A habitat suitability index model to assess moose habitat selection at multiple spatial scales

Abstract

We developed a habitat suitability index (HSI) model for moose (Alces alces) in the boreal forest. The model used two components: a suitability index for food (SI_food) and another for the interspersion between cover and food (SI_edge). We used forest maps as the input data source, and the value of each stand type in terms of cover and food was based on field surveys. To validate the model, the habitat preference of moose equipped with global positioning system telemetry collars was assessed at both landscape and home-range scales. We expected the habitat-preference index to correlate with suitability indices determined using the global model and each of its two components. Habitat suitability was assessed in evaluation plots of 500, 100, and 10 ha. Unexpectedly, the habitat-preference index correlated better with SI_food and SI_edge than with the global model. The suitability indices also performed better when assessed in large plots. Selection of 500 ha plots related mostly to SI_edge, but SI_food was more important when smaller evaluation plots were used, especially for males. Females preferred plots with intermediate SI_food values. At the fine scale, SI_edge was not as attractive to moose as was previously observed, presumably because snow conditions prevailing in our study area were relatively moderate. We recommend utilizing the model with SI_edge in large plots (ca. 500 ha) and SI_food in smaller plots. Our model could be adapted and applied to other areas by using empirical data to adjust the relative value of stand types in terms of cover and food.