Edge effects created by clear-cutting on habitat use by sika deer on Mt. Goyo,northern Honshu,Japan

Clear-cutting increased the species diversity and amount of undergrowth plants in a habitat of Sika deer (Cervus nippon) on Mt. Goyo, northern Japan. The number of species increased from 15 to 48 as a result of clear-cutting. Among the plants,Sasa nipponica (a dwarf bamboo), an important forage plant for Sika deer, was predominant. Fecal pellets of deer were abundant in the forest and at the “adjacent zone” (from the edge to 150 m out of the forest) and thereafter decreased suddenly. The intensity of utilization ofSasa nipponica was also heavy in the forest, moderate at the adjacent zone and light 200 m from the forest edge. Since the amount of the bamboo in the forest was small, the removal of bamboo was greatest at the adjacent zone. Clear-cutting creates a favorable feeding area for Sika deer in this zone by increasing the available plant production and securing forest cover.     

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.     

Characteristics of Sasa nipponica grassland as a summer forage resource for sika deer on Mt Ohdaigahara, central Japan

Recently, the sika deer, Cervus nippon Temminck, population has increased on Mt Ohdaigahara, central Japan. The dwarf bamboo, Sasa nipponica Makino et Shibata, is a primary forage plant for sika deer in this area. To demonstrate the characteristics of S. nipponica grassland, especially as summer forage for sika deer, the habitat use intensity of sika deer was estimated by fecal densities, and biomass, growth rate, removal by deer and crude protein content were examined. Sika deer utilized the S.nipponica grassland on Mt Ohdaigahara during summer when the biomass, growth rate and crude protein content of S. nipponica were high. The recent increase in the deer population seems to be partly due to S.nipponica grassland being a favorable summer habitat.     

Diversity of dung-beetle community in declining Japanese subalpine forest caused by an increasing sika deer population

The Ohdaigahara subalpine plateau in Japan has recently suffered a reduction in primary forest land caused by an increasing population of sika deer (Cervus nippon). Deer have debarked many trees, causing dieback, gradually changing the primary forest first to light forest with a floor that is densely covered with sasa grass (Sasa nipponica) and then to S. nipponica grassland. To examine the effects of vegetative transformation on the dung-beetle community, we compared the diversity and abundance of dung-beetle assemblages in the primary forest, transition forest, and S. nipponica grassland using dung-baited pitfall traps. The species richness and species diversity (Shannon-Wiener index) were significantly highest in the primary forest and lowest in the S. nipponica grassland. The evenness (Smith-Wilson index) was highest in the primary forest and nearly equal in the transition forest and S. nipponica grassland. The abundance was apparently greater in the transition forest than in the primary forest and S. nipponica grassland. These results suggest that loss of primary forest resulting from an increasing deer population decreases the diversity of the dung-beetle community while increasing the abundance of dung beetles in the transition forest. Sika deer use transition forests and grasslands more frequently than primary forests as habitat, but an increase in dung supply there does not necessarily increase the diversity or abundance of dung-beetle assemblages.     

Use of mires and food habits of sika deer in the Oze Area,central Japan

Sika deer Cervus nippon entered the Oze Area, a snowy area in central Japan, in the 1990s. The use of mires and the food habits of this species were studied in 1999 and 2000. Deer used the mires immediately after snow melted and did not use the mires in mid summer, although they did use them lightly in autumn. The summer food habits differed from those of the deer population living in Nikko in the lower area: non-Sasa graminoids and other monocotyledonous leaves occupied more (approximately 30%) of the feces in the former population, whereas Sasa nipponica, a dwarf bamboo, was the dominant food (60%) of the latter population. Seasonal changes in fecal composition in the Oze deer were that mire graminoids occupied a considerable portion of their food in spring (11.6%) and summer (17.0%), whereas the amount of dwarf bamboo increased in fall (26.0%). Despite the small size of the mires, Oze deer appear to prefer mires to forests. Nitrogen concentrations of the mire plants did not differ from those of the forest plants; however, foraging efficiency would be greater in the mires and this may explain the preference observed. Despite the small total biomass, leaf biomass of the mire was equivalent to that of the adjacent forest floor. In addition, biomass was concentrated near the ground, or the biomass concentration was greater than that of the forest floor.     

Summer dietary compositions of sika deer on Yakushima Island,southern Japan

Summer food habits of Sika deer (Cervus nippon yakushimae) on Yakushima Island, southern Japan, were studied focusing in particular onPseudosasa owatarii, a dwarf bamboo native to the island. Fecal analyses showed that the food habit of the Sika deer on Yakushima island was plastic: the dietary composition was dominated by graminoids (ca. 90%), particularlyP. owatarii (50%–60%) in the bamboo grassland of theP. owatarii zone above the timber line, whereas leaves and non-leafy parts of woody plants were important in the crytomeria forest and evergreen broad-leaved forest below the timber line. The maximum culm age ofP. owatarii was 8.5 yr, but the majority of leaves (97.8%) were younger than 2.5 yr. Since the weight contribution of the leaves is great (27.7%) and the turnover rate is high, theP. owatarii grassland affords a good foraging place for the Sika deer on Yakushima Island.     

