Rangeland Health New Methods to Classify, Inventory, and Monitor Rangelands (1994) / Chapter Skim
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3 CURRENT METHODS OF RANGELAND ASSESSMENT
3 CURRENT METHODS OF RANGELAND ASSESSMENT
Pages 51-96
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From page 51... ...
The need for more thorough assessments was evident. DEVELOPMENT OF CURRENT THEORY AND PRACTICE OF ~NGE~ND ASSESSMENTS Between 1890 and 1905, 11 state agricultural experiment stations published 879 range management-related bulletins dealing with the control of weeds, pests, poisonous plants, soil moisture, fertility, conservation, rangeland inventory and analysis, water use, fencing, and other topics (Beetle, 1954~.
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From page 52... ...
State agricultural experiment stations begin to issue reports on the condition of rangelands and range management practices.
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From page 53... ...
R Standing proposes questing rangeland assessments by messur~g volume of vegetation rawer man eshmat~g plant cover The Taylor Crazing Act ~i~dra~s all remaking public lad Nat is not under We jur~dichon of We OSFS or over federal agencies into grazing districts Under me jur~dichon of me Bureau of Land Management OLD)
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From page 54... ...
: ~.~ use of successional stages as measures of rangeland condition by proposing the measurement of range condition as a departure . ~ from climax vegetation for a specific range site.
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From page 55... ...
.. 55 The first Resources Planning Act Assessment of resources, including rangelands on national forests, is published.
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From page 56... ...
BLM adopts SCS range site and range condition procedures for assessing rangelands. The Society for Range Management recommends that SCS, BLM, and USES adopt common terminology to classify rangelands and make ecological status ratings.
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From page 57... ...
recognized the need to develop a scientifically credible and economically feasible method of surveying rangelands to carry out its mandate. Since the goal of most of the early rangeland professionals was to provide high-quality livestock forage, the techniques and systems they developed for rangeland assessments concentrated on the effects of livestock grazing on forage production.
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From page 58... ...
New Theoretical Foundation for Rangeland Surveys At the same time that sardine was developing his method for evaluating rangelands, ecologists were developing theories of community dynamics (how plant communities develop and change) that would provide the foundation for new methods for evaluating rangelands.
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From page 59... ...
Rangelands would be classified on the basis of differences in climax plant community composition and assessed on the basis of the divergence of the current plant composition from the climax plant community composition. SUCCESSIONAL STAGES AND RANGELAND ASSESSMENT Sampson (1917)
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From page 60... ...
Dyksterhuis defined those areas that support a unique climax community as a range site. Each site-defined by its climax plant community, soil, and climatic environment would support a characteristic assemblage of plants, and this vegetation would persist unless it was disturbed by grazing, fire, drought, or other factors.
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From page 61... ...
Estimations of livestock carrying capacity were linked to range sites, condition classes, and successional stages. By 1950, the measurement of range condition (Soil Conservation Service iSCS]
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From page 62... ...
and range site (Laycock, 1989) classifications, yet the Range Inventory Standardization Committee of the Society for Range Management recommended governmentwide use of the ecological site classification system (Society for Range Management, Range Inventory Standardization Committee, 1983)
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From page 63... ...
or ecological status (USFS and BLM) as the degree to which the vegetation of a site is different from the climax plant community or potential natural community characteristic of that or similar sites.
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From page 64... ...
The following is a comparative analysis of the definitions each agency uses. Terms of Reference Agency Definition Status Rating Ecological status BLM, USES Range condition SCS Range site Ecological type Four classes used to express the degree to which the makeup of the present vegetation reflects the potential natural community.
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From page 65... ...
. Up represents a change toward a climax of potential natural community; down means a change away from a climax or potential natural community; not apparent means there is no recognizable change.
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From page 66... ...
is defined as a native plant community, no introduced or exotic species can be considered part of the climax plant community used to define the range site (SCS)
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From page 67... ...
Data for this purpose are derived from many sources, including the following: · evaluation of the vegetation and soils on rangelands that have been protected from disturbance for long periods of time; · comparison of areas that are used to various degrees by livestock with similar ungrazed areas; · evaluation and interpretation of research dealing with natural plant communities and soils; · review of early historical and botanical literature; and · prediction of climax vegetation on the basis of information gathered from areas with similar soils and climates. SOILS AND CLIMATE Soils and climates that result in the same climax vegetation and annual biomass production are considered to make up the same range site (SCS)
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From page 68... ...
au x o · cn EM o On a' a; En o au o o · - ~ o o ·_1 · v)
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From page 69... ...
On the basis of the lower productivity of the plant community growing on Goodington soils and differences in species composition and proportion of species between the communities growing on the Hoelzle and Bancroft soils, Williams and Hugie concluded that all three were unique and represented three distinct range sites (SCS) (Shiflet, 1973~.
