Distribution and Abundance of Primates in Rain

International Journal of Primatology,Vol.25,No.5,October2004(C 2004) Distribution and Abundance of Primates in Rain Forests of the Western Ghats,Karnataka,Indiaand the Conservation of Macaca silenusH.N.Kumara1and Mewa Singh1,2Received December3,2003;accepted December29,2003We assessed the distribution and abundance of4species of diurnal primates viz.lion-tailed macaque,bonnet macaque,Nilgiri langur and Hanuman lan-gur,in2areas—Brahmagiri-Makut and Sirsi-Honnavara—in rain forests of the Western Ghats in the state of Karnataka,India.The Nilgiri langurs in Brahmagiri-Makut and the lion-tailed macaques in Sirsi-Honnavara are the northernmost populations of the2species in the Western Ghats.The2regions represent changes in ecological zones in the Western Ghats.In Brahmagiri-Makut,Hanuman langurs and bonnet macaques occupy lower elevations whereas Nilgiri langurs live in relatively higher altitudes.Only one group of lion-tailed macaques was in Brahmagiri-Makut.In the forests of Sirsi-Honnavara,3species of primates viz.lion-tailed macaque,bonnet macaque and Hanuman langur were in larger numbers throughout the forest.A self-sustainable single population of32groups of lion-tailed macaques occurred in Sirsi-Honnavara.Few subspecies of Hanuman langurs exist in the study regions.Due to local hunting practices,the relative abundance of primates in Brahmagiri-Makut is lower than that in Sirsi-Honnavara.KEY WORDS:primates;lion-tailed macaque;bonnet macaque;Nilgiri langur;Hanuman langur;rainforests;Western Ghats;Karnataka;Hunting pressure.INTRODUCTIONThe Western Ghats,a series of hill ranges,run parallel to the western coast of southwestern India from21◦N to8◦N(Pascal,1988).Being close to 1Biopsychology Laboratory,University of Mysore,Mysore-570006,India.2To whom correspondence should be addressed;e-mail:mewasingh@sancharnet.in.10010164-0291/04/1000-1001/0C 2004Springer Science+Business Media,Inc.1002Kumara and Singh the Arabian Sea,they receive heavy southwest monsoons.Whereas the west-ern slopes and the ridges contain primarily tropical evergreen rain forests, the eastern slopes,which are in a rain shadow,contain deciduous and scrub forests.The Ghats,with a length of about1600km from north to south and with an east to west width of30–80km,are a mosaic of heterogeneous habitat types.Although humans have been active in the hills since prehistoric times, organized state sponsored forestry and non-forestry activities began about 200years ago(Chandran,1997).Commercial plantations,tea and coffee cultivation,hydro dams and power generation,brought millions of people to the hills.Consequently,natural habitats have undergone drastic changes. The most conspicuous effect has been fragmentation of the rain forests.In most places,the rain forests fragments are isolated because of gaps cre-ated by plantations and commercial crops.Nonetheless the Western Ghats still harbor a diversity of plant and animal life,because of which they are one of the8hottest hotspots of biodiversity in the world(Myers et al., 2000).Due to canopy contiguity and the availability of a variety of trees bear-ing fruits throughout the year,the rain forests of the Western Ghats are extremely rich in arboreal fauna.The most conspicuous of the arboreal mammals are4species of diurnal nonhuman primates including lion-tailed macaques(Macaca silenus),bonnet macaques(M.radiata),Nilgiri langurs (Semnopithecus johnii),and Hanuman langurs(S.entellus).Whereas lion-tailed macaques and Nilgiri langurs are restricted to the Western Ghats,the other two species are widespread throughout southern India.The effect of rain forest fragmentation and habitat deterioration has been most drastic on lion-tailed macaques.Because of their highly selective feeding habits,limited overall range(ca.2500km2),delayed sexual maturity, long interbirth interval,low population turnover and small wild population (ca.3500individuals),they are endangered(IUCN,1996).Further,the