Food habits and home range use of Japanese macaques on an island inhabited by deer

Food habits and home range use of a troop of Japanese macaque Macaca fuscata Blyth on Kinkazan Island (9.6km²), northern Japan, were studied from the spring of 2000 to the winter of 2002. The home range of this troop covers the area where vegetation is modified by foraging of sika deer Cervus nippon Temminck. The core areas of the home ranges of the macaque troop corresponded closely to the distributions of the staple food plants in every season. For example, leaves of Berberis thunbergii DC. and leaves of Zelkova serrata Makino in spring, berries of Berchemia racemosa Sieb. & Zucc. in summer, nuts of Zelkova serrata and Carpinus spp. in the fall of 2000 and winter of 2001, seeds of Torreya nucifera Sieb. & Zucc. in the fall of 2001, and bark of Zanthoxylum piperitum DC. in winter of 2002. Among the staple food plants, Berberis thunbergii and Zanthoxylum piperitum are more abundant on Kinkazan Island than other macaque habitats in northern Japan because they are spiny and unpalatable to sika deer, hence survive under the heavy foraging by the deer. Further, another staple food plant, Berchemia racemosa, a liana, grows abundantly at the edges of Illicium forests. Illicium anisatur is toxic and is not consumed by sika deer. Monkeys of this troop using the unique vegetation induced by sika deer grazing, fed on several plants which are not consumed by monkeys in other areas, and the home range was heavily affected by the distributions of these plants.     

Food habits of sika deer and nutritional value of sika deer diets in eastern Hokkaido, Japan

Rumen content analysis and field observations were used to investigate the food habits and diet quality of sika deer (Cervus nippon yesoensis Heude) from 1991 to 1993 in eastern Hokkaido, Japan. Diets varied seasonally, with deer consuming graminoids and browse in winter, forbs and agricultural crops in spring and summer and all of these plant foods in autumn. Eighty-four plant species with sika deer bite marks were identified and their use also varied seasonally. The diversity of food resources available provided both critical protein and digestible energy, allowing for physiological maintenance and seasonal growth. With these high-quality diets, deer maintained good body condition in eastern Hokkaido, where the population density was relatively low.     

Nitrogen content in feces and the diet of Sika deer on the Boso Peninsula, central Japan

Fecal and rumen nitrogen content of Sika deer (Cervus nippon Temminck 1838) on the Boso Peninsula, central Japan, were analyzed concerning their seasonal fluctuations and local differences at four areas on the Boso Peninsula. The mean fecal nitrogen was high in August and low in February in all the areas. The seasonal variation, however, was relatively small. This may be the result of the following reasons: the Boso deer feed on evergreen broad-leaves containing a high and stable nitrogen content in winter; little snow falls there; and the deer consume foods relatively low in nitrogen in summer. The fecal and rumen nitrogen content in both summer and winter depended on deer density.     

Seasonal food habits of a sika deer population in the warm temperate forest of the westernmost part of Honshu, Japan

The rumen contents of 63 sika deer (Cervus nippon Temminck) shot in the westernmost part of Honshu were analyzed by the point-frame method. The rumen contents were dominated by forbs and the majority of these were evergreen monocotyledonous plants, probably Ophiopogon spp. Evergreen browse leaves (woody leaves), such as Eurya japonica Thunb., Ilex crenata Thunb. and Trachelospermum asiaticum Nakai, were also important, constituting 20–40% of the rumen contents. Other categories accounted for only small proportions, although in summer, graminoids increased but twigs and bark decreased in importance and in fall and winter, fruits and seeds increased in importance. The diet of the deer was characterized by high-quality foods even in winter and by a stability or less-pronounced seasonality throughout the year than found in the northern deer. These results were compared with those from other populations, including a northern sika deer population in Japan.     

A comparison of food habits of two sympatric ruminants of Mt. Yatsugatake,central Japan: sika deer and Japanese serow

Comparison of food habits of sympatric animals provides understanding of interspecific relations. Previous studies of food habits of the two ruminants of Japan, sika deer (Cervus nippon) and Japanese serows (Capricornis crispus), have shown that sika deer are variable, and they are gazers in northern Japan, but browsers in southern Japan, whereas Japanese serows are browsers. However, these studies described the food habits of each species separately, and no study has compared the food habits of these species living in sympatry. Therefore, we examined these species on Mt. Yatsugatake, central Japan, using microhistological analyses and nutritional analyses of feces. Sasa nipponica, a dwarf bamboo, predominated in the fecal composition of sika deer, whereas both S. nipponica and dicotyledonous plants were found in the feces of Japanese serows. Crude protein levels of serow feces were higher than those of deer. The particle sizes of plant fragments in serow feces were smaller than those in deer feces, suggesting that serow fed more selectively on digestible plants than deer did. These results support the suggestions of previous studies conducted in different habitats and show that sika deer are less selective grazers, and Japanese serows are more selective browsers. Thus, food differences are likely explained by the feeding ecophysiology of the animals and not habitat differences.     

