A better year for monarchs

A better year for monarchs

The summer of 2014 brought a little bit of hope to lovers of the famous orange butterfly. A fair number of clues point to a substantial increase in the monarch population compared to last year, which had been described as catastrophic.

2013: the smallest population ever recorded

Nature watchers will tell you that it was almost impossible to find monarchs during the summer of 2013. Anyone who could claim to have spotted even one or two was lucky. The dramatic decline in the population was confirmed when, as is the case every winter, specialists measured the surface area of Mexican forests covered by monarchs in diapause. Results: the butterflies occupied only 0.67 hectare, the smallest population ever recorded, and a drop of close to 50 percent from the year before.

2014: encouraging signs

Under scrutiny since March, meaning since their departure from Mexico to make the trip back north, monarchs seem to have reproduced at a good pace during the spring and summer of 2014.

Monarchs butterflies can count on the interest shown in them by the public, who follow their progress and note the observable changes in their populations. Websites like e-butterfly and Journey North compile the spottings of amateur and professional naturalists all over the North American continent. For example, in 2014 the number of monarch spottings recorded on ibutterfly was five times more than in 2013, and the number of individuals observed increased tenfold.

The Monarch Larva Monitoring Project (MLMP) out of the University of Minnesota relies on a squad of volunteers to tally monarch eggs in patches of milkweed. In the northern United States, the quantity of eggs found in mid-July (2nd generation) was five times greater than the previous year, 0.1 to 0.2 monarch egg per plant (compared with 0.02 to 0.04).

We’ll have to wait till winter

All these signs are encouraging. Nevertheless, this autumn, monarchs born north of their natural range (the best breeding area) still have to cross up to 4,000 kilometers before reaching the oyamel firs in Mexico’s Sierra Madre, where they’ll spend the cold season. It’s a risky journey, full of pitfalls, many of which have their source in climate change (drought, cold, storms…). It’s only once they’re all together in the mountain forests that we’ll have an idea of the true size of the population in eastern North America. Some researchers are already making estimates. Chip Taylor, the founder and director of Monarch Watch, a program that among other things does monarch tagging, believes that if everything goes well during the migration the population will have at least doubled compared to that of last year.

Cautious optimism

All lovers of the monarch and of nature in general will only rejoice if the area covered by monarchs doubles and reaches 1.4 hectare. But that will still be a long way from the annual average of the last 20 years, which is close to eight hectares. For the past 10 years, the number of monarchs has dropped steadily. Most researchers agree that destruction of the breeding habitat is the principal factor in that decline. Large areas that were once welcoming for the monarch are no longer so, in particular the region of the northern Midwestern U.S. known as the Corn Belt. The intensive cultivation of genetically engineered corn and soybeans that can put up with the heavy use of herbicides brings with it the elimination of the common milkweed, a plant that 90 percent of monarch caterpillars feed on (the others choose different species of milkweed). It may therefore be wise to look on the wonderful summer of 2014 as just a break in the downward slope of the monarch population.

Taking action

But all is not lost! The primary cause of monarch decline is well known: habitat loss. So let’s plant milkweed to feed the caterpillars and nectar-producing flowers for the adults. Starting next spring, create an Oasis for monarchs at home!

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4 Comment(s)
Laura lipton's picture
Laura lipton

I have seen a few more this year, but am afraid the caterpillars don't have much to eat. No visible milkweed in my yard, but I have seen the babies munching away on the dill weed in my garden, which I understand is a second choice. Hope they make it..

alicebobby's picture

Although I'm worried the caterpillars don't have much to eat, I have seen a few more this year. There isn't much milkweed visible in my yard, but I have noticed the young gorging themselves on the dill weed in my garden, which I know is a backup option. I hope they succeed. retro bowl college

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