Pigs, Peccaries and Hippos Status Survey and Action Plan (1993)

 

Chapter 4.3

 

The Forest Hog

(Hylochoerus meinertzhageni)

 

Jean-Pierre d'Huart

 

Status and Action Plan Summary

 

Status category 3 - 5 (rare to endangered) according to subspecies or population.

 

The available data on the biology and distribution of this species are far from complete, though its conservation status is already a matter for concern in many parts of its former range. Three subspecies are recognized. Of these, the only truly 'giant' form, H. m. meinertzhageni, has the smallest range but appears relatively secure in its eastern montane habitats. However, various threats (including over-hunting for local markets and deforestation) are identified as causative factors in the diminution and fragmentation of the species' range and numbers in Central and, especially, West Africa. The lack of an adequate network of protected areas for the long-term protection of the smallest and most threatened race, H. m. ivoriensis, in West Africa is particularly worrying and is reflected in the conservation measures proposed. These measures also emphasize the need to assess the taxonomic (and conservation) status of the poorly known, isolated populations of the southern Ethiopian highlands, and to review of status of populations in the contact zone between the Central African subspecies, rimator, and the eastern giant, meinertzhageni. Other proposals include the possible restocking of animals in newly protected forests in Rwanda/Burundi, assessment of population status in some still poorly known areas, the revision of protective legislation in several countries, and the creation of new parks and reserves in the most critical parts of its fragmented range. In addition, some specific recommendations concerning the most threatened populations in Central and West Africa detail needs for the allocation of forest concessions, studies of bush-meat markets and desirability of a captive-breeding initiative for H. m. ivoriensis.

 

 

Introduction

 

The 'giant' forest hog, Hylochoerus meinertzhageni, is one of the most recently discovered large mammals, being first described in 1904 from specimens collected near Kaimosi in Kenya. These specimens proved to be of relatively large size, since there is an east to west cline in body size in this species, with adult males of the nominate H. m. meinertzhageni, from the highlands of East Africa, reaching a body weight (>225 kg), total (head + body + tail) length (>230 cm) and shoulder height (>110 cm), greater than any other extant suid. By comparison, the largest male H. m. ivoriensis, reported by Rode (1944), weighed only 150 kg and measured 205 cm total length, 94 cm shoulder height. Apart from their body size, the enlarged, discoidal snout and antorbital protuberances are diagnostic, as is their relatively long, but sparse, bristly black pelage.

 

Forest hogs occupy a variety of essentially closed habitats over a wide altitudinal range. As such, the species is potentially a useful indicator of natural and human-induced changes in its forest habitat. As a social, sedentary species, it is susceptible to hunting pressure, though its population biology and other aspects of its ecology and behaviour remain rather poorly known owing to its retiring and essentially nocturnal habits. However, studies have been conducted in east Zaire (now Democratic Republic of Congo) by d'Huart (1978) and in Kenya by Kingdon (1979), whose accounts include references to earlier published data on the species' systematics, anatomy, pathology, behaviour in captivity, distribution and trophy measurements.

 

Seven subspecies have been described, but the most recent revision of the genus (Grubb, 1985 and this vol., Section 4.1), suggests that only three of these are valid, i.e.: H. m. meinertzhageni (East African highlands), H. m. rimator (Central Africa) and H. m. ivoriensis (West Africa). This treatment, which is followed here, does not recognize the separation of the two Central African populations (i.e. the western 'ituriensis' and eastern 'rimator') as distinct subspecies, but it acknowledges that the systematic relationships of the forest hog populations in Ethiopia remain unknown. It is probable that the Ethiopian hogs are derived from the H. m. meinertzhageni stock, since sightings have been reported in southern Sudan and eastern Uganda, on the right bank of the Nile (Cotton, 1936). However, given the wide and early separation of these two populations by the ancient eco-climatic montane boundary along the 4th parallel North, which might favor the evolution of a distinct race, it is possible that the Ethiopian population comprises a different, as yet described, subspecies (d'Huart, 1978; Yalden et al., 1984; J. C. Hillman in litt.). The approximate former and present distribution limits of all these forms is shown in Fig. 8.

