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Percent Vegetative Cover
Vegetative cover is the portion of ground area that is covered by vegetation (canopy cover), which may be in natural landscapes or agricultural areas. It can be from a canopy of a variety of things (e.g., field crops, cover crops, trees).
How to operationalize the metric
Method of data collection and data needed to compute the method:
These methods are described in Anderson and Ingram (1993) Sections 3.1.2 for herbaceous vegetation and 3.1.1 for tree vegetation. For details on the quadrat method, see the Crop Residue Productivity Indicator, measurement method 1, in the Productivity Domain. Several other environmental indicators (e.g., biodiversity, weeds, invasive species) can also be assessed using quadrats and transects.
Method of data collection and data needed to compute the method:
A simple assessment of land cover is available through the Land Potential Knowledge System and associated Land Cover App (https://www.landpotential.org/), which provide a tutorial and advice on how to gather simple information on types of vegetation, both living (trees, bushes, crops) and dead (residues), and calculates indices that can be compared to other sites.
Rough approximations of the area covered by each species or type of plant (trees, grasses, shrubs) can be quickly carried out using the Braun-Blanquet scale described in the table below (Wikum and Shanholtzer, 1978).
Unit of analysis:
The unit of analysis is an observable area of land. This scale could be used for an entire plot or field if the whole is easily observable (i.e., tree cover on a small plot). In many cases, it will be necessary to sample portions of a field or plot, following the instructions for quadrats.
Limitations regarding estimating and interpreting:
Because this scale provides a rough approximation of vegetative cover, it is not sensitive to small changes. It instead provides a rapid assessment of vegetative cover useful for discerning major differences.