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Understanding the Complexity of Monarch Environmental Engagement

Understanding the Complexity of Monarch Environmental Engagement

Alex Wierbinski's picture

By Alex Wierbinski - Posted on 19 March 2019


Female Monarch Butterfly: Orange
Monarch butterfly by Kenneth Dwain Harrelson, wiki.
Males have reddish hue, Wiki. Photo by Kenneth Dwain Harrelson, Wiki

Many, Many Monarchs
Many, many Monarchs, credit to MSU, by Karen Oberhauser.
MSU, by Karen Oberhauser, big show-shot.


Understanding the Complexity of Monarch Environmental Engagement

When it comes to Monarchs, Fall Migration Matters,
Michigan State University, March 18, 2019.


Huge Declines
“Monarch butterflies in eastern North America have declined by 84% on Mexican wintering grounds since the observed peak in 1996.”

Key Culprits
“...traditionally focused on two sources for their decline – winter habitat loss in Mexico and fewer milkweed plants in the Midwest.”

“...herbicide use and habitat loss have diminished over the past decade, yet monarchs continue to decline.”

Mystery Divergence
“...population indices from northern US breeding grounds do not show a consistent downward trend. ”

It’s the Fall Migration
“This discrepancy has led to speculation that autumn migration may be a critical limiting period.”

A New Approach
“...re-evaluated the long-standing base on which monarch estimations are made. Rather than consider the winter population as a single entity, their model used the numbers from all 19 known colonies individually.”

A Complex Butterfly…
“…our model shows that all seasons are important; summer, fall and winter factors are all connected.”

“In particular, we found that landscape greenness during the fall migration, in addition to the peak summer population size and the amount of habitat at local winter colonies, were the key factors influencing the winter population size.”

Nectars of a large Effort
“Decades worth of continental-scale data from across all seasons fuel it (this new perspective). Climatologists, collaborators in Mexico and citizen scientists all have contributed critical information.”



The Monarch in and across the High Sierra

Art Shapiro



Recent Monarch Research

Florida Monarch Butterflies dropped 80 percent since 2005

Bye Bye Butterfly: Monarch Decline

Monarch butterflies disappearing from western North America



Alternative Migration Strategies Part of Monarch Decline?

Western Monarch Butterfly Migration Measured: Long Fliers

Monarch Survival Strategies Dependent on Climate-Controlled Chemical Connection

Coldness triggers northward flight in migrating monarch butterflies




Butterfly News

Bugs Forum



March 2019 News of Man & Nature








Nature News


Climate Destruction News



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Spider Forum

Bird News

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Health and Fitness

Mountain Safety

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Female Trail

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Astro-Phys, Space, & Science News

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Monarch, monarch butterfly, migration, Fall, environmental, factors


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