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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
641

Conservation of private land by means of compensatory mechanisms and incentives

Glazewski, Jan January 1986 (has links)
Includes bibliography. / This report reviews the potential of financial incentives and compensatory mechanisms for achieving conservation goals on privately owned land in South Africa. Legal concepts, such as the notion of absolute ownership of property, are examined in the context of South Africa's historical and political circumstances to highlight how they have contributed to a highly individualistic attitude to land ownership in South Africa. The achievement of environmental objectives has relied largely on outright control of, and prohibitions on, the use of land. Incentives and compensatory mechanisms offer complementary methods of encouraging the diminution of ownership rights in private land for the public interest. A review of some foreign legal systems shows that compensation for the diminution of private rights in land is a grossly neglected area of South African law. It is found that attention should be given to the development of satisfactory principles of compensation as well as to the incorporation of incentives into South African legislation. It is concluded that the success of such recommendations is dependant on the fulfilment of certain administrative prerequisites, including the formulation of a national strategy for the conservation of private land in South Africa and the constitution of a formal body of experts to advise on compensation and incentive schemes.
642

The impact of a 'trough' Concentrated Solar Power facility on birds and other animals in the Northern Cape, South Africa

Jeal, Corey January 2017 (has links)
The environmental impacts of solar power generation and particularly Concentrated Solar Power (CSP) are not well understood. There have been reports of birds injured and killed by concentrated solar radiation at power 'towers' and from collisions with mirrors at both tower and 'trough' facilities. This study assesses the impacts of a utility-scale 50 MW 'trough' CSP facility - Bokpoort CSP Power Plant - in the Northern Cape, South Africa. To assess the changes in functional and structural changes in bird communities, bird counts in the solar fields (mirror arrays) were compared with transects from rangelands adjacent to the CSP plant. Invertebrates were sampled with sticky and pitfall traps adjacent to the power block, in the solar fields, and in the rangeland landscape to assess changes in invertebrate communities. There were significant changes in bird distribution across the landscape with more species richness and two orders of magnitude greater abundance in the rangeland compared to the solar fields. Fewer invertebrates were caught, but with a greater taxonomic richness in rangeland compared to the power block and solar field. The facilities' evaporation ponds created novel wetland habitat for birds; 23 species were recorded that would have been absent from the area prior to construction, including three breeding species. The solar fields were surveyed for bird injuries or fatalities over 3 months; only eight dead birds were found, all but one was too old to determine the cause of death (>1 month); the remaining carcass likely died from a mirror impact. Western Barn Owls (Tyto alba) made up half of the mortalities. Biases in mortality estimates due to searcher efficiency and scavenger removal were substantial only for small birds. Twenty-one animals (3 reptiles, 12 mammals, 6 birds) likely drowned in the evaporation ponds after being unable to escape. The recorded mortalities were very low in comparison with similar studies on CSP facilities. No threatened or endangered species were killed. Overall, the facility had a low impact on bird populations, but the drowning risk posed to animals by evaporation ponds requires mitigation. The negative impacts observed could be minimised through careful site selection of solar facilities and careful design and mitigation considerations particularly with regard to evaporation and water ponds in arid areas such as the Northern Cape.
643

Using Conditioned Food Aversion (CFA) to reduce Pied Crow (Corbus albus) predation of plover nests

Ferguson, Angela January 2016 (has links)
Nest predation is one of the principle constraints on bird breeding success, accounting for 20 to 80% of all nest failures. It can be exacerbated by anthropogenic factors and the resultant increased predation pressure has caused the decline of numerous bird species worldwide. Identifying management strategies to reduce nest predation is consequently a priority for biodiversity conservation. Many lethal and non-lethal methods of predator control can be ineffective, unethical, time-consuming and expensive to implement. An alternative is the use of Conditioned Food Aversion (CFA), a method by which animals are deliberately induced to avoid nests following consumption of eggs treated with an illness-inducing toxin. Previous studies suggest that this technique is effective but many have been subject to several methodological flaws that limit their applicability. Here I employ an improved experimental design that uses both spatial and temporal controls and incorporates quantification of predator identity and abundance. By so doing the resultant effects can be attributed to CFA treatment with higher certainty. In the Berg River Estuary, South Africa, nest losses of the Kittlitz's Plover (Charadrius pecuarius) are high due to Pied Crow (Corvus albus) nest predation. I used this common plover as a model species to test whether CFA can be used as a conservation management tool to reduce nest predation. I used a field experiment to assess whether provisioning quail eggs treated with carbachol, an illness-inducing chemical, resulted in reduced nest predation. To assess the effects of treatment, nest survival data for both artificial plover nests containing quail eggs and natural Kittlitz's plover nests, as well as predator abundance were compared across three experimental phases (pre-treatment, treatment and post-treatment) and according to treatment type (carbachol versus water).
644