Landscape structure affects food quality of sika deer (<Emphasis Type="Italic">Cervus nippon</Emphasis>) evidenced by fecal nitrogen levels

Evaluating the quality of wildlife habitat is essential for understanding and predicting population dynamics in heterogeneous environments. We used fecal nitrogen levels as an indicator of habitat quality of sika deer (Cervus nippon) and explored important landscape elements influencing nitrogen levels, taking deer density into account. We established 92 plots differing in deer density and landscape structure on the Boso Peninsula, central Japan, and collected fecal samples along a 1-km transect at each plot. The regression models involving two independent variables, i.e., deer density and the length of forest edge within an area of 100 or 200 m from the transect, were selected based on the Akaike’s Information Criterion (AIC). Levels of fecal nitrogen were positively correlated with the length of the forest edge and negatively correlated with population density of deer. The area of 100 or 200 m from the transect most likely reflected the behavioral scale of the deer. Coverage of palatable understory vegetation increased with proximity to forest edge and decreased with deer density. Variability in the level of fecal nitrogen could thus be explained by food availability in the landscape. These results suggest that landscape alterations increase the carrying capacity of sika deer and thereby increase impacts upon the ecosystem.     

Sexual variations in food quality and gastrointestinal features of sika deer (Cervus nippon) in Japan during winter: implications for feeding strategy

We assessed sexual variation in food quality and gut macrostructure in adult male and pregnant female sika deer, Cervus nippon (Temminck, 1838), in Japan during winter. These variations might have important implications relative to sexual differences in habitat use, forage acquisition, and digestive strategy. According to the sexual dimorphism-body size hypothesis the larger males would feed on poorer forage and have heavier stomach contents and heavier intestine contents and longer intestines than smaller females. However, the food quality in rumen contents of males was higher than, or at least similar with, that of pregnant females. In correspondence to food quality, the relative weights of stomach contents and intestines with contents, the relative lengths of intestines to the lengths of body and total intestines in pregnant females were similar to adult males. The relative weights of omasum and abomasum tissues in pregnant females were greater than in males. Our findings suggest sexual differences in feeding strategy in sika deer in Japan during winter. To meet greater nutritional demands of high metabolic rate and gestation, pregnant females seemed to maintain a greater volume of digesta in guts and had more stomach tissues than expected by the sexual dimorphism-body size hypothesis to compensate for poorer forage quality.     

Forest edge creates small-scale variation in reproductive rate of sika deer

Habitat edges are considered to have an important role in determining the abundance of deer in forest landscapes, but to our knowledge there are few lines of evidence indicating that forest edge enhances the vital rate of deer. We examined pregnancy of female sika deer in Boso peninsula, central Japan, and explored how forest edges, food availability in forests, and local population density influence the pregnancy rate of sika deer. Local deer density was estimated by the number of fecal pellets, and food availability in forests was estimated by combining GIS data of vegetation distribution and the relationship between vegetation biomass and local deer density. Forest edge length was also determined by GIS data. Model selection was performed with multiple logistic regression analyses using the AIC to find the best model for accounting for the observed variation in pregnancy rates of the deer. Multiple logistic regression analysis showed that the length of forest edge had a positive effect on the pregnancy rate of females, whereas food availability in forests and local deer density had little effect. This forest edge effect was detected in a 100–200-m radius from deer captured locations, indicating that deer pregnancy is primarily determined by habitat quality within a 10-ha area. This result was confirmed by tracking females with GPS telemetry, which found that the core areas of the home range were less than 12 ha. The positive effect of edges and the lack of density dependence could be a result of high plant productivity in open environments that produces forages not depleted by high deer densities. Our results support the view that land management is the cause of the current problem of deer overabundance. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Fallen leaves and unpalatable plants as alternative foods for sika deer under food limitation

Feeding behavior and rumen contents of sika deer (Cervus nippon Temminck) under food limitation were studied on Nakanoshima Island, Hokkaido. During the phase of population growth, the deer subsisted on tree bark and twigs, deciduous leaves and dwarf bamboos (Sasa spp.) in the winter. After a crash in population, the deer began feeding on the fallen leaves of deciduous trees and continued to do so throughout the year. They also ate unpalatable plants Cephalotaxus harringtonia var. nana Rehd., Senecio cannabifolius Less. and Cynanchum caudatum Maxim. as winter foods, which used to remain untouched by deer, and had accordingly expanded their distributions, following a decrease in the amount of dwarf bamboos available. These facts suggest that sika deer drastically shift their foods and exploit alternative foods under conditions of food limitation.     

