Increasing conflicts and social insecurity are expected to accelerate biodiversity decline and escalate illegal wildlife killing. Sahara-Sahel megafauna has experienced recent continuous decline due to unsustainable hunting pressure. Here, we provide the best available data on distribution and population trends of threatened, large vertebrates, to illustrate how escalating regional conflict (565% growth since 2011) is hastening population decline in areas that were formerly refugia for megafauna. Without conservation action, the unique and iconic biodiversity of Earth's largest desert will be forever lost. We recommend: (1) establishing strong commitments for change in global attitude toward nature; (2) engraining a culture of environmental responsibility among all stakeholders; (3) fostering environmental awareness to drive societal change; (4) reinforcing regional security and firearms control; and (5) implementing local research and wildlife monitoring schemes. We identify relevant international partners needed to tackle these challenges and to make strong policy change for biodiversity conservation and regional stability.

We investigated the phylogeography and subspecies classification of the ostrich (Struthio camelus) by assessing patterns of variation in mitochondrial DNA control region (mtDNA-CR) sequence and across fourteen nuclear microsatellite loci. The current consensus taxonomy of S. camelus names five subspecies based on morphology, geographic range, mtDNA restriction fragment length polymorphism and mtDNA-CR sequence analysis: S. c. camelus, S. c. syriacus, S. c. molybdephanes, S. c. massaicus and S. c. australis. We expanded a previous mtDNA dataset from 18 individual mtDNA-CR sequences to 123 sequences, including sequences from all five subspecies. Importantly, these additional sequences included 43 novel sequences of the red-necked ostrich, S. c. camelus, obtained from birds from Niger. Phylogeographic reconstruction of these sequences matches previous results, with three well-supported clades containing S. c. camelus/syriacus, S. c. molybdophanes, and S. c. massaicus/australis, respectively. The 14 microsatellite loci assessed for 119 individuals of four subspecies (all but S. c. syriacus) showed considerable variation, with an average of 13.4 (±2.0) alleles per locus and a mean observed heterozygosity of 55.7 (±5.3)%. These data revealed high levels of variation within most subspecies, and a structure analysis revealed strong separation between each of the four subspecies. The level of divergence across both marker types suggests the consideration of separate species status for S. c. molybdophanes, and perhaps also for S. c. camelus/syriacus. Both the mtDNA-CR and microsatellite analyzes also suggest that there has been no recent hybridization between the subspecies. These findings are of importance for management of the highly endangered red-necked subspecies (S. c. camelus) and may warrant its placement onto the IUCN red list of threatened animals.

Managers of threatened species often face the dilemma of whether to keep populations separate to conserve local adaptations and minimize the risk of outbreeding, or whether to manage populations jointly to reduce loss of genetic diversity and minimise inbreeding. In this study we examine genetic relatedness and diversity in three of the five last remaining wild populations of dama gazelle and a number of captive populations, using mtDNA control region and cytochrome b data. Despite the sampled populations belonging to the three putative subspecies, which are delineated according to phenotypes and geographical location, we find limited evidence for phylogeographical structure within the data and no genetic support for the putative subspecies. In the light of these data we discuss the relevance of inbreeding depression, outbreeding depression, adaptive variation, genetic drift, and phenotypic variation to the conservation of the dama gazelle and make some recommendations for its future conservation management. The genetic data suggest that the best conservation approach is to view the dama gazelle as a single species without subspecific divisions.

One of the greatest challenges in restoring species to the wild is insufficient knowledge about their habitat requirements and movement ecology. This is especially true for wide-ranging species such as the scimitar-horned oryx (Oryx dammah). Once widespread across Sahelo-Saharan grasslands, oryx were declared Extinct in the Wild in 1999. Here, we integrate GPS/satellite tracking, remote sensing, and movement analyses to assess how reintroduced oryx respond to wild conditions. We monitored two groups of oryx, reared under different captive management regimes and released in different seasons, for 12 months after release. Our study provides the first movement trajectories and home range estimates for this species. We expected oryx movements after release to represent trade-offs between risky, energetically expensive exploration and resource exploitation. Oryx raised under semi-free ranging conditions and released during the wet season ("ranging") exhibited this pattern of exploration followed by home range establishment. In contrast, oryx raised in small pens and released during the dry season ("penned") explored far less novel terrain. Ranging oryx exhibited seasonal shifts in activity and movement timing, while penned oryx simply reduced overall movement and continuously accessed supplemental food and water. Sahelian ecosystems exhibit strong seasonal cycles and extensive spatial variation. In this highly variable environment, reintroduced oryx will need to disperse from the release site to acquire adequate forage throughout the year. Thus, we experimentally varied acclimation period, and expected dispersal to decrease with acclimation period length. Post-release dispersal ranged from 2 to 90 km: ranging oryx acclimated for ca. 6 months moved 40-60 km from the release site, while penned oryx acclimated for ca. 1 month remained within 5-25 km. Our results demonstrate that captive management and environmental conditions at release strongly influence the extent to which reintroduced oryx disperse and adapt to wild conditions. We also show that-in contrast to previous studies-longer acclimation periods do not necessarily lead to site fidelity. Finally, our findings demonstrate the importance of tracking a large proportion of reintroduced individuals to (1) accurately record post-release behaviors and vital rates, and (2) adaptively evaluate pre-and post-release management actions to improve conservation outcomes.

