79 research outputs found

    Spatial patterns of land-use by immature African white-backed vultures (Gyps africanus) captured in the North-West Province, South Africa

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    As obligate scavengers Gyps vultures provide an important ecosystem service as the main consumers of ungulate carcasses in African savannas. Throughout the continent, however, multiple threats are causing vulture populations to decline, especially outside protected areas. Although the African white-backed vulture Gyps africanus is the most numerous and widely distributed Gyps species in Africa, its foraging ecology and land use preferences remain poorly understood. Furthermore, while protected areas are known to be important for vultures in East and West Africa, their role in South Africa has not been fully investigated. This study uses GPS-GSM tracking units to investigate the movement and land-use patterns of six immature African white-backed vultures that were caught at Mankwe Wildlife Reserve in the North West Province of South Africa. Immature individuals were chosen because they were expected to travel extensively and be exposed to the full range of threats. The tracking units recorded the GPS location, speed, altitude and direction of travel three times per day. The size and extent of the vultures‟ foraging ranges were estimated using three methods: minimum convex polygons (MCPs), fixed kernel density estimation (KDE) and grid cell range (GCR) estimation. The vultures‟ use of protected areas and areas of different cattle densities (zero, low, medium and high) was assessed to determine whether they were visited more or less than expected based on the area they occupied within the vultures‟ foraging ranges. The distances travelled by the vultures and their flight speeds and altitudes were also calculated, as well as the amount of time that they spent in the vicinity of supplementary feeding sites. The vultures were tracked for between 101 and 313 days and the GPS tracking units acquired 99.44% of expected GPS locations. The vultures ranged extensively and generally travelled in a nomadic manner. While three individuals occupied foraging ranges (mean 95% KDE contour area = 106,282.33 km2) either side of the South African borders between Botswana and Zimbabwe, the other three travelled more extensively through southern Africa, entering six different countries (mean 95% KDE contour area = 563,564.67 km2). The vultures rarely visited protected areas in South Africa but two of the vultures regularly used protected areas in northern Botswana and Zimbabwe. Areas of high cattle density were used less than expected by all vultures, but not at a significant level, while two of the vultures used areas with zero cattle density more than expected due to their regular use of supplementary feeding sites in those areas. Areas of medium cattle density were the most regularly used, containing an average of 30.72% of each vulture‟s stationary GPS locations. The vultures travelled an average of 33 km/day and a maximum of 267 km/day, flying at an average of 50 km/h (maximum = 107 km/h) at 561 m above ground level (maximum = 2,267 m). This study provides the first description of movement and land-use patterns of immature African white-backed vultures tracked continuously from South Africa. Their extensive foraging ranges and limited use of protected areas implies that the vultures could potentially encounter the full range of threats in the region, and it is clear that their future conservation will depend upon conservation strategies that extend across international borders. CopyrightDissertation (MSc)--University of Pretoria, 2011.Paraclinical Sciencesunrestricte

    The State of Coral Reef Ecosystems of Southeast Florida

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    The northern extension of the Florida reef tract and a complex of limestone ridges run parallel to the subtropical Atlantic coastline of southeast Florida. Spanning 170 km from the northern border of Biscayne National Park (BNP) in Miami-Dade County to the St. Lucie Inlet in Martin County, the reefs and hardbottom areas in this region support a rich and diverse biological community (Figure 5.1). Nearshore reef habitats in southeast Florida include hardbottom areas, patch reefs and worm reefs (Phragmatopoma spp.) exhibiting abundant octocoral, macroalgae, stony coral and sponge assemblages. Offshore, coral reef associated biotic assemblages occur on linear Holocene Acropora palmata mid-shelf and shelf margin reefs that extend from Miami Dade County to Palm Beach County (Lighty, 1977; Figure 5.2). Anastasia Formation limestone ridges and terraces colonized by reef biota characterize the reefs from Palm Beach County to Martin County (Cooke and Mossom, 1929). The coastal region of southeast Florida is highly developed, containing one third of Florida’s population of 16 million people (U.S. Census Bureau, 2006). Many southeast Florida reefs are located just 1.5 km from this urbanized shoreline. Despite their unique position as the highest latitude reefs along the western Atlantic seaboard, the reefs of southeast Florida have only recently received limited scientific and resource management attention. Andrews et al. (2005) discussed the reefs of southeast Florida and the critical need to implement actions that fill resource knowledge gaps and address conservation and threats to reef health. This report further examines and updates the list of stressors imperiling the health of southeast Florida’s reefs, and presents information gained from new research, monitoring and management efforts to determine the extent and condition of reef resources in this distinctive region

    Understanding continent-wide variation in vulture ranging behavior to assess feasibility of Vulture Safe Zones in Africa: Challenges and possibilities