 

Link to Fig. 8: Approximate former and present distribution of the forest hog, Hylochoerus meinertzhageni ssp.

 

Former and Present Distribution

 

Forest hogs are unevenly distributed through the still forested areas of west-central Africa. This distribution is similar to that of the bongo (Boocercus eurycerus), and although both species have habitat preferences, they are not confined to particular forest communities. In West Africa (south Guinea, Sierra Leone, Liberia, south Ivory Coast and south Ghana), the range of the subspecies ivoriensis now roughly corresponds with the least disturbed remnants of the lowland humid forests. In other parts of Guinea, Sierra Leone and Ivory Coast, the species also occurs in montane forests (e.g. in the Mamou Mts., Foutah Djallon, and Loma Mts.), and in gallery forests (Outamba N.P., Comoe N.P.) in the Guinea savanna zone. Some of these sites are now isolated, and it is certain that forest hogs have been extirpated from many intervening sites in the primary forest and in the Guinea savanna, in some of which they still occurred until recent times (e.g. in Guinea Bissau and in south Togo; d'Huart, 1978). Their present distribution is becoming increasingly fragmented, though the full extent of this process is poorly documented.

 

Western populations of the subspecies rimator (i.e. those between the rivers Niger/Benoue and Zaire/Oubangui - see Fig. 8) still occur in five countries from the Nigeria /Cameroon border to north Gabon, north Congo and extreme south-west Central African Republic. However, though their presence in Nigeria, where only four sites are known, was reported only as recently as 1976. The species is absent from Bioko Island (T. Butynski, in litt.) and is believed to be extinct in the vicinity of the Rio Muni in Equatorial Guinea. Forest hogs have also disappeared from many areas in west Gabon and south Congo, though recent data indicate their continued occurrence in numerous protected and non-protected areas in south Cameroon and south-west Central African Republic (Table 5). Further east, this subspecies remains almost continuously distributed along the right bank of the Zaire River to the southernmost limits of the equatorial forest in central-east Zaire (now Democratic Republic of Congo) in the south, to extreme north and north-east Zaire, east Central African Republic and south-west Sudan in the north. It occurs in all types of primary, secondary and gallery forests. The northern limit of its range is the vicinity of the Massif des Bongo, south of the Manovo-Gounda-St. Floris National Park, though the progressive fragmentation of the forest galleries linking the Massif to the forests in the south is likely to isolate this population in the future. This subspecies has also disappeared from several sites in north Central African Republic and north-west Zaire. Its reported presence in three sites on the left bank of the Zaire River (Schouteden, 1947) has never been confirmed.

 

In the easternmost limits of the forest hog's range (along the west branch of the Rift in east Zaire, west Uganda and Rwanda, and in some locations along the east branch in east Uganda, west and central Kenya and north Tanzania), the giant form, H. m. meinertzhageni, now survives only in isolated montane forests, from 1,000 to 3,800 m. Some connecting corridors still exist within the complex of the Ruwenzori/Virunga N. P./Queen Elizabeth N.P. /Bwindi Forest/Virunga Volcanoes, but most of the remaining populations in this region are now isolated. A similar situation obtains in south-central and west-central Ethiopia (J. C. Hillman, in litt., Yalden et al., 1984), where the fragmented populations of south-central Ethiopia are isolated from the nearest neighboring populations of Kenya and Uganda.

 

 

Habitat, Ecology and Behavior

 

In common with the red river hog, Potamochoerus porcus, Hylochoerus is more dependent on forest than the other African suids. Throughout its range, it inhabits a wide variety of forest types, including forest galleries, lowland humid forest (even in marshy areas), secondary forests, escarpment forests, lowland and montane dry forest, montane mosaics, montane forests up to 3,800 m in the Ruwenzori Mts. and certain thickets and woodlands. Within these habitats, however, it is more likely to occur where there is a convenient and permanent water source, thick understory cover in some parts of the home range, and a variety of vegetation types. The forest hog is an ecotonic species, which seems to prefer intermediate habitat zones, where the edge effect is maximized. In the central plain of Virunga National Park in Zaire (now Democratic Republic of Congo), forest hogs inhabit forest galleries (dominated by Croton sp., Pterygota sp. and Rauwolfia sp.), dry forests (Euphorbia sp., Olea sp.) and bush thickets (Capparis sp.). These three habitats constitute a sequence in the natural succession from forest to savanna, and forest hogs move from one habitat to the other.

