Association ofofWUdlifeand Wildlife and Human Society

- Biosphere Conservation 2 (1) :35 44. 1999

Changes in the dynamics ofJapanese serow and sika deer as a result opopulationf competitive interactions in the Ashio Mountains, central Japan

Masaaki Koganezawa

Utsunomtya Uhiversity 1lorests hacutty ofAgricutture, Utsunomlya U}tiversiC}; Z556 funyu, Shiqya-machi, Shiqya-gun, lbchigi 329-2441, Jbpan

Abstract Changes in the population dynamics ef the Japanese serew Capricornis crispus and the sika deer

Cervus nippon were studied in the Ashio Mountains ofNikko National ParK [[bchigi Prcfe¢ ture, Japan, from March

1982 to December 1995. Although the geographical distributions of the two species overlap in many areas ofJapan, wherever the snow is not deep, Japanese serow and sika deer are usually found living allepatrically. In Ashio,

however, they occurred sympatrically, but their populalions have changed drastically and they have segregatecl during the 1980s and 1990s, l propese two factors that may contribute to their shift from sympatry towards an allopatric existence. The primary contributing factor may be the overlap in the food habits of the twe species.

Japanese serow were found to feed on the leaves ofdeciduous trees and herbaceous shrubs during the summer, while

in winter they feed mainly on the needles ofconiferous trees. In contrast, sika deer were found to feed mainly on

graminoid species year reund. On]y in severe winters did the deer extend their diet to include the needles ofconif- erous trees, and the twigs and bark of deciduous trees. During such winters their diet then overlaps that of the serow,

and this oyerlap may result in a rapid depletion oflimited food supplies. The deer. with their more flexible dietary habits may be better able to telerate such poor foraging conditions, whereas the serow may suffer from an unbal- anced diet and face a deficiency of food thus forcing them to move away from areas where deer are present. A

secondary cause may be the increased interactions between the species, Serow are tenitorial and essentially solitary, and so are presumed to be sensitive to both intra- and inter-specific crowcling, whereas sika deer are not territorial, occur in herds and are usually very toierant of other animals, In order to ayoid encounters with sika deer, the sensitive serow may emigrate from areas with high deer population densities. This competitivelavoidance relatien-

ship between the Japane$e serow and sika deer may help to explain why the two species generally occur allopatri-

ca]]y in Japan. Key words: competitive interaction, food habit, Japanese serow, population dynamics, sika deer

INTRODUCTION cuT), the area of spatial overlap of these species is about

20%. Even in areas of local overlap, the species are

The Japanese serow Capricornis crispus, a moun- usually allopatric; with few serow occurring in areas tain dwelling ungulate, is distributed throughout with high deer densities, such as at Mt. Geyo, Nikko,

Honshu, Kyushu and Shikoku islands; its habitat in- [[hnzawa,Nishi-yatsugatakeandOhdaigahara.Therea-

cludes both warm-temperate and cool-temperate for- sons for this spatial segregation have not yet been iden-

ests. The distribution of the sika deer Cervus nippon tified. In Ashio, adjacent to Nikko, in central Honshu,

overlaps that of the serow, except in heavily snow- both species lived sympatrically. During the 1980s

coveTed areas. Sika deer are unable to tolerate snow and 1990s, howeveT, drastic changes in both species

depths of more than 50 cm, and tend to avoid aTeas numbers and distribution have occurred, and segrega-

with fifiy days or more of such deep snow (Tbkida et tion has occurred. al. 1981, Maruyama 1981). In the main islands ofJa- The objective of this study was to assess the possi-

pan, except Hokkaido (wheTe the seTow does not oc- bility that competitive interaction might be occuning

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Mt.

