Living Acres

The Problem

August 17, 2016

The monarch migration through North America is a natural phenomenon. As the only butterfly that makes an annual two-way migration, the monarch has captured the attention of scientists and nature enthusiasts across the continent. Butterfly experts began keeping record of population sizes in 1993 and have since seen a 68 percent decline in numbers, leading to the question, “What is happening to the monarchs?”

Multiple factors have contributed to this staggering drop in population, including changing weather patterns, the loss of overwintering sites in Mexico and the reduction of milkweed habitat in the United States. Over the last decade, massive Pacific weather systems have moved through central Mexico. These systems brought heavy rain, hail, high winds and even freezing temperatures in January and February of 2002, 2004 and 2010. The severe weather conditions ushered in mortality rates ranging from 50 percent in 2010 to 80 percent in 2002, devastating monarch overwintering populations.

Another issue facing the monarch population is the demolition of oyamel fir forests in Mexico, a common overwintering site for the butterflies. Monarchs prefer oyamel fir because it serves as a blanket and umbrella during the winter, protecting them from extreme cold and precipitation. According to Lincoln Brower, service professor of zoology emeritus at the University of Florida, the oyamel forests are the Achilles’ heel of the monarch.

While there are multiple government regulations and incentives put into place to preserve the oyamel firs, these efforts have not proven very effective. Illegal logging accounts for most the encroachment on monarch habitat. Even so, authorized extraction for firewood and timber adds to the overall loss of trees. Other strains on the landscape, including unregulated tourism and climate change, contribute to the decline of overwintering sites.

However, the biggest contributor to this decline may be the loss of milkweed habitat in the United States. Milkweed is essential to the monarch’s reproductive cycle. It serves as the location for mating, egg laying and larval feeding. Without milkweed, monarchs struggle to make their annual commute through America’s heartland.

Luckily, milkweed habitat loss is easy to fix and nearly every landowner can help make a difference. Living Acres, a research initiative from BASF, aims to increase the amount of milkweed habitat in non-crop areas on farms. Already, this initiative has led to the development of best planting practices for sustainable milkweed. For instance, though it is common to plant milkweed by seeding, only a small number of common milkweed seeds germinate. For this reason, researchers suggest that farmers establish milkweed through a planting process using root sections or transplanted seedlings. Following the seven steps outlined in the planting guide will optimize the success of milkweed habitat creation, allowing farmers to increase biodiversity while focusing on crop production.

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