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which activities are the most damaging.
Two patterns that have emerged in the
research show that off-trail travel—like
my detour to avoid the moose—is one
of the most alarming issues for wildlife,
because animals habituate to humans
behaving in predictable ways on roads
and trails. Another finding concludes
that loud noises have an adverse effect
on wildlife.
There may be no single “worst”
user group, but taken all together,
outdoor recreationists rank among
the top threats to species that are
listed as federally threatened or
endangered. One review of feder-
ally subsidized resource extraction
activities placed outdoor recreation
at number two, while another study
put it at number four (behind non-
native species, but higher than energy
extraction and pollution).
Another factor researchers must
account for is that species vary in their
tolerances for human beings (magpies
thrive near us; golden eagles don’t).
Some adaptations in animals may have
far-reaching consequences on the eco-
systems critters are a part of. One 2018
analysis published in Science found that
at least 62 species are avoiding human
contact by becoming more nocturnal—
so when mountain bikers and runners
don powerful headlamps and take to
the dirt during summer’s coolest hours,
we’re pursuing wildlife into their very
last refuge: darkness.GRAY MIST AND A RAW, bone-chilling
wind make the flat grassland of
Roberts Ranch seem more like the
Scottish Highlands than the Front
Range of Colorado, but inclement
weather doesn’t deter Rick Knight.
Ever since his Boy Scout days, he’s
made outdoor recreation a rain-or-
shine habit, and on this 35-degree day
in May, he and his wife, Heather, have
saddled up their riding mules to mon-
itor raptor nests near Steamboat Rock
north of Fort Collins.
Knight retired from CSU in
2017 after 30 years of teaching and
conducting research on wildlife
conservation. But as an emeritusbillion to Colorado’s economy in
2017 (up from $34.5 billion in 2013).
Colorado’s population has also grown;
we now number 5.7 million humans,
compared to 2.9 million in 1980. To
keep pace, we’re adding new trails to
our 39,000-mile network. Colorado
Parks and Wildlife (CPW) estimates
that by 2026, municipalities and state
parks will need to build 3,464 more
miles of trail to accommodate the
state’s hunger for adventure.
That’s a lot of biggering, to quote
my daughter’s favorite Dr. Seuss story,
The Lorax. And, like that book’s mus-
tachioed title character, scientists are
documenting how humans can have
unfortunate consequences for nature.
Courtney Larson, a Ph.D. student
in ecology at Colorado State Univer-
sity, reviewed 274 studies performed on
recreation and wildlife in a literature
review that PLOS ONE published in- In 93 percent of those papers,
recreation had at least one effect on
wildlife, and many of those effects (59
percent) were negative.
Some of the studies documented
how increasing trail traffic may mean
that animals spend most of their time
avoiding humans rather than find-
ing food, mating, or caring for young.
Other papers monitored elevated
heart rates in animals that didn’t (or
couldn’t) flee—suggesting wildlife may
be more freaked out by our presence
than they seem. “One person walk-
ing quietly for a couple of miles on a
trail doesn’t seem like it would be very
impactful, so people have a hard time
believing that they’re actually affecting
wildlife,” Larson says. “But it’s cumu-
lative. It’s the effect of hundreds or
thousands of people.”
Research hasn’t yet identified just
how many people are too many and
made everything seem limitless,
even me. Specks of crimson, cobalt,
purple, and ivory dotted the grasses
like marks from a pointillist’s brush,
and the small lakes I passed blazed
blue along the trail linking the Rabbit
Ears rock formation to the Steamboat
Springs ski area some 20 miles away.
At the last lake on the route, I saw a
moose. And it saw me.
I braked to a stop, and my rid-
ing buddies halted behind me. Seeing
moose around Steamboat isn’t unusual;
the animals have taken to loung-
ing on the ski runs and in the aspens
separating those trails. But moose are
crotchety creatures, as likely to charge
humans as to flee from them, so as
soon as we noticed this one wading
among the reeds at the edge of the
pond, we dashed off-trail into the pines
to give it space. The 50 feet between
us grew to 75, then 100 as we hiked
through dense shrubbery that scratched
my legs and pulled at my bike.
Once we’d skirted the pond and
rejoined the trail to continue our ride,
we congratulated ourselves for our
wildlife-savvy evasion. Yes, traipsing
around off-trail was onerous, but we’d
respected the moose’s need for space.
Or so we thought.COLORADO APPEARS TO BE different
than the rest of the United States,
where people reportedly spend about
90 percent of their lives indoors. Here,
residents make a point of getting out-
side to hike, picnic, ski, run, climb,
fish, hunt, mountain bike, or pilot an
off-highway vehicle: 69 percent of
Coloradans log some form of out-
door recreation one or more times per
week. Many of the state’s 84.7 million
annual visitors come to do the same.
All that recreating contributed $62.5ONE MORNING THIS
PAST AUGUST, I
PEDALED MY
MOUNTAIN BIKE
THROUGH HIGH-ALPINE
MEADOWS THAT