Plant Talk | Science Talk

Monarch Numbers Dwindle Dramatically

Joyce H. Newman holds a Certificate in Horticulture from The New York Botanical Garden and has been a Tour Guide for more than 8 years. She is the former editor of Consumer Reports GreenerChoices.org.


MonarchAs we wait for the weather to warm and some of our most stunning visitors to return to our outdoor collections, we are reminded of the increasing importance of conservation as a consideration in garden planning. Case in point: A new report finds the number of monarch butterflies wintering in the mountains of central Mexico much lower than ever recorded, largely due to the destruction of their habitat, extreme weather, and loss of food supply, the milkweed plant, up north.

These findings mean that cultivating and conserving the monarchs’ sole source of food in our area is more important to their survival than ever. In the Native Plant Garden, there are several species of milkweed, all of which attract monarchs, one of the most highly visible and numerous insects to see throughout the summer months.

The new report, headlined “Monarch Population Hits Lowest Point in More Than Twenty Years,” notes a “43.7% decrease in the total amount of forestland occupied by monarchs in and near Mexico’s Monarch Butterfly Biosphere Reserve. The research was conducted by the World Wildlife Fund and Mexican government agencies over several weeks in December 2013 and the decrease is in relation to December 2012 research.”

The findings underscore the fact that milkweed plants, which monarchs depend upon, have dwindled due to the more regular, widespread use of certain herbicides in U.S. agriculture. Their largest use is on sites for soybeans, field corn, pasture and hay, but these herbicides kill the many varieties of milkweed plants along with other vegetation. The report further highlights the importance of maintaining the Native Plant Garden at NYBG and other gardens like it across the country as places where monarchs and milkweed plants can grow and prosper together.

  1. Pat Gonzalez says:

    This might explain why I saw so very few of them at the Garden last year. Got tons of images of swallow tails, but hardly any monarchs.

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