Mt STUDYAREA

l

O 5 10km LFig. - 1. Location of the Ashio study area (November 1983 November 1991) including the Matsuki-zawa, Kuzo-zawa and Akakura obscrvation sites in Nikke National Park, central Honshu, Japan.

between the two species, through an ana]ysis of their August (based on data gathered at the Nikko VVeather

population dynamics, theiT food habits and their inter- Station, 1944-1996). The average annual precipita-

specific social tendencies. tion was 2,230 mm, with snowfall varying with eleva-

tion. Little snow accumulated below 600 m, whereas

STUDY AREA at around 1,200 m snow averaged 30 cm in depth

thToughout the winter during the study period. In the This study was conducted from March 1982 to unusually severe winter of 1983-1984, snow accumu-

December 1995 in the Ashio Mountains in Nikko lated to a depth of 120 cm, but that was exceptional

National Park, Tbchigi Prefecture, situated approxi- (Fig. 2), Severe winters, with heavy snow, also oc- mately 100 km north of [Ibkyo (Fig. 1). The average curred in both 1990-1991 and 1991-1992. rnonthly temperature at Chugushi, which is situated at The study aTea is complex with rugged terrain, Due 1,292 m, just seven kilometres north-east of the study to past copper-mining activity and forest fires, most -4,4eC OC area, ranged from in FebiuaTy to 18.4 in (75%) ofthe natural vegetation has been lost and this

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so7esot

50i

40Ian

3020too

19e2-83 19S3-S4 tgS4-S5 ri9e5-S6 19e6 1987 lgSB 19S9 1990 1991 1ss2 1993 t994 t995 ･e7 ･Be ･e9 -90 -91 -92 -93 -94 -95 ･96

Fig. 2. Number ef duys with snowfall over 20 cm and 50 cm in Chugushl (1,292 m altitude), 7 km north-east of the study area, between 1982-1996.

resulted inheavy erosion between the 1890s and the pseudo-acacia forest growing close to the village. 1960s. At present, Miscanthus sinensis grasses, herbs suchasRaynoutriajaponicaandAtiryriumyokoscense, METHODS

and brush such as Clethra barvinervis,Robinia pseudo- acacia, and Pinus thumbergii, have been planted to Serow were counted with binoculars (x 8) and tele- facilitate ecosystem recovery, scopes (× 20, x 40) usually at a distance of 500 m

of the The populationdynamics both Japanese se- (ranging from 150 to 750 m) while scanning opposite

row and the sika deer were studied in three study ar- slopes across valleys, Observations weTe made dur-

eas on the slopes of the Ashio Mountains. These were ing the daytime on three consecutive days in April and at Kuzo-zawa (64 ha) and Matsuki-zawa (84 ha), which December each year from 1982 to 1995, Each serow were studied from 1982 to 1995, and at Akakura (125 was individually identified on the basis of its distinc- ha) which was studied from 1992 to 1995 (Fig. 1). tive physical features, resulting in an actual count of These s]opes are very steep, measuring 30-40 degrees. serow present within the study area. Kuzo-zawa islocatedin the centre of the study area Sika deer were also counted on the same days and

and Tanges from 700 m to 1,200 m in elevation, Re- on the same slopes as the serow. When counting sika

planting was begun on this slope in 1956, and the veg- deer, each study area was divided into three units, each etation now consists of young pines, deciduous bToad- of20-30haeach,withoneresearcherassignedtowatch

leaved bushes, and Miscanthus grasses. Matsuki-zawa, each unit. Counts were macle six times each day, at which ranges in elevation from 900 m to 1,500 m, is hourly intervals, over the three consecutive days in

located four kilometres west ofKuzo-zawa. Re-plant- April and December from 1983 to 1995 and in Febru- ing was begun on this slope in 1970, and most of this ary 1991. Sex, age, and group size were recorded at

s]ope now consists of Afiscanthus grasses and bare each count, and times, locations and directions of

rocky Akakura, which ranges in elevation ground. from movement were plotted on maps (1:5,OOO), Tlie maxi-

600 m to 1,200 m, is located two kilometres south of mum number of deer observed during the six counting Kuzo-zawa and is a[ljacent to a vi]lage. Re-planting periods for each of the three days was averaged and of this slope began in the late 1970s, and the vegeta- used as a density index for each study area.

tion now consists of a thin cover ground of the herb The food habits of the Japanese serow and the sika Athyrium which grows on rocky ground, with Robinia deer were determined using two methods, Direct ob-

