Theory, R functions & Examples
Roberts (1992), used by author as example dataset in library
The dataset contains 160 circular 375 m2 plots, where all herb species and their cover was recorded (using so called Pfister scale, similar to Braun-Blanquet scale - see the table here. Altogether 169 vascular species were recorded. The woody species, although also recorded in the original study, are not included in the dataset (authors argument that woody species more than ecological factors reflect successional status of the vegetation).
Bryce Canyon National Park has an area 14000 ha, and is located in Southern Utah (USA) on the floristic boundary between flora of Rocky Mountains and Colorado Plateau. Typical vegetation of the park consists of badlands in lowlands, Pinus-Juniperus forest and Pinuse ponderosa savanas at middle elevation and mixed coniferous forests in higher elevation.
|Name of the variable||Description|
|annrad||Annual sum of direct radiation|
|av||aspect = (1+cos(asp-30)/2)|
|depth||Soil depth [deep and shallow]|
|east||UTM coordinates of latitude|
|grorad||Radiation during the vegetation season|
|north||UTM coordinates of longitude|
|pos||Topographical position [bottom, low_slope, mid_slope, ridge, up_slope]|
|quad||USGS 7.5 minute quadrant|
# If you need to install labdsv package, use the following: # install.packages ('labdsv') library (labdsv) data (bryceveg) # matrix with species data (160 samples in rows and 169 species in columns) data (brycesite) # matrix of environmental variables (160 samples in rows and 11 environmental variables in columns)
Roberts D.W. (1992): Plant Community Distribution and Dynamics in Bryce Canyon National Park: Final Report for Project PX 1200-7-0966 (www)