Managing The Ecosystem

Monarch

Monarch Emerging From Its Chrysalis

The drastic decline of the Monarch population in the first half of this decade (the 2010s) combined with a longer term decline over the past 20 years has raised questions about land management practices. Why has the population declined? Several factors contribute including loss of habitat due to changes in land management practices and changes in climate. A petition has been made to add the Monarch to the Threatened Species List and to protect critical habitat. The overwintering site in Mexico is an obvious candidate that is on everyone’s must protect. Protecting sites for larval growth and development is under discussion.

Corn and Soybean fields have traditionally contained some milkweed, but a far smaller percent than Right of Ways or Conservation Reserve Land. However, land planted to corn has expanded with the increased use of corn to produce ethanol and Conservation Reserve Land decreased. Use of transgenic crops in combination with herbicides have reduced the milkweed population within fields. This combination has reduced the milkweed available to monarchs as land with substantial milkweed is replaced by crop land with little to no milkweed.

Efforts to increase milkweed populations would likely involve establishment of refuges, and restricting planting to the most productive lands. Limits on suburban sprawl could protect more monarch habitat. The highest density of milkweed is in the Right of Ways. Changes in management practices could have a substantial impact. If mowing is delayed until after monarchs have completed development in the fall, amount of habitat could be increased.

Monarchs also need sources of nectar on the journey south to fuel their flight. Right of Ways can be managed to produce more nectar sources for monarchs and other insects. Governments can change their Right of Way management practices if presented with a workable plan. The importance of considering impacts on the larger ecosystem increases as the percentage of managed land increases.

About jjneal

Jonathan Neal is an Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in Endangered Species, Environment, News, Policy. Bookmark the permalink.

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