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Seminar on the conservation and restoration of Sahelo-Saharan antelopes,Djerba, Tunisia February 1998.  
Report on the status and perspectives of a species. UNEP, Convention on migratory species.

Report on the status and perspectives of a species :

    Oryx dammah
    Cover drawing: J. Smit, in Sclater and Thomas, 1898. Reproduction: 
    M.O. Beudels.

    Report prepared by Pierre Devillers and Jean Devillers-Terschuren.
    Institut Royal des Sciences Naturelles de Belgique

This report is based on documents prepared for the Convention on Migratory Species by Pierre Pfeffer (1993b, 1995) and on supporting documents for the action plan on Sahelo-Saharan antelopes adopted by the 4^th Conference of the Parties of the Convention, documents that were prepared by Roseline C. Beudels, Martine Bigan, Pierre Devillers and Pierre Pfeffer (1994). The information it contains originates mainly from the general accounts and regional action plans edited by Rod East (1988, 1990), and the fundamental work of Hubert Gillet (1965, 1969) and John E. Newby (1974, 1988, in particular). It is completed by a new review of the literature and a survey of actors in the field conducted in 1996 and 1997 by Tommy Smith (1998) with the support of Koen de Smet. Roseline C. Beudels, René-Marie Lafontaine, Marie-Odile Beudels, Tommy Smith, Yves Laurent and Chris Kerwijn have contributed to the preparation and finalizing of this report.

1. Taxonomy and nomenclature

1.1. Taxonomy.

Oryx dammah belongs to the Hippotragini tribe, of the Hippotraginae subfamily within the Bovidae family, which comprises one extinct species and seven surviving species together with two evolutionally distinct subspecies in the genera Oryx, Addax and Hippotragus (Simpson, 1945; Corbet, 1978; Murray, 1984; Corbet and Hill, 1986; Wacher, 1988). All the hippotraginids are adapted to the exploitation, at low density, of difficult, low productivity habitats (Kingdon, 1982; Murray, 1984; Wacher, 1988; Beudels, 1993). The genus Oryx comprises five evolutionary isolates, of which one, Oryx leucoryx, is adapted to deserts, three, Oryx dammah, Oryx gazella beisa, Oryx gazella gazella, to subdesert or semidesert habitats, the last, Oryx gazella callotis, to somewhat more productive savannas (Wacher, 1988).

1.2. Nomenclature.

1.2.1. Scientific name.

Oryx dammah (Cretzschmar, 1826)

1.2.2. Synonyms.

1.2.3. Common names.

French: Oryx algazelle, Algazel (Buffon, 1764), Algazelle (Cuvier, 1819), Antilope oryx, Oryx blanc.
English: Scimitar-horned Oryx, Scimitar Oryx.
Arab: Wach, Begar al Ouach.

2.1. Distribution.

2.1.1. Historical distribution.

The historical distribution of permanent or temporary presence and of movements of the Scimitar-horned Oryx includes all of Saharan and sub-Saharan North Africa between the Atlantic and the Nile. However, this range was never uniformly occupied, the distribution and the extent of ranges of individuals have always been conditioned by the location of subdesert zones to which the Oryx is adapted. On a surface compatible with its possibilities of making seasonal migrations,the Scimitar-horned Oryx seems to need an adequate time sequence of therophyte pasturage, of perennial graminid formations and dry woodland, in particular, of acacias (Brouin, 1950; Malbrant, 1952; Gillet, 1965, 1969, 1970; Newby, 1974, 1988; Dragesco-Joffé, 1993). This combination of habitats is especially characteristic of regions where the annual precipitation is between 75 and 400 mm (Newby, 1988; Thomas and Newby, 1990). In the arid conditions that have prevailed in the Sahara over the last three millenia (Le Houérou, 1986; Newby, 1988), these requirements essentially limit the potential distribution of the species to the northern and southern subdesert fringes, that is, to the Sahel and to the transition region between the Mediterranean zone and the Sahara (Rattray, 1960; White, 1983; Le Houérou, 1986; Ayyad and Ghabbour, 1986; Monod, 1986; Newby, 1988; Ozenda, 1991). The ecological conditions favourable to the species can also develop in the Atlantic Sahara and the surrounding areas, but on more restricted surfaces, or in an unstable way (Rattray, 1960; White, 1983; Ozenda, 1991), on the periphery of central Saharan mountain massifs (Rattray, 1960; White, 1983; Le Houérou, 1986; Ozenda, 1991), and in particular locations where there is access to the water table (Le Houérou, 1986), in particulier, around large aeolian depressions in the Libyan Desert (Osborn and Helmy, 1980; Ayyad and Ghabbour, 1986; Zahran and Willis, 1992).

The main, Sahelian, range of distribution of Oryx dammah coincides with the Sahel semi-desert grassland of White (1983), forming his unit 54a in region XVI. This well-characterized band is also the Sub-Saharan Aristida steppe zone of Rattray (1960), comprising his units A11, A13, A15, the subdesert steppes of Newby (1974), the Saharan savannas of Schulz (1988) and of Ozenda (1991). They extend across the center-south of Mauritania between 18° (locally 20°) and 16° latitude north, the center of Mali between 18° and 15°, of Niger between 17° and 15°, of Chad between 17° and 14°, and of Sudan between 17° and 12° 30' (Malbrant and Maclatchy, 1949; Brouin, 1950; Audas, 1951; Dekeyser, 1955; Gillet, 1965, 1969, 1970; Kock, 1970; Newby, 1974, 1975, 1988; Lamprey, 1975; Schnell, 1976; Wilson, 1978, 1980; Monod, 1986; Ayyad and Ghabbour, 1986; Hillman and Fryxell, 1988; Sournia and Verschuren, 1990; Heringa, 1990; Grettenberger and Newby, 1990; Thomassey and Newby, 1990; Millington et al., 1991; Dragesco-Joffé, 1993; Hashim, 1996). The range of the Oryx also included more southern latitudes, advancing into the band of Sahelian deciduous bushland (White, 1983, region XVI, unit 43), in particular, in Senegal (Sournia and Dupuy, 1990), in Burkina Faso (Heringa et al., 1990), in Mauritania (Trotignon, 1975), in Chad (Gillet, 1965; Newby, 1974), in the Sudan (Audas, 1951; Kock, 1970; Wilson, 1980), and even into the Sudanian dry woodlands (White, 1983, region III, unit 29a), notably in Chad, where the 11^th parallel was reached during the exceptionally dry years (Gillet, 1965) and probably in the Sudan (Audas, 1951). The species also advanced northward, along the Nile Valley in the Sudan, to 20° N (Kock, 1970).

