Geoscience Reference
In-Depth Information
species), and a small herbaceous plant known as coman-
dra or bastard toadflax. comandra, the plant, is com-
monly found growing in dry mountain meadows and
is itself an obligate root parasite on sagebrush and vari-
ous other plants. the disease therefore usually develops
only where sagebrush, comandra, and lodgepole pine
occur near one another. this arrangement is common
ally be attributed to the rust directly, but the treetops
die back and often a forked trunk develops. this is a
problem for forest managers focused on wood produc-
tion, because it causes a reduction in the amount of har-
vestable wood. As with dwarf mistletoe, however, it is a
native species and is part of the ecosystem.
Animals also have significant effects on forest com-
munities (table 11.2). For example, deer and elk can
reduce the rate of aspen regeneration by browsing the
small sprouts produced by the root system, and seed-
caching birds (such as clark's nutcracker) influence the
distribution of limber and whitebark pine in forests
as well as the foothills (see chapters 10 and 15). Pine
seeds are an important source of food for red squirrels
(fig. 11.4), with the cones being cached by the squir-
rels for winter consumption. However, not all seeds are
eaten, partly because the pine trees have adaptations
that deter squirrels; for example, the cones are resinous
ming have red squirrels, but where they are not found,
to the north and west of Wyoming, the cones are less
massive and have twice as many seeds. Also, the seeds
are more easily removed. in such situations, the nut-
crackers are more abundant. Where the nutcrackers
and squirrels do coexist, Wyoming ornithologist craig
Benkman and his associates have found that the bird's
bill is longer and stouter, presumably to give the bird a
better chance of prying open the scales of the heavy-
duty cones that have evolved in the presence of the
squirrels.
22
the
serotinous cones
produced by lodgepole pine
retain large numbers of seeds, which has made the
cones an especially rich food source for squirrels. As
noted, however, thicker cone scales have evolved to
minimize accessibility. this, in turn, has favored the
evolution of larger jaw muscles in squirrels (compared
to those of squirrels in Douglas-fir forests, which do
not have serotinous cones). craig Benkman and Matt
table 11.2. Some mammals, birds, amphibians, and
reptiles found primarily in mountain landscapes
MAMMALS
Bear, black
Bear, grizzly
a
Bobcat
b
chipmunk, least
b
cougar
coyote
b
Deer, mule
b
elk
b
Ground squirrel, Wyoming
b
Hare, snowshoe
Marmot, yellow-bellied
Marten, American
Moose
Mouse, deer
b
Pika, American (alpine)
Pocket gopher, northern
b
Porcupine
b
Sheep, bighorn
Squirrel, red
Vole, heather
Vole, southern red-backed
Wolf
a
Wolverine
Woodrat, bushy-tailed
b
BiRDS
Bluebird, mountain
b
chickadee, black-capped
b
chickadee, mountain
crossbill, red
crossbill, white-winged
Dipper, American
Duck (various species)
b
Finch, cassin's
Flicker, northern
b
Flycatchers (various species)
b
Goshawk, northern
Grosbeak, evening
Grosbeak, pine
Grouse, dusky
Grouse, ruffed
Hawk, red-tailed
b
Jay, gray
Jay, pinyon
b
Jay, Steller's
Junco, dark-eyed
b
Kinglet, ruby-crowned
nutcracker, clark's
nuthatch, red-breasted
owl, boreal
owl, great horned
b
Pipit, American
Raven, common
b
Robin, American
b
Rosy-finch, gray-crowned
Rosy-finch, black
Rosy-finch, brown-capped
Sapsucker, red-naped
Sapsucker, Williamson's
Solitaire, townsend's
Sparrow (various species)
b
Swallow, violet-green
tanager, western
thrush, hermit
thrush, Swainson's
Veery
Warbler (various species)
b
Woodpecker, American
three-toed
Woodpecker, black-backed
Woodpecker, downy
b
Woodpecker, hairy
b
AMPHiBiAnS
toad, boreal
Frog, boreal chorus
b
Frog, columbia spotted
Frog, northern leopard
b
Frog, wood
Salamander, tiger
b
RePtiLeS
Boa, rubber
Gartersnake, wandering
b
Snake, smooth green
a
Found only in the Greater Yellowstone ecosystem.
b
Also found away from the mountains.
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