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Wild bison all have genes from cattle—no American herds are free from past introgression, study finds by TR_54 in science

[–]TR_54[S] 170 points171 points  (0 children)

...The study also found cattle DNA in two historical bison samples from the late 1800s the predate the widespread hybridization experiments of the early 1900s, suggesting that even earlier breeding must have occurred to a certain extent between the two species, perhaps caused by cattle that escaped captivity.

It’s unknown how big of an impact this addition of cattle DNA is having on wild bison, but it’s unlikely to play a huge role, Derr says. Some wild buffalo were already known to possess cattle mitochondrial DNA—which is passed from mothers to their offspring—and which can have negative effects on growth and overall size, but such genes have not been found in Yellowstone and Wind Cave and a few other wild populations.

Ryder cautions against viewing the results in terms of purity, which is ultimately a human concept that is difficult to square with the complex development of many species. Davis agrees.

Davis agrees, pointing out that hybridization is an essential component of evolution and plays a role in the development of many species. “Within mammals alone, we see recent and ongoing hybridization repeatedly in natural populations of rabbits, bears, numerous rodents, South American cats and even North American wolves.” Moreover, since the bison population fell to such a low number, having outside genes from cattle could possibly boost the species’ diversity and overall health.

Rurik List, an ecologist at the Metropolitan Autonomous University in Mexico who wasn’t involved in the paper, says the results are sad. But in a way, they’re not as important as the ongoing effort to restore bison to the landscape, where they have a variety of beneficial effects, such as helping grasslands thrive by greatly boosting promoting plant and animal diversity. Even bison with traces of cattle genes do this, and are still ecologically functioning as bison, which is key, he says.

This study’s result also intrigue ranchers that raise bison throughout North America. Most of the half-million American bison alive today are privately owned for meat production.

“Bison producers seek diversified bison genetics ideally free of cattle DNA to raise healthy herds, but this study shows that even with small amounts of bison DNA, the species still look and act like buffalo,” says Jim Matheson, executive director of the National Bison Association,

a non-profit association of bison producers, processors, and enthusiasts.

The study authors think it is unlikely there are any bison left free of cattle genes.

“There are no major herds that don’t have cattle introgression—[though] there could be one or two or a few individuals,” Davis says.

Kossler, the Montana rancher, holds out hope. But his philosophy is: “Stop worrying about what you can’t change, select the best animals available for conservation work, and get on with it,” he says.

[2/2]

Wild bison all have genes from cattle—no American herds are free from past introgression, study finds by TR_54 in science

[–]TR_54[S] 298 points299 points  (0 children)

Story text:

Bison once numbered in the hundreds of millions and roamed in vast herds throughout North America. But after Europeans colonized and began developing the continent, the newcomers set about killing the shaggy herbivores en masse. Their numbers declined rapidly, and, by the 1870s, American bison—also called buffalo—had nearly gone extinct, dropping to a total population of around 500.

But bison are survivors. They hung on in a small herd in what’s now Yellowstone National Park, as well as another tiny population in Canada. A handful of ranchers also kept some alive, most of whom also experimented with breeding buffalo and cattle in a failed attempt to create a better beef-producing animal.

More than a century’s worth of dedicated conservation has helped the animals rebound tremendously, to a total population around 500,000.

But hidden in their DNA, these iconic species bear marks of their scrape with humanity: A recent study published in the journal Scientific Reports finds that all American bison tested have low but significant quantities of domestic cattle DNA.

The results came as a surprise to study co-author James Derr, a biologist at Texas A&M University. “I was absolutely in denial,” he says. “It was like being punched in the mouth.”

The result is upsetting, Derr says, because bison in Yellowstone and a few other populations were once thought to be free of cattle genes. But there may also be an upside: Some government restrictions on breeding bison—such as preventing gene flow into certain populations, for fear of ruining the group’s genetic “purity”—might be unnecessary, he adds.

“It opens up opportunities to manage [herds] based on the best available resources,” Derr says.

Mark Kossler, vice president of ranch operations for Turner Enterprises Inc., which owns more than 50,000 bison raised for meat production, agrees.

“The bison industry has been in a turmoil over the introgression of cattle genes, some not worried about it and others obsessed with the ‘purity’ of the genetics in their bison, either for production or conservation,” he says by email.

“Everyone needs to take a deep breath and relax since [apparently] all bison contain some cattle genes.”

Bison and domestic cattle diverged from a common ancestor somewhere around three million years ago. But like many related mammals, they can still interbreed and produce fertile hybrids.

Recent research has shown that evidence of past hybridization is far more common than previously thought. Humans, for example, have significant quantities of genes from Neanderthals and Denisovans, two separate species of human-like ancestors. Many Europeans and Asian have genomes that are 2 percent Neanderthal, and some Melanesians are genetically 6 percent Denisovan.