 

On a continental scale, the variety of forest habitats occupied implies a high degree of adaptability to local climatic conditions. Mean annual rainfall, for example, varies from 750-800 mm in the Masai-Mara National Park in Kenya to 3,200 mm in western Liberia. Over most of its range, mean monthly midday temperatures vary between 20oC and 30oC, but night temperatures often fall to 0oC in some montane habitats where the species occurs.

 

Forest hogs feed mainly on grasses, selecting a few species preferentially at different times of the year. In forest, their diet also includes many dicotyledons. Carrion and eggs are consumed occasionally, and coprophagy and geophagy are common. Details of diet and foraging behaviour are given in d'Huart (1978) and Rahm & Christiaensen (1963).

 

Forest hogs are naturally retiring, and their shy and essentially nocturnal behaviour, coupled with a relatively low density population and forest habitat, accounts for the rather poor understanding of their ecology and behaviour over most of their range. In Zaire (now Democratic Republic of Congo), forest hogs live in family sounders in rather small territories, each of which includes resting sites situated in the densest thickets, a network of tracks, a water hole (which is also used for mud-bathing), saltlicks (where soil is dug out with the tusks), and latrines. Semi-diurnalism may be acquired in areas where the animals are not hunted, but the species is nocturnal over most of its range. In Virunga National Park, the hogs are active for about 10 hours per day, of which about 60% is spent grazing in savanna. The distances covered daily are between 8 and 12 km.

 

Sounders, usually of 6-14 individuals, are led by an adult male, but normally include one or more other adult males, as well as two or more adult females and dependent juveniles or infants. Sex ratio of sounders is usually about 1 male:2 females. Larger groupings of several sounders have been reported occasionally. Fighting behaviour is less ritualized than in some other suids (e.g. warthogs) and can be violent. Combatants are often wounded, sometimes fatally. Sexual maturity is attained at 18 months in both sexes and reproduction is strongly seasonal. In the Virunga National Park, there are two distinct mating seasons in February/April and August/October; the corresponding birth seasons being in January/March and July/September, respectively. The gestation period is approximately 151 days, and 2-4 piglets are born in nests of tall grasses under piles of branches, constructed by the mother. Weaning occurs at about 9 weeks. Growth is relatively rapid and adult body size is reached by about 18 months. The juvenile mortality rate of approximately 50% is attributed to predators, crushing by the mother or weaning stress. Dispersal of young males and fighting amongst older animals are important mortality factors, as well as parasitism and, in older animals, extreme wear of teeth (d'Huart, 1973; Grzimek, 1963). The age structure observed in Virunga National Park was 67% adults, 15% subadults and 18% young. Maximum longevity is around 18 years and mean life expectancy (all age classes combined) exceeds 5 years in natural conditions. However, further studies are required to ascertain whether the behaviour, ecology and population biology of the hogs in Zaire is similar in other parts of the continent.

 

 

Population Status and Threats to Survival

 

According to the recent (1989/90) Pigs and Peccaries Specialist Group questionnaire survey, the population status of forest hogs was reported as 'giving cause for concern' in all west African countries, except Guinea and the Ivory Coast where this was thought to be 'satisfactory'. Elsewhere, its status was also reported as satisfactory except in Gabon and in Zaire (now Democratic Republic of Congo) where the extent of deforestation and hunting (i.e. poaching) pressure were causing concern.

 

As summarized in Table 5, the species is reported as having a 'restricted distribution at low density' over most of its range and that not all suitable habitats within the same biogeographical zone are occupied. The exceptions to this pattern are Guinea and the Ivory Coast, where the national population status was categorized as 'widespread at low density, but locally abundant', and the Congo, where the species is reported to be 'widespread at high density'.

