E. Roads
1. Each linear mile of dirt road ruins an average of approximately 4
acres of ecosystem.  Accordingly, Western public land's minimum of
500,000 miles of official and de facto ranching roads represents a bare
area of about 2 million acres--about the size of Delaware and Rhode
Island combined.  (Jacobs 1991:223)

2. Roads block waterways and drainages, hamper interrelationships,
fragment habitat and create edge effects.  They act as barriers to the
normal movement and activity of native animals and they serve as
corridors for the spread of opportunistic plants and associated pests
and pathogens.  (Jacobs 1991:224)

F. Vegetation Management
1. Livestock grazing is frequently accompanied by the massive
manipulation of vegetation to increase forage production.  This includes
such practices as herbicide spraying, plowing and seeding, mechanical
control such as chaining (the practice of removing brush by dragging a
heavy anchor chain between two Caterpillar tractors), and controlled
fire.  (Cooperrider, Wilcove et al. 1995:78)

2. Major herbicides used on public ranges include 2,4-D, Picloram,
Dicamba, Atrazine, Dalapon, Tebuthiuron, Glyphosate, and Hexazinone.  Of
these, 2,4-D accounts for a large percentage of acreage treated.
Herbicide is used to kill sagebrush, snakeweed, mesquite, acacia,
shadscale, greasewood, creosote, scrub oak, manzanita, rabbitbrush,
other brush and shrubs, juniper, pinyon, tamarisk, cacti, yucca, and a
great variety of "weedy" plants and livestock-unpalatable grasses.
(Jacobs 1991:237-238)

3. Unfortunately, few if any vegetation manipulation projects have been
carried out to restore biodiversity or even species diversity.  Rather,
these projects have been conducted with the single-minded purpose of
increasing livestock forage, and they have been evaluated by their
success in achieving that limited objective over a short time period.
Vegetation manipulation to restore or increase livestock forage can
severely affect biodiversity and should not be confused with the more
difficult task of restoring biodiversity on rangelands.  (Noss &
Cooperrider 1994:243)

           --------------------------------------

In summary, these manipulations of the environment inherent in livestock
production--fencing, water developments, pest and predator control, fire
control, roads and vegetation management--destroy and degrade natural
processes and systems.


IV. Livestock as Destructive Agents of Native Biodiversity

Cattle and domestic sheep, as animals exotic to all the ecosystems
encompassed by our public lands, are themselves agents for degradation
and destruction of native biodiversity, native bioproductivity, soil
quality and water quality.  Here are the principle ways in which these
impacts occur.

A. Truncated Nutrient Flows
Under natural conditions forage goes into native species that
subsequently die and provide food for scavengers and decomposers.  When
we put forage into a cow, we remove them and their biomass from the
landscape.  Furthermore, since cattle consume forage that would
otherwise support native herbivores, even a "predator friendly" rancher
is negatively affecting native predators like wolves by effectively
reducing the prey base.  (Jacobs 1991:111-121; Public Employees for
Environmental Responsibility 1993:10-13)  Among ungulate species, bison,
bighorn sheep, and pronghorn antelope have declined the most, each
existing at less than 5 percent of their primeval numbers.  (Wagner
1978:139)

B. Exotic Weeds
Almost nothing has contributed more to the spread of exotic weeds than
livestock.  Not only do livestock degrade soils, trample soil crusts
(that can prevent the germination of weedy species), but they
selectively remove desirable species, giving weedy species an advantage
in the race for water and nutrients.  Plus cows help to spread the seeds
of exotics.  This is not to suggest that other factors aren't also
contributing to the spread of weeds, but cows are undeniably one of the
chief factors in their spread.  Consider these findings:

1. Alien annual grasses such as cheatgrass and medusahead and forbs such
as the starthistles and knapweeds and leafy spurge have invaded over 40
million hectares of Western grasslands, shrublands, and woodlands.
(Mack 1989; Whisenant 1990; Billings 1990; Pellant & Hall 1994)

2. Invasion by nonindigenous species are suspected of being the second
main cause, following loss of habitat, for the listing of all threatened
and endangered species in the United States (Flather et al. 1994;
Wilcove et al. 1998)

3. Water tanks and ponds developed for livestock, and the roads
constructed to access them, act as loci for weed spread.  These
disturbed sites are highly invisible (Rickard 1985; Tolsma et al. 1987),
and act as conduits for invasion into surrounding communities.  (Gelbard
& Belsky 2000)

4. Nonindigenous plant species are most likely to invade sites that
experience disturbances that differ in type or frequency from their
natural disturbance regimes.  Native wildlife species do not appear to
be major causes of weed invasions.  (Schiffman 1997)

