摘要: The recovery program for desert tortoises in the Mojave and Colorado deserts (USFWS, 2011) requires range-wide, long-term monitoring to determine whether recovery goals are met. Specifically, will population numbers within recover... 展开 The recovery program for desert tortoises in the Mojave and Colorado deserts (USFWS, 2011) requires range-wide, long-term monitoring to determine whether recovery goals are met. Specifically, will population numbers within recovery units remain stable or increase over a period of 25 years. In 1999, the Desert Tortoise Management Oversight Group endorsed the use of line distance sampling (Buckland et al., 2001) as the method for estimating range- wide desert tortoise density. From 2001 to 2005, and again from 2007 through 2009, desert tortoise populations in 5 of the 6 recovery units have been part of a coordinated, range-wide monitoring program using line distance sampling. (The Upper Virgin River Recovery Unit is monitored by Utah Division of Wildlife Resources (McLuckie et al., 2012).) This report describes the full set of quality assurance steps and final results for the 2008 and 2009 monitoring efforts. Since monitoring started again in 2007, the above recommendations guided improvements to the program (USFWS, 2009a). In 2008, the focus continued, with particular emphasis on a more comprehensive training program, on the premise that training is the opportunity to develop and evaluate quality data collection and to build consistency between separate field teams. 收起