re-maining population consists of49subpopulations isolated in rain forest frag-ments in8locations(Molur et al.,2003).Since forest fragments are also under intense human pressure,there are significant effects on demography,rang-ing patterns,feeding habits and reproductive rates of lion-tailed macaques (Kumar et al.,1995;Singh et al.,2001).Whereas some studies are available on lion-tailed macaques,the information on the other species of primates in the Western Ghats is scanty(Bhat,1982;Green and Minkowski,1977; Karanth,1985;Kumar et al.,1995;Kurup,1978;Ramachandran and Joseph, 2001;Singh et al.,1997a,b,2000,2002;Sugiyama,1968).A study of the distri-bution of primates in the Western Ghats has attained a special significance recently due to an update of primate taxonomy by Groves(2001).WhereasPrimates in Rainforests of the Western Ghats1003 lion-tailed macaques and Nilgiri langurs are considered monotypic,and two subspecies of bonnet macaques(M.radiata radiata and M.radiata diluta) have been described,confusion still prevails regarding Hanuman langurs (Brandon-Jones et al.,2004).Several subspecies of Hanuman langurs present in the Western Ghats are now being classified as distinct species(Groves, 2001).However,fewfield data are available on their distribution and sta-tus from extant populations,and the classifications have been made largely on the basis of museum specimens collected decades ago.Accordingly,it is necessary,not only to survey the primate populations in the Western Ghats afresh but also to determine the ecological correlates of the distribution pat-terns and to assess the impact of anthropogenic factors on the remaining populations.We focused on the status and distribution of primates in the rain forests of Brahmagiri-Makut and Sirsi-Honnavara in the state of Karnataka.Very little information was available on primates in the rain forests of the Western Ghats in Karnataka,and the sample localities represent2distinct eco-zones.They also differ in anthropogenic factors.We also hoped to identify viable localities for the conservation of endangered lion-tailed macaques.STUDY AREASBrahmagiri-Makut is at the southern end and Sirsi-Honnavara is a northern region,of the Western Ghats(Fig.1;Table I).The forests of Brahmagiri-Makut lie between75◦50 –76◦3 E and12◦5 –12◦13 N with an area of324km2in Kodagu district(Fig.2).The area re-ceives both southwestern and northeastern monsoons with an average an-nual rainfall of ca.6000mm.The region includes3administrative forest ranges:Srimangala and Makut(Wildlife),which form Brahmagiri Wildlife Sanctuary,and Makut(Reserve Forest).West of these hills is the state of Kerala with agricultural villages,on the east are coffee and cardamom plan-tations,on the north are wet evergreen forests and grassy mountain slopes, and on the south is a continuation of moist deciduous forests of the Rajiv Gandhi National Park.The forests of Brahmagiri-Makut are broadly clas-sified by Pascal(1988)as Medium Altitude Forest Type with Mesua ferrea-Palaquium ellipticum type of vegetation.Cullenia exarillata,a species with a special importance for primates is abundant southwards in the Western Ghats,but is absent in these forests.The forests of Sirsi-Honnavara lie between74◦35 –74◦47 E and14◦15 –14◦25 N in the district of Uttara Kannada.The focal study area with about1004Kumara and SinghFig.1.The Western Ghats and the2study locations in the state of Karnataka,India. 