Saving Our Monarch Butterflies, part 1

 

Monarch Butterfly Life Cycle: Egg to Caterpillar to Pupa to Adult

 published in the Pacifica Tribune January 28, 2020

What’s Natural

Saving Our Monarch Butterflies, part 1

With their clownishly colored caterpillars and bold black and orange adults, monarch butterflies get featured in most children’s nature books. Monarch’s ability to migrate thousands of miles, is one of nature’s greatest wonders. But worrisomely, monarch abundance plummeted by 90% over the past 2 decades. Fearing monarchs could be vulnerable to extinction, the US Fish and Wildlife was petitioned in 2014 to list monarchs as “Threatened” under the Endangered Species Act. But due to several contentious issues, more extensive studies were needed. A determination is now expected by the end of 2020. So, what is killing monarchs?

In the 1970s scientists discovered that virtually the entire population of monarchs that breed east of the Rocky Mountains, migrate to extremely small patches of high mountain forests in central Mexico. There they spend the winter from November to March. Since the early 1990s, scientists began estimating monarch abundance by measuring the areas occupied by wintering butterflies. The greatest winter abundance, estimated in 1997, was confined to an area equal to 40 football fields. By 2013, wintering monarchs occupied less than 2 football fields.

In January 2002, a winter storm brought cold rains followed by clear skies. Without the clouds’ greenhouse effect, clear skies allowed temperatures to plummet to 23°F (- 4°C). Still damp, millions of butterflies simply froze in place. Many millions more fell to the ground creating an eerie carpet of dead and dying butterflies several inches deep. Altogether, 500 million butterflies died that winter, killing 80% of the entire eastern population. That the survival of the entire eastern monarch population could hinge on conditions affecting such a small area became a huge concern.

Carpet of Dead Monarchs from Brower (2002)

Such devastating effects from freezing storms emphasized the need to protect the forests where monarchs spend their winters. The intact forest canopy creates a microclimate that had protected monarchs for hundreds of thousands of years. A closed canopy inhibits freezing. But recent logging opened the canopy and enhanced rapid cooling. The Mexican government eventually agreed to ban all logging wherever the butterflies overwinter. Nonetheless, there has always been significant winter storm fatalities. So, a few degrees of global warming would minimize those cold weather massacres.

(In contrast, monarchs breeding west of the Rocky Mountains migrate to forests along the coast of California each winter where freezing is not a concern. The bad news, populations are still collapsing, and monarchs choose to winter in introduced Eucalyptus trees that many people try to eradicate. It remains to be seen how Eucalyptus will be managed.)

Every scientist agrees 2 key factors are reducing monarch abundance. First is degradation of wintering habitat. Second is the loss of milkweed, the caterpillars’ only food plant. The good news is humans are working to restore landscapes to benefit monarchs. However, media outlets hyping a climate crisis, falsely claim climate change is thwarting our attempts to protect the monarchs. But whether global warming is natural or man-made, warmth benefits monarch survival.

Despite horrific winter losses, monarch populations can rapidly rebound. Surviving adults leave their Mexican wintering grounds in March, and soon arrive to breed in Texas and other Gulf Coast regions. They lay eggs, then die. One female can lay up to 1100 eggs. However, for each female, perhaps 40 eggs survive to produce the next generation of females. Depending on temperature, the transformation from egg to adult takes 30 days. Wherever temperatures are favorable, 3 to 4 more generations can be produced throughout the summer. So, a single female arriving in Texas can eventually give rise to 6400 adults by the 3rd generation.

Temperature controls much of monarch growth. Overall, warmer temperatures increase the speed of development, with an optimal temperature approaching 84°F. If temperatures fall below 53°F then eggs, caterpillars and pupa stop growing. If temperatures exceed 91°F, they also stop growing. But research shows if exposed to higher temperatures for just a few hours, there are no detrimental effects.

Monarchs also actively control their body temperature. Caterpillars feed on the top of milkweed leaves during cool weather to enhance warming by the sun, but feed underneath the leaves as temperatures rise. If midday temperatures get too hot, caterpillars seek shelter in shaded leaf litter.

Monarchs linger in their Mexican winter habitat waiting for optimal spring-time temperatures to develop in the USA’s Gulf Coast states. As summer conditions become too warm along the Gulf Coast, monarchs then migrate northward. Favorable warm temperatures, in places like Kansas, allow 4 new generations each year. Further north in cooler Minnesota, only 2 generations are possible. Thus, favorably warmer temperatures allow more generations per year, and more generations allow the monarch’s abundance to multiply and quickly rebound from their winter losses. The 2019 winter count determined wintering monarchs tripled their abundance from their 2013 low point.

Of course, each generation is also dependent on their food plant abundance, which landscape changes and pesticides greatly affect; a topic for part 2.