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From page 70... ...
to Ed o us Ad .t 'a · - ~ o On o a; to o .= o o us o .= to a, Ad ·o On o - o An au N O X A: can o o o C' O 0 ~= ~0 CJ ( - 0 o ._ U)
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From page 71... ...
~ ~ 1 Can CO ED I1 LC)
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From page 73... ...
At ~cN ~on ~ NcO cN ENEN ~1o *
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From page 74... ...
that would be expected to produce a characteristic potential natural community (USFS and BLM) that has a predictable plant composition and annual production.
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From page 75... ...
Forest Service, l991b:Section 2090.11-2.15~. Evaluation of Range Condition and Ecological Status SCS, USFS, and BLM evaluate successional change on rangelands by comparing the composition and annual biomass produced by the existing vegetation with a previously determined benchmark plant composition and production.
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From page 76... ...
Plants that grow on the deteriorated area are replaced by species that are typical of a later stage of succession until the climax plant community (SCS) is ultimately restored.
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From page 77... ...
are not considered part of the climax plant community (SCS) for the Middle Cobbly Loam range site (SCS)
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From page 78... ...
a; · - / at)
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From page 79... ...
a) 20 o 'Salt I 79 Composition of Climax ~ Plant Community · Composition ., ~ A~ x:~\~~ tz,~.~~ cabs e,.0' FIGURE 3-1 Comparison of actual plant composition with climax plant community composition for range condition (SCS)
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From page 80... ...
rating, which is calculated as a percentage of the potential natural community composition and production, is calculated on the basis of field measurements of plant composition and production by weight. Ecological status (USFS and BLM)
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From page 81... ...
or ecological status (USES and BLM) is now strictly defined as an evaluation of whether the plant composition and production of a particular rangeland is becoming more similar or less similar to the defined climax plant community (SCS)
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From page 82... ...
, and (4) estimation of whether a rangeland is changing in ways that will make it more or less similar to the defined climax plant community or potential natural community (USES and BLM)
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From page 83... ...
The reliance on differences in the expected climax plant community (SCS) or potential natural community (USES and BLM)
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From page 84... ...
The difference in this definition from that of the earlier committee (Society for Range Management, Range Inventory Standardization Committee, 1983) is the omission of a reference to a potential natural community (USES and BLM)
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From page 85... ...
SITE CLASSIFICATION FOR ASSESSING RANGEIAND HEALTH SCS, USES, and BLM should adopt common site classif~cationsfor the purpose of coordinating rangeland health inventories and monitoring efforts. Although methods of site classification between the agencies are similar in concept, differences in the definitions of climax plant communities (SCS)
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From page 86... ...
use of climax plant community (SCS) or potential natural community (USFS and BLM)
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From page 87... ...
The committee inspected a site near Reno, Nevada, that illustrates the difficulty in clearly relating the degree of similarity to an established benchmark plant composition to the degree to which the soil and ecological processes are being conserved. The existing plant composition was dominated by desert needlegrass (Stipa speciosa)
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From page 88... ...
The similarity of current plant composition and biomass production to that of a climax plant community (SCSJ or potential natural community (USES and BLAT should not be used as the primary standard of rangeland health. The degree of similarity to the plant composition and annual biomass production of a climax plant community (SCS)
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From page 89... ...
or potential natural community (USFS and BLM) composition may still have enough soil cover to be protected from water and wind erosion, whereas another site, also supporting 40 percent of its expected climax plant community (SCS)
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From page 90... ...
The manipulation of livestock grazing allows rangeland managers to maintain a particular plant composition at some point along the successional gradient characteristic of that site. The choice of that point along that gradient that should be maintained depends on whether the goal of management is to maximize or optimize the production of livestock, wildlife, or some other product or value.
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From page 91... ...
It could be argued, however, that the desert sites described simply have not had time to recover from historic overgrazing and to reestablish the potential natural community (USES and BLM)
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From page 92... ...
or ecological status (USES and BLM) rating if these species make up a small percentage of the plant composition and annual biomass production of the climax plant community (SCS)
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From page 93... ...
The problem is not that plant composition and biomass production are unimportant attributes of rangeland ecosystems; rather, the problem is that they are typically the only attributes measured. A system that used only plant density, erosion, litter cover, seedling density, or compaction as a single measure of range condition (SCS)
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From page 94... ...
Overgrazing, accelerated erosion, or other influences that result in loss of the capacity to produce the plant composition and annual biomass production characteristic of the climax plant community (SCS) or potential natural community (USES and BLM)
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From page 95... ...
Management would be designed so that the plant composition could be changed to reflect that described for the desired plant community. This may or may not represent a change toward the climax plant community (SCS)
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From page 96... ...
The presence of seedlings of desirable plants was also interpreted as an upward apparent trend because those seedlings indicated that the plant composition was evolving toward the climax plant community (SCS) or potential natural community (USFS and BLM)
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