200km2of rain forest is between the Sharavathy and Aghanashini Rivers (Fig.3).The official status of the forest is Reserve Forest with interspersed revenue lands.Villages with large areas under cultivation of commercial crops including areca nut(Areca catachu)and paddy(Oryza sativa)are scat-tered inside.The forest was broadly classified as Low Altitude Rainforest by Pascal(1988)and as“West Coast Tropical Evergreen Forest”by Champion and Seth(1968).Due to the human interference,the Dipterocarpus indicus-Diospyros condolleana-Diospyros oocarpa vegetation that occurs south-wards has been replaced by Persea macrantha-Diospyros spp-Holigarna spp vegetation type(Pascal,1988).It extends up to the plateau of the Aghanashini River and forms the northern limit of the evergreen forests of the plains and low elevations.Primates in Rainforests of the Western Ghats1005T a b l e I .P h y s i c a l f e a t u r e s o f t h e t w o s t u d y r e g i o n sA d m i n i s t r a t i v e F o r e s t A l t i t u d e R a i n f a l l G e o g r a p h i c a l l o c a t i o n F o r e s t D i v i s i o nF o r e s t R a n g es t a t u s r a n g e (m a s l )(m m )F o r e s t t y p eB r a h m a g i r i -M a k u t 75◦V i r a j p e tS r i m a n g a l aP A 800–16086000G r a s s h i l l s ,S h o l a ,E v e r g r e e n a n d M o i s t -d e c i d u o u s 50 –76◦3 E M a k u t (W L )P A 65–1110”E v e r g r e e n a n d M o i s t -d e c i d u o u s 12◦5 –12◦13 NM a k u t (R F )R F 60–1744”G r a s s h i l l s ,E v e r g r e e n a n d M o i s t -d e c i d u o u s S i r s i -H o n n a v a r a S i r s iJ a n m a n e R F 275–5405000E v e r g r e e n a n d M o i s t -d e c i d u o u s 74◦35 –74◦47 E K y a d a g i R F 424–700”E v e r g r e e n a n d M o i s t -d e c i d u o u s 14◦15 –14◦25 NS i d d a p u r a R F 401–542”E v e r g r e e n a n d M o i s t -d e c i d u o u s H o n n a v a r aK u m t a R F 134–545”D e g r a d e d r a i n f o r e s t a n d M o i s t -d e c i d u o u s H o n n a v a r aR F 98–470”E v e r g r e e n ,M o i s t -d e c i d u o u s a n d D e g r a d e d r a i n f o r e s t G e r s o p p a RF 172–615”E v e r g r e e n ,M o i s t -d e c i d u o u s a n d D e g r a d e d r a i n f o r e s tN o t e .W L ,W i l d l i f e ,P A ,P r o t e c t e d A r e a ;R F ,R e s e r v e F o r e s t ;m a s l –m e t e r s a b o v e s e a l e v e l .1006Kumara and SinghFig.2.Brahmagiri-Makut showing3administrative Forest Ranges.Numbers indicate places mentioned in Table II.RF—Reserve Forest;WL—Wildlife.Fig.3.Locations of lion-tailed macaque groups in Sirsi-Honnavara,see Appendix I.Primates in Rainforests of the Western Ghats1007METHODSWe conducted the study from November2001to January2002in Brahmagiri-Makut,and from February2002to April2002in Sirsi-Honnavara.We followed the methods of total count for lion-tailed macaques and encounter rate(NRC,1981;Whitesides et al.,1988)to estimate the distribution and abundance of other primate species.Researchers have used the methods reliably in the Western Ghats,including the Sringeri Forest Range(Singh et al.,2000),Silent Valley National Park(Ramachandran and Joseph,2001)and Anaimalai Hills(Singh et al.,1997a,b,2002).We walked 238km in Brahmagiri-Makut and198km in Sirsi-Honnavara at the aver-age speed of0.8km/h on pre-existing trails,animal paths or predetermined routes.Pedometers recorded the distances walked.The average distance covered per day is6.4km(±2.49)and4.5km(±2.22)during41and44days in Brahmagiri-Makut and Sirsi-Honnavara,respectively.Since both study areas had tropical rain forests,we assumed that neither the visibility factor nor the detectability factor would affect observations or bias the data signif-icantly.After sighting a group,we spent sufficient time to get a proper count of individuals.We classified individuals as adult male,adult female and im-mature,including subadults,juveniles and infants,based on morphological characteristics(Harvey et al.,1991;Kumar1987;Ramachandran and Joseph, 2001;Roonwal and Mohnot,1977;Singh et al.,2002).The location and the demographic data allowed the groups to be differentiated and given distinct names for lion-tailed macaques.We represent the abundance of a species as encounter rate i.e.groups/km.We gathered information on hunting practice and intensity via interviews of local people,forest officials,hunters,encoun-ters with hunters,and animal traps in the forest(Kumara and Singh,in press).RESULTSAll4species of South Indian diurnal primates—bonnet macaques,lion-tailed macaques,Nilgiri langurs and Hanuman langurs,occur in Brahmagiri-Makut.In