A subdesert fringe somewhat equivalent to the Sahel occurs north of the Sahara in the transition zone between the Mediterranean region and the desert. It is formed of the sub-Mediterranean steppe band with Stipa tenasissima and Lygeum spartum (Rattray, 1960, units ST1, ST2, ST3; White,1983, region XVIII, unit 55), including woodlands of Argania spinosa (unit 49) or of Acacia gummifera (unit 79), completed by a part of Rattray's (1960) northern Aristida pre-steppe band, forming his unit A16. This Mediterraneo-Saharan fringe is developed over some width and with some continuity only from the Atlantic, where it descends to 27° latitude north, to Tunisia (Rattray, 1960; White, 1983). It exists in a fragmentary way in extreme northwestern and extreme northeastern Libya. The presence of the Oryx in this Mediterraneo-Saharan zone is documented during Roman times, at least in Algeria (Heim de Balsac, 1931; Kowalski and Rzebik-Kowalska, 1991) and in Tunisia (Sclater and Thomas, 1899). Climatic conditions then were similar to those that prevail today, but the habitats were very different, with an important representation of thermo-Mediterranean and sub-Saharan dry forests, often dominated by Aleppo Pines (Pinus halepensis) or Arbor-vitae (Tetraclinis articulata), and of Mediterraneo-Saharan steppes and wooded steppes (Le Houérou, 1986; Damblon and Vanden Bergen, 1993). The Oryx was then associated with several species that are now distinctly Sahelo-Sudanian, in particular, Alcelaphus buselaphus and Loxodonta africana. There is no indication of the presence of stable populations of the species in the Mediterraneo-Saharan zone posterior to Antiquity nor of any indication as to choice of habitat in this zone. The last record for Tunisia is from the 20^th century (Lavauden, 1920) but with an imprecise locality and could pertain to erratic animals wandering from southern regions, which could also be the case of two Libyo-Egyptian records, one hypothetical (Hufnagl, 1972), the other confirmed (Osborn and Helmy, 1980). In Algeria the only post-Antiquity records date from the 16^th century and are hypothetical (Kowalski and Rzebik-Kowalska, 1991). In Morocco, no historical records exist except in the Atlantic region, from the oued Noun, in the south (Joleaud, 1918), including the Drâa basin (Loggers et al., 1992). This region was, however, probably supplied from Sahelian populations, across the Atlantic Sahara.

Several central Saharan or south Saharan massifs (Heim de Balsac and Mayaud, 1962; Simon, 1965; Ozenda, 1991) offer steep gradients of humidity and vegetation with precipitation attaining 1100 mm in the higher altitudes (Rattray, 1960). They include notably sub-desert steppes with Aristida, sensu Rattray (1960), corresponding to his unit A14, and various ligneous formations (Schnell, 1977; Ozenda, 1991), in particular, in the valleys. Thus, locally, they reproduce conditions somewhat similar to those of the Mediterranean and Sahelian sub-desert fringes. The southernmost constitute protruding peninsulas of the Sahel (Monod, 1986), rather than islands, or are enclaved in the Sahel. They are the Adrar des Iforas in Mali, the Aïr in Niger, the Ennedi in Chad, the Darfur in the Sudan. All have been part of the Sahelian range of the Scimitar-horned Oryx. The other massifs are insular (Heim de Balsac and Mayaud, 1962; Ozenda, 1991). They include the vast complex formed by the Hoggar and the Tassili des Ajjers in Algeria, the Tibesti in Chad and in Libya, the Djebel Uweinat within the confines of Libya, Sudan and Egypt. In these regions there is no indication of a stable presence of the Oryx in historical times (Regnier, 1960; Gillet, 1969; Osborn and Krombein, 1969; Hufnagl, 1972; Misonne, 1977; de Smet, 1989; Kowalski and Rzebik-Kowalska, 1991). Dalloni's (1936) mention for the Tibesti is apparently not based on any record except rock carvings, and Wilson's (1980) record is erroneous since he cites Blancou (1958) who reported on Chad and never on the Tibesti.

The Atlantic Sahara is a cold-current coastal desert. It is an attenuated desert (Monod, 1958; Ozenda, 1991) in which atmospheric humidity and low evaporation compensate the reduced precipitation (Valverde, 1957). These conditions allow the Sahelian flora and fauna to penetrate far north (Valverde, 1957). This coastal desert comprises a narrow coastal band, from 30 to 60 km wide, forming the oceanic Sahara or Atlantic coastal desert (Valverde, 1957; Quézel, 1965; Schnell, 1977; White, 1983, unit 68a; Ozenda, 1991), and a sublittoral zone, extending to 200 or 300 km from the coast, with an abundance of steppes and acacia stands (Valverde, 1957; Rattray, 1960; Quézel, 1965; Schnell, 1977; Ozenda, 1991). This zone is located almost entirely within the former Spanish Sahara and northwestern Mauritania. It is in contact with the Mediterraneo-Saharan zone in the north, the transition being at about 27° N according to White (1983), farther north according to Edmondson et al. (1988). In the south, it is in contact with the Sahel, losing its oceanic character around 18° N (White, 1983). The acacia woods and associated steppes of the oceanic subzone, limited in northern areas to favourable sites, notably at the foot of escarpements (Valverde, 1957; Lafontaine, 1995), becoming more and more numerous and extended, while taking on a more and more Sahelian character, in the south (Valverde, 1957; Schnell, 1977; Ozenda, 1991). Numerous observations of the Scimitar-horned Oryx have been made in the Atlantic Sahara, particularly in the southern part, until the middle of this century (Morales Agacino, 1950; Valverde, 1957; Loggers et al., 1992). This range of distribution was in continuity with the Sahelian range and Müller (1996) suggests that it is during periods of drought in the Sahel that the species occupied the Atlantic Sahara as well as the southern Atlantic part of the Mediterraneo-Saharan zone. This hypothesis of irregular presence is coherent with the records given by Morales Agacino (1950). Valverde (1957) suggests, however, a permanent presence in the pre-Sahelian Atlantic Sahara.

A discontinuous distribution of the Scimitar-horned Oryx persisted until the middle of the 19^th century in the Libyan Desert of middle Egypt, in regions of extremely low precipitation, of less than 50, or even 25, mm (Kock, 1970; Osborn and Helmy, 1980). The range was evidently linked to the great oases formed in the vast aeolian depressions reaching to the water table, characteristic of this desert (Osborn and Helmy, 1980; Ayyud and Ghabbour, 1986; Le Houérou, 1986; Goodman et al., 1986; Zahran and Willis, 1992). These depressions and the adjacent areas supported woods of acacias (Acacia raddiana, A. ehrenbergiana) and palms (Hypophaene thebaica) and dense grassy steppes, in a combination of habitats with a Sahelian physiognomy (Osborn and Helmy, 1980). Moreover, the distribution of the Scimitar-horned Oryx coincided with that of Alcelaphus buselaphus, a distinctly more mesophile species. Essentially limited to Egypt, these oases extend just over the Libyan border at Jaghbub (Bundy, 1976; Goodman et al., 1986). The oases where a historical presence of the Oryx is documented (Kock, 1970; Osborn and Helmy, 1980) includes Siwa in the northwest, Wadi Natroun, Faiyum and Wadi el Ruwayan near the lower Nile, Dakhla and the Kharga complex between 24° and 26° N.

It is possible that other areas of presence have existed within historical times, and perhaps as late as the 19^th century or the beginning of the 20^th century, in Saharan regions where suitable, though probably fragile and unstable, vegetation complexes would have occurred in conjunction with wadi systems or the piedmont of hill ranges. The occupation of such areas by stable populations could explain frequent occurrences in regions far removed from presently known centers of distribution, such as the recurrent captures in southern Tunisia at the end of the 19^th century and at the beginning of the 20^th century (Lavauden, 1920; Kacem et al., 1994). Precise data do not, however, seem to be available to document such a possibility.

2.1.2. Decline of the range.

The distribution of the Scimitar-horned Oryx has regressed continuously since Antiquity. The northern sub-Saharan range ceased supporting permanent populations at an unknown date, but almost certainly before the 19^th century and in any case by the second decade of the 20^th century. (Lavauden, 1920; Kowalski and Rzebik-Kowalska, 1991; Loggers et al., 1992). The generalized destruction of the habitat goes back to Roman times (Le Houérou, 1986), in a regressive sequence, spontaneously irreversible, that leads to the the disappearance of the Mediterranean dry forests, then of their substitution steppes (Le Houérou, 1986). During the same periods, the large-scale taking of all the great North African fauna was practiced. (Newby, 1988). The oases of the Libyan Desert were abandoned at the beginning of the second half of the 19^th century (Osborn and Helmy, 1980), the Atlantic region in the middle of the 20^th century (Newby, 1988). The Sahelian range was still almost continuous in the 1960's (Gillet, 1969), fragmented into several important nuclei in the 1970's (Newby, 1988), apparently reduced to two fragments, in Niger and in Chad, in the beginning of the 1980's, and, finally, to one in Chad (Newby, 1988). Table 1, taken from Newby (1988), summarizes the probable dates of disappearance of the species in each country within the historic range of distribution. Figure 1 summarizes schematically the evolution of this range.

