PARENT SESSION
Oral Session #67: Ecotoxicology and Applied Ecology.
Presiding: W. Snyder
Wednesday, August 7. 1:00 PM to 4:45 PM. Cochise Meeting Room, TCC.
Effects of environmental variation and partial control of management actions on optimal management decisions.
HUNTER, CHRISTINE*,1, RUNGE, MIKE2, 1 University of Georgia, Athens, Georgia2 USGS Patuxent Wildlife Research Center, Laurel, MD
ABSTRACT- Stochastic dynamic programming (SDP) is promoted as a way to improve decision making in wildlife management by providing a formal decision-making process and by explicitly accounting for uncertainties. Four types of uncertainty may be included: 1) environmental variation; and our ability to 2) determine the current system state; 3) precisely implement management decisions; and 4) model system dynamics. Despite the increasing use of SDP in wildlife management and conservation the relative effects of different sources of uncertainty on optimal strategies has received little attention. We evaluate the effects of environmental variation and incomplete control of harvest rates on optimal harvest strategies for white-tailed deer. Greater environmental variation resulted in more conservative optimal policies, but in general had little effect. Only high variability in winter survival rates noticeably changed the optimal policy. Variability in harvest rates had a greater effect on optimal policies, but again only for high levels of variability (CV ≥ 0.20). Average population density was relatively insensitive to increased uncertainty but the variability of population density was strongly affected. Uncertainty in survival rates had a greater effect than variability in harvest rates. Further investigation is needed to determine if these results hold for other objectives, model structures and life histories. However, these results imply that reasonable management decisions can be made in the presence of environmental variation and imprecision in management actions.
KEY WORDS: adaptive management, uncertainty, harvest