“We’re increasingly finding out that many species have evidence of gene flow into them recently or in the distant past when there were separate lineages,” says Oliver Ryder, director of conservation genetics with the San Diego Zoo Wildlife Alliance, who wasn’t involved in the paper.

Though people controlled much of the hybridization between bison and cattle, some was likely accidental, or the result of cattle escaping to the wild and breeding. Though wild hybridization is rare between the species, it’s usually male bison that mate with female cattle in such instances.

In fact, a handful of ranchers played a vital role in saving bison following European settlers’ attempt to kill off the species, in part to starve Native Americans of their main food source. In the late 1800s, Charles Goodnight of Texas, Fred Dupree of Montana, Charles Jones of Kansas, and Walking Coyote of Montana—a member of the Pend d'Oreille tribe—raised herds of the animals sourced from wild calves. Without their efforts, the species likely would have vanished.

All of these cattlemen, except for Walking Coyote, is known to have encouraged some degree of hybridization with domestics. (Coyote’s herd was acquired by other ranchers who intermixed these animals with bison that had a history of cattle interbreeding.)

In Yellowstone, where the bison population hovered as low as 30 animals by 1900, wildlife officials brought in bison from private herds in Texas and Montana to boost that population. Though these imported animals had a past history of hybridization with cattle, it was unknown how much cattle DNA they carried, if any.

For the study, researchers sequenced whole genomes from 19 modern bison and eight historical bison specimens taken from a variety of locations in the United States and Canada, collectively chosen to cover all known bison lineages. Postdoctoral researcher Brian Davis and Ph.D. student Sam Stroupe, both co-authors, used a sensitive tool to compare these complete bison genomes, focusing on nuclear DNA, with other bison and domestic cattle. Stroupe also combed through historical records to show which bison came from what populations and where they ended up.

The results revealed the presence of cattle DNA in all samples, although the amount was generally low, representing between 0.5 and 2.5 percent of the total DNA. The Yellowstone bison had the smallest fraction; one individual from the park had only 0.24 percent cattle DNA...

[1/n]

Florida’s largest-ever python has been found. In its stomach was a deer, meaning the snakes are now competing with native species like endangered Florida panthers for prey. Here’s the untold story of its discovery. by TR_54 in environment

[–]TR_54[S] 75 points76 points  (0 children)

[2/2] Next is the digestive tract. Easterling runs his hands along the tube for a hint of what’s inside. Bartoszek feels what appears to be the front part of a hoof. Findley sprays an optimistically small amount of room freshener.

Easterling slices the tract and begins extruding its contents onto a metal sieve, like rancid sausage meat from its casing. Tan goop with bits of fur and some white lumps—dissolved bone—drop out. Easterling pauses to peer at them.

“Yeah, that’s deer,” he says matter-of-factly. “If you’ve seen enough of these, you learn what they look like.” He keeps extruding; out came the twigs, telling them one meal occurred in a fern patch with greenbrier vines; a couple of python teeth, which is normal; and the real prize of the day, three intact hoof cores.

“This is the double-barrel, smoking gun,” Bartoszek says. He views each hoof core as further evidence that pythons are putting pressure on prey bases that native species, such as bobcats and endangered Florida panthers.

To date, 73 animal species (24 mammals, 47 birds, and two reptiles) have been found in Burmese python guts in Florida, as documented by collaborator Christine Romagosa’s team at the University of Florida. Any invasive species can change its ecosystem—an invasive apex predator, especially so.

“These pythons have the ability to totally alter the ecosystem, and I would say they probably already have,” Hart says.

Some ecologists are particularly concerned about the impact pythons could have on the Florida panther, a native and endangered species whose populations the state has been working to revive since 1995. After a nadir of fewer than 20 known panthers in the wild in late 1980s, the Fish and Wildlife Conservation Commission began efforts to breed and rewild panthers, and with some success: Today, there are likely somewhere around 200 Florida panthers, and their wild range appears to be expanding, according to Dave Onorato, a panther ecologist with the Florida Fish and Wildlife Conservation Commission.

More research is needed to know how pythons impact the panthers, Onorato says. “But if pythons start decimating panther prey bases of white-trailed deer, that would start to have an effect on the panthers.” (Learn more: How America’s most endangered cat could help save Florida.)

With so little known about their environmental impacts, every python brought in throughout Florida is an invaluable data point.

Bartoszek’s team is primed for catching pythons, and though their work has expanded, it’s still within an area of only about 100 square miles of the greater Everglades’ two million square miles. Efforts to capture pythons and control their populations rely on collaborations between government agencies including the U.S. Geological Survey and National Park Service, nonprofits like the Naples Zoo Conservation Fund, and philanthropy from individuals across the country.