Sirsi-Honnavara,Nilgiri langurs were absent,and the other 3species were present.Table II and Fig.2present the distribution of primates in Brahmagiri-Makut.On the eastern slopes of the southern Srimangala Range where the forest is moist deciduous,we saw only bonnet macaques.At the south-eastern tip of this Range with small patches of forests and coffee planta-tions,Hanuman langurs and bonnet macaques were sympatric.At higher elevations with thin shola forests—narrow patches in hollows amidst grass1008Kumara and SinghTable II.Distribution of primates in Brahmagiri–MakutAltitude range Species Location Forest type(m asl) BM Kuppangal(1),Irpu(2),Evergreen forest,Moist deciduous811–1308BM,HL Naathangal(3),Makut(16)Evergreen forest,Moist deciduous60–655BM,LTM(?),NL Sempole(7),Perumalumalai toAabylu(8)Evergreen forest755–1170BM,LTM(?),HL South of Aabylu(9),Mepalli(10),Nadakani(11),Pookala(12),Votekolli(13),Sollekolli(14),Kottarchipari(15),Arabithittu(17),Kulimakki(18),Matre(19),Kooratu(21)Evergreen forest60–1744 BM,LTM,HL Udumbe(20)Evergreen forest200–600NL Munikal shola(4),Dharekadu(5)Evergreen forest,Montane shola1305–1400None Sholas aroundNarimalai(6)Montane shola1300–1400Note.BM,bonnet macaque;LTM,lion-tailed macaque;NL;Nilgiri langur;HL,Hanuman langur;numbers in parentheses indicate locations in Fig.2;LTM(?),possible occurrence of lion-tailed macaque.lands on mountain top—around Narimalai,all primate species were ab-sent.However,in a similar type of shola at Munikal and Dharekadu west-wards,Nilgiri langurs were the only primate species present.They com-prise the northernmost population of Nilgiri langur in the Western Ghats. In the rain forests that continued northwest along the Kerala border at Sempole and Perumalumalai to Aabylu,bonnet macaques and Nilgiri lan-gurs are sympatric.In the rain forest at northern Aabylu,Mepalli,Nadakani and Pookala of Srimangala Range,Votekolli,Sollekolli,Kottarchiparai of Makut(Wildlife)Range and Arabithittu,Kulimakki,Matre and Kooratu of Makut(Reserve Forest)Range,bonnet macaques and Hanuman lan-gurs are sympatric.Along with bonnet macaques and Hanuman langurs, lion-tailed macaques are sympatric at Udumbe of Makut(Reserve Forest) Range(Fig.2).Except one group each at Nathangal,Udumbe,Puliparai and Kulimakki,which were isolated stray groups,the remaining groups are between Votekolli and Makut.Primates in Rainforests of the Western Ghats1009 In Sirsi-Honnavara,north of Sharavathi river to Chiksuli in Kyadagi Range,bonnet macaques,lion-tailed macaques and Hanuman langurs are sympatric.In rest of the region,bonnet macaques and Hanuman langurs are sympatric.Because lion-tailed macaques are an endangered species,we especially attempted to locate all groups of them(Appendix I).We assigned each group an identity on the basis of location(Fig.3)and demographic structure.In total,we noted32groups.They are the northernmost population of lion-tailed macaque in the Western Ghats.Table III presents information on distribution of primates at different altitudes.In Brahmagiri-Makut,the Nilgiri langurs live between700–1400m asl,though71.41%of them were above900m asl.Conversely,50%of the Hanuman langur and41%of the bonnet macaque groups were between 200–400m asl.Because we recorded only one group of lion-tailed macaques at430m asl in the region,it is not listed in Table III.In Sirsi-Honnavara, primate species were between150–700m asl,though79%of the groups of all species were between400–600m asl.Table IV presents the data on abundance of primates in the2study re-gions.Bonnet macaques and Hanuman langurs were in all the ranges.Nilgiri langurs were only in Srimangala.Lion-tailed macaques were in Makut(RF) in Brahmagiri-Makut and in all the ranges except Janmane and Kumta in Sirsi-Honnavara.A total of15groups of bonnet macaques provided an en-counter rate of0.06groups/km.The encounter rates of bonnet macaques in Srimangala and Makut(RF)are0.037and0.058,respectively,whereas it is higher in Makut(WL)(0.129groups/km).The