ifrllt.M( ~ p~ - f\ ~\f --c;)5 + 1. r77 I) -n IiJf~J 44 1994, 3 29 :J / :J", )( 7/{v= / F +1E1L0I11K~J@\T.:5:1" I) =7 (Gorilla gorilla gorilla) 0) ~NJtm}EC: ~N1idJJX;O)!ttf11& Population density and group organization of gorillas (Gorilla gorilla gorilla) in the Nouabale-Ndoki National Park, Congo Tomoaki Nishihara** The population density of western lowland gorillas in the Nouabale-Ndoki National Park, northern Congo, was estimated both by the "bed-census" method and the "counting" method based on bed-count and direct observation. The density was calculated as 1.92 - 2.56 animals/km2 and 2.29 - 2.61 animals/km2 respectively. Because this was the first time to attempt the "bed-census" method in the Ndoki forest, direct comparison of population density was possible between western low­ land gorilla populations at all study sites. It was concluded that the density of the Ndoki gorillas was highest. High population density of the Ndoki gorillas was considered to be possible because they have access to a wide repertoire of foods such as highly nutritious terrestrial herbaceous vegetation (THV) and various kinds of fruits and seeds, corresponding to the seasonal fluctuation of food availability. Although the feeding habits and habitat were different between western and eastern gorillas, they shared a basically one-male group composition, large group size, and unit groups that largely shared their home ranges with each other. et al., 1993)0 =-:/ 0 -7'/ 1-' :::{I) 7 (Gorilla gorilla gorilla) IC-::>~ 'Lli, A-:fittJ{113llt-c.t>0 ~ c c~ .l) 0 ttll J:!.~ O):{IJ 7 0) [email protected];It0)tlnrw.; i- 0) :{ t*I*JO).fJlWO)~~ :6'';iffffl@l{*1J? '/ He J: 0 Itlt ~70)~@~ll~0)~*~~~m~~4~oo~ HIJE';i:JoOJ:pnL~'tJ:~\o U1.~-C, =-:/0-7 '/ ~1~ -C, "< 1) '/T '/ :::i I) 7 (Gorilla gorilla beritlgei), ,...::tl) 7 0)ItltffUE Ie Ii, r~':1 "".-e,/-tj-.Af!J l:: if ~ 0 - 7 '/ I-':{ I) 7 (Gorilla gorilla graueri) ("bed-census" method) (1J':t!,/: Tutin & IC-:J~\Lli, rMJ{*l&fifl~fld <"direct count" Fernandez, 1984; CP!k:77 I) ;f} : Carroll, 1986, method), -:Jj;~@I(*;f}1)'/t-~~,;t ""1&1)1)'/ 1988; Fay, 1989; ::J '/::J' : Fay et ai, 1989; Fay t- IcU·:j"~\Lltl.lttJ{~11l ~ n L ~ t::. <Schaller, & Agnagna. 1992), r71 '/. I- 7 '/-e:7 t- rEJ 1963 ; Goodall & Groves, 1977; Harcourt et al., ("line transect" method) (::J '/:::{. '/ ,... -f- : .=. 1981: Murkyak, 1981; Yamagiwa, 1983; Yamagiwa ft, 1990a; Mit/Jni, 1992; Milani et al., 1993) , ~.~.c~~~·1J?'/I-~J:orm~l&m~ * ~m*$rn!