African penguin (Spheniscus demersus) distribution during the non-breeding season : preparation for, and recovery from, a moulting fast

Roberts, Jennifer January 2016 (has links)
Little is currently known about the spatial ecology of the endangered African penguin during the non-breeding season. As foraging success during this period is critical to adult survival, this project explores their dispersal patterns, as well as the degree of overlap with commercial purse-seine fisheries which target the same prey. African penguins from two colonies (Bird Island, Algoa Bay, south coast and Dassen Island, west coast) were tracked over 3 non-breeding seasons using Platform Terminal Transmitters and Global Positioning System devices to explore their pre- and post-moult dispersal patterns. Dispersal trips varied greatly between individuals, but there were still significant differences in the dispersal patterns found between islands and between life history-stages at Dassen Island. Bird Island penguins tended to make frequent, short trips, returning to their breeding colony in between, whereas Dassen Island penguins followed one of two strategies: either making few (up to 3) very long trips (up to 4000km), or adopting a central-place foraging pattern based at a point along the coast, distant from their breeding colony. At Dassen Island a clear spatial divide is evident with most pre-moulters dispersing south whereas most post-moult birds dispersed north, off the west coast. Bird Island penguins all moulted at their breeding colony and seldom visited either the adjacent coastline or other islands. During pre-moult, Dassen Island birds often spent nights close to shore along the coast or at other colonies and about a quarter of them moulted at another colony, most often at Stony Point, on the mainland east of Cape Point. Five dispersal patterns (defined in terms of the direction and distance of the furthest point reached) were identified for birds from Dassen Island and there is some indication that different dispersal patterns have distinct survival implications. Over 60% of PTT loss (a proxy for penguin mortality) occurred in a small area in the northern part of St Helena Bay, offshore from Lambert's Bay and Strandfontein and could be due to high levels of seal predation, which has been previously documented in the area. Commercial small pelagic fishing data were analysed over three years (2012-2014). Average fishing effort decreased each month from September to December (when hardly any fishing occurred in any of the three years) and there was much greater fishing effort along the west coast than on the south coast. Commercial fishing effort was compared to penguin track data to assess the degree of potential overlap between these two pelagic predators. Firstly, the spatial overlap between core penguin non-breeding dispersal areas and core fishing areas was assessed on a broad temporal scale (three years). Bird Island penguins were found to be more spatially removed from fishing activity with no overlap in core fishing and dispersal areas on the south coast. Compared to the size of their dispersal area, Dassen Island penguins which stayed along the lower west coast showed the highest overlap with core fishing areas. The two most common dispersal patterns exhibited by Dassen Island penguins both involve journeying to areas outside the range of purse-seine fishing, indicating the possibility of avoidance behaviour once the pressures of breeding are lifted. Direct (daily) overlap between commercial fishing effort and penguin tracks was studied although the low frequency of the penguin position data restricted the analysis to a 20 km scale. The results were similar to those described above, with most direct overlap occurring between Dassen Island and Gansbaai.
645

Vegetation and land-use data collection methods for environmental management purposes, with particular reference to the rivers entering False Bay, Cape, South Africa

O'Callaghan, M January 1985 (has links)
The increasing population and urbanization occurring in South Africa is threatening the survival of many environments, particularly those in close proximity to urban areas. Present legislation does not adequately protect the environment, and methods are needed to collect data to guide the development of conservation-orientated management and developmental policies. These data should provide a general description of the environment, Indicating sensitive areas, while taking physical, socio-economic and natural features into account. To be most meaningful, these data should be stored in a survey information system which is accessible to any person or institution involved in management or developmental policy formulation. Chapter 2 describes some of the components of such a system. Chapter 3 discusses the data collection component of the survey Information system. The use of vegetation features to describe the natural environment, and the use of land-use features for the socio-economic environment, are emphasized. Numerous methods are available to collect vegetation and land-use data, but for management purposes the methods should be elementary enough to be used by non-specialists while still supplying meaningful data. Aerial photography can be applied to vegetation and land-use studies. However, numerous inaccuracies can occur when using aerial photography as a source of data and Chapter 3 also discusses some of these limitations. The study area used to test proposed methods of collecting vegetation and land-use data for a management information system are described in Chapter 4. The study area consists of eleven study sites, each at a river mouth on the False Bay coast.
646

