Among a growing list of species in need of federal protections, the U.S. Fish and Wildlife Service has placed the Knowlton’s cactus and Uncompahgre fritillary butterfly on the endangered species list. According to Fish and Wildlife, an endangered listing is any species in danger of extinction through all or a significant portion of its range, whereas a threatened listing is any species that is likely to become endangered within the foreseeable future.
For a brief moment in time, Southwest Colorado was home to one of the rarest species of cactus in the United States. But only for a moment. In 1958, Bayfield resident Fred Knowlton stumbled upon a small, penny-sized cactus in the piñon-juniper woodland near the Colorado and New Mexico border, which was sent off to a lab and determined an unidentified species. The newly discovered cactus, eventually named the Knowlton’s cactus, was thought to be growing on the Colorado side of the border, until a revised land survey proved otherwise. “It turns out that there was an old fence they thought was the state line, but it wasn’t actually the state line,” said Fish and Wildlife biologist Aimee Brittendon. “When they put up a new fence, they realized the cactus didn’t extend into Colorado.”
However, when the Knowlton’s cactus (Pediocactus knowltonii) was listed on the endangered species list in 1979 in an effort to stave off staggering population declines, areas on the Colorado side of the border were deemed suitable habitat for the plant. No documented populations of Knowlton’s cactus have been found in Colorado, but it’s unclear to this day whether that’s because it does not naturally occur here or the species was wiped out before it was identified. That’s because shortly after the Knowlton’s cactus was discovered, plant collectors ravaged the hillsides around Navajo Dam in search of the rare species, causing populations to drop from an estimated 100,000 plants in 1960 to just 1,000 in 1979.
With Fish and Wildlife’s endangered listing came a host of new protections for the plant, but it has seemingly proved too little, too late. Brittendon said attempts in the 1980s and 1990s to replant the Knowlton’s cactus overwhelmingly failed, with only a few plants surviving the fickle process. “We don’t have a good enough understanding to even know why these populations didn’t take off, but they didn’t,” she said. That left Fish and Wildlife with one last ditch option: protect the only remaining plot of land where the cactus could still be found. That land, which remains undisclosed, was purchased by the Nature Conservancy in the hopes of keeping the population alive. Over the years, Fish and Wildlife was able to document more clusters of the cactus and curb illegal collecting. By 1992, researchers thought the plant was on the rebound when a survey showed 12,000 plants. But with new threats associated with climate change, namely drought, the species has declined 60 percent from 1992 to 2015. Today, only 3,500 Knowlton’s cacti are thought to exist on a 25-acre hillside near Navajo Dam in New Mexico. “We need a better understanding of habitat characteristics because then we can better focus efforts,” Brittendon said. “With one population, it’s hard to know its specific needs.” Fish and Wildlife has collected and stored seeds from Knowlton’s cactus should biologists figure out a way to successfully replant the species. “At least with seeds we’re keeping the species in existence,” Brittendon said. “Then as we collect more information, hopefully, we can find a way to be successful at planting.”
Uncompahgre fritillary butterfly
Last summer, when Fish and Wildlife staff members went to conduct an annual population count of one of the last remaining Uncompahgre fritillary butterfly (Boloria acrocnema) colonies, their worst fears were realized. The colony – located high in the alpine tundra of the San Juan Mountains – was gone. “That colony had been declining slowly over the last few years for reasons we don’t know,” said Terry Ireland, a biologist with Fish and Wildlife. “It’s a little scary.” By all estimates, there are only 11 known remaining colonies of the Uncompahgre fritillary butterfly – one of the last species of North American butterflies to be discovered. The butterfly was first found in the San Juan Mountains in 1978 and was named after the nearby Uncompahgre Peak. Subsequent monitoring has shown the insect only exists in this area of the Colorado Rockies, clinging to high elevations between 12,000 to 13,600 feet. The species is thought to be an arctic relic left behind from the last ice age nearly 10,000 years ago, surviving in select pockets of the mountains that didn’t freeze.