Table 1. Dates of probable extinction of the Scimitar-horned Oryx in the countries within its range, after Newby (1988).

(a) Le Houérou, 1992; (b) de Smet and Mallon, 1997; (c) Osborn and Helmy 1980; (d) Millington et al., 1991; (e) Heringa et al., 1988.

Figure 1. Historical distribution of the Scimitar-horned Oryx Oryx dammah.

1. Sahelian nuclei surviving at the beginning of the 1980's (Newby, 1988).
2. Sahelian distribution in the 1960's (Gillet, 1969).
3. Main Sahelian range (Sahelian vegetation 54a of White, 1983)
4. Atlantic range occupied until the 20^th c. (Trotignon, 1975; Loggers et al., 1992)
5. Libyan Desert range in Egypt occupied until the 19^th c. (Osborn and Helmy, 1980)
6. Probable southern Mediterraneo-Saharan range, Antiquity (zones 55, 49, 79 of White, 1983)
7. Central Saharan massifs, no historical data.

2.1.3. Residual distribution.

The only population of Scimitar-horned Oryx for which survival is probable is that of the Sahelian regions of Chad south of the Ennedi, in the Ouadi Rimé-Ouadi Achim region (Newby, 1988; Thomassey and Newby, 1990; Moksia and Reouyo, 1996), where the species has not, however, been seen since the 1980's, in spite of searches carried out since 1991 (Pfeffer, 1993a, 1993b, 1995; Beudels et al., 1994; Tubiana, 1996a, 1996b). Other regions where a possible survival could be confirmed include the border region between Mali and Burkina Faso (Duvall et al., 1997), the Adrar des Iforas in Mali (Kowalski and Rzebik-Kowalska, 1991), the Aïr-Ténéré-Termit in Niger (Grettenberger and Newby, 1990), the Wadi Howar region in the northern Darfur in Sudan (Hashim, 1996).

2.1.4. Recolonisation prospects.

The zone of potential distribution of the Scimitar-horned Oryx is the subdesert. It lies between two boundaries, of which one is the limit of the more desert-like regions of the Sahara, the other is that of the more mesic regions of the Sahelo-Sudanien or Mediterranean zones. Towards the desert, the limit is clearly climatic, corresponding to the degree of aridity beyond which adequate grazing land is unable to develop or to maintain itself. Towards the Sudanian and Mediterranean regions, on the contrary, the limit is probably a matter of interaction with other species. Competition with more mesophilous wild ungulates and predation probably play a role, and Brouin (1950) evokes the abundance of parasites as a limiting factor in the south during the rainy season. It is certain, however, that nowadays it is competition with domestic herds and human predation that are the determining factors. The pockets of survival of the species are located in zones of compromise between a too extreme aridity and a too strong human pressure. It is the least unfavourable combination of these two factors that must be sought for the reintroduction or recolonization zones. Moreover, the more these are located in climatically marginal zones the more they require seasonal displacements and thus vital space (Newby and Sayer, 1976).

The human occupation in the Sahel increased considerably in the middle of the 20^th century under the coupled effects of a relative peace, above average precipitation, and the boring of deep wells (Newby, 1988). Overgrazing has become generalized, agriculture has progressed and hunting has become motorized and has become universal (Gillet, 1969, 1970; Newby, 1974, 1988; Wilson, 1978; Ayyad and Ghabbour, 1986). Recent Sahelian zones of presence of Oryx dammah correspond generally to the proximity of mountain or hill massifs that enlarge the bands of favourable habitats, augment their diversity and delimit the regions of reduced accessibility. They obviously constitute the first possibilities to consider for habitat protection or reintroduction efforts. They are, by order of importance, the Ouadi Rimé-Ouadi Achim zone south of the Ennedi in Chad (Gillet, 1965, 1969; Newby, 1974, 1988; Thomassey and Newby, 1990; Dragesco-Joffé, 1993; Pfeffer, 1993a, 1995), the Termit in Niger (Lhote, 1946; Jones, 1973; Newby and Jones, 1979; Newby and Grettenberger, 1986; Newby, 1988; Grettenberger and Newby, 1990; Millington et al., 1991; Bousquet, 1992; Dragesco-Joffé, 1993; Poilcot, 1996a, 1996b), the Wadi Howar zone and the north of the Darfur in Sudan (Lamprey, 1975; Wilson, 1978, 1980; Hashim, 1996), with the neighbouring Chadian massifs, the Adrar des Iforas in Mali (Lhote, 1946; Sayer, 1977; Sidiyène and Tranier, 1990) and its periphery, to the south of Algeria (deSmet, 1989; Kowalski and Rzebik-Kowalska, 1991), the southeast of Mauritania (Trotignon, 1979; Vincke et al., 1987).

A second approch could rely on the more southerly zones of the range, probably the most favourable to a restoration on a small surface, as long as human pressures can be controlled in regions of high human occupation. Several relatively detailed analyses of the ecology of the species, carried out during periods when it was still well represented (Lhote, 1946; Brouin, 1950; Audas, 1951), insist on the favourable character of the southern part of its Sahelian range and suggest that the restriction of the Scimitar-horned Oryx to the northern fringes is a result of the human pressure and was not ecologically happy. The Ferlo in Senegal (Bille et al., 1972; Bille and Poupon, 1972; Sournia and Dupuy, 1990; Diop et al., 1996; Clark, 1996), the region of Gourma (Réserve des Eléphants) in Mali (Pavy, 1996), the Ansongo-Menaka reserve at the Mali-Niger border (Heringa, 1990), Sahelian Burkina Faso (Heringa et al., 1990) and Gadabedji reserve in Niger (Dixon and Newby, 1989; Grettenberger and Newby, 1990) appear, in this optic, as interesting deployment possibilities. Protection of the Oryx was, moreover, originally, the principle objective the Gadabedji reserve (Newby, 1988).

In the Mediterraneo-Saharan transition region, habitat degradation dates back to Antiquity and was already advanced in the first centuries of our time. Le Houérou (1986) indicates that dry forests, most often dominated by Pinus halepensis or Tetraclinis articulata occupied most of the arid zone. He shows that Stipa tenacissima steppes succeeded them but that they cannot regenerate in the absence of the protective shade of the trees. The over-exploitation transform them into shrub formations poorly suited for pasturage. Approaching the desert, these habitats are completed with formations of Acacia raddiana and relatively fragile subdesert steppes (Le Houérou, 1986). By extrapolation from what is known of the ecology of the Scimitar-horned Oryx in the Sahel, a hypothesis can be made that the woods of Acacia raddiana with their accompanying cortège and the sub-Mediterranean steppes of Stipa tenacissima or sub-desert steppes of Aristida that accompany them constitute the optimal reimplantation zone for the Oryx in the southern Mediterraneo-Saharan fringe (Kacem et al., 1994). Adequate woodland, in juxtaposition with steppes, do not seem to subsist except in a very few places. In Tunisia, Kacem et al. (1994) indicate that the conditions favourable to the reintroduction of the Oryx exist only in the region of Bou Hedma. Müller (1996) identifies a region with similar characteristics in the lower Drâa valley in Morocco. These two sectors appear thus to be by far the most important for the redeployment of the species in the Mediterraneo-Saharan zone. Other localities can be considered, for example, in Tunisia, the region of the Sidi Toui National Park and the edge of the Great Eastern Erg (Kacem et al., 1994), but they would probably need considerable manipulations of the habitat, in particular, the reimplantation of Acacia raddiana and its cortège (Kacem et al., 1994). More Mediterranean sites, in which open dry forests of Pinus halepensis or Tetraclinis articulata and Stipa tenacissima wooded steppes persist or could be rehabilitated, might also be considered.