Age-sex differences in the diets of Sika deer on Kinkazan Island,northern Japan

Dietary differences in the ages and sexes of Sika deer (Cervus nippon) were studied on Kinkazan Island, northern Japan from October 1990 to July 1991. Larger deer consumed more graminoids than smaller deer except in spring, and less dicotyledonous leaves in all the seasons. Fecal nitrogen concentrations were lower in larger deer than in smaller deer in all the seasons. The age-sex differences in foods were smaller in summer and winter when foods were most abundant and scarce, respectively, while they were greater in spring and autumn when food availability was intermediate.     

The evolution of nettle resistance to heavy deer browsing

We examined whether heavy browsing by sika deer, Cervus nippon Temminck, changed morphological characteristics of a Japanese nettle, Urtica thunbergiana Sieb. et Zucc., in Nara Park, where a large population of sika deer has been maintained for more than 1,200 years. Wild nettles of Nara Park exhibited smaller leaf area, 11–223 times more stinging hairs per leaf, and 58–630-times higher stinging hair densities than those of other areas where there was no evidence of sika deer browsing. There were no significant differences in stinging hair length between the areas. Nettles from Nara Park that were cultivated from seeds in a greenhouse retained a larger number and higher density of stinging hairs. In the field, nettles of Nara Park were less frequently browsed by sika deer and showed higher survivorship than nettles that were transplanted from an unbrowsed area into Nara Park. These results indicate that: (1) the U. thunbergiana population of Nara Park has an extremely high stinging hair density compared with those of unbrowsed areas; (2) this characteristic has a genetic basis, and (3) stinging hairs serve as a defensive structure against sika deer, contributing to an increase in survivorship. Thus, we conclude that a U. thunbergiana population in Nara Park, with extremely high stinging hair densities, has evolved through natural selection due to heavy browsing by sika deer.     

Food habits of sika deer in the Shiranuka Hills,eastern Hokkaido: a northern example from the north–south variations in food habits in sika deer

Seasonal changes in the composition of the diet of the sika deer population in the Shiranuka Hills, eastern Hokkaido, in 1998 were determined by fecal analyses. The deer were dependent on Sasa nipponica, a dwarf bamboo, throughout the year, particularly in winter when it accounted for as much as 77.7% of the diet. It accounted for 33.1% and 45.6% in spring and summer, respectively, and this decreased to 12.2% in autumn. Besides S. nipponica, all the graminoid categories accounted for large amounts (66–96.7%), while dicotyledonous plants accounted for little (3–8%) except in autumn when they accounted for 31%. The strong dependence of the Shiranuka population on graminoids was different from other Hokkaido deer populations, for example the population from Ashoro/Onbetsu and the extremely high density population on Nakanoshima Island. In spite of these differences, food for all Hokkaido sika deer was poor in winter. Along the north–south geographical cline in the food composition of sika deer along the Japanese archipelago, the Shiranuka population was positioned as a grazer type, in contrast to the southern populations. However, it is important to note that variations are great among local populations in Hokkaido.     

Effects of a Typhoon on Foraging Behavior and Foraging Success of <Emphasis Type="Italic">Macaca fuscata</Emphasis> on Kinkazan Island,Northern Japan

We studied the effects of typhoon damage on the food habits, time budgets, and moving distances of Japanese macaques (Macaca fuscata) on Kinkazan Island, northern Japan. Before the typhoon (pre-typhoon phase), the macaques fed on various food items, including fruit in trees (Swida macrophylla) and nuts (Torreya nucifera) on the ground. After the typhoon passed (post-typhoon phase), the macaques fed intensively on the seeds of Perilla frutescens (a forb) and the nuts of Quercus serrata on the ground. One may attribute the changes to decreased food availability or foraging efficiency of fruits and nuts on the ground, due to their concealment by leaf litter and mud and their consumption by other animals, such as sika deer (Cervus nippon) and field mice (Apodemus argenteus). In the post-typhoon phase, the macaques fed more quickly on seeds of Perilla frutescens, spent less time traveling, and moved over shorter distances. The differences may be due to changes in the distribution of staple foods between the 2 phases. We also evaluated the energy intake and energy balance of the macaques in both phases, based on observations of foraging and nutritional analyses of the food items. There is no significant difference in either parameter between the 2 phases. The changes in food habits and movement behavior may have compensated for the reduced food availability or foraging efficiency caused by the typhoon. Both behavioral changes and nutritional issues are important when investigating the effects of storms on animal ecology.     

