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Ground Cover

Ground cover describes the proportion of the soil surface covered by some type of protective material, which usually includes litter, gravel, rocks, microphytic crusts, in addition to standing plant material. Unprotected bare soil can be determined as

Bare soil = 100% - Ground Cover

References and Further Reading

Society for Range Management. 1989. A glossary of terms used in range management. Society for Range Management, Denver, CO. 3rd ed. p 8.

Graphing Techniques

Sampling precision is improved by increasing sample size because data describing the vegetation attribute is collected for a greater proportion of the population. At some point, however, we begin to collect information that is repetitious and additional sampling becomes inefficient.

Rangeland Inventory, Monitoring, and Evaluation:
General Principles

Introduction | General Principles | Sampling Concepts | Vegetation Attributes
Rangeland Evaluation | Management Applications | Chapter Outline

Methods to Determine Frequency

There is only one general approach to determining frequency and it is based on identifying key species in each quadrat. It does not require that individuals are distinguished or counted. Therefore, variations of the basic method to determine frequency relate to properties of the sample unit and data manipulation.

Data Recording and Calculations to Determine Frequency

The field sheet to record frequency usually includes a species list and a tally is made for every quadrat where the species is recorded. Only a single tally is made for each quadrat, which represents the presence of the species regardless of its abundance. If nested quadrats are used, more than one column is needed to separately recorded each quadrat.

Frequency

Frequency is the vegetation attribute that describes the probability of finding a species within a particular area. The probability is based on the occurrence of that species in a series of sample units. For example, if a species has a frequency of 75%, we expect it to occur in three out of every four quadrats examined.

Rangeland Evaluation

Introduction | General Principles | Sampling Concepts | Vegetation Attributes
Rangeland Evaluation | Management Applications | Chapter Outline