Evaluating approaches for monitoring terrestrial vertebrates in United States national parks: An example from Tonto National Park Monument, Arizona

Abstract

I evaluated different approaches for monitoring of amphibians, reptiles, and mammals in national parks based on data from Tonto National Monument, Arizona, and 3 criteria: statistical power, cost, and ability to meet monitoring goals. Detecting a declining trend in abundance (18% over 10 years) with 80% power would require approximately 65 person-days of annual sampling for the 2 most common rodents, and 110 person-days for the 2 most common lizards. Detecting this trend in species richness of terrestrial vertebrates (reptiles, amphibians, and mammals) would require only 30 person-days annually. Monitoring abundances of vertebrates is often recommended for parks, but my study suggests that this approach is too expensive for most parks, and results may be inadequate for achieving agency goals of monitoring biological diversity. I advocate use of species richness in monitoring, and provide field and analytical methods for estimating this parameter.