QUÉBEC MOOSE AERIAL SURVEYS: METHODS TO ESTIMATE POPULATION CHARACTERISTICS AND IMPROVED SAMPLING STRATEGIES

Abstract

We present methods to estimate various parameters of moose populations using stratified random sampling and double sampling. Québec's winter moose population outside parks and reserves between 1987 and 1991 was estimated at 52,543 individuals. The confidence interval of this estimate is 4,917 moose, which represents a relative error of 9 % (α = 0.10). sex ratio is often imbalanced, with males representing less than 35 % of the adult segment. We noticed important regional variability in productivity. Southern populations were the most productive (> 60 calves / 100 females), whereas the western and northern ones were the least productive (22-44 calves / 100 females). We checked if a flight over the same sample plots could raise the power of statistical comparisons between two aerial surveys. We compared term to term moose densities in fifty-seven 60 km² sample plots, from two independent aerial surveys, spaced 3 to 6 years apart. Based on the 6 territories analyzed, the surface are of the track networks, as well as the number of moose per plot, which represent two density indicators, were not generally correlated between the two surveys. Variance component analysis, however, showed that the variance due to sample plots was between 4 and 72 % in the 6 territories under analysis. This shows that repeated survey design could be useful to detect changes in population densities between two aerial surveys.