Abstract
A multiple stressor risk assessment was conducted at Yuma Proving Ground, Arizona, as a demonstration
of the Military Ecological Risk Assessment Framework. The focus was a testing program at Cibola
Range, which involved an Apache Longbow helicopter firing Hellfire missiles at moving targets, M60-
A1 tanks. This paper describes the ecological risk assessment for the missile launch and detonation. The
primary stressor associated with this activity was sound. Other minor stressors included the detonation
impact, shrapnel, and fire. Exposure to desert mule deer (Odocoileus hemionus crooki) was quantified
using the Army sound contour program BNOISE2, as well as distances from the explosion to deer. Few
effects data were available from related studies. Exposure-response models for the characterization of
effects consisted of human "disturbance" and hearing damage thresholds in units of C-weighted decibels
(sound exposure level) and a distance-based No Observed Adverse Effects Level for moose and
cannonfire. The risk characterization used a weight-of-evidence approach and concluded that risk to
mule deer behavior from the missile firing was likely for a negligible number of deer, but that no risk to
mule deer abundance and reproduction is expected.
