… and what you can do to help them
By Ruthanne Johnson
Did you know that Boulder’s Long Canyon has the West’s most southerly surviving remnants of an ancient boreal forest, including a rare stand of paper birch trees? Or that colonies of two federally threatened bat species migrate to Boulder caves every summer to roost, give birth and raise their young? You may be amazed to hear that Boulder County still has a few burrowing owls. If you know just the right prairie-dog colonies to stalk, you can watch through binoculars as the owls pop up from abandoned burrows and fly at lightning speeds across the landscape in search of insects, mice, snakes, and maybe even a frog or salamander.
There’s a reason this is a hot spot for such unique plants and animals. “The meeting of the Great Plains and southern Rocky Mountains creates a great diversity of habitats,” says Lynn Riedel, a plant ecologist with the city of Boulder Open Space and Mountain Parks. “This sort of choppy, elevationally diverse landscape [provides] different moisture regimes, north- and south-facing slopes, canyons, prairies and open mesas, and cliffs for raptors and bats.”
But some of these species face extinction here in Boulder County and beyond. White-nose syndrome, a fungal disease, is decimating cave-dwelling bat populations throughout the central and eastern United States. The paper birch stand is dwindling, and burrowing owls are declining as prairie dogs lose ground.
Already gone from Colorado are wolves, bison and grizzly bears. Lynx populations continue to struggle since being reintroduced into the state in 1999. In 2013, 35 black-footed ferrets were reintroduced to Walker Ranch in Pueblo County, Colo., yet the imperiled species won’t be returning to Boulder anytime soon, since a minimum of 3,000 acres of prairie-dog colonies is needed to consider reintroduction. And, as of April 2013, only one lone wolverine had been spotted in the state. His radio collar revealed that he’d migrated from the Grand Tetons all the way to Estes Park, where officials doubt he’ll ever find a mate.
But the news isn’t all bad. Since 1979, the Colorado Natural Heritage Program has been tracking the state’s rare plants and animals. According to the organization, Boulder County has more than 100 rare, threatened or endangered species and other “species of concern.” And “that’s a lot for a relatively small area,” Riedel says. The data help scientists with conservation efforts, from monitoring and conducting field studies to preserving native habitat, as well as closing caves to prevent the spread of white-nose syndrome and routing hiking trails away from sensitive plant areas.
Below are a few examples of the rarest and most ecologically significant plants and animals living in Boulder County. Helping these species could be as simple as staying on designated trails or planting native vegetation to benefit wildlife. You can also support city and nonprofit conservation programs through donations and volunteering.
Tallgrass Prairie & Eastern Woodland
Most people don’t think of an entire ecosystem as being endangered, yet much of America’s tallgrass prairie is imperiled by conversion to farmland and real-estate development. You can still find intact prairie systems on Boulder County open space, where big bluestem, yellow Indian and switch grasses grow taller than a person in moist areas, and provide habitat for northern leopard frogs and ground-nesting birds such as bobolinks. An example of the tallgrass prairie occurs west of Highway 93 along the South Boulder Creek West trailhead and Big Bluestem Trail in southern Boulder County. On drier mesa tops and side slopes, the grasses support a variety of rare prairie butterflies and their larvae. Grasshopper sparrows also use the tall grass, but because of their sensitivity to human activity, their numbers have declined.
To support this dwindling ecosystem, plant native grasses rather than ornamentals, which can be invasive. “Some of these prairie grasses are just gorgeous,” Riedel says. “In the fall, they turn red and orange, and they’re just really fun to garden with.” Be sure to plant seeds from this region; you can get them by signing up for the fall volunteer seed-collection program. Check for opportunities at bouldercolorado.gov/osmp or with Wildland Restoration Volunteers (www.wlrv.org).
Another imperiled ecosystem here is the Eastern Woodland Community, a glacial-age relict nestled in Long Canyon on the north side of Green Mountain. This small and fragmented ecosystem has survived because of our moist, cool canyons, says Megan Bowes, a plant ecologist with the city of Boulder. “It’s nice and shady there when it’s hot and dry in town.” The paper birch stand grows in the canyon, along with hazelnut shrubs, wood lilies and calypso orchids. Bowes says it’s also a great place to spot butterflies.
