Bighorn Sheep Analysis

March 2023

Slope or terrain ruggedness is important for sheep to observe and escape predators

This slide depicts highest slopes in the northern Peloncillos (blue colors) and flat terrain as brown

Slope overlaid with location data from bighorn sheep rams (green dots) provided by the Arizona Department of Game and Fish

Sheep were tracked from 2017-2020

Selection of Slope

Slope (degrees)

Plots of resource selection functions showing how sheep used slope, aspect and the land cover types.

Negative values indicate avoidance while positive numbers show greater selectivity.

Slope and land cover seemed valuable to include in further models. Aspect was not.

Using the relationships shows in previous slide, I created a habitat suitability index based on landcover and slope.

Both layers was parameterized such that the highest habitat suitability was a 1 whereas the lowest a 0. intermediary values ranged between these 2 end points.

I then used a harmonic mean to calculate the final suitability index which also ranged from 0 to 1.

Habitat Model Fit

Predicted Habitat Quality

This is the validation of the model to what sheep actually used. In general, the model shows high selection by sheep where we predict the best habitat and avoidance in bad habitat.