It is not entirely clear that the Atlantic Sahara constituted, in the recent past, a zone capable of permanently harbouring autonomous populations of the Scimitar-horned Oryx, without exchange with the Sahel. Nevertheless, an attempt at establishment should be made, by means of protection and, if the case arises, restoration of the habitat. The projected national park in the Dakhla region, in the zone of the highest density of historical observations of Oryx dammah (Loggers et al., 1992) offers the most favourable site, on the condition that the sub-oceanic ensembles of grassy steppes and acacia woodland (Valverde, 1957) can be included or reestablished in sufficient quantity.

At the other extremity of the range of the species, the feasibility of rehabilitation of sedentary populations around one of, or several of, the oases of the western desert of middle Egypt should be studied. Such a project would depend on the possibilities of controlling human pressures in sites that are necessarily of multiple use, and of which the habitats are profoundly modified since the period of presence of the Scimitar-horned Oryx (Goodman et al., 1984). The oasis of Siwa, relatively isolated and near to another complex of oases in Libya, could be the best suited (Meininger, 1998).

Given the absence of historical observations, the Centro-Saharan massifs do not appear to be very favourable to the implantation of the Scimitar-horned Oryx. Still, the presence in Algeria of national parks, constituted or projected, of exceptional dimensions on a continental scale (Bousquet, 1992), the Hoggar and the Tassili des Ajjers, could be favourable for an experiment. Rehabilitation of some habitats would very likely be necessary. These could be concentrated onoueds of the piedmont and their gallery woods (Schnell, 1977).

These considerations allow the identification of 15 zones that appear particularly favourable to reimplantation of the Oryx. They are summarized in Table 2.

Table 2. Zones of potential reimplantation for Oryx dammah.

2.2. Habitat.

Precise data on the habitat of Oryx dammah are based in majority on the Sahelian populations and have been collected in Chad (Malbrant, 1952; Gillet, 1965, 1969; Newby, 1974, 1988; Dragesco-Joffé, 1993), in Niger and in Mali (Lhote, 1946; Brouin, 1950; Malbrant, 1952; Grettenberger and Newby, 1990) and, to a lesser extent, in Sudan (Sclater and Thomas, 1899; Wilson, 1978, 1980). Precise information exists also for the Atlantic Sahara (Valverde, 1957). There does not seem to be any first-hand data on the ecology of the species in the Libyan Desert of middle Egypt (Kock, 1970; Osborn and Helmy, 1980), or, a fortiori, in the Mediterraneo-Saharan zone. The habitat of the species in these regions cannot be understood except by extrapolation of the Sahelian information combined with an examination of the poor data on stable presence and of the historical likelihood of the distribution of the habitats. All the sources converge to establish the typically Sahelian, in particular, north Sahelian, subdesert, character of the habitat of the Scimitar-horned Oryx.

The Sahelian populations of the Scimitar-horned Oryx seem to have fed, during the hot, dry season, from March to June, on the perennial grasses of the Sahelian steppes, notably Panicum turgidum, Aristida mutabilis and other species of Aristida (Gillet, 1965; Newby, 1974, 1988; Dragesco-Joffé, 1993), the fallen pods of Acacia tortilis (Malbrant, 1952; Gillet, 1965; Newby, 1974, 1988; Dragesco-Joffé, 1993), foliage of persistent shrubs, including had, Cornulaca monacantha, Chrozophora senegalensis, Cassia italica (C. obovata) and a few herbs, including Heliotropium strigosum (Newby, 1974; Dragesco-Joffé, 1993). Panicum turgidum seems to also offer cover for newborn calves (Newby, 1974). During the rainy season, from July to September, and during the cold months, from November to February, they use mainly temporary pastures formed by the emergence of annuals, including the grasses Cenchrus biflorus ( cram-cram), Dactyloctenium aegyptiacum, Echinochloa colona, the Aizoaceae Limeum viscosum, as well as young green shoots of shrubs belonging to the families Fabaceae (Indigofera), Nyctaginaceae (Boerhavia), Amarantaceae (Aerva) (Gillet, 1965; Newby, 1974, 1988; Dragesco-Joffé, 1993); they went north at this time, following the formation of temporary pastures (acheb, gizu) to the edge of the desert (Gillet, 1965; Wilson, 1978; Newby, 1988). Water was provided by these formations of annuals or by other newly green plants, or, in their absence, by succulents growing along wadis and in depressions of the Sahel (Newby, 1988) that remain green until far into the dry season (Newby, 1974). The wild melon, Colocynthis vulgaris (Citrullus colocynthis), particularly characteristic of the Sahelian subdesert steppes, plays, from this point of view, a particularly important role (Brouin, 1950; Malbrant, 1952; Gillet, 1965; Newby, 1974, 1988; Dragesco-Joffé, 1993). Shade, an essential element of the habitat during the hot months, was assured, like the humidity, by the accessibility, in the Sahelian steppe, of thickly wooded wadis and interdunal depressions (Brouin; 1950; Gillet, 1965; Newby, 1974, 1988; Dragesco-Joffé, 1993). Dense shade trees such as Maerua crassifolia were particularly sought-after (Gillet, 1965). Commiphora africana, various acacias (Acacia senegal, A. seyal, A. arabica, A. nilotica, A. sieberiana, A. raddiana) and several other Sahelian trees formed fairly dense woods in the preferred zones of occupation in Niger (Brouin, 1950). In sparsely wooded regions shade can be brought by a clump of Panicum turgidum (Gillet, 1965). Access to salt deposits was likely indispensable during certain periods (Gillet, 1965).

For the Atlantic Sahara information is more fragmentary. Morales Agacino (1950) observed the importance of Aristida plumosa. Valverde (1957) mentions Andropogon laniger. The distribution of the species noted by Morales Agacino (1950) corresponds to the Sahelo-Saharan zone of diffuse acacia woodland and steppes of Aristida defined by Valverde (1957) and in which he notes the abundance of Colocynthis vulgaris and the shrubby leguminous shrub Crotalaria, in company with a largely Sahelian cortège.

2.3. Estimation and evolution of the populations.

No estimate of the strength of populations of the Scimitar-horned Oryx in the 19^th century were attempted. In the 20^th century, members of the species were almost entirely limited to the Sahel. Until the middle of the century, the species seems to have been common there, herds of several hundred head and sometimes several thousand were recorded several times , notably in Chad and Niger (Lhote, 1945; Brouin, 1950; Malbrant, 1952). in the 1950's and the beginning of the 1960's, the Sahelian populations were still substantial (Newby, 1988). Herds of the order of 100 individuals or more were still regularly reported in Chad in the beginning of the 1960's (Gillet, 1969). At the end of the 1960's, Gillet (1969) estimated that there were only small populations left in Niger and farther west, and a very few, probably errant, animals in eastern Chad and eastwards. Groups of more than 100 animals were still recorded in Niger during this period (Dragesco-Joffé, 1993).

