Giraffe populations have declined in abundance by almost 40% over the last three decades, and the geographic ranges of the species (previously believed to be one, now defined as four species) have been significantly reduced or altered. With substantial changes in land uses, loss of habitat, declining abundance, translocations, and data gaps, the existing geographic range maps for giraffe need to be updated. We performed a review of existing giraffe range data, including aerial and ground observations of giraffe, existing geographic range maps, and available literature. The information we collected was discussed with and validated by subject‐matter experts. Our updates may serve to correct inaccuracies or omissions in the baseline map, or may reflect actual changes in the distribution of giraffe. Relative to the 2016 International Union for Conservation of Nature Red List Assessment range map, the updated geographic range maps show a 5.6% decline in the range area of all giraffe taxa combined. The ranges of Giraffa camelopardalis (northern giraffe) and Giraffa tippelskirchi (Masai giraffe) decreased in area by 37% (122432 km2) and 4.7% (20816 km2) respectively, whereas 14% (41696 km2) of the range of Giraffa reticulata (reticulated giraffe) had not been included in the original geographic range map and has now been added. The range of Giraffa giraffa (southern giraffe) showed little overall change; it increased by 0.1% (419 km2). Ranges were larger than previously reported in six of the 21 range countries (Botswana, Ethiopia, Mozambique, South Sudan, Tanzania, and Zimbabwe), had declined in seven (Cameroon, Central African Republic, Chad, Malawi, Niger, Uganda, and Zambia) and remained unchanged in seven (Angola, Democratic Republic of Congo, eSwatini, Namibia, Rwanda, Somalia, and South Africa). In Kenya, the ranges of both Giraffa tippelskirchi and Giraffa camelopardalis decreased, but the range of Giraffa reticulata was larger than previously believed. Our updated range maps increase existing knowledge, and are important for conservation planning for giraffe. However, since rapid infrastructure development throughout much of Africa is a driver of giraffe population declines, there is an urgent need for a continent‐wide, consistent and systematic giraffe survey to produce more accurate range maps, in order to inform conservation and policy planning.
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.
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.
Deserts are among the most poorly monitored and understood biomes in the world, with evidence suggesting that their biodiversity is declining fast. Oil exploration and exploitation can constitute an important threat to fragmented and remnant desert biodiversity, yet little is known about where and how intensively such developments are taking place. This lack of information hinders local efforts to adequately buffer and protect desert wildlife against encroachment from anthropogenic activity. Here, we investigate the use of freely available satellite imagery for the detection of features associated with oil exploration in the African Sahelo-Saharan region. We demonstrate how texture analyses combined with Landsat data can be employed to detect ground-validated exploration sites in Algeria and Niger. Our results show that site detection via supervised image classification and prediction is generally accurate. One surprising outcome of our analyses is the relatively high level of site omission errors in Niger (43%), which appears to be due to non-detection of potentially small-scale, temporary exploration activity: we believe the repeated implementation of our framework could reduce the severity of potential methodological limitations. Overall, our study provides a methodological basis for the mapping of anthropogenic threats associated with oil exploitation that can be conducted across desert regions.
Aim To assess the distribution and occurrence of addax (Addax nasomaculatus), the most critically endangered ungulate species globally, and dorcas gazelle (Gazelle dorcas), for which the ecology in the southern Sahara is virtually unknown. Location Tin Toumma desert, Niger Methods Integrating field surveys, collected over a 7‐year period (2008–2014), with remote sensing‐derived measures of vegetation productivity (NDVI) and surface roughness, we fit models in a generalized linear regression framework to predict and evaluate the occurrence of addax and dorcas gazelle. Results Addax declined significantly over the course of the study, strongly affecting the outcomes of our regression models. Other factors, namely surface roughness and the occurrence of the perennial grass Stipagrostis acutiflora, were important in predicting addax occurrence. Dorcas gazelle, inhabiting areas further to the south of our study area, were more positively associated with increases in vegetation productivity than addax. Both species were observed to have a strong negative response to human disturbance. Predictive models, relying only on remotely sensed derived variables, provided insight into areas of habitat suitability and highlighted niche partitioning across the Sahelo‐Saharan biome. Main conclusions Our results provide improved insight into the factors contributing to the occurrence of this critically endangered (addax) and vulnerable (dorcas gazelle) species and may help guide future field surveys across the region to locate small and geographically isolated populations. Developing statistically based ecological habitat models provide a first‐step towards improved management and policy development for the long‐term conservation of these species and complement field surveys conducted across the region to monitor species that are increasingly being pushed to extinction.
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