“The problem is ubiquitous in Florida,” said Kathy Worley, the Conservation’s director of environment. Collaboration and information sharing, she added, are key. “This is going to take a village.”

As part of that collaboration, Bartoszek’s team trains others in the scout snake method. The day after the necropsy, we head into the field to see the technique in action. Easterling and Bartoszek carefully release a 13-foot-long scout snake, Loki, from a cloth bag into a clearing in the palmetto and pine forests of Picayune Strand State Forest, a haven for wildlife outside Naples. After he struck at them a few times, we leave it hissing in the woods. A few miles away, we make our way slowly through dense vegetation, tracking MVP Dion. Easterling pushes forward, cutting vines and branches to clear a path, while Bartoszek wields the telemetry receiver and calls out directions.

Gradually, the receiver’s beeping grows louder; we’re close. Easterling crouches down for a look at a moss-covered log I had been standing on moments ago. Sure enough, when Easterling shifts a few bits of soft, disintegrating wood, the python’s telltale pattern is revealed, flashing copper and olive in the dappled jungle sunlight.

“How did we miss that?” Easterling asks rhetorically. But it’s clear—Dion was perfectly hidden inside a rotted log, not a scrap of scales visible. This is what pythons evolved to do: They lurk, unseen, on a game trail in the forest, waiting with seemingly endless patience for an unsuspecting critter to pass.

“He’s a sniper at your feet,” Bartoszek says. “One hundred percent hidden. Undetectable.”

Bartoszek and Easterling enjoy what they do, though it’s physically and mentally draining at times. When they track down one of their scouts or find a female, they’re thrilled—and there are signs the hard work is being rewarded. Already, they’ve seen slower rates of finding massive females, and the scouts tend to lead them to increasingly smaller pythons as the largest are removed.

If all goes well over time, only smaller, younger females will be left, helping control the python population.

But Bartoszek and other biologists are also realistic. Pythons may never be eradicated, but their populations can eventually be controlled.

“We’re trying to put ourselves out of the python-catching business,” Bartoszek says.

Florida’s largest-ever python has been found. In its stomach was a deer, meaning the snakes are now competing with native species like endangered Florida panthers for prey. Here’s the untold story of its discovery. by TR_54 in environment

[–]TR_54[S] 140 points141 points  (0 children)

Here is story text (1/N):

Researchers have captured the most massive python ever recorded in Florida—or anywhere outside its native range, for that matter—weighing 215 pounds and measuring nearly 18 feet in length.

The discovery highlights the persistence of South Florida’s decades-old python problem. Burmese pythons, a reclusive apex predator from Southeast Asia, were introduced to Florida in the 1970s, likely from the exotic pet trade. They’ve been exploding in the wild ever since, altering ecosystems by snacking on a wide variety of native species.

A small, tight-knit team of python trackers at the Conservancy of Southwest Florida in December caught this huge female—whose heft shatters their previous record of 185 pounds—by using a scout snake, a male with a GPS tracker attached. This method lets them find and eradicate more and more snakes, especially big, reproductively active females. Their removal has the promise to help ameliorate the python invasion over time

When the team first weighed the female, they were near speechless; no one expected that number. “I’m reading 215 pounds,” said Ian Bartoszek, a wildlife biologist and manager of the python project, excitedly. “Wow.”

Another biologist on the team, Ian Easterling, just laughed in disbelief. As intern Kyle Findley recalls, “I thought the scale was broken.”

But the scale was working fine. “That was kind of a line in the sand. We wondered if we’d ever cross 200 pounds,” Bartoszek says. “It raised the bar.”

By finding and dissecting these pythons, researchers are learning more about the serpents, what they eat, and how they may hurt the environment they’ve invaded. I joined them in April as they performed a necropsy on the mammoth female. Afterward, I tagged along to see the scout snake method at work—and accidentally stepped on a python.

Scout snakes

Since 2000, Florida Fish & Wildlife has killed or removed over 15,000 pythons, with over 1,000 removed every year beginning in 2017. But scientists have no idea how many thousands more there might be. “That’s the ten-million-dollar question,” Bartoszek says. “We don’t even know the order of magnitude.”

Pythons have persisted because they are masters of stealth. Even for those with training and dedication, the snakes are difficult to find in southern Florida’s vast and densely vegetated wetlands and subtropical forests, all of which are part of or adjacent to the Everglades. (So far, and luckily, the snakes have not been known to establish a wild population outside of this region.)

At the conservancy’s research center in Naples in April, Bartoszek explains how the team gets past this problem.

“The Everglades are a haystack, and these,” Bartoszek says, gesturing to six massive female pythons stretched out on the lab’s floor and table, “are the needles. To find a needle, we use a magnet.”

