Indicator Species

February 14, 2024 5:38 AM

Monarch butterfly numbers in Mexico plummet to near record low - "Biologists pin the blame for the nosedive on higher-than-usual temperatures and drought conditions where the butterfly reproduces, mostly in northwestern U.S. states like Washington, Oregon and California."

• NYT (archive): "Western monarchs were just 5 percent of their population in the 1980s, when numbers were often in the low millions, according to Xerces Society, a nonprofit group dedicated to insect conservation that participated in both surveys."

Migratory monarchs are listed as vulnerable, or threatened with extinction, by the International Union for Conservation of Nature Red List of Threatened Species, the world’s leading scientific authority on the status of species. They were initially classified in the more imperiled category of endangered, but their status was adjusted in September. The United States government has placed monarchs on what is essentially a waiting list for protection under the Endangered Species Act; the species qualifies for protection, officials have said, but others take priority.

• AP: "Ryan Drum, a biologist with the U.S Fish and Wildlife Service, said 'these low numbers we see here are a challenge for all of us.' He said the new data would be taken into account when U.S. experts make their recommendation on whether to list the migratory monarchs as endangered or threatened species. A decision on that recommendation is due in October."

Experts noted there were almost no butterflies at some traditional wintering grounds, because the monarchs appeared to have moved to higher, cooler mountain tops nearby. About two-thirds of the butterflies counted this year were found outside the traditional reserves. “The monarchs looked for other sites ... they are looking for lower temperatures,” Tavera said. Because some of the newer wintering sites aren’t included in the population count, there may have been more monarchs this year than the numbers suggest.

Horseshoe crabs, living fossils of the sea, draw endangered species petition - "These spine-tailed sea creatures named for the shape of their body shells have been crawling ashore since long before the age of dinosaurs, and in modern times were a familiar sight to summer beachgoers along the U.S. mid-Atlantic and Gulf Coasts."

But horseshoe crab populations have crashed in recent decades, with spawning numbers down two-thirds from 1990 in the Delaware Bay estuary that was once their biggest stronghold, according to conservation groups. Research also shows their egg densities falling more than 80% in the past four decades.

Those trends are tied to stress on other marine species that feed on their larvae and eggs, including the rufa red knot, a migratory shorebird whose own 2014 threatened-species listing cited horseshoe crab harvests as a contributing factor...

Harlan said non-industry research shows about 30% of horseshoe crabs collected for blood extraction die in the process. He added that synthetic alternatives are widely used in Europe, but U.S. companies have been slow to adopt them.

• The Blood of the Crab - "Horseshoe crab blood is an irreplaceable medical marvel—and so biomedical companies are bleeding 500,000 every year. Can this creature that's been around since the dinosaurs be saved?"[1]
• Vaccines are still tested with horseshoe crab blood. The industry is finally changing - "The U.S. Pharmacopeia, the regulatory body in charge of setting national safety standards, announced a proposal on Aug. 22 that would make it simpler for companies to use the alternatives. The new standard, which is expected to take effect in early 2024, is one of several changes enacted since NPR reported in June on the lack of oversight in the horseshoe crab blood harvest on the east coast, including in areas where the crabs' eggs are considered an important food source for rare birds."
• Horseshoe crabs: Ancient marvels facing modern threats - "Straddling both water and land, horseshoe crabs are a symbol of adaptability and resourcefulness in several cultures across the globe. It would be a shame if this prehistoric creature that survived mass extinctions is lost to anthropogenic exploitation. The horseshoe crab is a stark reminder of why we should revisit our existing relationship with nature, and rethink our overuse of its precious resources."

One in five of world's migratory species at risk of extinction - UN report - "Billions of animals make journeys across deserts, plains or oceans every year to breed and feed, and 'unsustainable' pressures put on migratory species could not only see their populations dwindle, but also disrupt food supplies and threaten livelihoods, the report said. Of the 1,189 species covered by a 1979 U.N. convention to protect migratory animals, 44% have seen numbers decline, and as many as 22% could vanish altogether, the report added."

The report, released on Monday, gives "a very clear direction" about what governments need to do to tackle the threats to migratory species, said Amy Fraenkel, executive secretary of the U.N. Convention on the Conservation of Migratory Species of Wild Animals. "It's always about implementation," she said ahead of the convention's meeting, held this week in Samarkand, Uzbekistan.

Humans pose the biggest threat, with activities including hunting, fishing and other forms of overexploitation impacting 70% of the species on the U.N. list. Habitat loss affected up to 75% of the species – underlining the need for more connectivity between isolated ecosystems... Conservationists urged governments to honour their 2022 pledge under the new global biodiversity agreement to set aside 30% of the world's land and sea territories for nature by 2030.

• State of the World's Migratory Species (pdfs) - "The world's migratory species of animals are in decline, and the global extinction risk is increasing."
• Smithsonian: "Van Doren shares one telling example. 'The Delaware Bay in the eastern United States is a crucial stopover point for many migratory shorebirds, especially the red knot, which is a poster child of a threatened migratory species,' he says. 'And if the horseshoe crab eggs they feed on aren't available at the right time and in the right quantities, then they won't make it to the Arctic in time to breed successfully, and their population may crash.'"

Benjamin M. Van Doren, a biologist at University of Illinois Urbana-Champaign who wasn’t involved in the report but whose research focuses on migratory birds, was startled by this fact. “The area of the most concern to me, or most surprising, given that I focused on birds, was that fish are so threatened,” he says. North America alone has lost about a third of its bird population since 1970. “But compared to birds, the report showed that migratory fish are in even more dire straits. I’m sure this wouldn't come as a surprise to a fish biologist, but for me, it was really eye-opening.”