Effects of Sika deer on the regeneration of aFagus crenata forest on Kinkazan Island,northern Japan

Kinkazan Island, a sanctuary island that has been conserved for over 100 years, is inhabited by a Sika deer population of high density (60 km⁻²). AFagus crenata forest, a climax forest of this region, was composed of only large sized trees (30–60 cm diameter breast height) and lacked young trees. However, many saplings were found inside a deer proof fence, indicating this forest had a potential to produce seedlings. They were tentatively protected by shrubs ofLeucothoe grayana var.glabra, an upalatable ericaceous shrub, but did not exceed the shrub height. Heavy browsing by the deer suppressed recruitment of saplings ofF. crenata. The forest will be reduced without population control of the deer.     

How do deer affect tree seedlings on a dwarf bamboo-dominated forest floor?

A field experiment was conducted in Mt. Ôdaigahara, west-central Japan, to reveal the effects of two herbivores, Sika deer (Cervus nippon) and mice (Apodemus spp.), on the seedlings of five cohorts of three tree species, Abies homolepis, Fraxinus lanuginosa f. serrata and Fagus crenata. The forest floor of the study site was covered with dwarf bamboo, Sasa nipponica, which would also affect the seedlings. Eight combinations of three treatments were set: exclusion of deer, exclusion of mice and removal of dwarf bamboo. Deer were expected to affect the seedlings not only negatively by foraging but also positively by browsing dwarf bamboo that overshadows seedlings. The survival of these cohorts was analyzed by survival analysis and the differences in their survival between the treatments were investigated. The results of the experiment showed that: (1) exclusion of deer increased the aboveground biomass of dwarf bamboo and made it more difficult for seedlings to survive under the regenerated dwarf bamboo stand, and (2) deer negatively affected the seedlings, but they had positive, indirect effects in some cohorts by decreasing the aboveground biomass of dwarf bamboo. However, such effects were not detected in some cohorts which were affected excessively by deer or dwarf bamboo. No clear results on the effect of mice on seedlings were obtained. We conclude that a positive, indirect effect of deer on seedling survivorship would be observable when the magnitude of a positive, indirect effect caused by decreasing dwarf bamboo is larger than that of a negative, direct effect of deer.     

Botanical and chemical composition of rumen contents of Sika deer on Mt Goyo,northern Japan

Botanical and chemical compositions of the rumen contents of 58 Sika deer on Mt Goyo, northern Japan, collected from summer of 1988 to spring of 1989, were analyzed.Sasa nipponica, a dwarf bamboo, was important in summer (35.0%) and winter (61.4%), but it decreased to 5.6% and was replaced by browse leaves in fall, and to 28.0% and was replaced by dead leaves, twigs and bark of woody plants in winter. Crude protein was 20–25% lower in the washed fraction than in the gross fraction. It was highest (16.2%) in summer and lowest (8.6%) in winter. High protein content in summer and fall foods was attributed to forb and browse leaves. Seasonal fluctuation in protein content in the foods of these Sika deer was greater than red deer on Rhum, Scotland and smaller than wapiti in Yellowstone National Park, Wyoming, USA. Climatically, winter severity of Mt Goyo is intermediate between the two localities, which seems to explain the seasonal fluctuation of the protein level. Crude fiber wasca 33% in the ‘washed’ fraction, and did not change seasonally.     

Effects of deer,mice and dwarf bamboo on the emergence,survival and growth of <Emphasis Type="Italic">Abies homolepis</Emphasis> (Piceaceae) seedlings

In the subalpine mixed forest of Mt. Ôdaigahara, mid-western Japan, the understory is dominated by dwarf bamboo (Sasa nipponica), which is the major forage of overly populous sika deer (Cervus nippon). In the present study, we monitored the survival and growth of Abies homolepis seedlings over 5years to determine how they responded to the experimental removal of dwarf bamboo and to the exclusion of sika deer and mice (Apodemus argenteus and A.speciosus). Deer and dwarf bamboo reduced the survival of seedlings but had different effects on growth. The stems of seedlings were shorter in the presence of deer, indicating that taller seedlings were apt to be browsed by deer, whereas the diameters of seedlings were smaller in the presence of dwarf bamboo, mainly owing to its shading effect. The presence of mice decreased the number of seedlings germinating in a particular site, but had no effect on seedling survival after germination. There was no significant indirect effect whereby the survival of seedlings was predicted to be facilitated by the decreased biomass of bamboo because of grazing by deer. We supposed that this might be because the direct negative effect of deer was so large as to conceal the positive indirect effect.     

