Natural Resource Ecology and Management
Journal or Book Title
Herpetological Conservation and Biology
Monitoring programs for species of conservation concern are notoriously flawed. Notably, many monitoring programs do not establish trigger points or a level of decline in population size that will result in management action. Here we report on the monitoring program for the Flat-tailed Horned Lizard (Phrynosoma mcallii) that has been established across its range throughout the United States by the Flat-tailed Horned Lizard Interagency Coordinating Committee (FTHL ICC). Impor- tantly, we examine whether a trigger point of 30% decline was detected in these populations. Between 2007 and 2013, we detected 955 P. mcallii on 2,714 occupancy surveys and captured 715 individuals on 1,861 demographic surveys. Occupancy surveys have demonstrated that the species occurs through- out the management areas and occupancy estimates range from 0.25–0.89. Demographic surveys have demonstrated that population trends over time are correlated across all management areas; however, they are probably driven by factors at smaller geographic scales. During the study no population decline > 30% was detected after accounting for natural and stochastic fluctuations. Continued mon- itoring is called for to gain a greater understanding of what is driving the trends in populations both range-wide and at the scale of management areas.
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Leavitt, Daniel J.; Collins, Jimmie; Crawford, Cat; Crayon, Jack; Grant, Tyler J.; Heatwole, Nicholas B.; Hollenbeck, Eric V.; Ingraldi, Michael F.; Piest, Linden; Ponce, Kevin; Powell, Robert J.; Roach, Aimee; Rosenberg, Abigail S.; Sirchia, Felicia M.; Steward, Daniel M.; Stewart, Erica; Trouette, Andrew; and Lovich, Robert E., "Multiyear monitoring (2007-2013) of flat-tailed horned lizards (Phrynosoma mcallii)" (2015). Natural Resource Ecology and Management Publications. 283.