encounter rate of Hanuman langur in Srimangala and Makut(RF)are0.012and0.05groups/km,respec-tively,whereas it is considerably higher(0.363groups/km)in Makut(WL). The overall abundance of bonnet macaques(0.28groups/km)and Hanuman Table III.Primate groups at different altitudes in Brahmagiri-Makut and Sirsi-HonnavaraBrahmagiri-Makut Sirsi-HonnavaraAltitude range Overall Overall (m asl)BM HL NL(%)LTM BM HL(%) <2003(17.7)2(10.0)—(9.2)1(3.1)1(2.1)5(3.3)(2.9)201–4007(41.2)10(50.0)—(30.4)1(3.1)5(10.6)19(12.6)(8.8) 401–500—3(15.0)—(5.0)10(31.2)24(51.1)72(47.7)(43.3) 501–6001(5.9)4(20.0)—(8.6)15(46.9)15(31.9)43(28.5)(35.7) 601–7002(11.8)——(3.9)5(15.6)2(4.3)12(8.0)(9.3) 701–8004(23.5)1(5.0)1(14.3)(14.3)————801–900——1(14.3)(4.8)————>900——5(71.4)(23.8)————Note.Values in parentheses indicate percentages.1010Kumara and SinghT a b l e I V .P r i m a t e g r o u p s e n c o u n t e r e d i n d i f f e r e n t a d m i n i s t r a t i v e r a n g e s o f B r a h m a g i r i -M a k u t a n d S i r s i -H o n n a v a r aB o n n e t m a c a q u eL i o n -t a i l e d m a c a q u e N i l g i r i l a n g u rH a n u m a n l a n g u rS t u d y r e g i o n R a n g ek m w a l k e d N o .G r o u p s /k m N o .G r o u p s /k m N o .G r o u p s /k m N o .G r o u p s /k mB r a h m a g i r i -M a k u tS r i m a n g a l a 80.230.040—90.1110.01M a k u t (W L )38.550.130—0—140.36M a k u t (R F )119.370.0610.0080—60.05T o t a l 238150.0610.00490.04210.09S i r s i -H o n n a v a r aJ a n m a n e 20.350.250—0—221.10K y a d a g i 95.4270.28170.180—870.91S i d d a p u r a 8.020.2520.250—50.62K u m t a 6.520.310—0—81.23H o n n a v a r a 19.450.2530.150—221.13G e r s o p p a 48.4140.29100.210—290.60T o t a l 198550.28320.160—1730.87Primates in Rainforests of the Western Ghats1011 langurs(0.87groups/km)in Sirsi-Honnavara is higher than0.06and0.088 groups/km,respectively,in Brahmagiri-Makut.Nine groups of Nilgiri lan-gurs occurred with an encounter rate of0.038groups/km only in evergreen forests bordering Kerala state and in the southwestern part of the Srimangala range.We saw lion-tailed macaques,with only3individuals in a group,in Makut(RF)in Brahmagiri-Makut.In Kyadagi,Siddapura,Honnavara and Gersoppa ranges of Sirsi-Honnavara,we recorded,32groups of lion-tailed macaques,an encounter rate of0.16groups/km.The encounter rates were almost even across all the ranges.In Sirsi-Honnavara,the abundance of Hanuman langurs(0.87groups/km)is higher than that of bonnet macaques (0.28groups/km)and lion-tailed macaques(0.16groups/km).Table V presents information on group size of different primate species. We were not able to gather data on group size in lion-tailed macaques and bonnet macaques in Brahmagiri-Makut since they were very shy.The group sizes of lion-tailed macaques and bonnet macaques were24.7(N=20) (range9–48)and19.0(N=5)(range5–36),respectively,in Sirsi-Honnavara. The group size of Nilgiri langur in Brahmagiri-Makut was4.25(N=4) (range3–6).The group size of Hanuman langur was6.5(N=6)(range3–9). The group size of Hanuman langur in Sirsi-Honnavara was10.31(N=13) (range5–16).Extrapolating to32groups of lion-tailed macaques,the esti-mated total population in Sirsi-Honnavara is ca.790individuals.The group density and the individual density are0.28groups/km2and6.9individuals/ km2,respectively.The numbers of groups in each group size category of11–20,21–30and31–40are6,6and5,respectively.Only two groups had<10 individuals and one group had>40individuals.The age/sex compositions are available for9groups(Table VI).The number of adult males per group varied from1to4,with a mean of1.9and median of2.More than50%of the groups had2adult males.Number of males in the group increased as the group size increased.Adult males constituted8.9%of a group.The number of adult females per group varied from3to15,with a mean of7.9and median of9.The adult females constituted37%of a group.The mean adult sex ratio is4.2females per male.The immature class(subadult,juvenile and infant)Table