By the end of the 1970's the world population was evaluated at 6000 individuals (Newby, 1988), located almost entirely in the region of the Wadi Rimé-Wadi Achim, where the Oryx were estimated to number 4000- 6000 head in 1975-1978, following an energetic antipoaching policy which permitted a strong augmention (Newby, 1988; Thomassey and Newby, 1990). The rest were located in Niger (Grettenberger and Newby, 1990), with perhaps a few small surviving groups elsewhere, in particular, in Mali (Heringa, 1990). At the beginning of the 1980's, the Nigerian population numbered less than 200 head (Grettenberger and Newby, 1990). The Chadian one was unknown, but probably reduced to the same order of magnitude, following the interruption of protection in 1978 (Thomassey and Newby, 1990). No observation has been made in Niger since 1986 (Grettenberger and Newby, 1990; Millington et al., 1991). If the species survives in Chad, it is certainly in small numbers (Pfeffer, 1993a, 1993b, 1995; Beudels et al., 1994; Tubiana, 1996a, 1996b).

2.4.Migration.

In the Sahelian range of the Scimitar-horned Oryx, seasonal migrations of a substantial amplitude, up to several hundred kilometres, have been recorded (Brouin, 1950; Malbrant, 1952; Gillet, 1965, 1969; Dupuy, 1967; Newby, 1974, 1988; Dragesco-Joffé, 1993). The migration cycle, particularly well-observed in Chad, can be summarized as follows (Gillet, 1965, 1969; Newby, 1974, 1988). During the hot season, from March to May, the Oryx are found in the south of their range; at the beginning of the rains, that appear in the south of the Sahel at the end of May or the beginning of June, they move further south, to the sub-Sahelian wooded steppes. At the end of June or in July, they perform rapid, massive migrations towards the north of their range, where the rains have started, taking advantage of the therophytic pastures to the extent that competition with domestic herds permits. In August they reach the northernmost latitudes, between the 16^th and 17th parallels. In October and November, the large herds disperse for the cold season. They return in March towards the summer quarters. This cycle varies in function of the irregularities of the annual rainfall. During low-rainfall years they can be forced to spend the largest part of the year near the summer quarters; inversely, during years with abundant rainfall, they can prolong their stay in the north. Similar migrations have been observed in Niger (Lhote, 1946; Brouin, 1950; Malbrant, 1952), and in Sudan (Audas, 1951; Schomber, 1963). Errant individuals or small groups in search of pastures probably often go beyond the limits of regular migrations (Wacher, 1988; Dragesco-Joffé, 1993). It is possible that this nomadism has increased recently under the effects of persecution and degradation of habitats (Dragesco-Joffé, 1993). This erratic behaviour, notably of isolated males (Wacher, 1988), explains, in any case, the isolated observations made relatively often far from the permanent ranges.

Cyclic migrations, seasonal or interannual, of the Scimitar-horned Oryx have a cross-border nature, at least between Mauritania, ex-Spanish Morocco and perhaps Algeria (Valverde, 1957; Trotignon, 1975), between Mali and Niger (Lhote, 1946), between one or another of these countries and Algeria (Lhote, 1946; Dupuy, 1967; Kowalski and Rzebik-Kowalska, 1991), between Mali and Burkina Faso (Heringa, 1990; Heringa et al., 1990), between Niger and Chad (Dragesco-Joffé, 1993), and between Chad and Sudan (Lambert, 1975; Wilson, 1980; Hillman and Fryxell, 1988).

Morocco (including ex-Spanish Sahara): Extinct.

The presence of the Oryx during the historic period is not documented except for the regions located south of the oued Drâa (Morales Agacino, 1950; Valverde, 1957; Loggers et al., 1992) or perhaps of the oued Noun (Joleaud, 1918). In the southeastern part of the Spanish Sahara, in the region of Sahelian affinity, groups numbering up to 25 or 30 individuals could still be seen, during the first half of this century, when pastures, particularly of Aristida plumosa, were abundant (Morales Agacino, 1950). In 1957, Valverde estimates that there remains no more than one or perhaps two groups. The last observations were in 1963 (Newby, 1988) and 1973 (Le Houérou, 1992), the latter record refers to a single, isolated, individual.

Algeria: Extinct.

The presence of the Oryx in the Mediterraneo-Saharan zone of Algeria is not documented beyond the Roman era, or perhaps the 16^th century (Heim de Balsac, 1931; de Smet, 1989; Kowalski and Rzebik-Kowalska, 1991). In the extreme south of Algeria, the southeast of Tanezrouft was likely part, until the 1960's, of the range of Malian populations from the Adrar des Iforas and the southwest of the Tassili Oua-n-Ahaggar that of the Nigerian populations from the Aïr, as Dupuy (1967) supposed. In any case, few observations confort this hypothesis (de Smet, 1989; Kowalski and Rzebik-Kowalska, 1991). Two individuals killed in the region of the Tassili des Ajjers in 1987 (De Smet and Mallon, 1997) could have been wanderers coming from the Sahel.

Tunisia: Reintroduced

The Scimitar-horned Oryx was present at least until Roman times in the Mediterraneo-Saharan zone of Tunisia (Sclater and Thomas, 1899). There are no later data, except for a few captures at the beginning of the 20^th century (Lavauden, 1920) that could pertain to wandering animals coming from southern regions. The species has been reintroduced in the Bou Hedma National Park (Bertram, 1988; Bousquet, 1992; Kacem et al., 1994), in an adequate environment and a habitat of steppes and Acacia raddiana woodland of which the restoration (Karem et al., 1993; Kacem et al., 1994) is a remarkable success and in fact the best example of this type in the northern fringe of the Sahara (Bousquet, 1992). In 1999, around 15 individuals originating from various European zoos were imported to Tunisia and introduced into Sidi Toui National Park et the Aïn Dekouk Reserve.

Libya: Extinct.

Rock paintings, notably in the Tibesti and the Djbel Uweinat, attest to the existence of prehistoric populations of the Scimitar-horned Oryx. There are no sure records of its presence in Libya during historical times (Hufnagl, 1982). However, in the 19^th century animals occupied the oases of the Libyan Desert of middle Egypt very near the Libyan border and Alcephalus busephalus, which is associated with the Oryx in most of the oases, was known from at least one depression within Libyan territory. Thus, it is possible that Libya was within the range of these populations. Dragesco-Joffé (1993) suggests that wandering animals belong to the Chadian population that might have entered southern Libya. A plausible, but uncertain, observation of an individual was made in the Mediterranean northeast in 1942 (Hufnagl, 1972). It brings to mind a record considered to be certain in northwestern Egypt in 1975 (Osborne and Helmy, 1980).

Egypt: Extinct.

Until the middle of the 19^th century, numerous observations of the Oryx were reported, in the oases of the Western Desert, in particular from the Siwa oasis in the northwest, the Wadi Natroun, the Faiyum and the Wadi el Ruwayan near the lower Nile, the enormous oases of Dakhla and the Kharga complex between 24° and 26° N (Kock, 1970; Osborn and Helmy, 1980). There are no records for this period outside these oases and their vegetation systems. This concentrated distribution is characteristic of most of the mammals of the Western Desert (Osborn and Helmy, 1980) and probably reflects the reality of distribution in this nearly unvegetated desert (Osborn and Helmy, 1980; Monod and Sers, 1994) rather than the distribution of observers. The latest records date from the 1850's and 1860's (Flower, 1932; Kock, 1970; Osborn and Helmy, 1980). A single more recent observation exists, that of an animal seen in the Mediterranean coastal desert in extreme northern Egypt in 1975 (Osbon and Helmy, 1980). This record probably pertains to a far-wandering animal coming from southern populations.

Mauritania: Extinct.

