Performance in Wild Ungulates: Measuring Population Density and Condition of Individuals

摘要

Measures of performance in wild ungulates can include characteristics indicative of condition and health such as body weights, fat reserves, blood values, reproductive rates, and parasite loads. Performance may also be inferred from habitat-related factors, such as diet and nutritional intake. However, these parameters interact with population density to form a homeostatic system that tends towards equilibrium over time, subject to other extrinsic variables. Therefore, performance in ungulates should be judged with reference to a specific population density. Estimates of population density can be derived from direct methods such as drive counts, aerial counts, line transect counts, spotlight counts, and remote sensing, as well as from indirect techniques such as mark-recapture methods, change-in-ratio methods, track and trail counts, and fecal pellet-group counts. Flowcharts presented offer help in choosing appropriate methods to determine population density and assess condition and health of individuals.