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so

2o

10

o50 19S2 19S3 lgB4 lgeS t9S6 19e7 198e t9e9 1990 1991 1992 lg93 1994 1995

MATUKI-ZAWA

roNEMxas-as-

3eit:1h Sikadeer

'

2e=-utEoa //

--Y-

---

le

Ar" }V- x sor il/VvVlle-."...---- o lg62 19e3 19B4 t985 19B6 19e7 198e 19B9 1990 lg9t t992 1993 1994 19g5 2o AKAKURA

10

o 19B2 1ce3 19B4

Fig. 3. Density of Japanese serow and sika deer in the Ashio Mountains, central Japan, between 1982 and 1995, based on early spring and early winter counts. (Solid dots = Japanese serow; open dots = sika deer.)

servations were made ofthe food items eaten, and the eas and at the same time as the serow. In the case of

stomach contents of culled animals were analysed. sika deer, however, it proved impossible to individu- all Direct observations were made of the feeding habits ally identify all the food items being selected by

ofJapanese serow in Akakura between April 1993 and the animals foTaging, so data were recorded every 15

the of May 1994, and in Kuzo-zawa between May and De- minutes. In order tomeasure quantity food items

cember 1992 and in February and March 1995. In consumed, stomach contents were analysed using the

each area, one serow was observed continuously for point-frame method (see Leader-Williams 1981). The

about eight hours duTing the daytime for three con- stomach contents of51 sika deerculled from Kuzo-

secutive days each month at a distance of less than zawa in February and March 1995 were analysed. The

250 m. Sika deer were also observed in the same aT- trophic niche breadth ofeach species, and the trophic

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niche overlap of serow and deer were calculated fbr deer in Kuzo-zawa from 1982 to 1995 (r = O.64, df = each season using Levins' measure of standard niche 21, p < O.Ol) breadth, and Pianka's niche overlap index and percent- In Matsuki-zawa (Fig. 3), both serow and deer re-

age overlap (Krebs 1989), mained at low-density levels with slight fluctuations The behaviour of both species, including interac- before 1987. Between 1987 and 1990, however,

tions between them, was Tecorded by direct observa- changes occurred in the densities of both species. In

tions from September 1994 to August 1995 in both December 1990, the deer reached a density of25fkrn2

Akakura and Kuzo-zawa. yet continued to increase further to 50fkm2 by Decem-

ber 1992. The fo11owing winter, 1993, the deeT den-

RESUorS sity dropped dramatically to just 7fkm2 and the den-

sity continued to fluctuate until the winter of 1995.

Populationdynamics Serow, on the other hand, rernained at very low densi-

In Kuzo-zawa (Fig. 3), Japanese serow were ob- ties (fewer than 4fkm2) from December 1991 onwaTds,

served throughout the entire study period, Before In Akakura, where counting was only begun in

1990, serow occurred at a high density of 12-25fkm2. March 1992, serow remained at a comparatively stable

During the same period, sika deer gradua]ly increased density of several per square kilometre. The deer den-

in number, although with prominent fiuctuations. A sity dTopped te almost zero in December 1993 (Fig.

drastic change in the numbers of both species occurTed 3), but recovered during March 1994 to almost the

suddenly in 1991. Serow density first dropped to 6/ same level as that of the serow.

km2, and then to less than 2/km2 where it remained,

meanwhile the density of deeT rose to 30/km2, The Food habits of sympatric species

density of deer decreased to about 10fkm2 in 1993, The foraging habits ofthe serow and the deeT were

but then recovercd to a high-density although with ]arge found to over]ap to a certain extent. Based on direct

fluctuations, A significant negative correlation was observation, more than 95% of the seTow's spring to

found between the density of Japanese serow and sika auturnn diet in Akakura, consisted of leaves of herba-

Thble 1.Food habits of Japancse serow in Akakura, Ashio Mountains, centrul Japan in 1993 and 1994.

Observed time {min.)