 

However, there is some doubt about the accuracy of these reports, which, in the absence of any proper census data, are highly subjective. Indeed, the only population density estimates ever made were in Zaire and these ranged from 0.4 animals per sq. km in Gangala na Bodio (Cornet, 1957) to 2.6 per sq. km in Virunga National Park (d'Huart, 1978). Even these estimates may be rather unreliable, since they were extrapolated from spot samples over large areas, in only part of which forest hogs may occur. Local population densities may therefore be much greater. This may be the case in Zaire, Uganda, Central African Republic and Sudan, where the species was reported to have a 'restricted distribution at low density, but locally abundant in the most suitable parts of its habitat'. However, the species was not reported to be 'very abundant' anywhere over its extensive range, except possibly in the immediate vicinity of well protected forests and neighboring cultivated areas. Forest hogs reportedly occurred in great numbers in this situation in the Rutshuru area of Kivu National Park, east Zaire, in 1950-1952.

 

 

Table 5.   Population trends, status and occurrence in protected areas of the Forest Hog,

                 Hylochoerus meinertzhageni ssp.

                                                              

 

______________________________________________________________________________________

                                              Population Population  Legal

Subspecies         Country          Status       Trend        Status      Protected Areas

______________________________________________________________________________________

 

H. m. ivoriensis   Guinea              W-LD-LA           U                    NP            No data

 

                                    Sierra Leone    RD-LD              D                    NP            Outamba N.P.; Loma Mts. N.P.; Gola Mts. 

                                                                                                                                   N.R.(?)

 

                                    Liberia               RD-LD              D                     G             Sapo N.P.; some F.R's.

 

                                    Ivory Coast        W-LD-LA          U                     G             Tai N.P.; Comoe N.P.; Azagny N.P.(?)

                                           

                                    Ghana               RD-LD              D                      G            Bia N.P.;  Bia G.P.R., Nini-Suhien N.P.,

                                                                                                                                  Ankasa Game Prod. R.

 

 

H. m. rimator (western populations)

 

                                   Nigeria               RD-LD              U                       GJK      Gashaka-Gumti G.R.;

 

                                   Cameroun        RD-LD               D                      H           Dja W.R.; Campo W.R., Douala-Edea W.R.;

                                                                                                                                 Takamanda F.R.; Pangar Djerem W.R.

 

                                   Gabon               RD-LD               U                      H           Ipassa-Makokou N.R.

 

                                   Congo               W-HD                  I                       H           Odzala N.P.

 

 

 

H. m. rimator (eastern populations)

                                       

                               Central African    RD-LD-LA          S,D                 HJK(+)    Dzanga-Sangha N.R; Zemongo W.R.;

                               Republic                                                                                    Manovo-Gounda St. Floris N.P.;

 

                                Zaire                    RD-LD-LA           S,D                HJK         Garamba N.P.; Maiko N.P.; Virunga N.P.;

                                                                                                                                   Kahuzi-Biega N.P.Okapi N.P.; Luama G.R.;

                                                                                                                                   Rubi Tele G.R.; Azande-Gangala-Mondo

                                                                                                                                   G.R.; Epi G.R.; Maika Penge G.R.; Bili-Uere

                                                                                                                                   G.R.(?)

 

H. m. meinertzhageni

 

                                Sudan                RD-LD-LA              S                   G              Bangangai N.R.; Bire Kpatuos N.R.;

                                                                                                                                   Mbarizunga N.R.

 

                                Uganda              RD-LD-LA             D                   HJK         Rwenzori N.P.; Queen Elizabeth N.P.;

                                                                                                                                   Bwindi Forest N.P., Toro G.R.; Kigezi G.R.;

                                                                                                                                   Kibale F.R.; Mgahinga F.R.

 

                                Rwanda             RD-LD                    D                  JK            Nyungwe F.R.; Volcans N.P.(?)

 

                                Burundi             (no data)             (no data)      (no data)    Kibira N.P. (?); Rusisi Valley

 

                                Tanzania            RD-LD                    U                  GJK         Ngorongoro C.A.; Ngurdoto Crater N.P.

 

                                Kenya                 RD-LD                    U                   HJK         Aberdares N. P.; Mt. Kenya N.P.; Masai

                                                                                                                                    Mara G.R.

