The forest buffalo Syncerus caffer nanus is one of the largest ungulates in West African forests but numbers have declined as a result of poaching and deforestation, and the conservation status of the subspecies is poorly known (Blake, Reference Blake2002; Melletti et al., Reference Melletti, Penteriani and Boitani2007a,Reference Melletti, Penteriani, Mirabile and Boitanib, Reference Melletti, Mirabile, Penteriani and Boitani2009a,Reference Melletti, Penteriani, Mirabile and Boitanib; Korte, Reference Korte2008a,Reference Korteb). In Nigeria there is little information on the distribution, abundance and status of the species (Cornélis et al., Reference Cornélis, Melletti, Korte, Ryan, Mirabile, Prin, Prins, Melletti and Burton2014).
Here, we present ecological and distribution data on the forest buffalo in south-eastern Nigeria (where remnant patches of rainforest are concentrated) based on field surveys and interviews with local hunters. Our aims were (1) to determine the presence and status of buffalo in the various forest blocks of Cross River State, and (2) to describe the habitat requirements of these populations. Cross River State is the only area in Nigeria where the forest buffalo occurs (E.A. Eniang et al., unpubl. data).
Field surveys were conducted in the Oban and Boshi Okwangwo Divisions of the Cross River National Park (c. 1,000 km2; Fig. 1a), in the neighbouring Obudu Cattle Ranch, in the Mbe Mountains, and in the Afi River Forest Reserve. This area, at an elevation of 150–1,700 m, lies north and east of the Cross River and extends along the border with Cameroon. Below 500 m the vegetation is mostly Guineo–Congolian high forest, with a closed canopy and emergent trees of up to 40–45 m height. Above 500 m there is Plateau forest, with abundant epiphytes and lianas. The study area includes four forest reserves, with mountainous and relatively inaccessible terrain: Afi River Forest Reserve, and three reserves in the Boshi Okwangwo Division of the Cross River National Park. Local people practise traditional agriculture, including burning activities, around the reserves.
Fig. 1 (a) Location of the sites surveyed for forest buffalo Syncerus caffer nanus in Cross River State in south-eastern Nigeria. (b) Trails in Boshi Okwangwo Division where transect surveys were carried out, and locations where forest buffalo were sighted during recce transects (grey circles), line transects (black circles) or both (grey/black circles).
Following interviews with local hunters we selected four areas on the basis of the reported frequency of buffalo occurrence: the Oban Division of the National Park, Mbe Mountains, the Boshi Okwangwo Division and Obudu Cattle Ranch (Fig. 1a). We surveyed these areas during November–December 2001, June–August 2005, June–August 2009 and September–October 2013. We spent 10 consecutive days in each survey area in each year, assisted by experienced hunters. By conducting recce transects in all areas we were able to identify predetermined or existing trails or river courses to survey by line transects. Recce transects were conducted opportunistically, depending on the landscape characteristics; when possible, line transects were conducted on the same day as the recce transects. On each day of surveying we conducted one randomly chosen diurnal (07.00–12.00) and one randomly chosen nocturnal (19.30–23.30) line transect survey (each 5 km in length). At night we used existing trails and carried out spot checks at salt licks, open fields and swamps, and river crossing points. We used hunters’ carbide head lamps and rechargeable flood lamps. The line transect surveys were conducted at different locations each day. The total effort was 160 field days, divided equally between wet and dry seasons and study areas. We also surveyed the bushmeat markets throughout the study areas and interviewed poachers and sellers of buffalo carcasses, recording the locations where buffalo were caught (Plate 1).
Plate 1 A forest buffalo Syncerus caffer nanus traded in a local market in Cross River State, Nigeria (Fig. 1); 16 November 2002.
Locations where buffalo were observed (Fig. 1b; Table 1) were recorded using a global positioning system. Presence data included all indicators of buffalo presence (direct observations, hoof prints, faeces, vocalizations, and carcasses and trophies kept by hunters and poachers) but we report only direct observations here because we recorded these at all locations where we found other signs. We attempted to confine the surveys to the same time interval each day to ensure data collection was consistent and unbiased but on some days circumstances required that we started earlier or later; for example, if we heard vocalizations at our night camps we attempted to follow the direction of sound before dawn, hoping to sight the group.
Table 1 Numbers of forest buffalo Syncerus caffer nanus sighted in four areas of the Cross River National Park and adjacent areas in Nigeria (Fig. 1) during both recce and line transect surveys, by study site and period, with habitat type indicated for each.
Our records of numbers of buffalo are estimates because it was difficult to count individuals as they ran through the forest. To minimize the risk of double-counting individuals we noted the location and the approximate group size; if the number of individuals differed from an earlier encounter we considered it was probably a different group. These data were validated by comparing age and sex distributions across groups.
