scholarly journals Evaluating methods for surveying the Endangered Cuvier's gazelleGazella cuvieriin arid landscapes

Oryx ◽  
2016 ◽  
Vol 51 (4) ◽  
pp. 648-655 ◽  
Author(s):  
Jose María Gil-Sánchez ◽  
F. Javier Herrera-Sánchez ◽  
Begoña Álvarez ◽  
Ángel Arredondo ◽  
Jesús Bautista ◽  
...  
Keyword(s):  
Distance Sampling ◽  
Population Monitoring ◽  
Arid Environments ◽  
Occupancy Modelling ◽  
Field Methods ◽  
Western Sahara ◽  
Western Africa ◽  
The North ◽  
Indirect Sign ◽  
North Western

AbstractThe Endangered Cuvier's gazelleGazella cuvieriis an endemic ungulate of north-western Africa. Information on the species has been based primarily on non-systematic surveys, and the corresponding status estimates are of unknown quality. We evaluate the effectiveness and efficiency of two field methods for systematic surveys of populations of Cuvier's gazelle in arid environments: distance sampling (based on sightings) and sampling indirect sign (tracks and scats). The work was carried out in the north-western Sahara Desert, in Morocco, where what is possibly the largest population of Cuvier's gazelle persists. A logistically viable survey was conducted over a total area of c. 20.000 km2in 10 expeditions during 2011–2014. A total of 67 sites were surveyed, with 194 walking surveys (2,169 km in total). Gazelle signs were detected at 50 sites, and gazelles were sighted at 21 sites (61 individuals). We found a relationship between sightings and abundance indices based on indirect sign, which could be useful for population monitoring or ecological studies. Additionally, the data could be used in occupancy modelling. Density estimates based on distance sampling required considerable effort; however, it is possible to survey large areas during relatively short campaigns, and this proved to be the most useful approach to obtain data on the demographic structure of the population.

Barriers for conservation: mitigating the impact on amphibians and reptiles by water cisterns in arid environments

2017 ◽  
Vol 38 (1) ◽  
pp. 113-118 ◽  
Author(s):  
Juan M. Pleguezuelos ◽  
Luis García-Cardenete ◽  
Jesús Caro ◽  
Mónica Feriche ◽  
María T. Pérez-García ◽  
...  
Keyword(s):  
Mixed Models ◽  
Cost Effective ◽  
Wire Mesh ◽  
Arid Environments ◽  
Western Sahara ◽  
The North ◽  
Management Condition ◽  
Conservation Concern ◽  
The Impact ◽  
North Western

Anthropogenic infrastructures are one of the major threats to biodiversity. In the north-western Sahara shepherds are increasingly building water cisterns of reinforced concrete for watering livestock. These infrastructures attract desert fauna and act as indiscriminate death traps for the amphibians and reptiles (herps) in the surrounding habitats. Here we propose an on-site, cost-effective management measure. We selected two groups of 36 cisterns, managed a group by covering the lateral openings with wire mesh (managed cistern), leaving the other group unmanaged (control cistern). Managed cisterns trapped fewer species, fewer individuals (one third), and individuals of smaller body size and of less conservation concern than did control cisterns. In a multivariate approach by Generalized Mixed Models, the best models explaining the number of species and individuals of herps trapped within cisterns included as the predictor only the management condition, with a trend for higher values in control cisterns.

scholarly journals The international legal status of Western Sahara

2021 ◽  
Vol 18 (4) ◽  
pp. 35-47
Author(s):  
Adrianna Kalicka-Mikołajczyk
Keyword(s):  
Legal Status ◽  
Present Condition ◽  
Western Coast ◽  
Western Sahara ◽  
World War 2 ◽  
North East ◽  
Western Africa ◽  
The North ◽  
Spanish Province ◽  
North Western

Western Sahara is a territory lying in North-Western Africa. It borders Morocco in the north, Algeria in the north-east, Mauritania in the east and in the south, and its north-western coast borders the Atlantic Ocean. The country was colonized by the Kingdom of Spain following the decisions of the Berlin conference held in 1884. After World War 2, it was a Spanish province. When it won the independence in 1956, Morocco demanded that Western Sahara should be “liberated”, claiming that the territory belonged to it. In 1963,following the passing of the information by Spain, on the basis of Article 73 letter e) of the Charter of the United Nations, the UN entered Western Sahara in the list of areas which were not governed independently. On 14 April 1976, Morocco and Mauritania signed a convention on establishing their frontier line, on the power of which they executed a division of the territory of Western Sahara. Nowadays the western – the larger – part of Western Sahara’s territory is controlled by Morocco. The main aim of this article is to provide an answer to the question of the present condition of the international legal status of Western Sahara.

