Grand Canyon National Park
Science and monitoring programs
Staff completed key data collection to support the park’s Colorado River Management Plan commitments to monitor and mitigate visitor use impacts and monitor visitor experience at destination sites.
Staff worked with members of the Hualapai Tribe to develop and implement companion resource monitoring programs in the lower Colorado River gorge. In addition to baseline work along the river, the soundscapes program worked on developing interactive software. They assessed the noise model used for overflights planning and completed acoustic data collection near Mexican spotted owl nests under air-tour routes.
On the ground, nine radio-collared mountain lions were monitored in 2009. Home ranges were delineated and foraging activities were described. Lions continue to use habitat near Grand Canyon Village but avoid entering the developed area.
For the first time since 2004, the endangered southwestern willow flycatcher (SWWFL) was found by survey crews on the Colorado River at historical
Grand Canyon National Park wildlife/human interactions biologist Brandon Holton measures a mountain lion’s teeth. NPS photo
2009/2010 Accomplishment Report
nesting territories between Lees Ferry and Phantom Ranch. Suitable patches of habitat were found along the river between Phantom Ranch and Diamond Creek.
Park staff, working with the U.S. Fish and Wildlife Service and the Arboretum at Flagstaff, AZ, continued to implement recovery plan actions for the park’s only endangered plant species– the sentry milk-vetch. Monitoring data suggest an 11 percent increase in the population at Maricopa Point. New individual plants also were found at the other known population sites in the park. Willow flycatcher. NPS photo
Park staff worked with the Tamarisk Coalition, based in Grand Junction, CO, to implement tamarisk beetle surveying and monitoring in August within the park. During monitoring, small numbers of beetle larvae were found on tamarisk trees along both sides of the river beneath Navajo Bridge and in an area 12 miles downstream from Lees Ferry. Staff also found adult beetles six miles downstream from Lees Ferry in September. Listed as endangered in 1990, sentry milk-vetch is at risk of extinction because the plant exists in just three separate populations in very small numbers. NPS photo