V.Group size in different speciesBrahmagiri-Makut Sirsi-HonnavaraNo.of No.of Mean group No.of No.of Mean group Animal groups animals size groups animals sizeBM———59519.0LTM———2049424.7HL639 6.51313410.31NL417 4.25———1012Kumara and SinghTable VI.Demography of Lion-tailed MacaquesAdult Adult Subadult and Total Group Size male female juvenile Infant immature Chiksuli302911819 Kerekulivotekodlu24297613 Hosathota1114246 Samplevore-A914314 Salikanu3641514317 Hasolli272118614 Kanukumbri913415 Suthlamane3121016319 Hukkali1526527 Total19217717034104 Mean 1.97.97.8 3.811.6%of group8.937.036.517.754.2 constituted54.2%of a group,whereas infants alone constituted17.7%.The adult female-to-immature ratio is1:1.5and the adult female-to-infant ratio is1:0.5.The overall adult to immature ratio is1:1.2.In Sirsi-Honnavara,villages were scattered throughout the rain forest and large tracts were cleared for planting commercial crops such as paddy and areca.However,the forest was still contiguous through hill slopes and valleys.Hunting pressure on primates is severe in Brahmagiri-Makut due to the preference for primate meat in almost all communities.Conversely, the belief systems in Sirsi-Honnavara prevented most people from hunting primates for meat.We report elsewhere(Kumara and Singh,in press)de-tailed data on interviews,trap sighting,encounters with hunters,and hunting rates.DISCUSSIONOne of the most outstanding observations from our study is the sight-ing of Nilgiri langur groups in Srimangala Range.Although,Nilgiri lan-gurs were recorded in Brahmagiri Hills in1912–13(Ryley and Shortridge, 1913),later reports indicated the presence of Nilgiri langur only up to Nilgiri Hills,south of the Brahmagiri Hills(Hohmann and Sunderraj,1990) or an uncertain status in the Brahmagiri Hills(Oates,1979).Further,they are the present northernmost population of the species in the entire Western Ghats.In the Western Ghats south of Brahmagiri-Makut,Nilgiri langurs are sympatric with lion-tailed macaques in the rain forests.However,the distribution of lion-tailed macaques continues northwards upto north of Sharavathy river.Hohmann and Sunderraj(1990)hypothesized that in thePrimates in Rainforests of the Western Ghats1013 central Western Ghats,Nilgiri langurs were probably hunted for meat,and habitat vacated by them was invaded by Hanuman langur.Our data do not support this argument because all primates are severely hunted in Brahmagiri-Makut and the hunting pressure on primates is very low in north-ern areas of the Western Ghats in Karnataka where lion-tailed macaques are still present.We propose that the absence of Nilgiri langur north of Brahmagiri-Makut is due to ecological factors.Brahmagiri-Makut marks a very specific ecotone with absence of Cullenia exarillata,but is rich in Lau-raceae.“This forest type occupies the medium elevations of the Western Ghats from almost its southern extremity up to Brahmagiri Ghats which form a natural border between Kerala and Karnataka.This relief forms a barrier,north of which Cullenia is no longer found”(Pascal,1988, p.113).The ecotonal demarcation probably explains the end of Nilgiri langur distributional range in the Western Ghats.The habitat and ecolog-ical correlation is further strengthened by our data,indicating that even within Brahmagiri-Makut forests,Nilgiri langurs occur only at higher al-titudes.Conversely,protection against hunting was maximum in areas at Votekolli and Makuta,which have high densities of other primates but Nilgiri langurs are absent.A unique feature of this population of Nilgiri langur is small group size(4.25individuals)versus group sizes of5.89and 11in Silent Valley(Ramachandran and Joseph,2001)and Anaimalai Hills (Singh et al.,1997a)respectively,in the southern populations in the Western Ghats.Since lion-tailed macaques are an endangered species,a special atten-tion has been paid to their distribution,status and conservation.The total wild population of about3500individuals is distributed