                                              

                                Ethiopia             RD-LD                     S                   HJK         Bale Mountains N.P.

_________________________________________________________________________________________

Key: Population status: W = widespread; RD = restricted distribution; LD = low density; HD = high density; LA = locally abundant. Population trend: U = trend unknown; S = stable; D = decreasing; I = increasing. Legal status: NP = no protection; G = total protection; H = partial protection; J = possession and/or national trade prohibited or regulated; K = international trade prohibited or regulated; (+) = stricter protection than any other taxon in same catergory. All data from Pigs and Peccaries Specialist Group African Suiform Survey (1989/90), excepting for some legal status data extracted from African Wildlife Laws (IUCN, 1986). See text for further explanation.

 

 

The principal threats to the species are habitat destruction and hunting pressure. Deforestation is undoubtedly the single most important reason for the diminution of its remaining range, especially in West Africa, where the lowland forests are being fragmented and destroyed at an alarming rate. Consequently, the species has already disappeared from most of its former range and in several countries it now occurs only in national parks and reserves.

 

Forest hogs are also widely hunted for food or in reprisal for their damage to crops. Subsistence hunting is generally not considered a particularly serious threat to their survival except possibly in lowland forests where their numbers have already been greatly reduced and the population fragmented. Nevertheless, subsistence hunting is practiced over most of their range, excepting much of East Africa and in some other areas where Islam predominates (mostly between 5º and 10º S), and the consumption of pork is taboo. Some tribal groups in the northern Congo also avoid hunting them or eating their flesh because of a local superstition, uniquely applied to this species, of calamity if they are killed. Elsewhere however, the species' social and sedentary habits make them a relatively easy target, especially for pygmies and other forest peoples who relish its meat (Carpaneto & Germi, 1989).

 

By comparison, commercial meat hunting for urban markets is a far more important cause of decline, especially in forested areas around cities. This trade represents an increasing threat to the species in north-east Zaire, Ghana, Liberia and Sierra Leone. There is no significant trade of other body parts, though hog tusks are sold as ivory in Liberia. Allocation of excessive quotas of hogs in hunting concessions in the Central African Republic also constitutes a potentially serious threat.

 

Persecution of the species for damaging crops has been reported from Guinea, Liberia, Ivory Coast and Zaire (now Democratic Republic of Congo). In the Rutshuru area of Zaire, an 18 months pest control operation in 1945-46 led to the destruction of 329 bush pigs, 77 warthogs and 619 giant forest hogs (Hubert, 1957).

 

In common with other suids, forest hogs are important vectors of rinderpest, but no specific eradication scheme to combat the spread of rinderpest has ever been organized.

 

 

Table 6:  Status of H. meinertzhageni ssp. according to the Pigs and Peccaries Specialist Group categories (Appendix One).   

______________________________________________________________________________________

 

Subspecies                              Populations                                                        Status Category 

                                                                                                                          Nationally      Overall

______________________________________________________________________________________

 

H. m. meinertzhageni               Kenya, Tanzania, Uganda, E. Zaire                                  3

                                                                                                                                                3-4

                                                Rwanda, Burundi:                                                           5

 

 

H. m. subsp?                            Ethiopia                                                            Indeterminate (poss. 4)

 

H. m. rimator                            S. W. Sudan, N. & N. E. Zaire,

(eastern populations,                  Central & N. Central African Rep.:                                   3          3-4

formerly ituriensis)

+

H. m. rimator                            S. W. Central African Republic,

(western populations)                 Congo, Gabon, S. Cameroon,

                                                                                                                                                4-5

                                                E. Nigeria, N. W. Cameroon:                                           5

 

H. m. ivoriensis                        Guinea, Sierra-Leone, Liberia,

                                                Ivory Coast, Ghana                                                         5          5

 

 

Conservation Measures Taken

 

H. meinertzhageni is accorded total protection or partial protection (i.e. hunting permitted only under license) in most countries where it occurs (see Table 5). The only exceptions are Guinea and Sierra-Leone, where the species has no legal protection, which is most unfortunate in view of the critical conservation status of the species in these two countries. Elsewhere, the existing protective legislation would probably be sufficient to ensure the survival of the species if the relevant laws were properly implemented, but this is seldom the case. According to the 1989/90 questionnaire survey, wildlife protection laws in a large majority of countries within the range of this species were either poorly enforced, or not enforced at all. In some countries legislation was reportedly implemented only in national parks (e.g. Ghana, Liberia, Zaire) or in hunting concessions (e.g. Central African Republic, Gabon), though even this was questioned by other informants.