Southern and western Mauritania make up part of the Sahelian and Atlantic Saharan range of distribution of the Scimitar-horned Oryx; these ranges are probably continuous, but the existing records do not document this. The first relatively precise information on the distribution of the species in the country seems to date from the 1930's (Trotignon, 1975). During this period, the Oryx was recorded in the west, the center and the east of the Sahelian steppe zone, as well as along the northern border of this zone in the regions of Dhar Tichit, Dhar Oualata, 'Adafer and Aklé Aouana. A second zone of presence is located in the Spanish Sahara. There are records, during the 1940's, for the east of the Sahelian zone and its northern limit (Trotignon, 1975). In the 1950's, the observations cited by Trotignon (1975) are confined, on the one hand, to the east of the Sahelian region, between Oualata, Nema and the Malian border, on the other hand, to the immediate vicinity of the south-eastern border of the Spanish Sahara, in continuity with the the records given by Morales Agacino (1950). The last observation apparently dates back to 1959 and pertains to the Atlantic population (Trotignon, 1975; Newby, 1988; Sournia and Verschuren, 1990).

Mali: Probably extinct. 

The Sahelian range of the Scimitar-horned Oryx extends across Mali from Irrigi in the west to Azouak in the east, between 18° and 15° latitude, with an extension to 20° and to the Algerian border at the periphery of the du massif pénésahélien of the Adrar des Iforas (Lhote, 1946; Gillet, 1969; Dupuy, 1967; Trotignon, 1975; Sayer, 1977; Newby, 1988; Heringa, 1990; Sidiyene and Trainer, 1990). Lhote (1946) indicates its presence in the entire Sahelian steppe zone, including in the Niger river bend, in particular, in the Hombori region, in the immediate vicinity of what is now the Faunal Reserve « des Eléphants « and on the latitude of the Ansongo-Menaka reserve. The last data from Mali date from the end of the 70"s and the beginning of the 80"s and came from the extreme eastern part of the country (Sayer, 1977; Newby, 1988; Heringa, 1990). An isolated observation has been made of two individuals in the Laga Koundiri region on the border with Burkina Faso during the 1986 rainy season (Heringa, 1990; Sidiyene and Trainer, 1990). It is situated within the normal range of the species.

Niger: Probably extinct.

The Sahelian range of the Scimitar-horned Oryx goes through Niger from the Azaouak south of the Ténéré, between the 15th and the 17th parallel (Lhote, 1946; Brouin, 1950; Gillet, 1969; Jones, 1973; Newby, 1988; Grettenberger and Newby, 1990; Dragesco-Joffé, 1993; Poilecot, 1996a, 1996b). In the 1940’s, the main concentrations were observed in the south of the Aïr, moving between Tadéras region and the southeastern edges of the massif, in the vicinity of the Ténéré (Lhote, 1946; Brouin, 1950). Brouin (1950) called the Tadéras region a « wooded area « , between 15° 30' and 16° 30' latitude, and, between 6° 30' and 9° longitude, favourite Oryx habitat, as well as favourite Gazella dama habitat. At the end of the 1960"s,  large groups of Oryx still occupied their traditional range (Dragesco-Joffé, 1993). During the 1970"s, the species seems to have been reduced to small groups (Dragesco-Joffé, 1993) living on the desert edges between Agadez and the Termit (Grettenberger and Newby, 1990). At the beginning of the 1980"s, dryness probably forced the survivors to the south of their normal range, in an area where they were exposed to increased anthropic pressure; at that time, the population was estimated at less than 200 individuals (Grettenberger and Newby , 1990). The last observations in Niger are from 1983 (Newby, 1988; Grettenberger and Newby, 1990) and 1986 (Millington and al., 1991).

Chad: Endangered, possibly extinct.

Chad has been, for a long time, the home of the post important populations of Scimitar-horned Oryx. Already in the 1930’s, the Oryx seemed much more abundant in Chad than in the more western or eastern regions (Malbrant, 1952). They were distributed over the entire Sahelian belt, mostly between the the14th and the 17th parallels, from the Niger border to the west as far as the Ouaddaï, the Kapka, and the Ennedi massifs and the Mourdi depression along the oriental border (Newby, 1974). Large herds of several hundreds, even several thousands animals were regularly observed (Malbrant, 1952; Thomassey and Newby, 1990). In the 1950’s and 1960’s, the species seems to have maintain itself throughout its range (Newby, 1974). In 1962-1963, herds of around a hundred individuals are still frequently observed, one herd of several hundred animals (at 14° 23' latitude) and another of 600 heads signalled (Gillet, 1965, 1969). Gillet (1969) believes that the number of animals has not been reduced, at least in the Oued Rimé-Oued Achim region, during the 1960’s. In the 1970’s, the Oryx practically disappeared from the region between the 20th meridian and the eastern border massifs (Newby, 1974). By then, it had become rare also in the western part of the country. In the mid- 1970’s, more than 95% of the remaining world population was concentrated in the Oued Rimé-Oued Achim region, between 18° E and 20° E and between 15° N and the southern part of the Djourab (Newby, 1974; Thomassey and Newby, 1990). In 1975-1978, the population in that region was estimated at 4000-6000 individuals, after a period of substantial increase due to a very efficient anti-poaching prevention policy (Thomassey and Newby, 1990). From 1978, a rapid decline took place in direct consequences of the military activities in the country. At the beginning of the 1980’s, the Chadian population was reduced "to the lower hundreds or less", following the interruption of the conservation policy (Newby, 1988; Thomassey and Newby, 1990). Recent surveys (Pfeffer, 1993a, 1993b, 1995; Beudels et al., 1994; Tubiana, 1996a, 1996b) could not confirm the survival of the species.

Sudan: Extinct.

At the beginning of the century, the Scimitar-horned Oryx was distributed throughout the entire Sahelian zone of the Darfur and the Kordofan (Audas, 1951; Kock, 1970; Wilson, 1980; Hillman and Fryxell, 1988). Along the Nile valley, it was found as far as the 20° N (Kock, 1970). In Kordofan, it was apparently common in the southern part of the northern-sahelian steppes zone (White, 1983, unit 54a) and in the entire southern Sahelian zone of deciduous shrubs (White, 1983, unit 43), between the 12° 30' and 16° parallels, to the south as far as the southernmost limit of the Sudaniens woodlands (White, 1983, unit 29a), migrating seasonally like in the other part of the Sahel (Audas, 1951; Kock, 1970). The last observations are from the end of the 1920’s (Audas, 1951). In the 1930’s, numbers were already dangerously low throughout the country (Audas, 1951). The Scimitar-horned Oryx remained however apparently well represented until the 1940’s in the Sahelian steppes of northern Darfur, adventuring north to the desert’s fringe to make use of temporary pastures or « gizu « (Lamprey, 1975; Wilson, 1978, 1980). From the 1950"s, data become rare (Wilson; 1980). The last precise data are from groups up to 50 individuals in the Wadi Howar region and on the temporary gizu pastures north of the Wadi Howar in 1964, observed by Hussain Dosa and reported by Lamprey (1975), and the capture of an individual at the westernmost part of the Sudanien Wadi Howar in 1973 (Lamprey, 1975). Newby (1982, 1988) estimates that extinction took place in the 1970"s.

Senegal: Extinct.

The southern part of the Scimitar-horned Oryx potential Sahelian range, the sub-Sahelian deciduous shrub zone, includes northern Senegal, from the Louga region to the west, to the Bakel region to the east (White, 1983). The species occurred there (Sournia and Dupuy, 1990). The extinction date is not clearly known. It is situated in the 1850’s by Newby (1988, on the basis of informations given by Dupuy), before 1914 by Sournia and Dupuy (1990).

Burkina Faso: Extinct.

