterflies in the United States Making of the Map Implications of the Project