scholarly journals A GIS-Based Approach to Inform Agriculture-Water-Energy Nexus Planning in the North Western Sahara Aquifer System (NWSAS)

2020 ◽  
Vol 12 (17) ◽  
pp. 7043 ◽  
Author(s):  
Youssef Almulla ◽  
Camilo Ramirez ◽  
Konstantinos Pegios ◽  
Alexandros Korkovelos ◽  
Lucia de Strasser ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
Mathematical Formulation ◽  
Western Sahara ◽  
Aquifer System ◽  
Water Abstraction ◽  
The North ◽  
Groundwater Source ◽  
Water Scarce ◽  
North Western ◽  
Agriculture Water

The North Western Sahara Aquifer System (NWSAS) is a vital groundwater source in a notably water-scarce region. However, impetuous agricultural expansion and poor resource management (e.g., over-irrigation, inefficient techniques) over the past decades have raised a number of challenges. In this exploratory study, we introduce an open access GIS-based model to help answer selected timely questions related to the agriculture, water and energy nexus in the region. First, the model uses spatial and tabular data to identify the location and extent of irrigated cropland. Then, it employs spatially explicit climatic datasets and mathematical formulation to estimate water and electricity requirements for groundwater irrigation in all identified locations. Finally, it evaluates selected supply options to meet the electricity demand and suggests the least-cost configuration in each location. Results indicate that full irrigation in the basin requires ~3.25 billion million m3 per year. This translates to ~730 GWh of electricity. Fossil fuels do provide the least-cost electricity supply option due to lower capital and subsidized operating costs. Hence, to improve the competitiveness of renewable technologies (RT) (i.e., solar), a support scheme to drop the capital cost of RTs is critically needed. Finally, moving towards drip irrigation can lead to ~47% of water abstraction savings in the NWSAS area.

scholarly journals Estimates of the relative abundance of long-finned pilot whales (Globicephala melas) in the Northeast Atlantic from 1987 to 2015 indicate no long-term trends

2019 ◽  
Vol 11 ◽  
Author(s):  
Daniel G. Pike ◽  
Thorvaldur Gunnlaugsson ◽  
Geneviève Desportes ◽  
Bjarni Mikkelsen ◽  
Gísli A. Vikingsson ◽  
...  
Keyword(s):  
Relative Abundance ◽  
North Atlantic ◽  
Distance Sampling ◽  
Field Methods ◽  
Pilot Whale ◽  
Globicephala Melas ◽  
The North ◽  
Spatial Coverage ◽  
Pilot Whales ◽  
Annual Distribution

North Atlantic Sightings Surveys (NASS) and associated surveys, covering a large but variable portion of the North Atlantic, were conducted in 1987, 1989, 1995, 2001, 2007 and 2015. Previous estimates of long-finned pilot whale (Globicephala melas) abundance, derived using conventional distance sampling (CDS), are not directly comparable to one another because of differing survey coverage, field methods and, in the case of the 1989 NASS, different survey timing. CDS was used to develop indices of relative abundance to determine if pilot whale abundance has changed over the 28-year period from 1987 to 2015. The varying spatial coverage of the surveys is accommodated by delineating common regions that were covered by: i) all 6 surveys, and ii) the 3 largest surveys (1989, 1995, and 2007). These “Index Regions” were divided into East and West subregions, and post-stratification was used to obtain abundance estimates for these index areas only. Estimates are provided using the sightings from the combined platforms for surveys that used double platforms or the primary platform only.Total abundance in the Index Regions, uncorrected for perception or availability biases, ranged from 54,264 (CV=0.48) in 2001 to 253,109 (CV=0.43) in 2015. There was no significant trend in the numbers of individuals or groups in either the 6 or 3 Survey Index Regions, and no consistent trend over the period. Power analyses indicate that negative annual growth rates of -3% to -5% would have been detectible over the entire period. The Index Regions comprise only a portion of the summer range of the species and changes in annual distribution clearly affect the results. Operational changes to the surveys, particularly in defining pilot whale groups, may also have introduced biases. Recommendations for future monitoring of the long-finned pilot whale population are provided.

Sign in / Sign up

Export Citation Format

Share Document