Factors affecting browsing by moose (Alces alcesL. ) on European aspen (Populus tremulaL.) in a managed boreal landscape

Macro-Nutritional Adaptive Strategies of Moose (Alces alces) Related to Population Density

The distribution area of moose in China has been shrinking back toward the north and northeast because of climate change and human disturbance, and the population number has been declining. Between 2011 and 2015, we studied moose at six sites in the northeast of China during the snowy seasons. We collected fecal samples and plant samples that were used to estimate population densities for moose, as well as their macro-nutrient selection. Out of a total of 257 fecal samples collected at six sites, we identified a total of 120 individual moose (57 females and 63 males). The population density (moose/km² ± SE) was highest at Hanma with 0.305 ± 0.064 moose/km² and lowest at Meitian with only 0.028 ± 0.013 moose/km². Forage availability was different among sites, with the lowest availability at Mohe (58.17 number/20 m²) and highest was Zhanhe (250.44 number/20 m²). Moose at Zhanhe, Hanma, and Nanwenghe had a balanced diet with higher N:C (1:7), while at Meitian, Shuanghe and Mohe the N:C was 1:8. Our results indicate that the southern areas had low forage quality and quantity and this may be the reason for the distribution of the population of moose shrinking northward.

Moose browsing and forage availability: a scale-dependent relationship?

Scale dependence is a fundamentally important topic in ecology because it determines whether results can be generalized over different spatial scales. We studied the relationship between forage consumption by moose ( Alces alces (L., 1758)) and forage availability across six nested spatial scales in south-central Sweden. By using multiple regression, we concluded that the amount of available forage was the best single variable explaining absolute consumption, irrespectively of scale. Forage species diversity, site productivity, and moose density were also important for predicting forage consumption, but their effects differed across the different spatial scales. A multiple regression including forage availability, moose density, site productivity, and forage diversity explained between 31% and 49% of the variation in forage consumption. The importance of a moose index as an explanatory variable decreased with increasing spatial scale, whereas the importance of site productivity increased. According to model selection based on Akaike's information criterion, the same model was ranked highest at the four smallest spatial scales, whereas the top-ranked models at the two largest spatial scales differed. Furthermore, the relationship between consumption and forage availability changed from underutilization at small scales to proportional use at the home range level. Thus, for a comprehensive understanding of moose browsing in relation to food resources, we conclude that a multi-scale approach is necessary.