Differential forage use makes carrying capacity equivocal on ranges of Scandinavian moose (Alces alces)

Availability of preferred forage is hypothesized to be positively related to demographic performance in selective ungulates. Comparing two regions with high density of moose ( Alces alces (L., 1758)) having contrasting demographic performance and different composition of available plant species, we show that such a positive relationship may not always apply. The high-performance region (HP) had an estimated 41% higher total availability of browse per capita than the low-performance region (LP), but the availability of preferred species did not differ between the two regions. Although birch (genus Betula L.) was the most abundant browse in both regions (comprising 66% and 50% of the shoot amount available per m 2 in HP and LP, respectively), it dominated the diet of moose only in HP (constituting, e.g., 69% of all trees browsed in summer compared with 22% in LP). Further research is needed to identify the cause of the seemingly suboptimal use of birch in LP. We also quantified factors that determine forage availability, of which recent logging clearly was the most important: it multiplied browse availability but also reduced coverage of bilberry ( Vaccinum myrtillus L.), an important forage plant. Our study shows that for selective ungulates, indices of carrying capacity based on forage availability may not apply uniformly across ranges.