Risk of agricultural and property damage associated with the recovery of Japanese monkey populations

Estimation of abundance and distribution of Japanese macaques using track counts in snow

“…It was historically confirmed that the macaque population has been fully distributed throughout the study area (Enari et al 2006;Enari and Suzuki 2010). Human impacts on the natural distribution and habitat utilization of macaques could be small, because the declines in human population and their activities have advanced drastically across this district in recent years (Enari and Maruyama 2005).…”

“…The same consideration holds true of macaques, because the additional factors that were not considered in the modeling (such as past catastrophes, e.g., heavy snow; historical human influences, e.g., overhunting; and geographic barriers, e.g., high mountains) have historically limited the occupation of macaques in the geographical space (Iwano 1980;Koganezawa 1991;Mito 1992;Mitani and Ikeguchi 1997;Enari and Suzuki 2010). The researcher who refers this model must therefore carefully interpret the output of niche-based distribution models with due consideration of possible limiting factors of habitat occupation in a subject area (Pearson et al 2007).…”

“…The distribution of macaques is primarily regulated by food resources and their refuge, which are defined by the conditions of vegetation, land use, climate, and topography (Iwamoto 1978;Iwano 1980;Mitani and Ikeguchi 1997;Hanya et al 2004;Enari and Suzuki 2010). In particular, in snowy areas, the climate conditions and the amount of snow in the winter limits macaques' activities (Wada and Tokida 1981;Watanuki and Nakayama 1993).…”

“…Then, we set up these transects by the following five steps: (1) dividing the entire study area into 50 m×50 m grid cells; (2) selecting several environmental factors that can potentially influence the probability of the macaque occurrence in a given area during winter (Table 1), according to previous studies (Iwamoto 1978;Iwano 1980;Wada and Tokida 1981;Hanya et al 2004;Enari and Suzuki 2010, see also "Animal under Study"); (3) assigning the mean value of each environmental factor to each grid cell; (4) repeatedly generating possible layouts for parallel transects at 2-km intervals within the study area, i.e., 2 km/50 m (grid cell size)=40 layouts; and (5) selecting the one that had the environmental components most similar to those in the entire study area. We completed these operations by using ArcGIS 9.1 (ESRI, Redlands, CA).…”

“…A major reason for these conflicts is the damage caused by macaques to agriculture and private properties (Sprague 2002). There is a pressing need to establish a valid management plan for simultaneous damage control and animal conservation (Enari and Suzuki 2010). Generally, it is difficult to achieve such a plan without an appropriate status assessment of the subject species, such as understanding its population and distribution in the areas of concern (Caughley and Gunn 1996).…”