Long-term variation in fruiting and the food habits of wild Japanese macaques on Kinkazan Island, northern Japan

We studied the relationship between the food habits of Japanese macaques (Macaca fuscata) and the availability of nuts (Fagus crenata, Zelkova serrata, Carpinus spp., and Torreya nucifera) on Kinkazan Island, northern Japan, from 1997 to 2005 to examine the long-term variations in both food habits and availability. The food habits of the monkeys showed clear seasonal changes: the staple foods were woody leaves and flowers in spring (May and June), woody leaves and seeds or fruits other than nuts in summer (July and August), nuts and seeds or fruits other than nuts in fall (September-November), and herbaceous plants in winter (December-April). The availability of nuts, combinations of masting species, and energy production varied among years. Food habits varied among years, but the magnitude of variability of food habits differed among seasons, with large variability during summer and winter, and small variability in spring. Food availability was poor in summer and winter, but in several years the monkeys were able to consume nuts during those seasons. We emphasize the importance of conducting long-term studies on both food availability and the food habits of animals in the temperate zone.     

Relationship between a high density of sika deer and productivity of the short-grass (<Emphasis Type="Italic">Zoysia japonica</Emphasis>) community: a case study on Kinkazan Island,northern Japan

An extremely high-density (ca. 800 deer km^–2) wild sika deer population uses a short-grass community dominated by Zoysia japonica on Kinkazan Island in northeastern Japan. To explain why the density of wild deer is quite high on the Zoysia community, (1) we quantified the seasonal productivity of the Zoysia community, (2) we compared food availabilities among the plant communities, and (3) we described the habitat selection by the deer in different seasons. Food availability was greater on the Zoysia community than in the forest understory from spring to fall. The productivity of the Zoysia community was high enough to support the actual high density of the deer (814 deer km^–2) in summer. However, the productivity markedly decreased in winter, when the deer density decreased to less than half (358 deer km^–2) of the summer value. In contrast, the deer density of the adjacent forests was highest in winter (154 deer km^–2) and lowest in spring (19 deer km^–2). These results suggest that the deer using the Zoysia community in summer left and were absorbed into the adjacent forest in winter. If such an adjacent community were absent, many deer would not survive, and consequently the deer density on the Zoysia community in summer would not be so high. This intercommunity movement is particularly important for the deer using a plant community like the Zoysia community, which is highly productive but has a small standing biomass.     

Effect of manure composition on seedling emergence and growth of two common shrub species of Southeast Alaska

Theidea that fecal material accompanying vertebrate-dispersed seeds at depositionsites plays an important role in enhancing seed germination and seedlingsurvival has, surprisingly, little empirical support. The present studyattemptsto experimentally test this hypothesis. We examined the effect that manurecomposition from brown bears (Ursus arctos), importantseeddispersers of Rubus spectabilis and Vacciniumovalifolium/alaskaense in the temperate rainforests of SoutheastAlaska, has on seedling emergence and growth of these two fleshy-fruitedspeciesin their natural habitat. The seeds of Rubus spectabilisshowed a significantly higher germination rate in manure composed of animalmaterial (mainly deer hair and bones) than in manure consisting of either fruitpulp or vegetation fiber and than in controls (potting soil with no manureadded). The final number of germinated Rubus seeds wassimilar between the animal material and the fruit pulp treatments, perhaps dueto similar water retention capacities, but was significantly higher than in thevegetation fiber treatment and the control. The germination patterns ofVaccinium seeds, in contrast, appeared to be unaffected bythe composition of manure in which they were embedded. Seedlings of bothspeciesgrew faster, and in the case of Rubus produced moreleaves,when manure consisted of animal material. A principal constituent of bone iscalcium phosphate, which may provide important minerals to growing plants.Manure containing vegetation fiber also enhanced seedling growth compared tomanure with fruit pulp or the control. For Rubus, manurewith fruit pulp did not affect seedling length significantly, although thenumber of leaves per seedling was greater in this treatment than in thecontrol. We conclude that the influence of frugivores on the final fate of seedsof fleshy-fruited plants appears to depend not only upon commonly consideredfactors such as distance of dispersal, treatment in the digestive tract, andlocation of deposition, but also on what material the dispersed seeds areembedded in, i.e., on what other food frugivores have consumed along with thefruits.     