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    Protected areas are intended as tools in reducing threats to wildlife and preserving habitat for their long-term population persistence. Studies on ranging behavior provide insight into the utility of protected areas. Vultures are one of the fastest declining groups of birds globally and are popular subjects for telemetry studies, but continent-wide studies are lacking. To address how vultures use space and identify the areas and location of possible vulture safe zones, we assess home range size and their overlap with protected areas by species, age, breeding status, season, and region using a large continent-wide telemetry datasets that includes 163 individuals of three species of threatened Gyps vulture. Immature vultures of all three species had larger home ranges and used a greater area outside of protected areas than breeding and non-breeding adults. Cape vultures had the smallest home range sizes and the lowest level of overlap with protected areas. RĂĽppell\u27s vultures had larger home range sizes in the wet season, when poisoning may increase due to human-carnivore conflict. Overall, our study suggests challenges for the creation of Vulture Safe Zones to protect African vultures. At a minimum, areas of 24,000 km2 would be needed to protect the entire range of an adult African White-backed vulture and areas of more than 75,000 km2 for wider-ranging RĂĽppell\u27s vultures. Vulture Safe Zones in Africa would generally need to be larger than existing protected areas, which would require widespread conservation activities outside of protected areas to be successful

    Use of avian GPS tracking to mitigate human fatalities from bird strikes caused by large soaring birds

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    Birds striking aircrafts cause substantial economic loss world-wide and, more worryingly, human and wildlife fatalities. Designing effective measures to mitigate fatal bird strikes requires an in-depth knowledge of the characteristics of this incident type and the flight behaviours of the bird species involved. The characteristics of bird strikes involving aircraft crashes or loss of human life in Spain were studied and compared to flight patterns of birds monitored by GPS. We tracked 210 individuals of the three species that cause the most crashes and human fatalities in Spain: griffon and cinereous vultures Gyps fulvus and Aegypius monachus and white storks Ciconia ciconia. All the crashes involved general aviation aircrafts, while none were recorded in commercial aviation. Most occurred outside airport boundaries, at midday, and in the warmest months, which all correspond with the maximum flight activity of the studied species. Bird flight altitudes overlapped the legal flight altitude limit set for general aviation. Policy implications. Mitigation of fatal bird strikes should especially address the conflict between general aviation and large soaring birds. Air transportation authorities should consider modifying the flight ceiling for general aviation flights above the studied species' maximum flight altitude. Moreover, policymakers should issue pilots with recommendations regarding the dates and times of peak activity of large soaring bird species to improve flight safety.This research was funded by Project RNM-1925 (Junta de Andalucía), Comunidad de Bardenas Reales de Navarra, Projects CGL2012-32544, CGL2015-66966-C2-1-2-R and CGL2015-66966-C2-1-R2 (Spanish Ministry of Economy and Competitiveness and EU/FEDER) and i-link 0564 (CSIC). E.A. was supported by La Caixa-Severo Ochoa International PhD Program 2015. A.C.-A. was supported by a postdoc contract from Govern Balear, Spain (PD/039/2017). Contributions by T. L. DeVault were partially supported by the U.S. Department of Energy under award # DE-EM0004391 to the University of Georgia Research Foundation. MW was also funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) by Germany's Excellence Strategy – EXC 2117 – 422037984.Peer reviewe

    Endothelial Dysfunction and Specific Inflammation in Obesity Hypoventilation Syndrome

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    BACKGROUND: Obesity hypoventilation syndrome (OHS) is associated with increased cardiovascular morbidity. What moderate chronic hypoventilation adds to obesity on systemic inflammation and endothelial dysfunction remains unknown. QUESTION: To compare inflammatory status and endothelial function in OHS versus eucapnic obese patients. METHODOLOGY: 14 OHS and 39 eucapnic obese patients matched for BMI and age were compared. Diurnal blood gazes, overnight polysomnography and endothelial function, measured by reactive hyperemia peripheral arterial tonometry (RH-PAT), were assessed. Inflammatory (Leptin, RANTES, MCP-1, IL-6, IL-8, TNFalpha, Resistin) and anti-inflammatory (adiponectin, IL-1Ra) cytokines were measured by multiplex beads immunoassays. PRINCIPAL FINDINGS: OHS exhibited a higher PaCO(2), a lower forced vital capacity (FVC) and tended to have a lower PaO(2) than eucapnic obese patients. (HS)-CRP, RANTES levels and glycated haemoglobin (HbA1c) were significantly increased in OHS (respectively 11.1+/-10.9 vs. 5.7+/-5.5 mg x l(-1) for (HS)-CRP, 55.9+/-55.3 vs 23.3+/-15.8 ng/ml for RANTES and 7.3+/-4.3 vs 6.1+/-1.7 for HbA1c). Serum adiponectin was reduced in OHS (7606+/-2977 vs 13,660+/-7854 ng/ml). Endothelial function was significantly more impaired in OHS (RH-PAT index: 0.22+/-0.06 vs 0.51+/-0.11). CONCLUSIONS: Compared to eucapnic obesity, OHS is associated with a specific increase in the pro-atherosclerotic RANTES chemokine, a decrease in the anti-inflammatory adipokine adiponectin and impaired endothelial function. These three conditions are known to be strongly associated with an increased cardiovascular risk. TRIAL REGISTRATION: ClinicalTrials.gov NCT00603096
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