- Traditional season-long livestock grazing strategy on western riparian areas
has been identified as one of the factors affecting rangeland productivity as well
as wildlife habitat in riparian zones. As alternatives to summer season-long
grazing, summer short-duration grazing (without haying), and fall short-duration
grazing (following haying), were considered in this study to determine their effects
on ranch production and profitability. Five grazing plans for the case ranch were
evaluated. A planning period of six years (1993-98) was used for each plan.
The present values (PVs) of net returns, using a 7 percent discount rate,
were positive for all the plans. Shifting from summer season-long grazing to plans
with summer short-duration grazing reduced the PVs of net returns by 13 percent,
on average. Reasons for reductions in net returns included i) higher labor as well
as fencing costs, ii) downward adjustment of herd size, and iii) increased overhead
costs per animal. Shifting from summer season-long to fall short-duration grazing,
in contrast, increased the PVs of net returns by 7-9 percent. But this system of
grazing involved 1) a large haying costs, and ii) a higher management requirement.
Although research results showed a difference in profitability between the three
grazing strategies, the differences can be viewed as evidence for "tendency" only.
This is so because those differences were so small and so sensitive to changes in
some parameters (i.e., changes of magnitudes which are smaller than the
measurement error) that they cannot be viewed as significantly different.
Recognizing non-pecuniary goals of the ranchers, economic sustainability
was determined by the criterion that the rate of return on ranch investment, on a
long-term basis, is at least 3 percent (one-half of the opportunity cost of capital as
measured by the annual yield rate on 10-year U.S. Treasury notes). The rate of
return on ranch investment, on average, was 3 percent. Thus, the ranch operation
was found economically sustainable under all grazing systems examined. However,
if public land grazing permit was reduced by 30 percent, then returns to
investment, on average, fell to 2.5 percent, signalling that ranchers no longer were
economically sustainable (based on the aforementioned criterion).
The study results indicated that grazing strategies correlate with the
structure of the riparian habitat. Fall short-duration grazing may be most
compatible with a riparian habitat structure that is generally viewed as being
ecologically more desirable than other forms of habitat structure. However, some
plants, bird, and mammal species preferred the habitat structure correlated with
other grazing strategies. Thus, from that perspective, a mixture of grazing
strategies (provided they are determinants of vegetation structure) is, at the
landscape level, more desirable than a single uniform grazing strategy for
encouraging species diversity.