It’s time to talk about the birds and the bees, and the moths and bats and wasps and birds and butterflies and lizards. Since we rely upon these animals to pollinate over 65 percent of the foods we consume, they are essential for a healthy ecosystem, and many of them are in decline. Even though insects comprise 5.5 million of the 8 million animal and plant species on Earth, it’s estimated that 40 percent of these species are in decline, and could be extinct within decades.

The mechanics of their roles are fairly simple. Pollinators flit from flower to flower, taking pollen from one as they consume nectar, and spreading the pollen onto the stigma of others, essential for the plant’s reproduction. The plants can then produce fruit, vegetables, seeds, and new plants. While some plants are wind pollinated, the vast majority rely upon these pollinators to get the job done.

To show how monarchs rely on national park sites, the National Park Service notes that some monarch butterflies overwinter at San Antonio Missions National Historical Park in Texas, recharge in Spring with nectar gathered from Riddell’s goldenrod at Ozark National Scenic Riverways in Missouri where they lay eggs for a second generation, spend some time in summer at Shenandoah National Park in Virginia where the third generation arrives, and end their summer in Acadia National Park in Maine where the fourth generation is born.

But what’s causing their decline? The reasons range from increasing land-use, agricultural controls, a changing climate, disease, and the influx of non-native species. Two types of pollinators seem to be seeing the most rapid decline: bees and butterflies.

Butterflies...

Two decades ago, there were millions of monarch butterflies (Danaus Plexippus) in North America. They would spend the winter months in Mexico and California, then migrate north over a number of generations. But, just since 2005, more than 80 percent of the Western monarchs have disappeared. In 2020, the U.S. Fish and Wildlife Service said that listing the monarch butterfly under the Endangered Species Act was warranted.

According to a just-released study by a Washington Department of Fish and Wildlife researcher, Braeden Van Deynze, and others, the collapse may be blamed on our own food production.

“Insecticides, more than herbicides, land use, and climate, are associated with declines in butterfly species richness and abundance in the American Midwest,” they write.

Their research specifically identifies neonicotinoid pesticides, and non-glyphosate herbicides as primary factors, common in today’s large, corporate agricultural operations, which indiscriminately kill good bugs and plants along with the bad.

And scientists in the National Park System have taken notice of the issue and have been documenting the populations of their pollinators, specifically monarchs and bees.

Monarch butterfly researchers in Dinosaur National Monument and Grand Canyon National Park have quantified not only the numbers of monarchs, but also the health of the milkweed plants, the monarch’s only food source. Monarchs only lay eggs underneath milkweed leaves, and caterpillars only feed on milkweed.

This perennial’s seed pods are filled with silk and produce a milky latex that is poisonous to most other animals. Some parks are encouraging, and even building, special pollinator gardens. Helping out the butterflies, rangers at Grand Canyon National Park have created two monarch butterfly habitats and pollinator gardens, one on each rim. Funded by the National Park Foundation, these gardens are also an educational opportunity for visitors to the park.  

Grand Canyon National Park has created two gardens to attract pollinators/NPS

Meanwhile, in Acadia National Park, surveys have identified 1,360 species of bees, butterflies, and moths on Mount Desert Island, most of which is lies inside the park. According to Catherine Schmitt, the science communication specialist at the Schoodic Institute, populations are changing.

“Over the last 10 years, contributors to the online global biodiversity platform iNaturalist have confirmed that 274 of those species still live in Acadia,” she says. “These volunteer scientists also identified 88 species not found a century ago that are presumed to have arrived here in recent decades. We continue to focus on pollinators in Acadia as part of our broader biodiversity monitoring efforts."

While there are 200 different species of milkweed worldwide, the common milkweed (Asclepias syriaca) is the only one found in Acadia National Park. The monarch butterfly migrates nearly 3,000-miles, from Mexico to Maine. They only travel from 5 to 10 miles per day. Each generation lays eggs in about 25 days, so it’s the fourth generation that reaches Acadia National Park. The migration of these butterflies is a natural wonder to see.  When Rachel Carson visited the Maine coast, she wrote of the monarch butterflies, “…most of all I shall remember the monarchs, that unhurried westward drift of one small winged form after another, each drawn by some invisible force.”

Tags help researchers track monarch butterfly travels/NPS

At one time, hundreds of millions of monarch butterflies migrated from the far north to Mexico every year, with a million of those headed to California’s west coast. At one time, amidst the giant redwoods in the 558 acres of Muir Woods National Monument, the arrival of the monarchs was truly a spectacle of nature every September. Monarch butterflies would head to the coast to overwinter, months when they would head to warmer climates and roost in trees.

"Like mammals hibernating in the winter, monarch butterflies consume enough nectar to sustain themselves throughout the winter without having to feed. However, monarchs do require water from streams, puddles, or even dew on tree leaves when overwintering," notes the Pollinator Partnership.

Mia Monroe just retired after 50 years with the National Park Service there, and has seen the drop in pollinators.

“I shared with people the wonder of the migration,” she says.

