Suchergebnisse

Context Resource partitioning of diet and microhabitat was examined for five sympatric species of freshwater turtles in the Daly River in the northern end of Northern Territory (Top End) in Australia. The Daly River supports a high diversity of freshwater turtles, making it the ideal place to study a freshwater turtle community. Aims To determine the dry-season diet and microhabitat use of Carettochelys insculpta, Elseya dentata, Chelodina oblonga, Emydura victoriae and Emydura subglobosa worrelli and examine intraspecific and interspecific niche overlap and ontogenetic dietary shift. Methods Gut contents were collected by stomach flushing, and microhabitat use was determined by recording where each turtle was first seen before capture. Diet and microhabitat use were compared using an index of relative importance. Niche overlap was measured with Horn's overlap index. Key results Carettochelys insculpta is an opportunistic omnivore that feeds mostly on ribbonweed (Vallisneria spiralis) and aquatic snails. Elseya dentata is herbivorous, feeding primarily on aquatic algae. The diets of C. insculpta and E. dentata overlapped moderately, but the overall niche overlap was low because they occupied different microhabitats within the river. Chelodina oblonga fed very little, and may use the Daly River as a dry-season refuge. Emydura victoriae is molluscivorous, consuming more molluscs as it grows. This ontogenetic dietary shift was associated with megacephaly (extreme broadly expanded head that is too large to fit into the carapace) and expanded triturating surfaces. This specialisation allows adult E. victoriae to feed exclusively on molluscs and so their diet overlapped little with other species. Emydura subglobosa worrelli was omnivorous, consuming mostly freshwater sponge and apparently preferring more lentic water. Conclusions The freshwater turtles of the wet–dry tropics are usually reported as being heavily reliant on the seeds, fruits and leaves of riparian vegetation; however, the present study showed that the dry-season diet in perennial rivers is primarily of aquatic origin. Implications The study suggested that populations of C. insculpta, E. dentata and E. victoriae could be threatened by broad-scale development in northern Australia if there were substantive impacts on aquatic macrophytes and molluscs in the Daly River system.

The diffusion potential of a targeted HIV/AIDS intervention that enlisted peer educators to disseminate 'safer sex' messages and condoms among female commercial sex workers and their clients was evaluated in the Dominican Republic. Levels of interurban interaction potential were ascertained that linked the targeted city of La Romana with the proximate cities of San Pedro de Macoris and Guaymate. Weekly service statistics generated over an 8-month period were analysed to establish activity areas for the peer educators. Data were entered and analysed using a geographic information system and interurban linkages were established. Project outcomes were examined via a series of three cross-sectional Knowledge, Attitudes and Practices (KAP) surveys conducted among convenience samples of commercial sex workers at the start of the intervention and at 4 and 8 months. The results attest to a high degree of interconnectivity between the targeted and proximate cities, and a pattern of interurban mobility that links commercial sex workers, clients and establishments in all three cities. The examination of project outcomes revealed statistically significant changes in condom use in the targeted city of La Romana among commercial sex workers, as well as among their counterparts interviewed in the proximate cities of San Pedro de Macoris and Guaymate. These data suggest a diffusion effect. It is concluded that a targeted intervention may influence proximate cities within a relatively compressed period of time. The findings suggest the importance of considering geographic diffusion principles, such as urban hierarchies, regional nodes and transportation linkages, when designing HIV/AIDS prevention efforts. It also has important implications in the selection of control sites when conducting experimental studies of HIV/AIDS interventions.

SummaryThis study was conducted in 1985 in Asunción, Paraguay, 6 years after the closure of the state supported family planning services. Data from national surveys in 1977 and 1987 permit a comparison of sources of contraceptive supplies before and after the elimination of government support for family planning. The purchase of pseudo-abortifacients from private pharmacies was used as an indication of induced abortion. After the loss of government clinics, it is suggested that some women turned to pharmacists to obtain pseudo-abortifacients when faced with unwanted pregnancy. There is an indication of increased pseudo-abortifacient use, particularly among unmarried women and those from poorer neighbourhoods.