Rangeland Ecology & Management
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- Inventory Monitoring PagePrecision and Error Precision of a sample can be described as the variation among all the samples used to estimate the population parameters. In this respect it is analogous to the sample variance,…
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52 Productivity
Productivity Productivity refers to the biomass produced at a site over a given period of time. Most vegetation assessments are actually limited to estimating net above-ground primary productivity,… - Inventory Monitoring PageRecent Proposals for Evaluating the Status of Rangeland Resources Dissatisfaction with long-standing procedures to describe and interpret range condition and range trend has stimulated much…
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54 Quadrats
Quadrats Quadrats are two-dimensional sample units of any size or shape. In some cases, a tape may be laid on the ground at each sampling location to define the quadrat, but more often the quadrat… - Inventory Monitoring PageSampling in Quadrats to Determine Cover Although other approaches are generally preferred, a variety of methods are available to determine cover quadrats. Depending on the technique, measurements…
- Inventory Monitoring PageQuadrats Arranged as a Group of Subsamples to Determine Density When the sampling layout for density involves quadrats arranged as a group of subsamples under the principles of systematic sampling,…
- Inventory Monitoring PageQuadrats Arranged as a Group of Subsamples to Determine Frequency Quadrats arranged as a group of subsamples under the principles of systematic sampling is the most common sampling design used for…
- Inventory Monitoring PageRandom Sampling In random sampling, any member of the population has an equal chance of being selected to contribute to the sample. In practice, this means that the set of potential sample units are…
- Inventory Monitoring PageRandomly Located Quadrats to Determine Density When the sampling layout involves quadrats located under the principles of random sampling, each quadrat represents a sample unit and values describing…
- Inventory Monitoring PageRandomly Located Quadrats to Determine Frequency When the quadrat layout follows the principles of random sampling, frequency is calculated as the proportion of quadrats where the species was found…
- Inventory Monitoring PageRange Condition Range condition describes an evaluation of the current status of rangeland vegetation. Condition assessments provide the framework to register information obtained by range…
- Inventory Monitoring PageRangeland Health In 1994, the National Research Council Committee on Rangeland Classification Systems published a report addressing current methods and possible improvements to assess the status of…
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63 Range Sites
Range Sites Range sites are the principal units of rangeland classification that are based on categorizing vegetation according to site potential. Site potential is defined as the capacity of an… - Inventory Monitoring Page
64 Range Trend
Range Trend Range trend refers to the change in the status of resources at a site detected by monitoring and is usually expressed as improving, declining, or stable. It originally pertained to any… - Inventory Monitoring PageReference Unit Method The reference unit method was developed by Andrew, Noble and Lange in Australia in the 1970s as a non-destructive method to determine biomass. Sampling is usually restricted to…
- Inventory Monitoring PageResidual Biomass Residual biomass refers to the weight of vegetation remaining after grazing is concluded. Residual biomass has important rangeland management ramifications because it acts as the…
- Inventory Monitoring PageResource Value Rating Resource value ratings have been proposed as an approach to meet the demands of multiple use principles, by evaluating the suitability of the current vegetation for a specific…
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68 Ground Rules
Ground Rules Ground rules are guidelines developed to minimize the subjectivity of sampling. Ground rules should be developed before field work commences, and should be clearly included in the… - Inventory Monitoring PageStatistical Analysis of Biomass Data When the layout of quadrats for biomass sampling follows the principles of random sampling, each quadrat represents a sample unit, and values describing biomass…
- Inventory Monitoring PageStatistical Analysis of Cover Data The appropriate statistical model for analyses to identify differences in cover between years or among sites depends on the method to determine cover that was…
- Inventory Monitoring PageStatistical Analysis of Density Data Density measurements obtained by counting individual plants may follow a skewed or Poisson distribution, caused by a preponderance of low or zero values. The…
- Inventory Monitoring PageStatistical Analysis of Frequency Data Frequency data may be analyzed by several different techniques, depending upon how the sample units were located and how the data was collected. Values…
- Inventory Monitoring PageSources of Sampling Error One of the advantages of measuring frequency is that there are fewer opportunities for observer bias due to inadequate or inconsistent ground rules than when determining…
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74 Sample
Sample A sample is that portion of the population which is actually measured. Sampling is a more practical way to obtain inventory or monitoring information because not all members of the population… - Inventory Monitoring Page
75 Sample Size
Sample Size Sample size, or sampling intensity, refers to the number of sample units that will be measured in the inventory or monitoring program. Sample size is an important consideration during… - Inventory Monitoring Page
