Calculate Change in Distribution Metrics

Calculate two metrics to help describe changes in species distributions - Center of Gravity and Area of Preferred Habitat

Usage

calculate_distribution_shifts(abund, area_threshold = 0.75, cell_area = 8 * 8)

Arguments

abund

model predictions, output from make_predictions as a rasterStack. Layers need names that correspond to the time stamps represented.

area_threshold

a value between 0 and 1, defaults to 0.75. The total area of grid cells with the probability of occurrence of a species equal to or above this threshold will be calculated.

cell_area

a number representing the area of a single model grid cell on which the model is predicted.

Value

a data.frame with three columns: 1) timestamp, equal to the names of the layers in abund; 2) COG; 3) Area of probabilities greater than the area.threshold