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Brenda Maas, 218-720-4280, [email protected]
Nora Kubazewski, (218) 720-4280, [email protected]
High Tech in the North Woods
High tech has once again hit the north woods of Minnesota. Researchers from the Natural Resources Research Institute (NRRI) at the University of Minnesota Duluth and St. Paul campuses are developing a computer model to simulate animal foraging. Currently, the model is being used to study the effects of moose eating habits on plant growth in an effort to better manage moose populations.
EASE, which stands for Energy Activity and Simulation Environment, uniquely combines four submodels into one and was designed specifically for ruminantsóanimals that initially eat great quantities of food and later regurgitate it from their ìfermenterî stomachs to completely digest the food.
The physiology submodel is a combination of experimental work done on ruminants by hundreds of researchers over the past 50 years. The population model simulates the annual survival and reproduction of individuals in a herd. The plant growth model simulates growth of hardwoods and conifers which were browsed by moose. The spatially-explicit foraging component is being tested with data from six moose wearing global positioning system (GPS) collars.
All four submodels have been customized for moose and are linked together so that EASE can predict energy balance, physiological parameters, population trends, and the reaction of vegetation to moose foraging.
Moose eating patterns are cyclical with the seasons. During each summer day, moose cows eat 25-30 pounds of aspen, hazel and willow leaves in addition to aquatic plants to reach weights of more than 880 pounds. However, the mooseÃs consumption slows as the days grow shorter and during the winter the same cow eats only 10 pounds of hardwood and conifer twigs each day. Because the food supply is limited, moose mobilize their fat and protein for additional energy. By spring, most cows have lost 200 pounds or more.
ìLooking at the moose in these terms, how does it survive? We developed EASE to help explain how this works,î explained John Pastor, lead moose researcher and forester at NRRI.
While Pastor and Yosef Cohen of the University of Minnesota Department of Fish and Wildlife brought their moose expertise to this National Science Foundation (NSF) project, doctoral candidate Ron Moen provided the thesis and wrote the individual computer programs.
Although EASEÃs interface is designed for scientists and not the average at-home user, if a viewer thinks of the screen grid as a Pac-Man maze, the mysterious moose movements begin to make sense. EASE tracks a pre-designated moose as it moves across the landscape, browsing and chewing its cud, just as the Pac-Man gobbles up the little dots.
As the moose makes decisions on what, where, when and how much to eat, and when to move to new grazing areas, EASE monitors the mooseÃs weight, body composition, energy requirements and various other physiological parameters. Using these values, EASE predicts energy and mineral requirements for deposition of fat and protein, gestation, lactation and antler growth.
ìBy combining the results of experiments done over the past several decades into a computer program for both domestic and wild ruminants, we can now predict daily nutritional requirements of cows and bulls and begin to examine spatially-explicit movements during foraging bouts,î explained Moen. ìIn addition, the model can predict the physiological effects of undernutrition, such as excretion of metabolites that can then be measured from urine samples.î
EASE also incorporates browsed vegetation into landscape models to predict the reaction of vegetation to moose browsing. According to Pastor, the modeling program is an invaluable and cost-effective way to manage both timber supply and moose populations. ìWe may be able to use EASE to predict the effects of timber harvest on the mooseÃs requirements for food and shelter,î noted Pastor.
According to Mark Lenarz of the Minnesota Department of Natural Resources (DNR), the boreal forest area of northeastern Minnesota supports about 5,500 cows and bulls. Moose are also found in the New England states, the Upper Peninsula of Michigan, North Dakota and many other western states including Alaska.
While EASE is being used for moose, itÃs physiological submodel could be used to simulate the physiology of many ruminants including deer, elk, cattle, goats, sheep, llamas and buffalo. The plant growth and population submodels are both currently implement specifically for moose. Still in the research mode, EASE is not available commercially. However, the Minnesota DNR and several other agencies across the nation have provided input while monitoring the project.
-- NRRI --
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