Co-occurrence of the cirolanid isopodEurydice nipponica Bruce & Jones and the ghost shrimpCallianasa japonica Ortmann on an intertidal sand flat

On a moderately protected intertidal sand flat in west Kyushu, Japan, most of the population of the cirolanid isopodEurydice nipponica Bruce & Jones (89%–100%) was found in the zones occupied by the thalassinidean ghost shrimpCallianassa japonica Ortmann in July, August and December 1980.C. japonica later extensively expanded its habitat, and in July 1984, when almost the whole sand flat had been densely populated byC. japonica, the range of the distribution ofE. nipponica was the same as that ofC. japonica with a density about 10 times greater than in July 1980. The occurrence ofE. nipponica has previously been recorded from several exposed sandy beaches as well as their adjacent subtidal areas of well oxygenated sands along the coast of Kyushu, but not on more protected shores like the present sand flat. It is suggested thatC. japonica, through its bioturbating activities, produces sediment characteristics approximating those of the exposed sandy beaches which are the preferred habitat ofE. nipponica. It is supposed thatE. nipponica is a facultative commensal ofC. japonica. In a field experiment to excludeC. japonica and to detect its positive influence onE. nipponica, the densities ofE. nipponica were found to be lower in the experimental plots than in the intact plots. Statistically, however, the difference was only weakly significant, and the possible reasons for this are discussed.     

Suppression of Regeneration in New Zealand Mountain Beech Forests is Dependent on Species of Introduced Deer

We compared the impacts on forest regeneration of introduced sika (Cervus nippon) and red (Cervus elaphus) deer in New Zealand. Plot data were used to compare mountain beech (Nothofagus solandri var. cliffortioides) regeneration between a region with sika deer, and four regions without sika deer. All regions surveyed had red deer present. In the region where sika deer had been present for more than a decade, there was evidence of poor mountain beech seedling regeneration. In the four regions without sika deer, there was evidence of a strong regenerative response at stands with low occupancy by trees. When compared to larger deer species, sika deer have a digestive morphology allowing greater dietary versatility, which may result in them impeding forest regeneration where red deer do not. In contrast to mountain beech, some small-leaved shrub species may have been competitively advantaged by intensive browsing from sika deer. This is contra to a current view that small-leaved shrub species with interlacing branches were able to tolerate browsing from extinct ratite birds, but not introduced deer. Sika deer have been introduced into countries where other deer species are indigenous, such as Canada, Denmark, Great Britain, Czech Republic, Ireland and the United States of America. Because of their dietary advantage, sika deer may have a greater potential to impede forest regeneration and competitively exclude larger deer species, particularly at low basal area sites where impacts on tree regeneration are likely to be greatest.     

Nitrogen leaching from surface soil in a temperate mixed forest subject to intensive deer grazing

We aimed to determine the grazing impact on soil nitrogen (N) mineralization and N leaching in a temperate mixed forest on Mt. Ohdaigahara, central Japan, where Sika deer (Cervus nippon Temminck; hereafter deer) grazing has decreased biomass of Sasa nipponica Makino et Shibata (hereafter sasa) that dominates the forest understory. Soil N mineralization and N leaching of the top 0.3-m layer were measured in situ from 2006 to 2007 by an ion-exchange resin core method inside and outside a deer exclosure. Deer grazing decreased the carbon to nitrogen (C:N) ratio of sasa litter because of the declining dead culm C:N ratio and the increasing ratio of leaves with a lower C:N ratio than culms in the aboveground biomass. Grazing increased N mineralization and nitrification rates as well as annual N (ammonium-N and nitrate-N) and nitrate-N leaching. In contrast, deer grazing did not increase the total soil C and N content. The positive effect of grazing on the N mineralization rate may have resulted from a qualitative change in sasa litter due to grazing. The higher annual N leaching resulting from deer grazing may have been related to the facilitated N mineralization rate and decreased N uptake in plants, e.g., sasa with less aboveground biomass due to grazing.     

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.     

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.     

Comparative rumen morphology of sympatric sika deer (Cervus nippon) and red deer (C. elaphus scoticus) in the Ahimanawa and Kaweka Ranges,central North Island,New Zealand

Eighteen sika deer (Cervus nippon) and 14 red deer (C. elaphus scoticus) were sampled from two areas where these closely related species are sympatric. Total body weight, carcass weight, age class, sex, and internal parameters (e.g. liver weight, kidney weight, rumen volume) were recorded. Samples of rumen wall mucosa taken from the dorsal rumen wall, atrium ruminis, caudoventral blindsac, and ventral rumen wall were used to compare rumen morphology between the two species (and also any area, sex, and age effects). Sika deer had significantly lower papilla densities in three of the four rumen wall sites and significantly smaller papillae than red deer in two of the four sites. Surface enlargement factors (SEFs) were calculated to provide comparisons of the effective absorptive surface within the rumens of the two species. The mean SEF for sika deer (4.76) was significantly less that for red deer (6.77), which suggests a greater degree of adaptation to digesting fibrous forage. In the central North Island, New Zealand, where the habitat has been considerably modified by introduced herbivores over the last century and food resources are depleted, such an adaptation would confer a competitive advantage on sika deer over red deer. It is postulated that this diet-related difference largely accounts for the ongoing replacement of red deer by sika deer where these two species are sympatric.     