Northern Burkina Faso, north of 14°, is situated in the south-Sahelian deciduous shrub zone (White, 1983). The Scimitar-horned Oryx used to occur there, and probably went extinct in the 1950’s (Heringa and al., 1990). Two individuals were observed however in the Laga Koundiri region, a waterhole situated on the border between Mali and Burkina Faso, during the rainy season of 1986 (Heringa and al., 1990; Heringa, 1990).

Nigeria: Uncertain passed presence.

The northeasternmost part of Nigeria, in the Lake Chad and Jawa, is situated in the south-Sahelian deciduous shrub zone (White, 1983; Anadu and Green, 1990). A much larger area, north of the 12th parallel to the west and of the 8th parallel to the east, is part of the Sudaniens savannahs and woodlands (White, 1983; Anadu and Green, 1990). The Scimitar-horned Oryx presence in either of these zones in the past (Sclater and Thomas, 1899) is possible but not clearly established (Anadu and Green, 1990).


4. Existing and potential threats

The Scimitar-horned Oryx regression took place under the combined effect of several factors acting simultaneously, anthropic degradation of habitats, environmental stochasticity in arid lands, poaching, loss of habitats due to human pressure. These factors remain active today.

4.1. Habitats degradation and regression

Catastrophic droughts. In the arid context that has prevailed in the Sahara for the last 3000 to 4000 years (Le Houérou, 1986; Newby, 1988), years of increased dryness, affecting particularly the Sahel, appear at irregular intervals (Monod, 1986). During the XXth century, severe Sahelian droughts took place in 1913- 1914 (Monod, 1986), in 1940-1945 (Monod, 1986; Newby, 1988), then, with a particularly high frequency, in 1968-1973, 1976-1980 and 1983-1984 (Monod, 1986; Newby, 1988; Hassaballa and Nimir, 1991). Those periods of droughts always have a catastrophic effect on arid lands fauna. The impact caused by recent episodes on migratory palaearctic birds wintering in the Sahel has been amply documented and commented. The effects of such natural catastrophes have been seriously aggravated by the fact that they were combined with anthropogenic factors. They hit Sahelian antelopes populations which had already been pushed, under anthropic pressure, towards sub-desertic zones at the limit of their aridity tolerance. They forced those antelopes populations to move southwards, where pastoralists and farmers pressure is higher (Newby, 1988) and the risk of being killed is greater (Newby, 1982). Beside, the human occupation level of much of the land often hampers vegetation-regrowing capacities after the droughts (Millington and al., 1991).

Degradation of pastures through overgrazing. The feeding capacity of the excellent grazing areas of the sub-desertic steppe to support an enormous primary production of graminaes and other perennial plants, combined with a relatively low competition and predation pressure, explain the past abundance of the Oryx (Newby, 1974). Important increases of the domestic stock and the multiplication of deep forages, created in that purpose, have made it possible for domestic stock to permanently use grazing grounds situated in waterless areas, and lead to generalised intensive overgrazing (Newby and Sayer, 1976; Newby, 1978a; Newby, 1988). For the whole of the Saharans and north-occidental sub-Saharans regions, Le Houérou (1986) estimates grazing pressure to be twice the carrying capacity, and notes, as a direct consequence, the elimination of perennial grasses and browsable shrubs, and soils stamping, compacting and eroding, which in turns increases eolian erosion. For the Sahel, Monod (1986) indicates grazing pressure of 0.8 to 1 sheep-equivalent per hectare, for a carrying capacity of 0.25 sheep-equivalent per hectare, a charge four time too high, leading to severe and generalised overgrazing. The effects of such overexploitation are well described for the Sudan by Bari (1991) who documents the transformation of rich pastures of short grasses and perennials into absolute deserts, and by Hassaballa and Nimir (1991) who note a 5 to 6 kilometres progression of the desert per annum. The destruction of feeding grounds, notably the Cornulaca formations, by overgrazing, has also been observed in Chad, in the areas of late remanence of the species (Newby, 1974).

Cutting of trees. Trees seem to be essential to the Oryx, for shade and for food. Their systematic destruction in the Sahelo-Saharan region is an historical consistency (Le Houérou, 1986). It increased sharply recently in southern fringe of the Sahara, under the combined effects of droughts and needs for charcoal (Newby, 1988; Bari, 1991; Hassaballa and Nimir, 1991). In Sudan, for example, Bari (1991) documents the total disappearance of Acacia tortilis, Acacia raddiana, Acacia senegal, and Merua crassifolia woodlands, and their replacement with absolute desert.

Loss of optimal habitats. It is likely that as early as1950's, the Oryx was pushed away from the most ecologically favourable areas by development pressure. Reduction, following droughts, of available range, and increased accessibility for the domestic stock to marginal lands, have progressively removed all buffer zones, then any separation between wild fauna and domestic animals (Newby and Sayer, 1976), the first ones quickly excluded from common use areas. During the Oryx last remaining years of survival in the Sudan, Wilson (1978) noted that "gizu", therophytic pasture, while still appearing in abundance, had become out of reach for the antelopes because of excessive charges in domestic stocks.

4.2. Direct exploitation.

Traditional hunting. Traditional hunting (Brouin, 1950; Gillet, 1965, 1969; Newby, 1978a, 1978b, 1988; Dragesco-Joffé, 1993), exercised mostly by nomads, with horses and spears, with horses and nets, or, from the Neolithic period, with bow and arrows, certainly played a role in the disappearance of the species, but probably only from the time when it started acting in conjunction with other factors, and exerted itself on already decimated populations.

Hunting by non- nomads. Brouin (1950) notes the considerable impact of capture done by traps by non-nomads in the southern part of the range. It is only one aspect of the pressure caused by increased contact with dense human populations with a distribution moving northwards.

Hunting with 4wd vehicles. Of far more consequences than traditional hunting, the generalised use of modern firearms and 4x4 vehicles has been the essential proximal factor of the species extinction. It was mostly carried out by mining or oilfield personnel, militaries, or people from the administrations, Africans or expatriates (Gillet, 1965, 1969; Newby, 1978a, 1978b, 1988; Hassaballa and Nimir, 1991; Dragesco-Joffé, 1993).

Tourism hunting. Like for all the Sahelo-Saharan antelopes, the slaughters perpetrated by tourism hunting, in particular from the Middle-East, and well documented for Sudan (Cloudsley-Thompson, 1992), Niger and Mali (Newby, 1990; Bousquet, 1992), are potentially a major threat.

4.3. Other threats.

All indirect forms of anthropic pressure likely to affect the species, such as the extension of domestic herds, the multiplication of deep wells, and the invasion of available habitats exert pressure through degradation or regression of habitats and increase susceptibility to direct killing (taking). They were treated under corresponding paragraphs.

5.1. International:

Bonn Convention : Annex I, resolution 3, 2, 4.
Washington Convention (CITES): Annex I

5.2. National:

The Scimitar horned Oryx is totally protected in Algeria, Tunisia, Mauritania, Mali, Niger, and partially in Sudan.

6.1. Ban on taking 

Tunisia (reintroduced): protected
Niger (probably extinct): protected

6.2. Habitat Conservation

Morocco (included ex-Spanish- Sahara)

The proposed national parks in the lower Drâa basin and the Dakhla region (Müller, 1996) appear to be well suited for the reintroduction of the species, in so far as the Dakhla proposed park will extend sufficiently inland, so as to include a substantial representation of steppes and Sahelian woodlands which characterised the local range of the species (Valverde, 1957). In both cases, past utilisation of those areas by the Oryx may have been seasonal or non-annual, and the current impracticability to insure secure movements towards other regions may impose a very active management of the habitat, temporary or permanent.