 

Although the forest hog is relatively well represented in the network of parks and reserves over its range (as listed in Table 5), it is doubtful if these areas are sufficient to ensure the protection of the species in several countries over the longer term. In West Africa, in particular, H. m. ivoriensis is already under heavy pressure from deforestation, and is now thought to be securely established in only three sites, i.e. Sapo N. P. in Liberia, Tai N. P. in the Ivory Coast and Bia N. P. in Ghana. In central-west Africa, the few large forest parks and reserves are unlikely to ensure the long-term protection of the western populations of H. m. rimator from the continued high levels of deforestation and hunting pressure, and additional protected areas for these populations are required as a matter of some urgency. The situation is less bleak for this race in central-east Africa, owing to the existence of several large parks and reserves in Zaire (now Democratic Republic of Congo), though the continuing pressure on these areas requires careful monitoring. Despite its much smaller range in East Africa, H. m. meinertzhageni is thought to be adequately safeguarded in its remaining montane forest habitats provided the existing reserves continue to be actively protected. In Ethiopia, forest hogs are reported in only one national park and in several non-protected forest areas and hunting concessions, but their overall status and management needs in this country need to be properly assessed.

 

On an international level, Hylochoerus is included on Class B of the African Convention on the Conservation of Nature and Natural Resources, which regulates or prohibits hunting, killing, capturing or trade of listed species. However, international trade in this species is negligible and it is not listed on the Appendices of CITES.

 

 

Captive Breeding

 

Relatively few animals have been kept in captivity, and no captive births have been reported. The maximum recorded longevities (a female in the Leopoldville Zoo, from 19.4.55 to 31.5.57, and a female in the Frankfurt Zoo, from 14.5.54 to 5.4.57) are less than 4 years. The species has been exhibited in only four other European collections (i.e. London Zoo: four males and two females from 1936 to 1938; Hamburg Zoo: three males and two females from 1938 to 1941; Antwerp Zoo: one male and two females in 1955; and Amsterdam Zoo: a female in 1954), in two collections in the U.S.A. (single females in the National Zoo, Washington, and in the Bronx Zoo, New York, in 1939) and in a few African zoos (e.g. Nairobi, Abidjan and Monrovia), though none of these animals survived for more than a few months. Grzimek (1963) and Mohr (1960) suggest that these failures might reflect a lack of knowledge of the species dietary requirements and other basic ecological needs. As far as is known, there are no forest hogs in captivity at the present time.

 

 

Conservation Measures Proposed:

An Action Plan

 

Given the varying status of this species in different countries within its range, it is hardly practicable to identify a single set of recommendations. The following priority objectives and recommendations are therefore directed at only the most threatened forms and/or topics of foremost research interest.

 

Objectives:

 

1. To promote the survival of the most threatened subspecies and those populations whose taxonomic status is uncertain.

 

2. To propose legislative revisions that could improve the protection and management of particular, threatened populations.

 

3. To identify topics of research interest which will provide a better understanding of aspects of the species' biology and future management requirements.

 

 

Priority Projects:

 

1. Assess the taxonomic and conservation status of the forest hog population in Ethiopia and carry out field surveys in selected areas.

 

The population in Ethiopia currently attributed to H. m. meinertzhageni, but which may represent an as yet undescribed taxon. Field surveys are also required as a matter of some urgency to: a) ascertain the distribution and status of the populations in south-central Ethiopia (possibly extending into the Sudan-Ethiopia border area around the 4th parallel N.); and b) develop of practical management initiatives to enhance protection of some or all of those populations, with particular emphasis on the regulation of hunting and the creation of additional reserves.

