Unequal inclusion probabilities

The Sonoran Desert is among the most extreme environments on Earth. Sampling in these remote, rugged landscapes requires a different approach. When the Park Service established monitoring in Organ Pipe Cactus National Monument they used an approach to select sites based on the cost of travel to sites on the broader landscape, visiting less “costly” sites with higher probability than more costly sites. The cost surface that defined the probability of inclusion of sites was developed using terrain data, and a tool that estimates the time to travel to any arbitrary location on the landscape.