Effective degradation of tannic acid by immobilized rumen microbes of a sika deer (Cervus nippon yesoensis) in winter

In winter seasons, wild sika deer (Cervus nippon yesoensis) inhabiting the Shiretoko Peninsula of Hokkaido Island, Japan, mainly graze woody materials (bark and twigs, etc.) as their feed source. Most of the tree species that they feed upon contain a high level of hydrolysable tannins within the inner bark. Tannins generally lead to low protein digestion and nutrient loss to these herbivorous mammals due to tannization of proteins. In winter months, it is speculated that wild sika deer develop a mechanism to degrade the tannins which are contained in their feed sources, but rumen fluid obtained from sika deer in winter months did not exhibit any ability to degrade tannins in liquid culture medium. However, constant degradation of hydrolysable tannin was observed when Ca-alginate gel beads were used for microbial immobilization and culturing. The gel beads that had been impregnated with 0.6×10⁴ fold-diluted rumen fluid of sika deer in winter and pre-incubated for 24 h under anaerobic conditions supplemented with a 1.5 g/L sugar were reacted with 5 g/L tannic acid solution. Under these conditions, the immobilized rumen bacteria grown in the macrogel beads effectively hydrolyzed tannic acid to release gallic acid monomers. Major bacterial colonies emerging in the Ca-alginate gel beads were identified as Streptococcus macedonicus and this bacterium (EC-D140) was regarded as the most likely candidate as the tannin-degrading bacterium.     

Altitudinal variation in the diet of sika deer on the Izu Peninsula: patterns in the transitional zone of geographic variation along the Japanese archipelago

Geographical variation in the diet of sika deer Cervus nippon Temminck, 1838 has been well characterised: northern populations are grazers, whereas southern deer are browsers. This variation largely reflects genetic-based differences in morphology. However, environmental factors would be also important. If a same genetic population live in different habitats, we can check altitudinal shifts in sika deer food consumption. We hypothesised that changes in the diet of the sika deer population on the Izu Peninsula, which is located within the transitional zone of resource (vegetation) variation and encompasses a broad altitudinal range, would mirror shifts in the composition of vegetation. Analyses of the rumen contents of the deer population indicated that dwarf bamboo accounted for 10.5, 46.2, and 74.3% of the deer diet in the low (<800 m), middle (800–1000 m), and high (>1000 m) altitudinal zones, respectively. In contrast, evergreen broad-leaved species accounted for 35.7, 23.1, and 5.9%, respectively. These results suggest that the diet of sika deer is more strongly affected by environmental factors, such as plant community composition, than by genetic factors.     

Survival and cause-specific mortality rates of female sika deer in eastern Hokkaido, Japan

Survival and cause-specific mortality rates of female sika deer (Cervus nippon) were studied using radio telemetry in eastern Hokkaido, Japan. We captured and radio-collared 18 female deer, and monitored their survival from April 1993 to May 1996. Estimated annual survival rate for adult females was 0.779 (95% confidence interval was 0.609–0.997). The harvest mortality rate of adult females was higher than the natural mortality rate. Experimental female hunting during 1994–1996 contributed to an increase in the mortality rate for females and was useful in the control of the sika deer population.     

Food habits of Sika deer on Mt. Goyo,northern Honshu

The food habits of Sika deer (Cervus nippon) on Mt. Goyo, northern Honshu (the main island of Japan), were studied. Among 88 plant species found in surveys, 36 species (40.9%) were eaten by the deer. The percentage frequency of feeding (F) was highest for graminoids (59.6%), followed by browses (16.6%) and ferns (7.7%) and lowest for forbs (5.4%). Though various kinds of plants were eaten, only limited species formed the bulk of the deer dietary composition.Sasa nipponica, in particular, was the most important constituent, ranking highest inF value (80.3%) and being the dominant component of feces. Fecal analyses revealed that, 1) in areas lower than 900 m in altitude,Sasa nipponica accounted for between 20 and 60% of the content and that pasture grasses were also important, and 2)S. nipponica occupied more than 50% in montane areas higher than 900 m, and even more than 80% in winter. The utilization ofS. nipponica as a forage for Sika deer was discussed. This plant can be a key forage species because it meets all the necessary conditions: abundance and stability of supply, palatability, nutritive quality and tolerance to grazing.