However, over the last three decades there has been an ongoing decline in monarchs that winter at Muir Woods, more than likely due to habitat loss and disruption.

“We were noticing a steady decline,” says Monroe. “There were less than 2,000 butterflies in 2020. It’s an extinction vortex. It’s very worrisome.”

Some neighboring landowners, like the Niman Ranch, have taken the monarchs' survival into their own hands by planting milkweed and other food sources. And, the West Main Monarch Sanctuary has plans to plant more than 1,000 native pollinators, flowers, shrubs and grasses.

“The community is supporting overwintering sites,” says Monroe. “There’s a little bit of increase, but they’re still in deep crisis.”

The Yosemite Conservancy also is working to replace meadow grasses with vegetation that pollinators need.

“Non-native, invasive grasses provide no value to pollinators and are food deserts to them," David Campbell, vegetation and ecological restoration scientist at Yosemite, said on the park's website.  “Native plant and pollinator diversity will not recover in these areas without our help."

And monarchs aren’t the only butterfly in trouble. There are more than 100 butterfly species in Everglades National Park, but it’s the Bartram’s scrub-hairstreak butterfly that is struggling to survive. Their only food source is the pineland croton, a native shrub. Underneath the tall pines, there is a short understory of shrubs, and the croton requires periodic cleansing by fire to grow. Fewer croton means fewer butterflies.

...And Bees

Of course, another signature pollinator that is in trouble are the bees.

There are more than 20,000 different species of bees worldwide and about 3,000 in North America that are responsible for pollinating more than 80 percent of all our flowering plants. In 2014, 30 national parks, 10 national lakeshores and seashores, and six national recreation areas, historical parks and parkways, along with Harvard University researchers, participated in bee inventories in three habitats: coastal, inland arid, and high elevation.

They sampled more than 43,000 bees from 2010 to 2013, and helped to establish a baseline study of where they were found, numbers, and species. These inventories are essential information for park management. Over the past decade, entomologists have continued to track the decline of many of these species.

For example, in Acadia, three species of the Ashton’s cuckoo bumble bee (Bombus ashtoni) and the Rusty-patched bumble bee (Bombus affinis) were all present in a 1900 survey but are not in the park today. In San Juan Island National Historical Park off the Washington coast, researchers have seen the Island Marble butterfly (Euchloe ausonides insulanus) move towards the protected area of the park after losing their habitat elsewhere.

Sometimes, park staff translocate species no longer present in their park, like the successful reintroduction of the Mission blue butterflies at Golden Gate National Recreation Area, after a fungal outbreak devastated their food source, the silver lupine.

A common eastern bumblebee/Sheila Colla

Dr. Sheila Colla is an associate professor of conservation science at York University in Toronto, and studies the native bumble bees. One species she has focused on is the rusty patched bumble bee (Bombus affinis) whose population is in decline, though it was once common from the Dakotas to the Eastern Seaboard.

“There are few remnant populations,” says Colla. “It’s disappeared from the vast majority of its native range. It’s an early-emerger, and an important pollinator for things like blueberries and cranberries. And, it’s one of the last species to go underground in October.”

While some point to the use of pesticides and habitat loss for the decline, Colla believes diseases introduced by honeybees are the culprit, with hives trucked back and forth across the country.

“Honeybees are brought to California to pollinate almonds, then [head] northeast for apples. Bees are being moved all over, they’re stressed out, and it’s not natural.”

While bumble bees are mostly used in greenhouses, honeybees don’t do well in enclosed spaces; hence, they’re more susceptible to disease. Also, honeybees don’t hibernate, as do native bees. They stay awake all winter, requiring pollen and nectar.

Bees are essential pollinators/Patrick Cone

Colla says that honeybee hives near protected areas, such as national parks, compete with native bees and spread disease. “They can fly up to 15 kilometers,” she says. “We need to think about having some sort of buffering area. It’s extremely dangerous to bring honeybees near protected areas. Honeybees have lots of PR; native bees not so much.”

And commercial beekeepers have been moving their hives more frequently onto U.S. public lands. In 2020 public land managers approved nearly 1,000 hives in Utah and Arizona’s five national forests. Utah’s Grand Staircase Escalante National Monument is one example where honeybees have impacted native bees. There are more than 650 native bee species in the monument, and lately beekeepers are seeking approval to store hundreds of millions of honeybees in 100 hives adjacent to the monument.

If native pollinators are being pushed out by invaders, can't the new ones provide the same service?

"Native plants and insects have co-evolved together over thousand of years," said Colla. "Many have specialist relationships like the well-known monarch and milkweed and others have relationships we are just beginning to understand."

Mankind has changed the landscape and ecosystems of the planet, many times will ill effects. By encouraging and protecting pollinators we’ll ensure not only a complete landscape, but keep them doing what they do: helping plants to reproduce.

What You Can Do To Help

• Cultivate nectar-rich flowers that are native to your area
• Abstain from the use of pesticides
• Let parts of your lawn grow wild to provide shelter and nesting habitat
• Leave leaves on the ground for small animals
• Consider setting water out