$$AUiiIHt~fiJf~~ $J (::J '/ ::J' • '/ ,... -f- : Kuroda, 1992, Yamagiwa, ** Faculty of Science, Kyoto University *~*) tJiffl~'';n -C~ t::. o 30 ;/ r' +T'i ~·I) 7 O)*AE\f.:f.Jbjifl!!.O)c'O)~:i!lt~ .J: I] b ~~, c C. hi. eni TO)1.J;itle.J: -:> LflH5 ~ n L~' 6 (Kuroda. 1992; Yamagiwa. *~~; ~ftli!l c. M\j'l!iJUJru' Mitani et a!" 1993)0 l;6)ltJhi G. cni'{';/ IDfJ1fll!!.'i, ~;/ ~·:jl*lm;;< 7' /< v = ;/ V +IT!YrL 1:+T'i~ ..) r" -iz;/-irAt.ttJiffJ~'GnLctJ.;6) 0~J*J le~uTi. ~ ~1/: (Nishihara. ~V'n1lp)o IDfJ i!i -:> 1:0)r:. -==-:/ 0 - 7 ;/ r'~· I) 7 o)ll!!.lilil~'{'O)m JUl/1fHi199UfI2JJ;6) G1992$11 R '* "'CO) 12 "T t:I. IEli~U::[jH-t!lU~1" 'i~iJJfjBTJs iWdfi~'i. =Frf01t1~tO)~~1} 6 C c. -:> 1: 0 1: C 8i- 287 EI,mT ib -:> 1'::0 T~fill'i. ;/ r' +0) ~" I) 7 i-x;J,%~I<::~ ';t V • -iz ;/ *fTib 1]. M1:.Ii. A '7 ;/7':f..t;. Gilbertiodendron ~ -It AtEle.J: 6 \f.' JJr ffE;g i-:to C tJ, -:> 1: 0 IF.J 1<:. t-f. iItfjJi::t-fO) 3 117'I<::}'J.lIJ~n60 1 ~TO'if:f:j* Kuroda (992) c. Yamagiwa (;kr~£D let Mml* (3J'l;6'G11J1iT) c.~* 02fj;6·G2JUT) txm)Ef1de:lkj'~' 1:~,[1,\$}S[ b;j(~ 1'::0 *liJfJ'i:O) 1<::. ,*/:m:JflI:.H(ltUUGL:;L~W:~* (4fj;6·G EJ (J~O) --:J Ii. ;/ fi +0)::( I) 7 O)\i'il!tf1UtMI i-. 9JJ'1T;Y...rF. !p.,c.~.ltX~f-c~\oj) c'1>utJ~* /V4-0~0)~~~0)-==-~D-7/V~~70)1: 00Fl ;6) G 3 ):J '* '{') C: Ie)} rl .; ~l6 (Nishihara ft. C: [illJiHlfQ-g- 6 L c. T. C ~l '* T c' O)ll1Jtj~ J: IJ & Suzuki, iVlIJINJ)o iJtJfi!I1JIL';l:. ~"I) 50)'i;/)· b ~.@, \f;/JrhijUj ~'c. mf~ ~ ~l L ~ I.:: ;/ I: +0) ~,. I) 7' ;//.;' /' y - (Pan troglodytes troglodytes) '\-> f:: ~ fIj~JiH1" flliO)Uhf11'J:fH(jhsri'il/frIY-Jle~,@, ~'6 :7 ®\f;/1( 6 c c. T J) 6 0 0)1l!!. 9 l T *liJfJ'CT'i it.::, ;/ V4- O)~· I) :7 O)l1H\L*~JO) C==:fr. 1990a; Mitani, 1990b)0 rm~liiS'i±'le* ~tM~[]lmO)fIJfI]tiJtO)mttrie :i!It~ mI&:. mQj-lt 1 7:. ';t I, '7 --.? :IX Ie ib 6 '/r) itio) oj tJ. ib '* IJ L -:J ~'L ~~. 7' r) ;/ j- ;/ ~. I) :7 "iJ I:: jl:/ 0 - 5 ;/ 1" ~"L ~'tH' ob 0) i-flJJIll. T ~ 6 rl~ IJ ll!!HlU(.j(liJ F ~. I) 70)1: n c.llfX l. ~' I) 5 JT~IUo rl6tlU] I] hi1=, L:; tJ ~'J: oj Ie L 1'::0 '* 1.::1i ~'Ie Ii'f'V-ff'"9 *~1&:0)1fW:le-:J~'L~~ l t.:: o 6 ~ti=fUU;H3~±O)rIJ91w.fJs 500m <.; ~'Ie tJ, 6 J: oj IcAIl'8tJlfl~liiSbi&AELt: (~1)0 o INLAND FOREST ~ SWAMP FOREST ~ OBSERVATION ROUTE ~ FRUIT CENSUS * CAMP ROUTE Ii :s.2 tI+-tt--t'lo.ft~a---f-"-~ 500m o Dr ~ PtJI-~~~"-=f,{::-=1\:-*~1 '---' 500 m Fig. 1 A map of the study area showing observation routes and fruit census routes. The Inland Forest combines Ci !/Jert iodendron Forest and Mixed Species Forest. The study area is . divided by grids of 500 m square. ilH~lfl~ c« "/ r ~AiI!Lt1:J) GO)~2=). ~«';I rO)f14fJxm~~~clfk ~~7~~~U~lk~~, ~~lfl~lk@~ It.:o j;t.:. ~0)~f1li~0)~.:tO):toJ:~O)t1iJ: C. ffPi, r 7 ~ ;./ 7', f!