We recorded vegetation data at each location where buffalo were observed, including dominant tree species and the type of undergrowth. Each buffalo sighting was assigned to one of the following habitat type categories: mature forest, secondary forest, savannah or agricultural land.
There were some limitations that may have affected our data. In conducting systematic surveys with the help of local guides at Obudu Cattle Ranch we were unable explore some steep escarpments where buffalo were heard. In the core areas of buffalo presence, as reported by local people, in Oyi-Mache and Boshi Okwangwo there were no trails and, given time and financial limitations, our surveys were confined to streams and river courses and existing paths.
We used Spearman's rank correlation coefficient to investigate correlation between survey period and number of buffalo observed, and a general linear model with a Poisson error structure to analyse the effects of survey area and period on the number of individuals observed. The number of individuals observed varied significantly across the four survey periods (Spearman's r = –0.80, P = 0.083). The general linear model indicated a statistically significant effect of survey area and habitat, but not of survey period or the survey area × survey period interaction, on the number of buffalo observed (Table 2). A greater number of individuals were observed at Oyi-Mache and a lower number at Obudu Cattle Ranch, relative to the other two sites, independent of survey period. Most records were from mature forest (65.6%), followed by secondary forest (25.9%); there were few records from savannah (6.1%) and agricultural land (2.3%).
Table 2 Results of general linear modelling of the effects of habitat type, survey area and survey period on the number of forest buffalo observed at four study sites (Table 1, Fig. 1).
The presence of buffalo was generally well known to hunters and local people in the study area. Farmers and hunters consistently reported that the seasonal movements of buffalo are in part determined by the collection of non-timber forest products (e.g. Irvingia, Prunus, Raphia) by local people, especially during June–October, which drives the buffalo to seek refuge in the nearby Takamanda National Park in Cameroon. We observed buffalo only rarely in savannah, although they have been reported from forest clearings and savannah elsewhere (Melletti et al., Reference Melletti, Mirabile, Penteriani and Boitani2009a); this may be attributable to anthropogenic disturbance and possibly overhunting.
The apparent frequency of occurrence of buffalo varied across forest zones but there was no decreasing trend over time. In three of the four surveyed areas direct sightings were not rare, and therefore the forest buffalo may be a potential flagship species for ecotourism development programmes, particularly in the Obudu Cattle Ranch escarpment area.
Buffalo are only occasionally targeted by hunters in the study area. This is because of the difficult terrain and the traditional system of having to share the meat with a large number of community members. Tradition demands that the hunter must send several parts of any animal hunted to family elders, regardless of how far away they reside. Hunters therefore target small to medium sized mammals (e.g. monkeys, cane rats, antelopes) to minimize the expense of delivering parts of the hunted animals to relatives living in distant places. However, forest buffalo are threatened by conflict with cattle herdsmen. Fulani herdsmen reported that since early 2001 fights have occurred between buffalo and cattle, and that they responded to the conflict by setting wire snares along trails and shooting buffalo. The effects of such conflicts require further investigation.
Although Syncerus caffer is categorized as Least Concern on the IUCN Red List (IUCN SSC Antelope Specialist Group, 2008), the Nigerian populations appear to be threatened. Given their scattered distribution, fragmented habitat and relatively low numbers, we suggest that the Nigerian populations require a separate, regional categorization on the Red List. We propose a categorization of Vulnerable according to criteria D1 & D2 (IUCN, 2014), based on records of < 1,000 mature individuals (D1) and presence at < 5 locations (n = 4 according to our studies).
Acknowledgements
We are grateful to the authorities of Cross River National Park for granting us the permits to conduct the study, allowing rangers and other staff to participate in the project, and providing logistical support. We thank the chiefs, hunters and youths of Anape, Balegete, Okwa 1 and 2, Okwangwo, Bamba, Obonyi 1, 2 and 3, Butatung, Bumaji and Kayang 1 and 2 for their participation; Clement Akpan, Edet Usuyak, Celestin Nkra and other local guides for their help in the field; and Dr Mario Melletti for a constructive review.
Biographical sketches
Edem Eniang works on the ecology and conservation of reptiles and mammals in southern Nigeria. Clement Ebin works on ecotourism and protected areas in Cross River State, Nigeria. Ayuk Nchor, Gabriel Agba and Idorenyin Gideon work on the conservation ecology of the forests of Cross River State. Giovanni Amori works on the ecology, systematics and conservation of mammals. Luca Luiselli works on the ecology and conservation biology of reptiles and mammals in West Africa, with a particular focus on Nigeria.
