Beatrice Ambo Fonge

Simulation of the impacts of three management regimes on carbon sinks in rubber and oil palm plantation ecosystems of South-Western Cameroon.

The impacts of managed, extended and complete rotation on carbon sequestration in rubber and oil palm plantations were simulated using the CO2FIX V.2 model, using degraded farmland carbon stocks as a baseline. Results showed that the extended rotation resulted in higher C-sequestration in rubber (264 Mg C/ha), and the complete rotation (88 Mg C/ha) for the oil palm plantation. There was better soil carbon recovery in rubber under the extended rotation, and better recovery in palms under a complete rotation. With respect to soil carbon fractions, fine litter had the highest value in rubber (19 Mg C/ha) and coarse litter in palms (63 Mg C/ha) all under complete rotation. Humus was the most permanently increasing soil carbon component, with the best sinks at 9 and 12 Mg C/ha in rubber and palm under the extended rotation respectively. Inclusion of such systems into post Kyoto Treaties, with incentives from carbon credits could be indispensable in alleviating rural poverty and expanding on forestry projects that mitigate climate change. Key words:

Investigating the Management of Geological Hazards and Risks in the Mt Cameroon Area Using Focus Group Discussions

The scientific evaluation of hazards and risks remains a primary concern in poorly known volcanic regions. The use of such information to develop an effective risk management structure and risk reduction actions however also poses important challenges. We here present the results of a series of focus group discussions (FGDs) organised with city councillors from three municipalities around Mt Cameroon volcano, Cameroon. The Mt Cameroon area is a volcanically and tectonically active region regularly affected in the historical past by lava flows, landslides and earthquake swarms, and has a potential for crater lake outgassing. The lower flanks of the volcano are densely populated and the site of intense economic development. The FGDs were aimed at the elicitation of (1) the knowledge and perception of geological hazards, (2) the state of preparedness and the implementation of mitigation and prevention actions by the municipalities, (3) the evaluation of the effectiveness of the structure of communication channels established to respond to emergency situations, and (4) the recovery from an emergency. In all three municipalities stakeholders had good knowledge of the risks, except for processes never experienced in the region. They generally grasped the causes of landslides or floods but were less familiar with volcano-tectonic processes. Stakeholders identified the lack of strategic planning to monitor hazards and mitigate their impacts as a major weakness, requesting additional education and scientific support. Response to natural hazards is mostly based on informal communication channels and is supported by a high level of trust between local scientists, decision makers and the population. Actions are taken to raise awareness and implement basic mitigation and prevention actions, based on the willingness of local political leaders. The strong centralisation of the risk management process at the national level and the lack of political and financial means at the local level are major limitations in the implementation of an effective risk management strategy adapted to local risk conditions. Our case study highlights the need for earth and social scientists to actively work together with national and local authorities to translate the findings of scientific hazard and risk assessment into improved risk management practices.

Weed management in banana production: The use of Nelsonia canescens (Lam.) Spreng as a non- leguminous cover crop

During a survey of weeds in the Tiko banana plantations, the plant Nelsonia canescens (Lam.) Spreng was found to have invaded large areas of the plantation with no visible adverse effects on the banana crop. The effects of this Acanthaceae on banana yield parameters, snails’ population and weed species diversity and abundance were evaluated, with the intension of recommending the plant as a cover crop in weed management in banana plantations. Of the 73 weed species identified in Tiko banana plantation, only nine were found growing in association with N. canescens. These weed species also showed reduced abundance and vigour. The reduction in abundance ranged from 60 to 100%. The reduction in abundance was more pronounced during the dry season when cover crop growth was dense, than in the rainy season when there was reduced growth. The pseudo - stem circumference, bunch weight and hand class were significantly higher (p > /0.05) for plants grown with cover crop than for those grown without. The number of snails on and around the pseudo - stem was also significantly reduced in banana grown with N. canescens cover crop than in plants grown without. N. canescens has an added advantage in that it is prostrate and does not climb on the banana pseudo - stem. This may be a good alternative weed management tool in banana production. The techniques of mass production need to be developed.

Patterns of land-use change and current vegetation status in peri-urban forest reserves: the case of the Barombi Mbo Forest Reserve, Cameroon

ABSTRACT Creation of protected areas is a cornerstone of nature conservation. However, with increasing population, the pressure on land for agriculture increases, especially in peri-urban areas. We investigated land-use changes in a peri-urban forest reserve subject to anthropogenic influence and assessed the extant plant community structure through various indices. The results show that there is active forest conversion into farmland, and this conversion affects surrounding waterbodies as well. A new guild of species dominates under anthropogenic activity and comprises cocoa farms and mosaic forest. Cocoa Farms were more diverse (H = 3.08) than Dense Forest (H = 2.75) yet both were strikingly dissimilar with high carbon stocks in Cocoa Farm (128 Mg/Ha) compared to Dense Forest (51.6 Mg/ha) indicating that the forest is highly degraded. Land cover change predictions indicate further increase in forest conversion to farmland and accommodation. Our results show that legislating protected areas needs to be accompanied by consistent monitoring, and poverty alleviation alternatives that relieve pressure from forests, if conservation is to be successful.