Since monitoring began, it’s been documented that the butterfly has been in precipitous decline. While questions remain, researchers agree domestic grazing in alpine meadows, butterfly collectors and, most damaging, increasing global temperatures have all contributed to the insect’s disappearance. As a result, the Uncompahgre fritillary butterfly – a black and brown mottled colored insect that measures an inch across its wings – was listed endangered in 1991. As part of the recovery effort, Ireland said Fish and Wildlife realigned domestic sheep grazing allotments and moved recreational trails where possible, but it’s unlikely that those measures had an impact on the butterfly’s population. Instead, much of the debate around the butterfly’s protection has revolved around whether the species is naturally doomed. With rising global temperatures, the butterflies have increasingly pushed farther up into the high country, and researchers worry they are running out of space.
“Other than of course reducing climate impacts, which is a very large thing to tackle, there’s perhaps not a whole lot we can do,” Ireland said. Of the 11 known colonies, Fish and Wildlife actively monitors three colonies on a yearly basis. Numbers of butterflies in a given colony can range into the thousands. Because Fish and Wildlife conducted massive sweeps over the years to find more of the insect’s population, Ireland doesn’t expect any new colonies to be discovered. Ireland said one option would be to reintroduce butterflies into suitable areas, but with the effects of climate change, that might just set up the insect for instant failure. “There appears to be more habitat than butterflies,” he said, “so that leads you immediately to question, why aren’t the butterflies there?”
Pagosa skyrocket
The Pagosa skyrocket (Ipomopsis polyantha) isn’t found in La Plata County, but its incredible rarity and sheer beauty warranted its inclusion in this series. The plant, which boasts white, purple dotted flowers, is exclusively found in Archuleta County: specifically, in just two locations in the town of Pagosa Springs, within about 13 miles of each other. According to Fish and Wildlife biologist Allison Jehly, the Pagosa skyrocket is able to grow only on barren, Mancos Shale outcrops at elevations between 6,400 to 8,100 feet. Once widespread, the flower numbered into the millions, thriving along the edges of ponderosa pine, Rocky mountain juniper and Gambel oak forests, as well in the grassland understories. But over the years, the plant’s numbers were alarmingly diminished by grazing and development. Now, the Pagosa skyrocket exists on only 388 acres, on two private parcels and scattered along roadsides.
Taylor Jones, an endangered species advocate for Wildearth Guardians, said the Pagosa skyrocket had been considered for federal protection for years but was never formally listed by Fish and Wildlife. But in 2011, the plant was included in a lawsuit that forced Fish and Wildlife to evaluate longstanding species up for federal protection. As a result, 174 out of the 252 species in the lawsuit were listed as endangered or threatened. The Pagosa skyrocket was listed endangered on Aug. 26, 2011.
“People tend to gravitate toward mammals and other beings, but plants are equally as important, and probably under represented in the Endangered Species Act,” Jones said. “So it’s great to see more plants getting the attention they deserve. They are foundational species.” Fish and Wildlife’s Jehly said the federal agency is starting to work with private landowners, as well as city, county and state representatives, to raise awareness about the plant in the hopes of preserving it. Jehly said Fish and Wildlife is actively plotting where the Pagosa skyrocket is found. That way, researchers can mitigate grazing, development and other risks to the plant when they arise. But other factors, such as the decline of bee populations, which pollinate the plant, and the past years of drought, could also be reasons the Pagosa skyrocket is on the verge of extinction. Fish and Wildlife has collected and stored Pagosa skyrocket seeds, which allows for both the possibility of replanting the species, as well as keeping the species alive. “It’s a really delicate plant,” Jehly said. “By learning more about them, we can learn how to protect them. But there’s still a lot of unknowns.”
Source: The Durango Herald, April 15, 2017
https://durangoherald.com/articles/150997-endangered-plants-butterfly-b…
- Login om te reageren