 

2. Assess management options for enhanced future protection and/or restoration (including possible restocking with translocated hogs) of the H. m. meinertzhageni populations in the newly created Nyungwe (Rwanda)/Kibira (Burundi) complex and in Mgahinga Forest Reserve (Uganda) where the local hog population has been depleted by over-hunting.

 

3. Re-evaluate the systematic relationships of the western and eastern populations of the subspecies rimator, which were formerly treated as two separate subspecies in the interface (or intergrade?) zone of the Zaire and Oubangui Rivers.

 

These two populations were formerly treated as two separate subspecies (i.e. rimator and ituriensis, respectively). The present separation of meinertzhageni and the easternmost populations of rimator (formerly ituriensis) along the western Rift, should also be reassessed in order to the identify possible local intergradation between these taxa.

 

4. Assess forest hog status in the north-western corner of Zaire (Bosobolo, Gemena, Businga areas) and gazette the projected Mondjo N.P. as the westernmost protected area for the eastern form of rimator (formerly ituriensis).

 

5. Promote conservation measures for forest hogs in the Central African Republic.

 

This will require: a) revising hunting quotas for this species; b) enforcing protective legislation; c) developing incentives to halt fragmentation of forest galleries along tributaries of the Oubangui river; and d) develop special conservation measures for the Massif des Bongo.

 

6. Assess status and management needs and promote conservation of the most threatened western populations of H. m. rimator.

 

Actions required include: a) surveys of their distribution and abundance in the northern Congo, especially between the Sangha and Oubangui Rivers; b) evaluation of the need for additional protected areas in north Congo, north Gabon and south-west Cameroon; c) creation of additional forest reserves in south Cameroon, as recommended by IUCN for EEC funding (Gartlan, 1988); d) securing the small populations inhabiting remnant forest sites along the Nigeria/Cameroon border, especially in the Obudo Ranch and Takamanda Forest Reserve area, where a trans-boundary conservation scheme should be initiated; and e) evaluating the level of implementation of both traditional and sport hunting legislation in Gabon and its effect on Hylochoerus populations.

 

7. Promote early implementation of measures designed to protect remnant populations of the smallest and most threatened subspecies, H. m. ivoriensis.

 

This should be done with particular reference to: a) improving protection measures for the now isolated populations in the Guinea Savanna zone of Guinea, Sierra Leone and Ivory Coast; b) promoting creation of large, new protected areas in lowland forest of Liberia, Ivory Coast and Ghana, where forest hogs still occur in relatively large numbers; c) revising forest land tenure and concession allocation systems and the implementing traditional hunting legislation in all range states, with a view to better conservation of forest mammals in general; d) investigating the bushmeat market and other related activities to ensure that utilisation of forest game is sustainable and to develop alternative sources of income for rural people; and e) initiating captive breeding and research programmes for this subspecies in the zoo community.

 

 

Acknowledgements

 

Grateful thanks are extended to Dr. J. Verschuren, Prof. P. Lebrun and Prof. J. J. Symoens whose enthusiastic support enabled the first field research on the forest hogs in Virunga National Park, Zaire, which was conducted by the author in 1972-75. I am also indebted to the following correspondents who completed the 1989/90 African Suiform Survey report forms, supplied reprints, unpublished data or other assistance: M. Alers, F. O. Amubode, D. Babu, A. Blom, T. Butynski, G. R. Cunningham-van Someron, G. Davies, R. Dowsett, J. M. Fay, J.-M.Froment, S. Gartlan, M. E. J. Gore, A. A. Green, J. A. Hart, P. Hecketsweiler, J. C. Hillman, K. Hillman-Smith, L. Macky, H. Mertens, N. Montfort, I. Nganga, M. Nicoll, B. Y. Ofori-Frimpong, A. Peal, R. Prickett, H. Roth, V. J. Selmeir, C. A. Spinage, M. Storz, G. Teleki, P. C. Trenchard, S. Werihkeand D. Yalden. Several Members of the Pigs and Peccaries Specialist Group also provided useful comments and suggested improvements to earlier drafts of this text, including W. Oliver, P. Grubb, D. Mason. P. Vercammen kindly provided much valuable information on captive forest hogs, and he and Peter Cuypers prepared the distribution map.

 

 

References

 

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