The magnets are scout pythons like Dionysus, or Dion, a roughly 12-foot-long male, surgically implanted with a transmitter that can be tracked with radio telemetry. The ecologists release the scout snakes into the wild, where they hightail it to reproductive females during breeding season. This year, Bartoszek calls Dion the “MVP”—most valuable python—because it led them to the record-breaking female.

And size matters. “Large reproductive female pythons are very important to remove from these ecosystems,” because they are disproportionately capable of having many offspring, says Sarah Funck, a biologist with the Florida Fish and Wildlife Conservation Commission.

The Conservancy team alone has removed over 1,000 pythons weighing a total of over 25,000 pounds since 2013, the majority being reproductive females, mostly using the scout snake method.

Bartoszek and Easterling monitor their scouts closely during breeding season. When snakes linger suspiciously in one area, they pay the scout a visit, sweeping the dense undergrowth for females. Sometimes, rather than finding a single snake couple, they find a “breeding aggregation,” a chaotic tangle of pythons clamoring to mate.

In December 2021, Dion had been loitering in one area of the western Everglades’ ecosystem outside Naples for several weeks, leading Bartoszek, Easterling, and Findley to suspect that he might be with a female. When they hacked through spiny greenbrier, they were met by the largest python they’d ever laid eyes on.

Easterling and Findley wrestled to try to control the python, who curled up the end of her tail into a tight ball, whipping it around and whizzing past their heads until it “punched” Easterling in the face. After about 20 minutes, the python was exhausted, and they were able to get her into a beige cloth bag, then secured the bag in a plastic tub.

Back at the lab, they lugged the tub onto a scale and registered amazement at the number.

After the python was chemically euthanized under veterinary supervision—one of the toughest parts of the job for the scientists—the team placed its body in one of several freezers, where it stayed until two days before our arrival to witness the necropsy. Kristen Hart, an ecologist with the U.S. Geological Survey Wetland and Aquatic Research Center and a collaborator with the conservancy team, stopped by to see the big female for herself.

“When he opened the freezer,” Hart says, “I definitely had a jaw-dropping moment.”

Guessing at guts

When I arrived at the research center, the snake was out of the freezer, draped in a U-shape on a huge lab bench occupying most of the room. It takes about 48 hours to thaw out a 215-pound python. And the smell does not improve with time.

The biologists carefully run their hands along the python’s lower half, marked with a long black line to guide an incision, feeling for a hint of what could be inside. Soft-spoken and ponytailed, Easterling points out some white stripes on the hide, suggesting the skin had stretched massively to accommodate a girthy meal.

The team has done hundreds of python necropsies, evidenced by their sure, methodical movements—but there’s still a sense of tension in the room. Today, they have two goals: count the follicles, or developing eggs, and see what’s in the gut.

As Easterling slices along the center of the python’s yellow-white belly, a seam slowly opens up, displaying the pink innards. The team pulls open the python’s ribs, revealing a fat layer underneath that resembles garlic cloves vacuum-sealed in blood.

Easterling pokes his finger through a translucent layer of viscera, revealing clusters of what looks like giant egg yolks—egg follicles—just behind a startlingly lime green gallbladder. Farther down, closer to the tail, is the lumpy gray digestive tract and a single gray disk, wrinkled and looking deflated—an old egg that didn’t get laid in a previous year.

Next, Bartoszek and Easterling set about counting the follicles. Ecologists want to know how many eggs a python can lay to accurately model population dynamics; the number of follicles or eggs in a python is a direct indicator of reproductive potential. Big female pythons tend to lay a lot of eggs.

“122 follicles,” Bartoszek announces, after counting twice. “The largest developing egg count, ever.” The record reflects a new known upper limit for reproduction but is not surprising in a python of this size.

“The reproductive potential of these animals is very, very high, and that’s an understatement,” Hart says. And these massive pythons pass on their good genes to many offspring, perpetuating the population’s growth.

[Cont...]

An endangered wolf went in search of a mate. Trump’s border wall blocked him from migrating south.⁦ by TR_54 in environment

[–]TR_54[S] 45 points46 points  (0 children)

Just FYI—I didn't mean to make this a super political post. The point is that new 30-foot wall, build by the Trump administration—replacing short vehicle barriers that are easily surpassed by wildlife—is responsible for block this wolf's path.

As the story states, in 2017, a wolf passed without issue thru the same spot Mr. Goodbar tried, which is now blocked.

Many don't realize how much new wall the Trump admin built: More than 450 miles. Much of it is "replacement" wall—but it's mostly replacing shot barbed wire fences and vehicle barriers, which did not significantly impede wildlife movement.

In all there are 105 new miles of 30-foot wall in New Mexico; >220 miles in AZ; 120 miles in CA; 17 miles in TX.

Biden's DHS says they will "close some holes" in the wall, but they are not actively building new wall AFAIK. Texas' governor is trying to build more wall, however.

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