in49subpopulations, many of which are single,isolated groups in forest fragments(Molur et al., 2003).There are only a few self-sustainable subpopulations where10to15 groups of lion-tailed macaques have adjacent or overlapping home ranges and form a substantially large breeding population.Our data provide a ma-jor base towards the conservation of this endangered species.We not only have described the northernmost population of lion-tailed macaques,but also have found a population of32groups in a single,contiguous tract of rain forest where≤6groups were reported earlier(Bhat,1982;Karanth, 1985).With the probable exception of Kalkad-Mundanthurai,the southern-most population of the species in the Western Ghats,the Sirsi-Honnavara population is the single largest subpopulation of lion-tailed macaques in the distributional range of the species.They deserve special attention to con-serve the species,which only a few decades ago was thought to be at the brink of extinction.In Sirsi-Honnavara,the lion-tailed macaque population appears to be healthy as indicated by a high frequency of groups with the1014Kumara and Singh modal group size,a favorable sex ratio,and a large percentage of immature individuals.All these factors show a healthy demography and breeding status.How-ever,a few concerns regarding long term conservation and management of lion-tailed macaques in Sirsi-Honnavara must be pointed out.The forests are only Reserved Forests and do not come under any legally notified Wildlife Sanctuary or National Park;The protection status is not optimum.Since agri-cultural villages are scattered throughout the region,construction of roads, buildings,encroachment into forest land and habitat deterioration appear to be imminent.It is not possible to shift the villages out of the forests,but if the area is declared legally protected as a lion-tailed macaque reserve,it may ar-rest further encroachment and habitat disturbance.The lion-tailed macaque population may then remain a large and biologically self-sustainable single population for the long-term conservation of the species.A unique feature of the population is the relatively large group size.In the Western Ghats, group size in lion-tailed macaques appears to consistently increase from south to north:16.3in Anaimalai Hills(Singh et al.,2002),19.6in Silent valley (Ramachandran and Joseph,2001),20.1in Sringeri(Singh et al.,2001)and 24.7in Sirsi-Honnavara.The ecological regulators of the distribution of primates in southern peninsular India are clearly discernible from our study.Bonnet macaques and Hanuman langurs are widespread species in a variety of habitat types. Conversely,lion-tailed macaques and Nilgiri langurs are endemic only to the wet forests of the Western Ghats.From the southern tip of the Western Ghats to Brahmagiri-Makut,Cullenia exarillata is a conspicuous tree species.How-ever,the dipterocarpus forests continue further north up to Sirsi-Honnavara. At Brahmagiri-Makut and at Sirsi-Honnavara,there are major ecological changes in the Western Ghats,and these ecotones interestingly also mark the northern ends of the distribution of Nilgiri langurs and lion-tailed macaques, respectively.Even within large ecological distributional ranges,microlevel ecologi-cal factors could be related to the distribution of primate species.Lion-tailed macaques are frugivorous/insectivorous,bonnet macaques are omnivorous, and the two langur species are primarily folivorous.The2macaque species and either one of the langur species are sympatric.Conversely,the two lan-gur species are rarely sympatric.Whereas Nilgiri langurs are restricted to the higher altitude rain forests,including the Montane shola forests occupied ex-clusively by Nilgiri langurs in Brahmagiri-Makut,the Hanuman langur live at lower ranges,extended even into typical deciduous forests of the adjoin-ing areas.In Sirsi-Honnavara,where Nilgiri langurs were absent,Hanuman langurs were present in most of the areas.This type of spatial separation has。