Food items Spring Summer Autumn Wlnter 995 401 347 245

Graminoids 1.0 (O.1%) 6.5 (1.9%) Miscanthussinensis 1.0 (O.1%) 6.5 (1.9%) Leaves of herbaceeus plants 963.7 (96.S%) 390.2348.3(972%)(86.7%)(10.4%)3342 (962%) le9.4 (44.6%} Athyriumyokoscense 528,1 (53.1%} 303.S (87.4%) 2.8 (1.1%) Raynoutriajaponica 412.2 (41.4%) 41.9 22.2 (6.4%} Artemisiamontana 12.2 (1.2%) 8.5 (2.4%) Eeuisetumarvense 112 (1.1%) Stellariamedia 106.6 (43.S%)

Leaves of broficl 1eaved trees 27.3 (2.7%) 2.6 (O.7%) 4.3 (1.8%)

Alnusfirma 20,8 (2.1%) 2,6 (O.7%) Salix sp. 6,5 (O.7%) 4.0 (1.6%) Carpinusturcxaninavii O,3 (O,1%) Remnantdumpedyegetable 132 (53.6%)

Others and unknown 3.4 (O.3%) 113 (2.8%) 4.0 (L2%) 2.7 (1.1%) [[Tephicnichebreadth' O.172 O.l54 O,060 0219

'/Levins' measure of standardlzed niche breadth (Krebs 1989).

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ceous plants; although in winter leftover vegetables the serow's diet (Tlable 2). The trophic niche breadth dumped by people contTibuted 54% (Table 1). Serow of the serow in Kuzo-zawa was O.107 in autumn and rarely fed on graminoids, The trophic niche breadth O.548 in spring. Based on direct observations in Kuzo-

of the serow in Akakura was O.060 in autumn and O.219 zawa, sika deer consumed graminoids at a high rate

in winter, In Kuzo-zawa, leaves ofbroad-leaved trees throughout the year ([fable 3), There, their trophic in winter. and herbaceous plants contributed more than 80% of niche breadth was O.O16 in spring and O,296

the food during summer, while in autumn conifer In winter, in Kuzo-zawa, the deer's trophic niche was trophic needles and twigs (64%) and herbaceous plants (20%) slightly broader than that of the serow, The contributed more than 80% of the serow's diet. In win- niche overlap of serow and deer in winter was O.119

ter, conifer needles and twigs (49%) and the bark and and the percentage overlap was 17.6%. Based on stom- twigs of broad-leaved trees (32%) contributed 80% of ach content analysis, bark and ]eaves, and fallen leaves

Thble 2.Food habits ofJapanese serow in Kuzo-zawa, Ashio Mountains, central Japan in 1992 and 1995.

Observedtime rnin.)

Food items Spring Summer Autumn Wintef 390 638 104 547

Graminoids 73.0 {18.7%} 4.0 (O.6%} 3.0 (2S%) 20.e (3.7%}

15,O Miscanthus sinensis' 2e.O (5.1%) (2,7%) Calamagrvsishakonensis 1,O (1.0%) 5.0 Eragrostiscurvula 2.0 (1.9%) (O.9%) Gramineaesp. 53.0 (13.6%) 4.e540.042.0498.0(O.6%)(S4.6%)(6.6%)(78,1%) Leavesofherbaceousplsnts 119.0 (30.5%} 21.0 (20.2%) 19.6 (3,6%} ReyneutriaJaponica 45.0 (11.5%)

4.5 Athyriumyokoscense 74,O (19.0%) 3.0 (2.9%) (e,8%) nijblium repens 3,O (2,9%) Mblachiumaquaticum 4.0 (3.8%) Chenopediumambrosioides 4.0 (3.8%) Plantage lanceolata 1.0 (1.0%)

Artemisia montana 6.0 (5.8%) Elscholtziacitiata 9.3 (1.7%)

5.8 Macleaya cerdata (1.1%) Lesves of broad leaved trees 27.0 (6.9%) 7.0 (1.1%) 2.0 (L9%} Robiniapuseudo-aeacia 27.0 (6.9%) 7,O (1.1%) Alnusfirma 1.0 (1.0%) Alnus hirsuta var. sibirica O.5 (O.5%)

Clethra barvinervis O.5 (O.5%)

