Mongolia’s Eastern Steppes are one of the last intact grassland ecosystems in the world.The movements of all animals are affected by their need for resources, and in particular, food. Where and how grazing animals move often depends on where the best vegetation resources can be found, and how predictable this food is from year to year. Some ungulate species with predictable environments (caribou in Alaska and wildebeest in Africa, for example) migrate seasonally. Other species (gazelles in Mongolia, for example) appear to make large-scale, long-range movements that are seemingly unpredictable. This “nomadism” likely occurs when the availability and location of resources vary considerably by season and by year.

The National Science Foundation has awarded UMass Amherst’s Todd Fuller and Craig Nicolson $533,000, and their collaborator Bill Mongolian gazelles, which are constantly on the move, are capable of traveling hundreds of kilometers across the steppes in a matter of days. Gazelle movements are as yet little understood, but may be related to stochastic rainfall events. Group sizes are extremely variable ranging from single individuals to megaherds of more than 200,000 gazelles. Inset: Gazelle calves are born end of June.Fagan at the University of Maryland College Park another $147,000, to make sense of these seasonal and annual movement strategies for individual gazelles in Mongolia (new field studies) and caribou in Alaska (historical data). The researchers will combine theoretical computer models and landscape-scale satellite images of vegetation with detailed movement data collected over several years.

By understanding long-distance animal movements, we will be in a much better position to know how environmental variability affects animal behavior. The conservation of these species and their habitats depends on understanding their large-scale movement patterns and ecology. This research will help identify the mechanisms by which animals ‘read’ their environment to know when and where to move over complex landscapes.