Food habits of sika deer on the Boso Peninsula,central japan

The rumen contents of sika deer (Cervus nippon Temminck) on the Boso Peninsula, central Japan, were analyzed to identify local, sexual and age-specific differences in food habits. Graminoids and woody plants were the primary foods throughout the year. In winter, the use of evergreen broad leaves increased. The food habits of sika deer on Boso Peninsula were intermediate between those of populations inhabiting northern and southern Japan. Acorns, mainlyLithocarpus edulis Nakai, were consumed in fall and winter with a peak in October. Since the availability of acorns is not influenced by foraging in previous years, it can be regarded as a stable food supply and hence may be important for deer on the Boso Peninsula. The local difference between the Amatsukominato (AT) area, having a large plantation ofLithocarpus producing acrons, and the Kamogawa-Katsuura (KK) area, having a small plantation ofLithocarpus, was recognized; seeds and fruit were consumed more in AT than in KK in fall and winter. Males consumed more seeds and fruit than females at both sites in fall. This can be attributed to sexual differences in nutritional requirement.     

White-Tailed Deer Foraging Habitat in Intensively Established Loblolly Pine Plantations

ABSTRACT Stand establishment techniques involving multiple herbicide applications are commonly used on industrial pine (Pinus spp.) plantations, raising concern over potential effects on white-tailed deer (Odocoileus virginianus) forage production. We tested effects of stand establishment intensity on deer forage in 1–5-year-old loblolly pine (Pinus taeda) plantations (n = 4) in the East Gulf Coastal Plain of Mississippi using forage biomass and 4 measures of nutritional carrying capacity that reflected crude protein or digestible energy requirements for body maintenance and lactation. We also assessed whether forage biomass combined with a deer use rating effectively indexed nutritional carrying capacity. Treatments were combinations of mechanical site preparation, chemical site preparation (CSP), and herbaceous weed control (HWC). Total forage biomass and forage biomass of grasses and forbs were reduced by broadcast HWC. Forage biomass of vines was reduced both by CSP and by multiple broadcast HWC applications. Maintenance-level carrying capacity estimates were reduced by broadcast HWC; lactation-level estimates were higher in moderate-intensity treatments. We believe the inherently low fertility of this region makes high-quality forage production a more important management priority than increasing forage quantity. Chemical or chemical and mechanical site preparation combined with banded HWC provided the best option for providing both forage quality and quantity in open-canopied, intensively managed pine plantations. Biomass-based indices may be suitable for indexing protein-based maintenance-level carrying capacity in this region, but our results indicated they were not useful for indexing other carrying capacity estimates.     

Effects of sika deer on tree seedlings in a warm temperate forest on Yakushima Island,Japan

High-density herbivore species often play an important role in forest regeneration. Native sika deer (Cervus nippon yakushimae) inhabit a high density (51.5–63.8head/km², estimated by a pellet count method) area in the western part of a lowland natural forest on Yakushima Island, Japan. To test experimentally the impact of sika deer on the mortality and the survivability of current-year seedlings, which are at a more vulnerable stage than the later stages, we constructed fenced exclosures, planted seeds of nine sapfruit tree species and compared the mortality and the survivability of current-year seedlings between fenced and unfenced quadrats. Large seeded species had significantly greater survivability in fenced quadrats than in unfenced quadrats. However, the survivability disagreed with feeding preferences. Sika deer activity increased seedling mortality of large-seeded species more than that of small-seeded species, and did not decrease much seedling survivability of not-preferred species. We found that the physical disturbance by the high density of sika deer resulted in mortality for both preferred and not-preferred species, and that deer herbivory was important for preferred species.     

More highly female-biased sex ratio in the fig wasp,Blastophaga nipponica Grandi (Agaonidae)

The sex ratio of the pollinator fig wasp,Blastophaga nipponica Grandi (Agaonidae), was examined in an experiment manipulating the number of foundresses. The sex ratio ofB. nipponica was conditional on the number of foundresses and corresponded to the qualitative prediction of the local mate competition (LMC) theory that the proportion of males increases as foundress number increases. However, the sex ratio ofB. nipponica was consistently more female-biased than predicted by extended LMC theories that incorporated effects of inbreeding, and these deviations were statistically significant. Plausible factors that would make predictions more female-biased are discussed.