Fallen Seayes of broad Leaved trees 6.0 (5.8%) 65.0 (11.9%)

P)'zanus lannesiana 6.0 (S.8%) Alnusfirma 65.0 (11.9%)

BArk and twigs efbroad leaved trees 173.1 (31.6%) Robiniapseudo-acacia 30,5 (S.6%) AtnusYirma 85.3 (15,6%) Clethra barvinervis 56.3 (le.3%)

Alnus hirsuta var. sibirica 1.0 (02%)

Needles and twigs of coniferous trees 2.0 {O.3%} 66.0 (63.5%) 26S.e (48.9%} Larixkaemrkri 2.0 (O.3%) 66.0 (63.5%) 20,5 (3,7%) Pinus thunbergi Z47.S (45.2%} Others snd unknown 171.0 {43.S%) 85.0 {133%} 6.0 (5.8%) 2.e (o.4%) Mo hicnichebreadth' 0548 O.117 O.107 0239

`:levins' measure of standa[dized niche breadth (Krebs 19S9),

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1lable 3. Feod habits of sika deer in Kuze-zawu, Ashio Meuntains, central Japun in 1992 and 1995.

No of deer observecl Food items Spring Summel Autumn WinteT

385 572 162 47

Graminoids 382 (99.2%) 5"535(95.1%)(93.5%)(1.6%)141 (87.0%) 37 (78.7%) Gramineaesp. 382 (99.2%) 134 (82.7%) Miscanthussinensis 9 7 (4.3%) 25 (53.2%) Eragrostiscurvula 12 (25.5%) Bark of bruad leayed tmes 3 (O.8%}3 2222{3.8%}(3.8%) 8 {49%)8 5 {10.6%} Robiniapseudo-acacia (O.8%) (4.9%) 4 (8.S%) Alnusfinna 1 (2.1%) Needlesofconiferoustrees 2 (O,3%) 3 (1.9%) 3 (6.4%) finus thunbergi 1 {2.1%) Others and unknown 4 (e.7%) le (6.2%} 2 (4.3%) Mephicnichebreadth' O.O16 O.035 O,111 O,296

*r levins'meusureofstandardnichebreadth(Krebs1989).

of broad-Ieaved trees contributed 58% of the deer's contrast, sika deer paid little or no attention to nearby

diet which was more than estiTnates based on visual serow. After the density of serow dropped and deer

observations, while graminoids contributed 31%, numbers increased, such behaviour by serows was no

which was lower than based on visual observations longer observed. As before, deer continued to pay

to serow. (Table 4). The trophic niche overlap of serow and littleor no attention deer in winter was therefore O,316 and their percent-

age everlap was 58.1%. DISCUSSION

Interactive behaviour between serow and deeT Anthony and Smith (1977) argued that competition

Three interactions between serow and deer were theory is oversimplified and fails to consider that in-

observed. During the period when serow populations terspecific competition can occur as a temporary and to a changing envi- were high and deer populations were low, individual transient phenomenon in response

serow were very conscious and alert whenever deer ronment or catastrophic disturbance. They also ar-

entered their territory. For example, if a deeT entered gued that competition could occur while one species

the area where a serow was Testing, the serow would was displacing another, which for ungulates may take

rise to its feet and watch the sika deer intently. In many years and may be primed by things such as veg-

Thble4.Sikadeerstomachcontents(basedonthepoint-framemethod)inKuzo- zawa, Ashio Mountains, central Japan in 1995,

February Stomachcontents n=26Marchn=25fotaln=Sl Graminoids 40,4% 20.5% 30,6% Broadteavedherbaceousplants 1.3%21.7%29.6% O.4%49.5% O.9%3S.3%22.8%

Bark and twigs of broad leaved trees

Fallcn leaves ofbroad leaved trees 15,7% Needlesofconife[oustrees 6.3% 13.4% 9.8%

