Landscape-scale evaluation of habitat uses by sympatric mammals foraging for bark and buds in a heavy snowfall area of northern Japan

Abstract

This study focused on influences of three different growing populations of mammals foraging for bark and buds—Japanese serows (Capricornis crispus), Tohoku hares (Lepus brachyurus angustidens), and Japanese macaques (Macaca fuscata)—on a cool-temperate forest in northern Japan. To acquire the initial knowledge to facilitate ecological monitoring of the influences, we evaluated habitat uses by each species on a landscape scale by using ecological niche factor analysis (ENFA), and identified commonalities and differences among the uses by using discriminant analysis (DA). Within a 50-km2 area, we selected five 5-km transects and recorded tracks of each mammal on the snow surface along transects during the month of March in 2008 and 2009. The track data were used as the proof of species presence for entry into ENFA and DA. Marginality and specialization of species habitat use, computed by ENFA, indicated that the macaque habitat represented the most heterogeneous distribution and the lowest environmental tolerance, which was strictly limited by altitude and terrain conditions to prevent exposure to severe cold climate conditions. This refuge selection by macaques resulted in habitat segregation from serows, although it appears that both mammals prefer the same young broadleaf forests. Meanwhile, the serow was observed to be distinctly inclined to use mountainous forests and to avoid artificial environments. As a result, its habitat could be differentiated from that of the hare, as confirmed by coefficients of a discriminant factor. These findings indicate that the impact of three different mammals foraging on the native vegetation could be quite restrictive.