Friday, January 31, 2014

The Plummeting Monarch Butterfly Population

The news is grim. The monarch butterfly population overwintering in Mexico plunged to a new low this winter. The signs were there earlier. Cooler than normal temperatures during the Spring migration delayed monarch movement into the northern part of the United States and Canada as well as slowing the growth of immatures for the next generation. The Fall migration was late mainly due to the late maturation of the migrating generation. Fortunately the weather along the migration route was warmer than usual across the board, helping monarchs reach Mexico to some degree. An early freeze could have been even worse.

Monarch Butterfly Fund -
How late? Monarchs usually begin to arrive in Mexico during the annual celebration of the Days of the Dead, Día de Muertos, on November 1 and 2. Fluttering orange wings of monarchs dancing through the skies, traditionally believed by local people to bring the return of the souls of deceased children and loved ones, were silent. Empty. No monarchs graced the skies to the lament of those holding this annual tradition dear.

Once the monarchs finally did arrive in Mexico the weather near the overwintering sites was inhospitable to further movement, cool and sometimes rainy, making it difficult for the monarchs to fly their final miles into the oyamel forest. But they did arrive in early December, nearly a month late.

When the monarchs first arrive in the oyamel forests they usually are dispersed through an area. As the temperatures get colder, they compact in clusters in the trees. Measurements of the monarch population are recorded frequently. For comparison, the count of the monarch population at the end of December, the time of the coldest temperatures and when the monarch clusters are the most compact, are used for comparison each year and are reflected in the graph above.

So the real question is, now what? We're grieving. Some are panicking and rushing into desperate plans that may not really benefit the monarchs in the long run. Take a few moments to think through what we all can reasonably do. In a conversation with Monarch Watch Conservation Specialists recently, Dr. Chip Taylor pointed out this sobering thought. "Yes, the numbers are low but they have surely been lower in the past. No one remembers the dirty thirtys - 8 years of drought and high temperatures. Based on how monarchs respond to high temps and drought in recent years it is likely that monarch numbers were lower in the late thirtys than they are now. The difference between then and now is habitat. There was more habitat then. The habitat loses now are extraordinary - over 24 million acres plowed under since 2008 and about a million lost each year due to development." You can read more important details about habitat loss in this recent Monarch Watch Blog .

Dr. Karen Oberhauser, Director of Monarch Larva Monitoring Project (MLMP), shared this sobering call to action when the population numbers were announced:"Four concrete things that people can do include:
  1. Plant locally sourced, native milkweed and nectar sources wherever possible
  2. Educate others and advocate for monarch conservation.  People can register their monarch habitats as monarch Waystations and add them to other success stories on the Monarch Joint Venture website.  They can talk to friends and neighbors about monarchs, ask local or county land managers to avoid mowing milkweed when monarch eggs and caterpillars might be present, and advocate to limit insecticide spraying at the local, state or national level
  3. Get involved in a monarch citizen science program and contribute data that will help us manage monarchs more effectively
  4. Donate money to organizations that support monarch, pollinator, and land conservation. 
Conservation  biology is essentially a science of hope, and the number of organizations and passionate individuals involved in monarch conservation across North America gives us reason for hope.  Given the conservation challenges facing monarchs and the clear evidence that their populations are declining, it is vitally important that we mobilize as many people as possible, and that our efforts are carefully planned to maximize their impacts.  For many people, monarchs represent a connection to nature that began in childhood, and our actions will allow generations to come to make this same connection." You can read more of Dr. Oberhauser's press release here.

 In response to the record low monarch population in Mexico and the increasing loss of monarch habitats in Arizona, the Southwest Monarch Study has partnered with Borderland Restoration Nursery to offer organic, pesticide-free milkweed for your gardens and nature centers. This Spring beginning in March we will have Desert Milkweed (A. subulata) and Arizona Milkweed (A. angustifolia) for the lower desert region. By May, for the higher elevations, we will have Showy Milkweed (A. speciosa), Butterflyweed (A. tuberosa), Antelope Horns Milkweed (A.asperula), Broadleaf Milkweed (A.latifolia), and for areas without horses/cattle we will also have a limited amount of Horsetail Milkweed (A.subverticillata). Your seeds are growing now. For more information as plants are available, please follow the Southwest Monarch Study Facebook page,

Milkweed seedlings at Borderlands Restoration Nursery

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