Others O.7%1oo.O% o.s%1oo.O% O.6%1oo.O% lbtal

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etation changes. I believe that such drastic environ- between the serow and the deer, as a result of both

mental changes, which may have resulted in the com-, habitat and food shortages,

between serow and sika, were observed petition dur- According to Hardin's (1960) principle ofcompeti- ing this study. tive exclusion and Zaret and Rand's (1971) interpre- One of these environmental changes was a direct tation, in order to minimise interspecific competition,

result ofhurnan activity. Copper was heavily mined diets of sympatric taxa should be most clissimilar dur- inAshiofrom1893 to 1956, and heavy SO, pollution, ing periods oflow food availability. Nelson (1982)

a by-product of the mining, resulted in virtually com- on the other hand argues that cempetition among un-

plete denuding of the vegetation on surrounding slopes gulates is usually inversely Telated to forage avai]abil-

(Ashio Local History Editorial Committee 1993). ity and competition can increase if availability is re- Although environmental restoration was begun soon duced by common utilization. Les]ie et al. (1984) after the copper mine was equipped with a desulfurizer found that the diets ofdeer and elk were most similar

in 1956, the s]opes remained free of vegetation for in winter, when food was least available. Anthony and

many years. Under these vegetational conditions, se- Smith (1977) a]so found an overlap of 84% of food

row survived but sika deer were not present. It may habits during winter which, coupled with a high over-

be speculated that deer were unable to inhabit the Ashio lap in habitat use and heavy use of key forage species,

Mountains because of the lack of trees andlor bushes, was believed to have led to direct competition. In this

which they require for shelter. study, I also saw an overlap of food habits of serow

A second environmental change involved the inva- and sika during winter, which I believe may have led

sion of sika deer. At present, deer are able to live to direct competition.

throughout the year in the Ashio Mottntains when win- Direct observations confirmed that Japanese serow

ters are mild, furthermore migrant deer now use the fedmainlyonherbaceousplantsandbroad-leavedtrees

area for wintering (Honma 1995). The Ashio deer from spring to autumn. In winter, they changed their

population, including both residents and migrants, has foraging habits to include dumped leftover vegetables

been increasing since 1985, This increase probably in Akakura, and the baTk and twigs of broad-leaved

Tesulted from an increase in vegetation coverage, pro- trees and the needles and twigs of coniferous trees in

hibition of hunting in the Ashio area, and shorter win- Kuzo-zawa. Similar observations on sika deer, showed

ters caused by recent climate warming in the area (Li that they fed mainly on gramineids throughout the year.

et al. 1996). Climatic warming has led to an increase Based on analysis of stomach contents, in winter sika

in deer in the Nikko area which now use various other deer fed mainly on the baTk and twigs ofbroad-Ieaved

wintering grounds, one of which is Ashio, trees and the needles of coniferous trees. In other

Although snowfall has decTeased in recent yeaTs, words they shared similar foraging habits in winter

winters with high accumulation do still occur. Such with serow. Because stomach content analysis is a

winters oecurred in 1990-1991 and 1991-1992. Heavy more reliable way of identifying dietary components

snowfalls in these winters forced sika deer from over- than direct observation is, I believe that there was in-

crowded areas in Nikko to migrate to new wintering deed a high overlap in the diets of the two species in

grounds, including the present study area where theTe wmter. was a high serow population density. This sudden Anthony and Smith (1977) stated that exploitatien crowding, causecl by the gradual increase in the Tesi- of food by one species might lead to the selective elimi-

dent deer population in Ashio, plus the seasonal mi- nation of anotheT. I believe that the clietary flexibility

grants forced south from Nikko duc to heavy snows, of the sika deer in severe winters to include not only

may have resulted from environmental changes. Tliese the serow's preferred choice of coniferous needles, but changes rnay have caused interspecific competition also the twigs and bark ofdeciduous trees, had a great

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influence on the displacement of the serow by the deer. years of this prQject. Ms Caitlin B. Angeli, Faculty of

