Lupinus perennis production field

The Decline of the Monarchs

Feb 13, 2015

Imagine a gorgeous meadow on a warm mid-summer afternoon. Native grasses and wildflowers nod in the breeze. You’re taking in this beautiful view when without a noise, a striking patch of orange and black—like a drifting, flickering candle—floats by. You’re fortunate enough to have crossed paths with a rare Monarch butterfly, slowly, steadily moving from blossom to blossom.

Monarch feeding on a swamp milkweed flower

Rare, you ask? Unfortunately yes, as Monarch populations have plummeted over 80% in the past 20 years, and this picture of an idyllic summer landscape has become increasingly uncommon.  Conservation groups have been concerned about this drop for some time, and cite that the Monarch has gone from a population estimated at over 1 billion in the mid 1990’s to a mere 35 million in 2014.

There are several threats that this iconic butterfly faces throughout its migration route--from deforestation to severe winter storms--but their continued decline is fueled primarily by one factor: a similar decline in native milkweeds (Asclepias spp.) over the past several decades. Milkweeds are the sole food source for Monarch caterpillars, and therefore are the only plants upon which adults will lay their eggs during the summer breeding season.

Monarch caterpillar on swamp milkweed leaf

In the past, milkweeds, particularly
Common Milkweed (Asclepias syriaca) would often be found growing in between rows of cultivated crops and fencerows. Since the late ‘90s, however, farmers have almost completely converted to the use of genetically modified corn and soybean varieties, which are resistant to the action of certain broad-spectrum herbicides. Milkweeds, unfortunately for the monarchs, are not.

Native habitat destruction, more generally, has also decreased the amount of forage for Monarch larvae and adults. Over 99% of native tallgrass prairie has been converted to agricultural land since the invention of the steel plough around 1840. Until recently, some 100 million acres of agricultural fields with lingering stands of milkweeds remained a refuge of sorts for the Monarch. But no longer.

As a result, conservation efforts are increasing. The Xerces Society is a nonprofit that promotes invertebrate conservation, and has been a key figure in the push to save the Monarch. Through partnerships with organizations like the USDA and U.S. Forest Service, Xerces has worked to incorporate and protect high-quality Monarch habitat on farms and federal lands around the U.S. They’ve also partnered with several native seed  companies—including Cardno Native Plant Nursery—to make milkweed seeds more widely available for habitat restoration activities. In fact in 2013, Xerces contracted with the Nursery to produce Wingstem (Verbesina alternifolia)  and Pasture Thistle (Cirsium discolor), two native pollinator-significant species which were under-represented in the marketplace.

Also, in August 2014, the Xerces Society, the Center for Biological Diversity, the Center for Food Safety, and Dr. Lincoln Brower filed a petition to the U.S. Department of the Interior to have the Monarch butterfly declared an endangered species. It’s too early to say if the Monarch will receive protection, or what form that protection may take, but U.S. Fish and Wildlife Service will now undergo a year-long review to determine the butterfly’s status and eligibility. Their findings aren’t expected until early to mid-2016.

Till then, celebrate the sight of every Monarch you come across. Plant pollinator gardens, include milkweeds in your landscping, or specify extra quantities of milkweed on your next restoration project. Check out www.xerces.org for more information about the benefits of including milkweeds and other natives in your plantings and projects. As landowners, landscape architects, groundskeepers, park and highway managers—even homeowners—we all have a part to play in saving this iconic butterfly.