*ftff. :i.21mlJff. ~tJ c: tliti [X 71 ~ £< VT c ~ tL 'L ~,~ (Schaller, 1963. 1:J) G7¥i£tJ iBJJ GtJ)ICli'(j;W~ tLt.:1Wf4>O)~.s1&, :to J: Tutin et al., 1992) o)T, *li)f~IC:to ~''L b« ';I r ~~tLGO)tt~~77~~~~lko k~l*m -If1 t-m[iliO):toJ: ~O)f"JV(,~~~t.:(\f)IC. ~!I2= JETli, jC{tlc1Wf*f&~;IJ?;./t--r'~t':c*'Jt!Jil tLt,:~O)lkff~«,y rC clcHiJllILt.:o t.:~~o)h~7HrrO)M~cIt.:o ::( I) 70)« 'Y r Ii. T;./ /'~;./ ::;: - 0) b 0) c I~J]IJ «';I r . ~ ;./-If~ti; -t~t.:(\f)lC, ::(1) 7tJiifllt.:c*rJtttT~tL~ <If'htJi Tutin & Fernandez (984) ClJ!I:VT, l t.:« ';I r p'!.(\f) GtL Ml!!J:« 'Y r, ~0)9Jb 'L ~, ~ ffiJ*l:O) • ~ =-' ~t ~ fl~~i[ L t.: 0):\;lc L t.:tJ i -:> 'L, ~.@. «'Y r. ~fm!'icitlcb~tJ)G~'-::>'LitlU:«'y rc \f,'[fti-HE5ELt.: (Carroll, 1988): fil]-:*fitlo) b 0) c ,¥IJtffr ~ tLt.:fMJ-:..-{ 'Y r. ::( I) 7 1:.Et~J1i (IiJi1&/km 2) O)~tJi~TO)tilil:T~JL:~; fLt.:fMl:« ';I rO) 4 '1 «~r~;./-If~-r'~A~hk..-{7r. 17'~, 71frrO)M~c Gt.: (cf Tutin & Fernandez, «'Y r~=-'-If~iliit't, 1984)0 i1.!Lt« 'Y r Ii 3 J 1 7" Ie 5} 11 Gn ~ 0 1 J) 1: Ffq]O)~-?~*Ul ~f.rJJfll t.:« ';I r (ti1i~)) x---- «';I t-' 0) Jfft/J «';I r: Plant bed) ; 2) :i l) 7tJ{±0)J:lc~t:8!~ t.:« ';I r (±« ';I r : Bare ground bed) ; 3) :J' ('('-r'~'?IiJif&cli. 1~1~-r'«';1 r~f'F~@j~O) I) 7 tJiit!!J:Ie~T l 'L ~'~ti!i11-mO)l:ICoo:t~~t.: ~T. L t.:tJ i -::> 'LJ;IJ ;./;j{ r) O).'i~1:J)tL~L c «';I r Wi11-m« 'Y r : Dead leaf bed)o «'Y r IOJ.o o «';I r' ~ =-'-if~ffiifmi, ~ ;./-if~)V­ Ii, ~O)Jfilfj:l*~'], t14tVZtill~))O)t1~. to J: U:« 'Y HE~ffi c )1/- I' tB~ 'O)~ ;./ -If A ~ffi c O)t1iT~To r IcIIPH~T ~ ftffl{O)t1 ~ 1:J' G. f~Jll~ 3 EI 0r~ c ID1iJ:J!iWJrfJ9 rI1 , fiJfJ.td (, ts. -::> t.:mw~ =-' -tt ~ 0))1/- t1EJE ~ tL ~ b O)t':'11 ~~c£'} l t.: o t.:t':'l.' (,0)fi1!. t-~..-{ ';I t-' • ~;./ -It ~ )1.'- t- c L t: (Nishihara Ul1&G1&hiiE6'(fIC 3 E1TtH'iJJfj~tlb:'i\5l;ll 'L. & Suzuki, ~V~i[P) (~l)o fijfJ llill. ilH12@) 71~O)M.Clk«~rO)t1~~~mm3B0~ O)m~~ ;./ -if ~ rplCJI/- t- rd~ '0)~iJ)20 mN IC:9~.w. ~nt:«';1 t-'~i-, ~;./-tt~lC1:J' t,H'l4 B0fi'.1-r'JJ ~ c l t.: o f5!!Jllm 3 - 4 E1Ja r-lt1 t-O)«,y ~O)bo)IeIllUElt.:o)li. !j!~'~~T3 - 4 Be' 1J>-:>t':«';1 rf&c-t~o ~ ;./-If~)I/- Ha~'O)« ~tJiJMI11-t~ (, c tJiJJ I), ~ O)t.B.i-&±« 'Y r ~tb ';I r,j:-t«'Lft!i!.~tL~(,c~WimcL. tll~:M' 11-f;.l« ") r hi« ';I t·... c l 'L'¥JJj]IJ L1!tt <tJ ~1J' Ge' leJ:~7t~i!.[f-10)/<1J~'H!WlLt.:o «'y rO)!.tf JJ ~o (,itc Ii, «';I rtJif'fGn'L1J' GliU~l'f.JlC« 'y r c :J"I) 70) 1-:;10)..-{,y r-if1 Hi.