Assessing Environmental Stress on the Loggerhead Sea Turtle (Caretta caretta) in Virginia Waters

Bellmund, Sarah A. 01 January 1988 (has links)
No description available.
647

Biogeography and conservation of terrestrial afrotropical birds

De Klerk, Helen Margaret January 1999 (has links)
Includes bibliography. / This study aimed to describe patterns of distribution in terrestrial Afrotropical birds, to investigate the causes of these patterns, and examine how aspects of distributional patterns may be used to prioritize local regions for conservation attention. Presence-only data were gathered and digitized at one-degree square scale for 1686 terrestrial bird species that breed on or regularly visit sub-Saharan Africa as non-breeding migrants. Biogeographical analysis of the 1437 species that are globally restricted to sub-Saharan Africa (Afrotropical endemics) revealed a suite of geographical areas that have a homogenous and characteristic avifaunal composition, termed avifaunal zones. The approach used in this study ensured representativeness in the resultant biogeographical classification scheme, which was not biased towards avifaunas that are species rich or that contain many narrow endemics, and further included avifaunas that consisted of few, but taxonomically and ecologically distinct species (e.g. the Namib Province). Analysis of zonal boundaries exhibiting high levels of turnover, defined specifically as species replacement, were distinguished from zonal boundaries that are characterised by species richness gradients. For instance, the northern forest-savanna boundary between the Guineo-Congolian and Northern Savanna Subregions was shown to consist of a sharp ecotone between forest and savanna, whereas the boundary between the Northern Savanna and Northern Arid Subregions was shown to be dominated by species drop-outs. This shows that whereas the Northern Savanna Subregion represents a unique avifauna that is distinct from that of the Guineo-Congolian Subregion, the Northern Arid Subregion is merely a depauparate subset of the Northern Savanna avifauna. Patterns of species richness and narrow endemism where shown to differ between species groups that exhibit different life history characteristics (e.g. residents vs. migrants) and distributional characteristics Atrotropical endemics vs. nonendemics). Differences can probably be attributed to island biogeography and aerography theory.
648

Assessing the anthropogenic threats to vultures in the communal farmlands of Namibia

Craig, Christie January 2017 (has links)
The use of poison by farmers to control livestock predators is a major threat to vulture populations across Africa. In Namibia, there is now some understanding of poison use on commercial farms, but the situation in the communal farmlands is still poorly understood. Using a series of 36 questions, I interviewed 367 communal farmers to assess the prevalence of poison use across the north-west, north and eastern communal land. I found that 18% (SE 2.8) of farmers had killed a predator in the last year and 1.7% (SE 2.1) used poison to do so. I mapped the probability of poison use across the communal regions surveyed and found that poison use is predicted to be higher (up to 7% of farmers using poison) in some areas of the upper north-west. In contrast to previous research, those living adjacent to protected areas did not experience greater losses to predators and as a result were not more inclined to use poison. I found that those using poison are more likely to own greater numbers of livestock, particularly large livestock. Overall, my study suggests that poison use is approximately 12 times lower in the communal areas than on commercial farms. A number of farmers expressed that it is dangerous to use poison on communal land as the risk of non-target impacts is much higher where the land is not fenced and is communally used. Nonetheless there are communal farmers who are using poison and this poses a risk to already threatened vulture populations. Lastly, I did a survey to look at the farmers' local knowledge about vultures, their attitudes towards them and any cultural value that vultures hold. Overall vultures were viewed positively by farmers. The cultural use of vulture parts appeared fairly uncommon, with 9.5% of farmers reporting that they knew of uses. Many farmers indicated that the cultural use of vulture parts was something practiced by previous generations. Feathers were the most commonly used part, mainly for decorations and making arrows. From my assessment, it appears that anthropogenic threats to vultures in communal areas are fairly low. The cultural use of vulture body parts is rare. In addition, poison is used but this practice is not nearly as common as it is on commercial farms. Since poison can have such devastating impacts on vulture populations, I nonetheless advise that reactive and preventative measures are put in place to reduce poisoning and minimise the impact when poison is used. The identified 'hotspots' of poison use will assist local authorities to focus their poison mitigation efforts.
649

Does the availability of shade limit use of water troughs by desert birds?