Jim Steele is Director emeritus of San Francisco State’s Sierra Nevada Field Campus and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism

Contact: naturalclimatechange@earthlink.net

No Meat For You!

Healthy Grazing and Grasslands

published in the Pacifica Tribune  January 2020

What’s Natural?

No Meat for You!

New York City Mayor Bill de Blasio recently announced NYC’s New Green Deal and his plan “to save our earth”. He stated NYC will reduce beef purchases by 50% and phase out ALL purchases of processed meat by 2030. It’s not clear how he defines processed meats, but the World Health Organization defines it as "meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavor or improve preservation."

Processed meats evolved before the era of modern refrigeration for good reason. Salting, curing, fermenting, and smoking meat increased the shelf-life of a limited food supply and thus increased human survival. But now processed meats are demonized. Certainly, some chemical additives are unhealthy, but demonizing all processed meats is just wrong. With good labeling people can freely choose what foods they trust.

But de Blasio’s edict would mean any institution run by NYC will no longer serve chicken nuggets, hotdogs, sausages, bacon, pastrami, ham, baloney, salami, pepperoni, corned beef and jerky. Fresh beef meals will be cut by 50% to “save the planet’s climate” from cow farts.  How far will these government actions go? Dairy cows fart too. Will milk, whip cream, cheese, yogurt and ice cream be next on the hit list? Will they later extend their ban to all of NYC? What if Mayor de Blasio ever became America’s president? Fortunately, de Blasio’s authoritarian actions are why so many Americans rightfully argue we need limited government!

There is no place for authoritarian diet control. We all experiment with our best personal diets. I went vegetarian for a few years. I liked learning to make tastier vegetables. But eventually I reverted to carnivorous ways. Most studies suggest our bodies evolved to eat both plants and meat, so I resent those who try to shame me for naturally eating meat. However, one PETA article did argue if you see dead animals on the side of the road, but are not tempted to stop and snack on them, you are naturally a herbivore. Really?

Nonetheless, vegetarians make a very valid point.  Over-grazing has been bad for the environment. Studies of temperatures in Arizona and Mexico determined lost vegetation from overgrazing caused soils to dry, raising regional temperatures by as much as 7°F compared to un-grazed adjacent lands. Over-grazing converts biologically diverse grasslands into barren deserts. But counter-intuitively, without grazing animals, grasslands still convert to deserts. Grasslands benefit from natural grazing and “holistic grazing” has been shown to prevent “desertification”. Unfortunately, overzealous radical vegetarians don’t understand - holistic grazing is a win-win for the environment and meat eaters.

Grasses do not decompose immediately. Nutrients get locked up for years while the accumulating “thatch” blocks the sun and inhibits the growth of new grasses. Accumulating thatch also enhances wildfires. Grazing animals not only remove thatch, their manure freely fertilizes the soil and promotes next year’s growth. Holistic grazing has demonstrated if we mimic the natural migrations of huge herds, as in Africa’s Serengeti, we can prevent desertification. Overgrazing typically happens when herds are confined to small pastures, too small to support the cattle’s needs.

I encourage everyone to google Allan Savory’s hope-filled TED talk titled “How to Fight Desertification and Reverse Climate Change”. Savory is originally from South Africa. There, cattle were removed from lands destined to become National Parks and Savory was charged with studying the results.  His studies revealed the park’s grasslands continued to degrade into desert despite removal of all cattle grazing. The “only” remaining explanation pointed to elephants. Regretfully he recommended culling elephants to sustainable levels. Such a recommendation was blasphemous, so government experts initiated another study. Unfortunately, government experts agreed. Too many elephants were ripping up vegetation. So, thousands of elephants were slaughtered.  The result - the land continued to degrade from grassland to desert.

Savory eventually understood holistic grazing was the only solution. If cattle were managed to imitate natural grazing, the land could be restored because cattle grazing would remove thatch, freely fertilize the ground, and supply a protective layer of moisture-holding mulch. Holistic grazing reversed desertification and stopped excessive warming of surface temperatures caused by overgrazing. And holistic grazing increased the storage of carbon in the soil.

The anti-meat-eating crowd often argues eating meat is a shameful, immoral and inefficient use of calories. They argue meat provides only a small fraction of the calories we would otherwise obtain by directly eating the grains fed to cattle. But that is a narrow perspective. By raising cattle holistically on grasslands, we efficiently obtain calories and protein that we could never acquire otherwise from inedible grasses. Globally there are huge swaths of land unsuitable for growing edible plant food, and where human populations must totally rely on grazing animals for survival.

So, feel no shame! Meat eating is not the ticket to climate hell! Holistic grazing is a win-win for meat eaters and the environment.

Jim Steele is director emeritus of the Sierra Nevada Field Campus, SFSU and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism.

Contact: naturalclimatechange@earthlink.net