5. "Reports of serious weed infestations in ungrazed [by livestock],
undisturbed grasslands and shrublands appear to be limited."  (Gelbard &
Belsky 2000)

6. "This review suggests that nonindigenous plants will continue to
spread through arid and semi-arid grasslands, shrublands, and woodlands
in the western United States unless selective grazing, nutrient
redistribution, and soil disturbances by livestock are greatly
reduced."  (Gelbard & Belsky 2000)

C. Social Displacement of Native Wildlife
Some wildlife species such as elk and antelope avoid areas that are
actively being grazed by domestic livestock and are thus socially
displaced into other habitat.  Whether this habitat is less desirable or
exposes the animals to greater predation or other impacts is seldom
considered.

1. In a study of female mule deer in the Sierra Nevada, Loft et al.
(1991:24) suggest that high quality forage may be limiting on summer
ranges grazed by cattle, thus contributing to suboptimal nutrition for
female deer and their offspring.

2. In central Arizona with moderate stocking of cattle, significantly
(P<0.05) fewer elk and mule deer were seen on pastures grazed by cattle
than on pastures not grazed by cattle.  Use of habitats by elk shifted
from open mesic and silviculturally disturbed areas to more closed
forest after cattle were introduced.  (Wallace & Krausman 1987:80)

D. Water Quality
Livestock production is the greatest source of non-point water pollution
in the West.  (Royte 1990)  Nearly all surface waters in the West are
fouled with livestock-related contaminants.  (Suk 1986)  Since cows like
to linger near streams and other water sources, they deposit a
disproportionate amount of manure and urine in waterways.  Pollution not
only affects water for human consumption, but can change the chemical
properties and clarity of waterways contributing to the decline of
native aquatic life.  Examples:

1. Overgrazing by livestock destroyed microhabitats frequented by
California golden trout.  (Matthews 1996)

2. Chronic, moderate siltation, such as that experienced downstream from
cattle crossings (Armour et al. 1991), can reduce the quality of food
resources for insects that feed on algae and other microorganisms that
cover exposed substrates (Davies-Colley et al. 1992).

3. Stream channel fenced from livestock afforded the opportunity to
compare sediment loads above (in livestock-grazed area) and below the
fenced area.  Sampling done at three run-off periods showed reduction in
sediment loads of 79%, 48% and 69% respectively after flowing through
3.5 miles of protected channel.  (Winegar 1977:12)

4. Cattle have been shown to produce 5.4 billion fecal coliform and 31
billion fecal streptococcus bacteria in their feces per day.  Since
cattle spend a significant portion of their time in or near streams,
lakes and wetland areas and average 12 defecations per day, they can
contribute significant numbers of these organisms to surface waters.
(Howard et al. 1983)

5. Livestock excrement deposited along stream banks and directly to
channels elevates stream water concentrations of inorganic phosphorus
and nitrogen (Lemly 1982; Mosely et al. 1993).  This fertilization of
stream water can result in an increased production by heterotrophic and
autotrophic microbes that, when current velocities are low, can
drastically reduce dissolved oxygen concentrations (Harris et al. 1994;
Fleischner 1994).

E. Fragmentation and Degradation of Aquatic Ecosystems
The major consumer of water in the West isn't golf courses or suburban
lawns.  It is agriculture.  And the primarily use of agricultural water
diversion and irrigation in the West is production of forage for
livestock.  The dams and reservoirs on our rivers have severely altered
natural waterways in numerous ways with detrimental consequences for
native species.  The removal of water from streams or by groundwater
pumping and subsequent dewatering of aquifers has been one of the major
factors that has led to the decline in native fish throughout the West.
Dewatering can eliminate spawning habitat, or change water quality to
favor non-native exotics.  In either case, native species have suffered
greatly from livestock production.

1. "Nearly 90 percent of the water taken out of streams in the Colorado
River basin is used for irrigation to grow hay and other crops for
livestock, according to a 1982 Living Wilderness article."  (Wuerthner
1990)

F. Trampling of Microbiotic Crusts
Microbiotic crusts (also referred to as biological, cryptobiotic,
cryptogamic, or microphytic crusts) typically grow on the interspaces
between grasses and shrubs throughout the Great Basin Desert, the
semideserts of the Colorado Plateau and in many pinyon-juniper
communities of Utah, Nevada, Arizona, Colorado, New Mexico and Wyoming.
These soil crusts reduce soil erosion, act as a mulch trapping moisture
in the soil, capture atmospheric nitrogen and make it available to soil
and plants, and prevent the germination of seeds--particularly annuals
that are typically "weeds" (Gelbard & Belsky 2000).  (Anderson et al.
1982; Belnap 1993, 1994; Johansen et al. 1986)  Trampling by livestock
can and does destroy these crusts, particularly in ecosystems where
large herds of native herbivores have been restricted or absent for
thousands of years.  Example studies:

