Terrestrial Wildlife

Overview

Unlike plants, soils, and water bodies, animals move around—a lot. This makes them difficult (and expensive) to monitor, especially because many Southwestern mammals don't tend to follow predictable migration patterns. For this reason and others, mammals were not one of the resources originally selected for monitoring by the Sonoran Desert Network.

Improvements in technology and monitoring methodologies, along with a new program that has made volunteers available through the Desert Research Learning Center, is helping to change that. A draft protocol for monitoring medium- and large-sized mammals (ranging in size from foxes to bears) using remote wildlife "camera traps" is being piloted at Casa Grande Ruins National Monument, Chiricahua National Monument, Gila Cliff Dwellings National Monument, Montezuma Castle National Monument (both units), Organ Pipe Cactus National Monument, and Saguaro National Park (Tucson Mountain District). The network hopes to implement this protocol at all 11 Sonoran Desert Network parks.

Methods and Goals

The cameras are heat- and motion-activated, and are positioned at a height designed to capture animals. They will be placed during times of the year when mammal activity is expected to be highest, depending on season and location. Because they can simultaneously sample nearly all species of medium and large mammals in an area, camera traps are useful for identifying trends in species across multiple trophic levels (herbivores, omnivores, carnivores).

This pilot project will help us to collect baseline data. Once fully established, the overall goal of this monitoring will be to track biologically significant changes at the community and population levels over time. A technique known as occupancy analysis will allow us to answer questions about the composition of mammal communities, such as, are we seeing as many medium-sized carnivores as we did 10 years ago? Are they the same species, or are some becoming more or less dominant than in the past? Is there as much variety? Such questions are important because changes at one trophic level (mid-sized mammals) may have cascading effects at other levels.

Knowing about these kinds of changes will help park managers and researchers to study the underlying causes of these trends, which will in turn lead to more effective management and conservation strategies. The results will be used in combination with results from the network's climate, uplands, and landbird protocols, but also as a standalone monitoring component that can provide early warning of the changes in occupancy. The photographs taken by camera traps can also be used for interpreting wildlife and wildlife monitoring to park visitors.

For more information, contact Andy Hubbard.