Habitat evaluation is considered an essential step for assessing the potential for an area to support a viable reintroduced population. Remote sensing techniques can support such investigations, by greatly enhancing the temporal and spatial coverage of habitat assessments. This study makes use of freely available earth observation data to evaluate the suitability of the Ouadi Rim e-Ouadi Achim Game Reserve in central Chad for the reintroduction of the Scimitar-horned Oryx. The reserve was the last stronghold of the species within its historical range, prior to extinction in the wild in the 1980s, providing a basis for reintroduction. Results show that since the 1980s, there has been a steady increase in average annual precipitation and satellite-derived estimates of primary production. The spatial downscaling of the average trend in primary production showed that the north of the protected area exhibited a drying trend over the period 1982-2008, while the south was associated with intense greening. As a result, the subdesert transition zone preferred by oryx is currently narrowing. If this is correct, this implies a potential reduction of favourable habitat for the oryx, which could have detrimental effects on the success of establishing a self-sustaining reintroduced population.

Very few reserves exist to protect the arid-lands fauna of West Africa, particularly in the sub-desert zone, and the large mammals, such as addax, scimitar-horned oryx and dama gazelle are disappearing. New reserves are planned but they could be too late. Many permanent waterholes have been dug, and the nomads (and their livestock) tend to stay near them, depriving the wild animals of their traditional dry-season haunts. Firearms have made hunting easier, and the slow-running desert animals cannot compete with motor vehicles -.many die of heat exhaustion, calves are abandoned in the chase and unborn young aborted. Rational utilisation of wildlife could be of immense benefit to the people, but protection is the first priority. To achieve this FPS and PTES have launched an appeal for the scimitarhorned oryx.Arid lands have few large mammal species, but in the past these few have had huge populations. Today in West Africa the larger mammals of the desert, sub-desert and sahelian zones are rapidly disappearing, and there are very few reserves to protect the survivors. The highly endangered scimitar-horned oryx and the addax typically inhabit the sub-desert lands -the transition zones between true desert (Sahara) and the Sahel, with a rainfall of under 200mm -and only one reserve exists to protect this sahelo-saharan fauna, the Ouadi Rime-Ouadi Achim Reserve in Chad.Sahel is an Arabic word meaning 'shore', referring here to the sparsely vegetated fringe of the saharan sand-seas. But today the Sahel is generally defined as the band of land south of the Sahara where the annual rainfall is 150-SSOmm; the true desert, the Sahara, has under 50mm.Several countries, including Mali, are planning new desert or sub-desert reserves, although usually the characteristic fauna has either vanished or is rapidly doing so, and to save anything at all will require strong protection measures by both governments and international bodies. But once given full protection all these well-adapted mammals of the arid lands could build up their populations again. All are capable of going without drinking water for 9-10 months of the year, addax probably longer, and most of them make annual or seasonal migrations in response to the climatic fluctuations.Addax Addax nasomaculatus, slender-horned gazelle Gazella leptoceros, and the Barbary sheep Ammotragus lervia are the most desert-loving species, all highly adapted to eking out their existence on the open regs (sterile pebbly plains) and ergs (sand seas) of the Sahara, or, in the case of the Barbary sheep, in and around the rocky desert massifs. Because their environment and behaviour are such very good defences against outside interference, the future for them looks more secure than it does for the species of the sub-desert lands.The scimitar-horned oryx Oryx dammah is the mammal par excellence of the sub-desert, and by far the most endangered. Animals of rolling dunes, grassy steppes and wooded inter-dunal depressions, scimitar-horned oryx very rarely penetrate either true desert or true sahel ...

Once the Sahel supported healthy populations of wildlife. Today only remnant populations exist, survivors of the ravages of drought, desertification, excessive hunting and competition for pasture. In the past few years the problems for these animals and for the people trying to conserve them have been exacerbated by a new wave of hunters. Arab princes and their retinues, having exterminated most of the prey species in their native land, are invading the Sahelian countries in search of new hunting grounds. The author, who has worked for 20 years in the Sahel, here describes what is happening in Niger and Mali and urges that steps be taken to stop the slaughter.

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