1. Both cryptogamic cover and number of cryptogamic species are reduced
by grazing.  It thus seems feasible that if soil stability is enhanced
even slightly by biologically induced crusts, the carrying capacity of
many arid ranges must slowly but steadily decline through time so long
as the grazing treatment precludes the re-establishment of some degree
of cryptogamic crust.  (Anderson et al. 1982)

2. "In the most arid communities of the Agropyron Province (caespitose
grasses), cryptogams cover all undisturbed soil surfaces not occupied by
vascular plants; such cryptogam cover may exceed 50% on a unit area
basis."  (Mack & Thompson 1982:764)

"Presence of large ungulates even at low density in the Agropyron
Province results in rapid, permanent loss of cryptogams through
trampling.  In turn the broken cryptogam crust is a major source of
microsites for alien grass establishment.  Prior to domestic livestock
introduction common ungulates were small (e.g., pronghorn antelope
versus cow/bison, 70 vs. 500 kg) and/or present in low numbers; their
localized trampling damage could be tolerated even by communities
ill-equipped to cope with such disturbance.  It appears that herbivorous
mammals are incompatible with maintenance of steppe where cryptogams
(particularly crustose lichens) occupy a significant fraction of the
soil surface."  (Mack & Thompson 1982:764)

3. Observations of recovery of cryptobiotic crusts from trampling by
livestock at three sites in Utah yielded estimates for full recovery of
45-85 years.  Moss recovery was much slower than that of the lichens.
At two of the three sites where mosses were found, no moss recovery at
all was seen.  At the third site, where some recovery was seen, full
recovery of moss cover would take over 250 years at the observed rate of
recovery.  (Belnap 1993:94)

G. Destruction of Riparian Areas
Riparian areas though limited in overall acreage are among the most
biologically important areas.  "[I]n the Great Basin of southeastern
Oregon, more than 75% of terrestrial wildlife species are dependent upon
or use riparian habitats.  In southeastern Wyoming more than 75% of all
wildlife species depend on riparian habitats.  In Arizona and New Mexico
80% of all vertebrates depend on riparian areas for at least half their
life cycles: more than half of these are totally dependent on riparian
areas.  Riparian areas provide habitat for more species of birds than
all other western rangeland vegetation types combined.  More than half
of all bird species in the southwestern U.S. are completely dependent
upon riparian areas."  (Chaney et al. 1990:2)

1. Cows love water.  They concentrate most of their daily activity in
and near streams.  As a consequence they have damaged approximately 80%
of the streams and riparian ecosystems in the arid regions of the
western United States.  (U.S. Department of Interior 1994)

2. "[E]xtensive field observations in the late 1980's suggest riparian
areas throughout much of the West were in the worst condition in
history."  (Chaney et al. 1990:5)

3. Livestock grazing has been found to negatively affect water quality
and seasonal quantity, stream channel morphology, hydrology, riparian
zone soils, instream and streambank vegetation, and aquatic and riparian
wildlife.  No positive environmental impacts of livestock on riparian
ecosystems have been found.  Livestock have also been found to cause
negative impacts at the landscape and regional levels.  (Belsky et al.
1999)

4. Yes, one can fence cows out of riparian areas, but this is both
expensive, and often merely transfers use to uplands that also have
other no less important ecological values.  Consider a rough estimate of
the financial cost of riparian fencing just on Western BLM lands.
Fencing costs per mile have been estimated at $8,000 to $12,000.
(Oppenheimer 1996)  There are reportedly 36,631 linear miles of riparian
zones on BLM lands in the 10 Western states (Washington not reported).
(Bureau of Land Management 1998:Table2-2)  Assuming that the number of
riparian miles grazed by livestock is directly proportional to the
percentage of Western BLM lands that are grazed by livestock, i.e. 94%
(Fleischner 1994:630), gives 34,433 riparian miles subject to livestock
impacts.  Fencing these areas would cost between $275 million and $413
million.  BLM lands provide approximately 13,303,068 animal unit months
(AUMs) of livestock forage annually (U.S. Department of Interior
1994:Fig. 2-5), at $1.35/AUM (as of FY 2000).  Only half of this money
is allocated for range development by the BLM.  This amounts to less
than $9.0 million annually available for all range improvements of which
fencing is just one consideration.

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