Africa

Africa is one of the lowest contributors to greenhouse gas emissions causing climate change, yet key development sectors have already experienced widespread losses and damages attributable to human-induced climate change, including biodiversity loss, water shortages, reduced food production, loss of lives and reduced economic growth (high confidence1).// Between 1.5°C and 2°C global warming—assuming localised and incremental adaptation—negative impacts are projected to become widespread and severe with reduced food production, reduced economic growth, increased inequality and poverty, biodiversity loss, increased human morbidity and mortality (high confidence). Limiting global warming to 1.5°C is expected to substantially reduce damages to African economies, agriculture, human health, and ecosystems compared to higher levels of global warming (high confidence).// Exposure and vulnerability to climate change in Africa are multi-dimensional with socioeconomic, political and environmental factors intersecting (very high confidence). Africans are disproportionately employed in climate-exposed sectors: 55–62% of the sub-Saharan workforce is employed in agriculture and 95% of cropland is rainfed. In rural Africa, poor and female-headed households face greater livelihood risks from climate hazards. In urban areas, growing informal settlements without basic services increase the vulnerability of large populations to climate hazards, especially women, children and the elderly. // Adaptation in Africa has multiple benefits, and most assessed adaptation options have medium effectiveness at reducing risks for present-day global warming, but their efficacy at future warming levels is largely unknown (high confidence)./

Oceans and Coastal Ecosystems and Their Services

Ocean and coastal ecosystems support life on Earth and many aspects of human well-being. Covering two-thirds of the planet, the ocean hosts vast biodiversity and modulates the global climate system by regulating cycles of heat, water and elements, including carbon. Marine systems are central to many cultures, and they also provide food, minerals, energy and employment to people. Since previous assessments1 , new laboratory studies, field observations and process studies, a wider range of model simulations, Indigenous knowledge, and local knowledge have provided increasing evidence on the impacts of climate change on ocean and coastal systems, how human communities are experiencing these impacts, and the potential solutions for ecological and human adaptation.Peer reviewe

Greener Journal of Agricultural Sciences Effects of water quality, flooding episode and management variables on the fish yield from self-stocked ponds in lower Rufiji floodplain, Tanzania

A study was conducted to determine fish yields from flood depended ponds in Rufiji floodplain, Tanzania. Eight ponds were constructed during dry season in two sites besides two floodplain lakes, Ruwe and Uba. These ponds were self-stocked with different fish species from the lakes. More than eight species were trapped and Oreochromis urolepis, Labeo congoro and Clarias species were considered as good candidates for aquaculture. Other small fish species were harvested immediately after flood recession and the three key species were cultured for the maximum of seven months. However, other species in small quantities were remained in the ponds for the whole period of experiment. Water quality parameters were monitored throughout the study period. The relationships between water quality variables and flooding events were determined using canonical correspondence analysis (CCA). Other parameters included in the relationships were fish density, manure and number of species trapped and cultured. Dissolved oxygen and pH decreased with time in both sites. Fish yields were influenced by some water quality, flooding episode and other management variables. Chlorophyll-a was the only environmental variable that showed a significant correlation with fish yield (P< 0.01). Fish density and number of species trapped showed a significant effect on the fish yield (P<0.05). Re-connectivity between ponds and lakes was strongly positively correlated with yield. It can be concluded that some water quality variables, flooding and management parameters were responsible for the observed yield

Geographic trends in mangrove crab abundance in East Africa

The aim of this work was to determine the abundance of crabs in mangrove communities along a latitudinal gradient along the eastern coast of Africa from 4°S to 32°S. Surveys were made at Mombasa (Kenya), Zanzibar (Tanzania), Maputo (Mozambique) and in the Transkei (South Africa). Crabs were estimated at three designated levels in the mangroves by visual census using a common protocol, and numbers were converted to biomass. Even after standardising the selection of sites and methods of census there was still extensive variability in the data, emphasising the complex heterogeneity of mangrove ecosystems. Lunar phase (full versus new moon springs) did not have a consistent effect on results, but shore height had several effects. Total crab biomass was similar in the two lower shore strata examined, but about twice as high at the top-Avicennia level. The ratio of grapsid biomass:ocypodid biomass also changed with height: from near unity in the lower mangrove, to 0.14 in the middle strata, but to 15 at the top. There was no consistent latitudinal trend in total crab numbers, but total crab biomass increased from north to south. In addition there was a consistent and marked change in the grapsid biomass:ocypodid biomass ratio: this swung from 0.65 at Mombasa to 6.8 in the Transkei. This has implications for the transfer of primary production through the food chain. Grapsids are important macrophagous feeders on the leaves and other parts of mangroves, whereas ocypodids are microphagous deposit feeders.Link_to_subscribed_fulltex