Scientists believe climate change is
causing the woodland to shrink. Another problem is the road base that washes over parts of the rare plant community. Since 1949, the paper birch stand—less than 100 trees in 1949—has shrunk to somewhere between 25 and 50. For folks interested in learning about the canyon’s unique woodland plants, city of Boulder naturalist Dave Sutherland typically offers a couple of guided “Destination Ice Age” hikes up Long Canyon in June. Check www.naturehikes.org to see what’s scheduled.
Preble’s Meadow Jumping Mouse
This tawny brown mouse has a distinctive dark-colored dorsal band, a long tail and big hind feet for jumping, digging and swimming. They live in smatterings of habitat along the Colorado and Wyoming Front Range, in lush wetland vegetation along streams and adjacent uplands. Nocturnal, they emerge from their burrows at night to collect berries and seeds and eat insects. After a summer of gorging and collecting, they settle into their burrows and hibernate until spring. In Boulder County, much of their habitat lies in open space west of Broadway along waterways such as South Boulder and Bear creeks.
The Preble’s has been federally protected in Colorado since 1998. Boulder is working to restore native streamside vegetation as habitat, and monitoring began this spring to determine the impacts of last September’s flooding on mouse populations.
The Ute Ladies’-tresses Orchid
This federally protected plant is found on only a handful of sites in the western United States. “It’s a tiny plant that gives this beautiful surprise in late summer, when vegetation in our riparian areas is pretty tall,” Riedel says. The slightly fragrant white flowers provide pollen and nectar for native bumblebees and hawk moths.
Disturbance from fire, flood and grazing hoofed animals is vital for the orchid’s propagation. In the absence of antelope, bison and larger elk herds, cattle have been filling the void. Threats include habitat loss and competing noxious weeds. Boulder maintains orchid-conservation areas, but has kept their locations under wraps after plants were dug up several years ago.
Fringed Myotis & Townsend’s Big-eared Bats
Boulder County has 11 different bat species. Listed as state threatened, the fringed myotis has only three or four known roost sites here, most of them caves they return to every summer from higher elevations to form nursery colonies and raise their young. “They also roost at the Der Zerkle climbing site,” says Boulder wildlife ecologist Will Keeley, “which is why it’s closed from April to September.”
Fringed myotis are known for their ability to maneuver razor-close to vegetation and cliffs while hunting for insects, and their wings can withstand thorny plants. (Just don’t expect some grand evening exodus, since the largest colonies living here have only about 35 bats.) Another cave dweller is the Townsend’s big-eared bat. Like the fringed myotis, they raise their young in a nursery-type system under the watchful care of many mothers. Boulder has two of the 11 known breeding colonies in Colorado.
Cave closures prevent disturbance of summering colonies. Eliminating pesticides helps natural insect populations on which bats feed. You can also sign up to help monitor closures and perform exit counts through the city’s Volunteer Bat Monitoring Program.
Black-Tailed Prairie Dogs
When you drive past Boulder County’s seemingly bountiful prairie-dog colonies, it’s hard to believe these animals are in trouble. But their populations have shrunk to only about 2 percent from an estimated 100 million acres of their historic range, and three of the five species are federally protected. For most of the black-tailed ones here in Boulder, life is relegated to smaller patches of land cut up by roads and developments, bearing little resemblance to the miles and miles of uninterrupted colonies that Lewis and Clark reported in their journals.
So important are these animals to the prairie ecosystem that if they disappear, dozens of other species could vanish. Animals such as prairie jackrabbits, rattlesnakes and tiger salamanders use prairie dog burrows for shelter. Burrowing owls use them for nesting. Golden eagles, ferruginous hawks, badgers, coyotes and foxes hunt prairie dogs for food.
To help this keystone species, Boulder is working with conservation groups to relocate prairie dogs from areas where they’re not wanted to protected land. Last fall, for instance, hundreds of prairie dogs were moved from Foothills Community Park in north Boulder to a large tract of open space in southern Boulder County. It was an exciting moment when badger tracks were spotted in the snow in the new location. Badgers are a rarity here, so keeping healthy prairie dog populations supports their presence.
Volunteer opportunities are available through the Prairie Dog Coalition, and possibly with the Boulder County Nature Association’s burrowing owl monitoring program.n
Ruthanne Johnson has written about animal-welfare issues since 2008. Animals have always been an important part of her life. For her, it’s all about sharing the habitat with the creatures all around. After all, they were here first.