CS699 - Agent Based Modeling
Craig Kasemodel & Guilherme Santos
2 Oct 2012
ODD Protocol for Alaska Wolf - Caribou
Predator - Prey Modeling
Overview
1.Purpose - Modeling the predator-prey patterns of Alaskan caribou and wolves. Are the caribou
movements currently affected by predation?
2. Entities, state variables, and scales Entities = caribou; wolves; lichen/forage; alternative prey
State Variables = total number of caribou in the herd; number of caribou bands; number of wolves;
number of wolf packs; number of alternative prey;
Environmental factors = ave snow depth, ave snow duration, temperature,
Spatial units = soil type, elevation, veg cover, lichen
Collectives = caribou bands, wolf packs
3. Process overview and scheduling = 1 time step = 1 month; 1 simulation = 100 years; 1 grid = 1 ha;
The model = 1000 ha^2
Design
Concepts
4. Design concepts
Basic principles - optimal foraging theory within social herding for caribou; predator - prey relationships defined
by Lotka–Volterra equations; multiple equilibrium theory (predator release);
Emergence - prey switching - potential linkages if moose were added
Adaptation - caribou move to the cell with the greatest quantity of forage
Objectives - twining rates of caribou
Learning - wolves learn to avoid areas of human activity; caribou might move toward areas of human activity if
the environment isn't negatively impacted; wolves learn about yearly caribou migration patterns
Prediction
Sensing - wolf pack territory & size
Interaction - wolf dispersal
Stochasticity - environmental factors = snow depth & duration, winter temperatures (crusty snow?)
Collectives - wolf packs, caribou bands within the herd
Observation - caribou population and bou pop growth rates
Details
5. Initialization = @ t=0; historical rates for bou and wolves (adfg) Unit 20
6. Input data = yes; model uses annual snow measurements and yearly duration totals (freeze to breakup)
7. Submodels = time steps are monthly to take into account migration patterns from winter range to
calving to summer to winter, typically in some circular motion
(Grimm et al., 2010 & Committee on Management of Wolf and Bear Populations in Alaska & National
Research Council, 1997)
Committee on Management of Wolf and Bear Populations in Alaska, & National Research Council. (1997). Wolves, Bears,
and Their Prey in Alaska:Biological and Social Challenges in Wildlife Management. The National Academies
Press. Retrieved from http://www.nap.edu/openbook.php?record_id=5791
Grimm, V., Berger, U., DeAngelis, D. L., Polhill, J. G., Giske, J., & Railsback, S. F. (2010). The ODD protocol: A review and
first update. Ecological Modelling, 221(23), 2760–2768. doi:10.1016/j.ecolmodel.2010.08.019
Polhill, J. G., Parker, D., Brown, D., & Grimm, V. (2008). Using the ODD Protocol for Describing Three Agent-Based Social
Simulation Models of Land-Use Change. Journal of Artificial Societies and Social Simulation, 11((2) 3), 3.
Retrieved from http://jasss.soc.surrey.ac.uk/11/2/3.html
Rands, S. A., Pettifor, R. A., Rowcliffe, J. M., & Cowlishaw, G. (2004). State–dependent foraging rules for social animals in
selfish herds. Proceedings of the Royal Society of London. Series B: Biological Sciences, 271(1557), 2613 –2620.
doi:10.1098/rspb.2004.2906