Another Butterfly Mystery

[arachadillo]

Last edited Sun Nov 17, 2019, 06:09 PM - Edit history (3)

A NY Times article produced much talk last fall and winter about the steep decline of Monarch butterfly populations. The push for Midwest corn based ethanol and the gm crops to fuel accounted for most of the causal explanation. Planting gm crops that are roundup ready effectively removed most Midwest milkweed. Environmental stresses such as illegal logging in the Monarch's Mexican wintering grounds complicates the problem.

Still, most people do not know that North America hosts two separate Monarch migration populations, a Midwest population and a Western population.

Another butterfly mystery of sorts is being reported for the Western Population
http://blogs.kqed.org/science/2014/01/17/the-mystery-of-the-missing-monarch-butterflies/

"This year, though, Ardenwood naturalist Mindy Castle reported that after a good showing of about 1,000 butterflies in November, the cold snap in December sent most of them fluttering to parts unknown. Only about 30 or 40 monarchs remain, most of them abandoned their Ardenwood overwintering site.

The unexpected dispersal from the Ardenwood site, coupled with the unrelated New York Times article which reported the late arrival and smaller numbers of eastern monarchs migrating to Mexico underlines scientists concerns about the overall decline of the North American monarch population. For over a decade, the Xerces Society annual Thanksgiving Monarch Count at overwintering sites in California has revealed a greater than 80 percent population decline across most sites with some sites faring significantly worse. For example, at Natural Bridges State Beach near Santa Cruz, the number of butterflies gathering each winter dropped from an estimated 120,000 in 1997 to just 500 in 2012.”

A quick look at the Xerces Western Monarch Butterfly count shows a problem from fifteen years ago.
http://www.xerces.org/wp-content/uploads/2011/04/WMTC-Data-1997-2012-Updated-1-NOV-2013.pdf

Consider the following aggregate statistics,

1997 average count 12232.6
1998 average count 5084.2
1999 average count 2267.6
...
2007 average count 939.5
2008 average count 1137.0
2009 average count 769.3
2010 average count 1267.2
2011 average count 1776.2
2012 average count 1112.7

According to this timeline, Monsanto introduced Roundup Ready corn in 1998.
http://2013.igem.org/Team:British_Columbia/humanpractices/GMOTimeline

The numbers on the Xerces count drop drastically in 1999, so there's a strong correlation between the introduction of roundup ready corn and long term Monarch population declines in the Western population.

However, I do not have the CA ag stats for how the ag community incorporated all GM crops and roundup use into their agriculture plans. It's documented in the Midwest though.

So, it appears as if the current Monarch populations declines in the West might not be statistically significant for the year. There were, for example, less Monarch butterflies counted in 2007 than in 2012.

Nonetheless, it does appear as if the long term Monarch Population trends have remained low, after the 1998 introduction of Roundup Ready GM corn.

Green Nature

[truedelphi]

1. I don't doubt that the Gm stuff is partly responsible, but it also

Has to do with how so many affluent households have landscapers and gardeners, who almost all use pesticides, even if they say they don't.

And then you have the fact that the Parks and Rec people are spraying empty lots, that thirty years ago would have gone to weed. Including milkweed, a staple in the butterfly diet.

Also furthering loss of butterflies is the loss of of habitat. Look at how ubiquitous vineyards have become. I just drove down Hwy 29 here in Lake County yesterday to notice yet another 400 by 200 acres of forest uprooted so that someone can grow grapes. Nothing can benefit from vineyards, except humans who drink wine. No birds or rabbits, deer, skunk. Or bobcat, cougar, fox, snakes, etc. I don't usually even see a single bird out on the vineyards; they are far too toxic with pesticides.

The poor animals end up driven onto the highways, where they get killed. Or else they starve to death. And what replaces the diversity? Just rows of metallic sakes with the leafy grape plants hanging on them.

[arachadillo]

2. butterfly loss

Also furthering loss of butterflies is the loss of of habitat. Look at how ubiquitous vineyards have become. I just drove down Hwy 29 here in Lake County yesterday to notice yet another 400 by 200 acres of forest uprooted so that someone can grow grapes. Nothing can benefit from vineyards, except humans who drink wine. No birds or rabbits, deer, skunk. Or bobcat, cougar, fox, snakes, etc. I don't usually even see a single bird out on the vineyards; they are far too toxic with pesticides.

That sounds reasonable....after the initial crash of the butterfly population due to the intro of the roundup ready crops, there was no push for alternative milkweed planting....gardens, vinyards, etc., go for the money making or glam plants, rather than plain old milkweed.

[truedelphi]

3. What is so surprising to find out is that there is

A glut of grapes on the market. So I guess the vineyard owners in many cases are using the vineyards as "place holders." Eventually over the decades, the folks in the SF Bay area will be living in my county, and those vineyards may be worth serious money as Real Estate.