Algeria

The Tassili des Ajjers National Park and the Hoggar National Parks offer, through their exceptional dimensions and their environmental diversity (Bousquet, 1992), obvious reintroduction potentials. The absence, however, of post-Neolithic observations in those Centro-Saharans massifs, which have been, for thousands of years, mostly at the limit or beyond the level of aridity tolerable for stable populations of the species, indicates that a reintroduction experiment will almost certainly necessitate rehabilitation efforts and possibly permanent habitat management measures.

Tunisia

A habitat rehabilitation programme, together with a reintroduction programme, has been conducted in the Bou Hedma National Park (Bertram, 1988; Bousquet, 1992; Kacem and al., 1994). Results obtained so far are remarquables (Bertram, 1988; Bousquet, 1992; Kacem and al., 1994; pers.obs). The Tunisians authorities efforts to expand the limits of the fenced area on the basis of a general consensus must be supported by all means. Although Bou Hedma NP appears today as the optimal reintroduction site for the species in Tunisia (Bertram, 1988; Kacem et al., 1994), supplementary sites could be looked for in order maximise the benefits accruing from the good conservation climate that prevails in Tunisia. Such sites could be identified, if the habitat was restored, as it was done for Bou Hedma, in the reserves situated south of Bou Hedma, but also, and possibly mostly, in the more northern regions, since it is unlikely that the centre of gravity of the antique range in Tunisia was situated very much into the south, and that the aridity of the habitat, if not that of the climate, has since then progressed northwards. Early 1999, around 15 individuals originating from various European zoos, were imported into Tunisia and reintroduced successfully in Sidi Toui National Park, and, to a lesser extent, into the Aïn Dekouk Reserve.

Mali

The Elephants Reserve and the Ansongo-Menaka Reserve are located within the recent distribution zone of the Scimitar-horned Oryx (Lhote, 1946) and within the part of the range that seems to be particularly favourable to a permanent fixation. Ansongo-Menaka had a substantial population of Oryx at the time of its creation (Newby, 1982). The two reserves offer good reintroduction potential, but pressures of all types, agronomic, pastoralists, residentials, as well as cynegetic, to which they seem to be exposed must first be controlled (Heringa, 1990). The Elephants Reserve potentials are of particular interest, with the excellent tourism perspectives represented by the combination of one of the last Sahelian population of Elephants (Loxodonta africana) and a spectacular antelope (Pavy, 1996).

Niger

The Gadabedji Reserve was created for the Scimitar-horned Oryx. Like the two Malian reserves, it is situated in the optimal climatic zone for the species (Newby, 1982; 1988; Dixon and Newby, 1989; Grettenberger and Newby, 1990). Unfortunately, anthropic pressures have never been sufficiently controlled, and the Oryx became extinct (Newby, 1988; Millington and al., 1991). It remains nevertheless an excellent potential reintroduction site, if those pressures can be alleviated. A habitat rehabilitation programme was undertaken in 1989 (Millington et al., 1991). Another reserve proposed in the Termit region would offer a second possibility. The Termit massif seems to be one of the most intact region of the Nigerian Sahel, with remaining populations of several ungulates and as well as relatively well conserved habitats (Newby, 1982, 1988; Newby and Jones, 1986; Grettenberger and Newby, 1990; Millington et al., 1991). The Aïr-Ténéré National Park, situated mostly in the Ténéré massif, and which only includes a small part of the oriental slope and piedmont of the Aïr, appears too arid for the Scimitar-horned Oryx (Newby and Jones, 1986; Newby, 1988).

Chad

The Ouadi Rimé-Ouadi Achim reserve is by far the most important site for the conservation of the Scimitar-horned Oryx (Gillet, 1965, 1969; Newby, 1974, 1988; Thomassey and Newby, 1990; Dragesco-Joffé, 1993; Pfeffer, 1993a, 1995). The fact that a few individuals may still be living there, in that case making it the very last frontier against extinction in the wild, and therefore the first conservation priority at the world level. The implementation of strict habitat and fauna conservation measures is indispensable. Any other action must be delayed, until proper evaluations of the species chances of survival in the wild, and therefore of the preservation of its original behaviour. In the longer term, the richness of the area makes it possible, when the populations have build up, to envisage perspectives of sustainable development by wise use of the large fauna (Grettenberger and Newby, 1990).

Sudan

The proposed Wadi Howar National Park in order Darfur would offer possibilities of reintroduction for the Oryx (Hashim, 1996). The conservation status of the steppes and associated woodlands in Sudan (Bari, 1985; Hashim, 1996) suggest that important habitat restoration programmes would probably be necessary. Efficient control of poaching pressure throughout large areas might be very difficult to implement (Cloudsley-Thompson, 1992).

Senegal

The two reserves of the Ferlo (Bille et al., 1972; Bille and Poupon, 1972; Sournia and Dupuy, 1990) offer excellent reintroduction potentials. The total area is a proposed National Park (Diop et al., 1996). A reintroduction programme has been planned (Diop et al., 1996; Clark, 1996). Its success will rely , mostly, like for every southern Sahelian site, on the feasibility of limiting human pressures, in order to protect the fauna and allow the vegetation to regrow (Diop and al., 1996).

Burkina Faso

The northern partial Sahel reserve could become the nucleus of a reintroduction zone in the Sahelian Burkina Faso. The reserve has been seriously affected by overgrazing, woodcutting and droughts (Heringa et al., 1990).

6.3. Attenuation of obstacles for migratory animals

Given the actual state of the populations, the question has no point. In case of recuperation, or progressively as reintroduction projects succeed, it gradually could be asked more and more. In the short and medium term, only the creation of protected areas which are sufficiently vast to include the entire necessary range, and in particular, cross-border reserves, seems to be an adequate answer. It seems in fact improbable that the security of movement between protected areas can be assured in a realistic manner in the foreseeable future.

6.4. Regulations concerning other detrimental factors.

For reasons exposed under 6.3, such rules only mean something in the framework of protected areas management plans. This paragraph therefore refers to paragraph 6.2.

6.5. Other measures

Tunisia

The Oryx reintroduction programme is highly successful so far in the Bou Hedma National Park, which is situated in the historic range (Bertram, 1988; Bousquet, 1992; Gordon and Gill, 1993; Kacem et al., 1994), as well as in the Sidi Toui National Park, near the Libyan border; early 1999 .

Niger

A semi-captive programme with possible reintroduction is being envisaged, in the Ekafrane ranch (Millington et al., 1991).

Senegal

A reintroduction programme in the Ferlo reserves, with preliminary acclimatisation in the Gueumbeul Sahelian wildlife reserve is being developed (Diop et al., 1996; Clark, 1996).

Outside range

There are captive or semi-captive bred herds or individuals in over 40 institutions (Newby, 1979), situated in several countries, in North Africa, the Middle East, Europe and North America.

7.1. Public authorities.

Tunisia: monitoring of reintroduction activities in Bou Hedma and elsewhere.

7.2. N.G.O

Recommended measures are part of an Action Plan developed in parallel with this status report (Beudels et al., 1998). The principal needs that they meet are listed above.

8.1. Total protection of the species

Necessary in all the countries of the historical range in such a way as to prepare for a possible redeployment of the species.

8.2. Conservation measures.

Establishment of a network of protected zones in all parts of the historical range of distribution, based on the guidelines stated in point 2.1.4., with absolute priority given to zones where the species could still be surviving in the wild, specifically, first of all, in the Ouadi Rimé-Ouadi Achim Reserve in Chad, and in Niger.

8.3. Localisation and monitoring of residual populations, and precision of their ecological requirements.

Energic search for residual populations, firstly in Chad, secondly in Niger.

8.4. Reinforcement and/or reintroduction of populations in the potential range.

Support to the Tunisian reintroduction programme. Preparation of programmes in other parts of the range, following the guidelines stated in point 2.1.4.

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