Abdu, Salamatu January 2015 (has links)
Includes bibliographical references / Climate change poses a major threat to living organisms, with maximum temperatures expected to continue to rise over the next few decades. Hot desert environments are particularly at risk because they experience high environmental temperatures, scarce vegetation, low productivity and unpredictable water sources. Endotherms such as birds face the challenge of maintaining a stable body temperature while avoiding dehydration. This study was carried out in the southern Kalahari, in South Africa's Northern Cape, where about 50% of bird species (36 species) depend on free-standing drinking water. Livestock farms within this area provide artificial water points, which benefit birds as well as livestock. This study determined the role of shade and cover in the use of these artificial water points by birds. An experiment was conducted at six waterholes using the Before-After, Control-Impact (BACI) design. After an initial baseline was established, three waterholes were shaded while the other three were left unshaded. Camera traps were used to record the pattern and intensity of water use by bird species at different times of the day and at varying air temperatures. A total of 36 bird species drank at the water holes, but data analysis was confined to the ten most abundant species. Of the ten, six species responded to the presence of shade/cover, with four species reacting positively (Cape Glossy Starling Lamprotornis nitens , Red - headed Finch Amadina erythrocephala , Black - throated Canary Serinus atrogularis , and Laughing Dove Spilopelia senegalensis ), four showing no significant change in drinking patterns, and two showing a decrease in visitor numbers when the site was shaded (Cape Turtle - Dove Streptopelia capicola, Namaqua Dove Oena capensis). This suggests that providing shade at waterholes is not a universal solution to the problem of increasing heat stress experienced by birds coming to drink. Certain species such as the Laughing Doves and Cape Turtle-Doves avoided waterholes during the warmest time of the day while the Namaqua Doves were frequent visitors at this time. However, the Laughing Dove took advantage of the shade provided at midday (warmest temperatures) as their numbers increased. The Red-headed Finch and Black-throated Canary also increased at water holes with temperature irrespective of the time of day. These patterns imply that the provision of shade modifies the behavior of some bird species in response to predation risk or heat stress. These species utilized shade at different times of day and with varying intensities as temperatures rose.
650

Fine-scale movements and habitat use of the Southern Ground Hornbill Bucorvus Leadbeateri

Zoghby, Blair Anthony January 2015 (has links)
Southern Ground-Hornbills Bucorvus leadbeateri are listed as Endangered in South Africa and there is a concerted effort to reverse their population decline. Understanding the factors affecting their movement patterns and how they interact with their habitat is useful to inform conservation and habitat management options for the species, to select sites for artificial nests and to identify suitable areas for reintroduction initiatives. In this study, I report daily and seasonal patterns of habitat use as well as patterns of roost site use of four Southern Ground-Hornbill groups in the Associated Private Nature Reserves, northeast South Africa, based on data from GPS-satellite tags collected over one year from October 2010 to September 2011. Home ranges varied from 5.9-10.3 km² and were larger in winter than during the summer breeding season. Daily travel distances were greater during the breeding season, when birds were constrained to forage close to their nest, and were lower in winter, when birds ranged more widely. Hourly travel distances were affected by time of day, season, air temperature and group. Birds travelled farthest per hour in the morning, decreasing in the afternoon in winter. However, in summer hourly travel distances were bimodally distributed, with a minimum during the middle of the day when ambient temperatures exceed 25⁰C. Acacia-dominated vegetation and riparian habitats were favoured disproportionately during the heat of the day in summer, presumably because they offer more shade than other habitats. The number of roost sites used per month decreased progressively throughout the Early Wet season (October-December) and was lowest during the Late Wet season (January-March) for three groups that bred successfully. Mean monthly nights per roost were highest for these groups in the Early Wet and Late Wet seasons, specifically over December and January, coinciding with the peak breeding period. Throughout the Early Wet season, all four groups frequently roosted in close proximity to the nest, with 54-83% of roosts being within 1 000 m of the nest. During the Wet season, riparian habitats were favoured for roosting by the three groups that bred successfully, while during the dry season, disturbed areas, combretum-dominated habitats and mopane-dominated habitats were used. I conclude that the optimal habitat configurations for ground-hornbills include a mosaic of habitat types, including open areas for foraging and dense trees for shade as well as adequate large trees for nesting and roosting, particularly in riparian habitats.

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