• The Conversation: "The world's most threatened listed species are fish. Of the migratory species that the convention lists as needing some level of protection, 97% are under threat of extinction. Over-exploitation from hunting and fishing stands out as the most significant threat to migratory species globally. The report spotlights fishing bycatch as a huge problem. Bycatch occurs where commercial fishers of one type of fish kill other marine creatures that get caught in fishing nets."[2]

posted by kliuless (9 comments total)

Monarch caterpillars only eat milkweed; no fields of milkweed and we get no monarchs.
posted by tofu_crouton at 6:07 AM on February 14 [2 favorites]

Monarchs were all over the place in southwestern Ontario when I was a kid. Now when you spot one it's a bit of pleasant surprise, like seeing a rainbow.
posted by The Card Cheat at 6:09 AM on February 14 [5 favorites]

Monsanto takes a big chunk of the blame here too:
We estimate that there has been a 58% decline in milkweeds on the Midwest landscape and an 81% decline in monarch production in the Midwest from 1999 to 2010. …
loss of agricultural milkweeds is a major contributor to the decline in the monarch population.

And monarchs are basically charismatic megafauna here, the loss of hedgerows spurred by rampant pesticide use enabled by glyphosate-resistant crops has trashed the populations of tons of bugs and birds.
posted by SaltySalticid at 6:26 AM on February 14 [11 favorites]

This was noticable; in the previous two seasons on the Gulf Coast you could always see one or two monarchs within eyeshot, but this year not very many.

And speaking of horseshoe crabs ... just flip 'em!
posted by credulous at 6:30 AM on February 14 [3 favorites]

It may seem small, but you can make a real difference to insects like monarch butterflies by planting native plant gardens. My wife planted a bunch of native plants in our small front yard when we lived in Philadelphia, and the impact on insect biomass and biodiversity in our yard was immediate and profound. We didn't intentionally plant milkweed, but some self-seeded and we kept it, and we did get to see monarchs a couple of times. Not like I remember when I was a kid, when you'd see them everywhere in the summer, but they came.

We are lazy gardeners and native plants were perfect, they did great with relatively little watering because they're well adapted for the local environment.
posted by biogeo at 9:54 AM on February 14 [5 favorites]

We've lived close to the north shore of Lake Ontario for > 30 years, and we see migrating birds as well as monarch butterflies "mass" on our shore in the fall, prior to the flight across. Yes it does seem like the monarch numbers are down.

My cynicism on the global situation overall is really high this year, but yeah, putting in some milkweed and other bug-friendly plants would be a good thing. Some parts of Toronto's parklands are being "rewilded".
posted by Artful Codger at 10:17 AM on February 14

My home garden is a certified wildlife habitat. Here's what I know about how to help monarchs through home gardening:

1.) To feed monarch caterpillars: Plant species of milkweed that are native to your region. This is really important. There are a wide variety of milkweed species native to different ecosystems. If you plant a type of milkweed that is not from your area, it emerges at the wrong time and blooms at the wrong time and goes dormant at the wrong time, and all of this can confuse butterflies into laying eggs at inappropriate times and also can promote the growth of parasites that can harm caterpillars. Also: it's best to plant a wild type of milkweed not a cultivar that has been selectively bred to produce an altered color or bloom size. This type of selective breeding can change the nutritional properties of a plant. We want to offer the caterpillars food they would naturally eat in their wild habitat. To find the best milkweed plants for your garden, talk to a local native plant gardening or pollinator gardening group or a nursery that specializes in selling native plants.

2.) To feed adult monarch butterflies (who need to eat nectar from a variety of flowering plants): Plant a variety of locally native wildflowers that are preferred sources of food for native butterflies. Monarchs particularly love flowers in the blazing star and goldenrod families. They also enjoy native coneflowers and asters. For best results try to plant a variety of flowers that bloom at different times from spring through fall, so there is a continuous food source during butterfly season.

3.) Avoid/limit the use of insecticides in your home garden as much as possible, especially in areas where you are trying to create monarch habitat. This includes organic insecticides like diatomaceous earth or neem oil (remember: if it kills bugs, it kills monarchs-- monarchs are bugs). Yes this means you might have to let the aphids chomp on your milkweed. You did put it there to get eaten, right?

4.) To the extent reasonable given local water conservation concerns, water your plants (even native plants) occasionally during periods of severe drought to make sure they can continue to produce nectar. A drought-stressed plant may fail to bloom, reduce nectar production to conserve water, or drop blooms early. This is one reason why last year's widespread drought in the US had such a negative impact on pollinators. Go ahead and let the grass lawn die but keep your native wildflowers blooming if you can.
posted by BlueJae at 10:57 AM on February 14 [14 favorites]

i have never ever been interested in gardening. it seems like a lot of work. but if i ever get a house, i am absolutely planting some native stuff because i want butterflies and fireflies again. of course there will probably be a city ordinance about lawns or some shit that won't let me.
posted by misanthropicsarah at 10:27 AM on February 15 [1 favorite]

You might be surprised at what you can get away with, misanthopicsarah. Some native flowering plants that support butterflies are quite conventionally pretty and would not look out of place in a formal garden setting. Even if all your local ordinances let you get away with is a little patch of purple coneflowers and butterfly milkweed (the most compact and well-behaved of the North American native milkweeds) you'll be doing something.
posted by BlueJae at 12:41 PM on February 16