rhrCoreArea: Estimate Core Area

In jmsigner/rhr: Reproducible Home Ranges with R

Description

This function estimates core areas for animal home ranges. A core area, is an area of animals home range that is used more intensively.

Usage

rhrCoreArea(x, method = "seaman90", ...)

## S3 method for class 'RhrProbEst'
rhrCoreArea(x, method = "powell90", ...)

Arguments

x	a RhrHREstimator* object
method	method used to calculate core area. At the moment only powell90 is implemented
...	none implemented

Value

object of class RhrHRCoreArea

Note

Core areas are areas within an animals home range that receive greater intensity of use than other areas. Core areas are often used to answer questions of territoriality or habitat selection. Oftentimes core areas are estimated by calculating home ranges at a level of 20 or 50

Seaman and Powell (1990) presented an area independent method for core area estimation, that does not rely on a predefined isopleth cut off values. This methods estimates the core area by estimating two values for each grid cell of the study area. First for each grid cell the number of relocations that fall within the cell are counted. In the next step the following two values are calculated for each cell:

1. Percentage of maximum relative frequency. The grid cell with the highest relative frequency of relocations is assigned a value of 100

2. Percent of home range, that is the percentage of pixels with a higher relative frequency of relocations. The percentage of maximum relative frequency is then plotted against the percent of home range. The point with the greatest distance to the line with intercept 1 and slope -1 is used as threshold.

References

Peter N. Laver and Marcella J. Kelly. A critical review of home range studies. The Journal of Wildlife Management, 72(1):290-298, 2008

Erran D. Seaman and Roger A. Powell. Identifying patterns and intensity of home range use. Bears: their biology and management, 243-249, 1990

jmsigner/rhr documentation built on June 26, 2020, 8:59 a.m.