In addition, debarking of trees by deer eventually leads AgricultuTe,1[bkyoUniversityofAgricultureandTbch-

to the death of individual trees, which in turn reduces nology, helped to revise the English. I would like to

the summer food supply available to the Japanese se- express my sincere thanks to the above organisations

row. and persons. A secondary Teason proposed for the intensity of

the interspecific competition between the two species REFERENCES

is their different social behaviout Whereas serow are

believed to be sensitive to both intraspecific and in- Anthony, R. G. and N. S. Smith (1977) Ecological re- terspecific crowding due to their aggressive territorial lationships between mule deer and white-tailed deer

traits, non-territorial sika deer are usually telerant of in southeastern Arizona. Ecological Monographs 47:

others. In order to avoid large deer populations, the 255-277. sensitive serow may emigrate out of areas with high Ashio Local History Editorial Gommittee (1993) Ashio deer densities. The few serow that remain in sympat- Kyodo Shi (Ashio Local HistoTy), 239 pp. Ashio. ric co-existence with deer may be the small propor- (in Japanese) tion of the population that are tolerant Qf others, or Hardin,G.(1960)Thecompetitiveexclusionprinciple.

their numbers may have fa11en to a level where com- Science 131: 1292-1297.

petition no longer occurs. Honma, K. (1995) A study of migration pattern and

I believe that displacement has already occurred in habitat use of sika deer (:lervus nijrpon in Oku-Nikko Kuzo-zawa and may be beginning to occur in Matsuki- and Ashio, MSc. Thesis, Joetsu University of Edu- zawa and Akakura. Looking at the relationship be- cation, 144 pp. (in Japanese) tween serow and deer numbeTs, based on the results Krebs, J. C. (1989) Ecological Methodo]ogy, Harper of surveys conducted in Kuzo-zawa, one can theorise Collins Publishers, New Ybrk, 654 pp.

that this is a result ofdirect competition. I suggest Leader-Williams, N., [ll A. Scott and R. M. Pratt (1981) that interspecific competition affects Japanese serow Forage selection by introduced reindeer on South to a much greater extent than it does sika deer, and Georgia and its consequences for the flora. Journal

thus probably prevents their occurring sympatrica]]y of Applied Ecology 18:83-106,

on a long-term basis. heslie, D. M., E. D. Starkey, and M. Vhvra (1984) Elk and deeT diets in old-growth forests in western Wash- ACKNOWLEDGEMENTS ington. Journal of Wildlife Management 48:762- 775.Li,

This study was supported by The [[bchigi Prefec- Y, N. Maruyama, M. Koganezawa and N. Kanzaki ture Museum and the Utsunomiya University Forests. (1996) Wintering range expansion and incTease of Dr Naoki Maruyama, of the Faculty of Agricu]ture, sika deer in Nikko in re]ation to global warming, Tbkyo University of Agricultttre and 1[bchnology, Dr Wildlife Conservation Japan 2:23-35. Sandro Lovari of the Department ofBiological Evo- Maruyama, N. (1981) A study of the seasonal move- lution, University of Siena, and Dr Kajetan ments and aggregation patterns of sika deer, Bul)e-

Perzanowski, of the International Center of Ecology, tin ofthe Fac. of Agr., [[bkyo Univ. ofAgr. and [bch. Po]ish Academy of Sciences, provided valuable com- 23:1-85. (in Japanese with an English abstract) ments and constructive reviews of the manuscript, I Nelson, J, R. (1982) Relationships of elk and other

also thank C. Satake, Y. Matsushiro, H, Imaki, T. large herbiveres. In: Thomas, J. W and D, E. [Ibweill Hashimeto, K. Ohnaka, and the students of Utsunomiya (eds.); Elk of North America: Ecology and Man- University, who helped with the fieldwork over the 14 agement.pp.415-442,StackpoleBooks,Harrisburg.

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BiosphereConservation2 <1), 1999

[[bkida, K., N. Maruyama, T. Ito, K. Furubayashi and vironment for all Japan. pp. 38-68, No. 2. 176 pp.

H. Abe (1981) Factors affecting the geographical (in Japanese with an English summary) distribution of sika deer. In: Japan Wildlife Research Zaret, T, M. and A. S. Rand (1971) Competition in Center (ed.); ReseaTch Report of Animal (Mammal) tropical stream fishes: support for the competitive

Distribution, the 2nd Basic Research ofNatural En- exclusion principle. Eco}ogy52: 336-342.

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