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Stratified Sampling
Stratified Sampling
Stratified sampling involves dividing the site into sections that are more homogenous than the entire area. Boundaries of the sections should be based on factors that are readily identified and mapped, such as different vegetation types, soil types, topography, range sites, range condition classes or utilization levels.
Animal Unit Months
Animal Unit Months
Animal unit months (AUM) is commonly adopted in rangeland situations as the unit used to express carrying capacity. AUM is a measure of forage supply within the management unit, based on the amount required to support an animal unit for 1 month. Animal unit days (AUD) and animal unit years (AUY) can also be adopted, but AUM better accommodates flexible or season-long grazing schedules.
Animal Unit Equivalents
Animal Unit Equivalents
Animal unit equivalents (AUE) have been developed to standardize grazing demand among different herbivore species. An AUE expresses the quantitative forage demand of a particular kind and class of animal relative to that of an animal unit, based primarily on metabolic bodyweight (Table 1).
Methods to Determine Utilization
Methods to Determine Utilization
Many methods have been developed to estimate utilization, but few have proven suitable for all situations. Depending on the objectives of the inventory or monitoring program, sampling may concentrate on describing utilization for several key species, or it may aim to describe grazing impacts on the entire forage resource.