12 research outputs found
Aspects of the ecology of trumpeter hornbill (bycanistes bucinator) across urban-forest mosaics in KwaZulu-Natal, South Africa.
Doctor of Philosophy in Ecology. University of KwaZulu-Natal, Pietermaritzburg 2016.Abstract available in PDF file
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Assessment of trace elements (Cu, Fe, and Zn) in Limnothrissa miodon from Lake Kariba, Zambia: implications for ecological and human health
This study examined Copper (Cu), Iron (Fe), and Zinc (Zn) levels in Limnothrissa miodon fish from Lake Kariba in Zambia and their potential impact on human health. Two-gram samples from each stratum underwent a 12-hour digestion, and concentrations were determined using Microwave Plasma Atomic Emission Spectrometer. Results indicated that Cu, Fe, and Zn concentrations fell within Food and Agricultural Organization and World Health Organization safety limits. Estimated Daily Intake (EDI) and Hazard Quotient (THQ) values for males and females remained under recommended thresholds, suggesting minimal health risks from consumption. Element concentrations followed the order Fe > Zn > Cu, all below Recommended Daily Allowances (RDAs). THQ values, with Zn posing the highest potential risk followed by Fe and Cu, were under one. Overall, the Hazard Index (HI) was 0.02, signifying a low non-carcinogenic risk from fish consumption. Despite safety, ongoing monitoring of heavy metal accumulation in the ecosystem is advisable for long-term safety. In conclusion, trace element levels in Limnothrissa miodon from Lake Kariba are safe for human consumption with low associated health risks. Nonetheless, continued monitoring of heavy metal levels is vital
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Efficacy of sodium bicarbonate (Baking soda) and clove powder (Syzygium aromaticum) as anaesthetic agents for Nile tilapia (Oreochromis niloticus, linnaeus 1758) juveniles
Anaesthetics in aquaculture serve as a stress avoidance mechanism, mitigating stress-related impacts during fish handling and transportation. This study assessed the efficacy of sodium bicarbonate and clove stem powder as anaesthetic agents for Nile Tilapia juveniles. Four hundred and twenty uniform O. niloticus juveniles (5 ± 0.5 g, 74 ± 5 mm) were exposed to varying concentrations of sodium bicarbonate (10, 15, 20, 25, 30, 35, 40 g/L) and clove stem powder (0, 1, 3, 5, 7, 10, 15 g/L) in 20 L transparent plastic tanks. The results showed an inverse relationship between anaesthetic concentration and induction time, a direct relationship with recovery time, and an inverse correlation between induction and recovery times for both agents (P < 0.001). The Appropriate concentrations were determined as 25 g/L for sodium bicarbonate and 10 g/L for clove stem powder. At these levels, induction and recovery times met ideal criteria (3-5 min induction, 5-10 min recovery), with fish exhibiting normal behavior and 100% survival after a week of monitoring
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Sustainability of agriculture extension services in the face of COVID-19: a study on gender-specific market systems
In the fourth industrial revolution, achieving sustainable agricultural development while feeding a growing world population and maintaining a balanced interrelationship between the economy, society, and the environment has been a significant challenge. However, COVID-19 disrupted agricultural extension and advisory systems, affecting all market participants. The complexity of the pandemic has impacted the private sector, public sector, extension staff, donor funding, education, and research systems, subsequently affecting human nutrition. This paper aims to expertly review COVID-19’s effects on the sustainability of gender-specific agricultural extension service systems. Demand and supply market stakeholders in the extension system are thematically discussed. The findings reveal various consequences of COVID-19 for market actors on both the demand and supply sides of the extension system. Private-sector players often support expansion directly or indirectly, with multi-sectorial support and funding strategies existing for sustainability. In many developing nations, the comprehensive extension system was disrupted by COVID-19, impacting household incomes and nutrition. The pandemic accelerated the adoption of digital technologies in many developing nations, transitioning from a centralized to a decentralized and pluralistic extension model. Multi-sector coordination and execution, especially from health and other sectors, are crucial in managing complex crises that disrupt the market system
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One hundred priority questions for the development of sustainable food systems in sub-Saharan Africa
Sub-Saharan Africa is facing an expected doubling of human population and tripling of food demand over the next quarter century, posing a range of severe environmental, political, and socio-economic challenges. In some cases, key Sustainable Development Goals (SDGs) are in direct conflict, raising difficult policy and funding decisions, particularly in relation to trade-offs between food production, social inequality, and ecosystem health. In this study, we used a horizon-scanning approach to identify 100 practical or research-focused questions that, if answered, would have the greatest positive impact on addressing these trade-offs and ensuring future productivity and resilience of food-production systems across sub-Saharan Africa. Through direct canvassing of opinions, we obtained 1339 questions from 331 experts based in 55 countries. We then used online voting and participatory workshops to produce a final list of 100 questions divided into 12 thematic sections spanning topics from gender inequality to technological adoption and climate change. Using data on the background of respondents, we show that perspectives and priorities can vary, but they are largely consistent across different professional and geographical contexts. We hope these questions provide a template for establishing new research directions and prioritising funding decisions in sub-Saharan Africa
Home range and habitat use of Trumpeter Hornbills <i>Bycanistes bucinator</i> in an urban–forest mosaic, Eshowe, South Africa<sup>§</sup>
<p>Despite the negative impacts of urbanisation, some species adapt to pressures of habitat loss and fragmentation. Trumpeter Hornbills <i>Bycanistes bucinator</i> are a large avian forest frugivore that uses urban environments in South Africa. Consequently, we used GPS/UHF transmitters to study their home range size, movement and habitat use in an urban–forest mosaic in Eshowe, South Africa from March to October 2014. We estimated the home range size using three methods: minimum convex polygon (MCP), kernel density estimation (KDE) and local convex hull (LoCoH). Our results showed that overall monthly home range size was 5.1 ± 1.28 km<sup>2</sup> (mean ± SE; 95% MCP), 4.6 ± 1.14 km<sup>2</sup> (95% KDE) and 1.9 ± 0. 46 km<sup>2</sup> (95% LoCoH). However, individual home range sizes varied monthly and seasonally. We found that all individuals tagged used mostly the indigenous forest and frequently utilised urban residential areas (gardens) with little or no use of cultivated land. Observed individual variations in monthly and seasonal home ranges could be a response to variations in availability of key fruit resources in the urban residential and indigenous forest mosaic. This study supports the use of more than one method of home range estimation for insight regarding home range and habitat use in urban–forest mosaics for this large forest frugivore.</p