76 Sample Units
Sample Units Sample units are the members of the population from which measurements are taken during sampling. Sample units are distinct and non-overlapping entities, such as quadrats or transects,… - Inventory Monitoring PageAllowable Use Allowable use, or proper use, refers to the level of utilization that promotes maximum grazing of forage sources without damaging the vegetation. Allowable use may refer to the entire…
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78 Animal Units
Animal Units Animal units (AU) are used as a basis to standardize and express stocking rates among different kinds and classes of livestock with similar dietary preferences. An AU is essentially a… - Inventory Monitoring Page
79 Attributes
Attributes Attributes are the characteristics of the population we wish to measure during sampling, such as species composition, biomass, cover, density, or frequency, at a site. Other attributes of… - Inventory Monitoring Page
80 Basal Cover
Basal Cover Basal cover or basal area is determined by considering the cross-sectional area of plants near the ground, usually taken at a height of 2.5 cm for herbaceous plants and 140 cm for trees… - Inventory Monitoring PageBelt Transects to Determine Density When the sampling layout is based on belt transects, density is calculated by dividing species tallies by belt transect area to estimate average density (number…
- Inventory Monitoring PageBinomial Distribution Binomial distributions are special sampling distributions generated when an attribute with only two possible outcomes is being recorded from a series of sample units. The…
- Inventory Monitoring PageDirect Methods to Determine Biomass Biomass sampling is usually conducted using a sample unit with defined boundaries, for example some type of quadrat, so that biomass can be expressed relative to…
- Inventory Monitoring PageEstimation Approaches to Determine Biomass Estimation approaches involve techniques that require observers to visually assess biomass in quadrats, rather than harvesting to determine biomass. Three…
- Inventory Monitoring PageHarvesting to Determine Biomass Direct harvesting of vegetation from quadrats of a known size is the most straightforward approach to determine biomass at a site. A wide variety of mechanized…
- Inventory Monitoring PageIndirect Methods to Determine Biomass Indirect methods to determine biomass are based on developing a relationship between plant weight and an easier-to-measure attribute such as plant height,…
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87 Biomass
Biomass Biomass is a commonly measured vegetation attribute that refers to the weight of plant material within a given area. Other general terms, such as 'yield' or 'production', are sometimes used… - Inventory Monitoring PageMethods to Determine Biomass Biomass can be determined using either direct or indirect sampling methods. Direct methods involve techniques that weigh or estimate the actual biomass of plants in…
- Inventory Monitoring PageBiomass Property Biomass is a general term that encompasses many special attributes. For example, inventory or monitoring programs focusing on grazing applications may only want to estimate…
- Inventory Monitoring PageSample Units for Direct Methods to Determine Biomass Direct methods to determine biomass typically involve sampling procedures using a sample unit with defined boundaries (ie., some type of quadrat…
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91 Browse
Browse Browse is the biomass from trees, shrubs, and woody vines that is available for consumption by livestock and wildlife. It includes leaves and small twigs, but excludes branches and trunks… - Inventory Monitoring Page
92 Canopy Cover
Canopy Cover Canopy cover or crown cover describes the area represented by the vertical projection of plant foliage onto the ground. Canopy cover is determined as the perimeter of the plant at its… - Inventory Monitoring PageMethods to Determine Carrying Capacity Determining carrying capacity and setting stocking rates are some of the most challenging procedures connected with effective rangeland management. In fact,…
- Inventory Monitoring PageCarrying Capacity Carrying capacity describes the number of grazing animals a management unit is able to support without depleting rangeland vegetation or soil resources. While stocking rates may…
- Inventory Monitoring PageClimatic Records Climatic conditions have an obvious effect on plant growth, especially influencing the biomass of annual and perennial herbaceous species. A strong relationship between rainfall and…
- Inventory Monitoring PageClosest Individual Method The closest individual method was developed by Cottam and Curtis in the 1950's as a plotless technique to estimate density. It is a straightforward distance method to…
- Inventory Monitoring PageComparative Yield Method The comparative yield method was developed by Haydock and Shaw in Australia during the 1970's as a rapid method to determine total biomass when sampling in quadrats. Species…
- Inventory Monitoring PageGrazed and Ungrazed Comparisons Utilization can be estimated by comparing biomass from paired grazed and ungrazed sample units, with the difference representing the amount of forage consumed (or…
- Inventory Monitoring PageDaubenmire Cover Class Method The Daubenmire cover class method was developed in the 1950s by Daubenmire, an ecologist who worked in the forests and rangelands of northwest USA. It is accepted as a…
- Inventory Monitoring PageDry Matter Content Biomass is usually determined on a dry matter basis, which is the weight of plant material after the moisture within the plant material has been extracted. Moisture content varies…