Effects of residue management on earthworm cast production after Chromolaena odorata short fallow in the humid tropics

We aimed to quantify the relative impact of slashing, mulching, burning and cropping on surface casting by earthworms and whether effects were due to treatments per-se or to the changes in soil temperature and water content they may induce. Surface cast production was monitored during two maize cropping seasons and the subsequent fallow phase. Slashing the vegetation caused a severe decline in surface casting activity, whether or not the plot was cropped afterwards. There was a significant interaction between burning and mulching such that there was significantly lower cast production when mulch was removed by burning than when it was removed by mechanical means. Soil temperature was lower when plots were cropped and mulched but no discernible effects of treatments upon soil water content were found. No correlations were found between surface cast production and soil water content or soil temperature

Seperating the agronomic effects of burning and biomass removal in a typical slash and burn rotation system in Southern Cameroon

Little research on slash and burn systems has investigated whether effects of burning are due to the fire per se or to the removal of biomass from the soil surface. In this experiment, the aim was to assess the effects of burning versus no burning and mulching versus no mulching on maize yields, chlorophyll levels, nutrient uptake and soil properties in a short fallow ‘no external input’ system in two consecutive cropping seasons on an ultisol in southern Cameroon. In the second maize cropping season, treatments were not re-imposed so any effects would be residual. In the first cropping season, when mulch was retained, grain dry mass was 2.79 Mg ha-1, more than the 1.41 Mg ha-1 obtained without mulch. Soil bulk density was higher in non-mulched than in mulched treatments and both grain yield and maize aboveground biomass were strongly (both r2 = 0.50) and negatively associated with soil bulk density. Under such short fallow conditions, farmers should be encouraged to mulch rather than burn residues when cropping maize, as this leads to higher yields within the usual time frame of the cropping cycle

Vulnerability, forest-related sectors and climate change adaptation : the case of Cameroon

In Cameroon and elsewhere in the Congo Basin, the majority of rural households and a large proportion of urban households depend on plant and animal products from the forests to meet their nutritional, energy, cultural and medicinal needs. This paper explores the likely impacts of climate-induced changes on the provisioning of forest ecosystem goods and services and its effect on the economic and social well-being of the society, including the national economy and the livelihoods of forest-dependent people. The analysis focuses on four identified vulnerable sectors — food (NTFPs), energy (fuelwood), health (medicinal plants) and water (freshwater) through a multi-stakeholder dialog at national and regional levels. We use a vulnerability assessment framework by combining the elements of exposure, sensitivity and adaptive capacity to conceptualize vulnerability in these sectors. The identified sectors in relation to the forest ecosystem are discussed in view of providing an understanding of the sector's potential adaptive capacities for policy intervention. Our analysis presents the possible implications of the vulnerability of these sectors for planning local and national adaptation strategies. Local and national adaptive capacities to respond to climate impacts in the orest sectors includes: reducing poverty, enhancing food security, water availability, combating land degradation and reducing loss of biological diversity

Climate Change and Forest Communities: Prospects for Building Institutional Adaptive Capacity in the Congo Basin Forests

Tropical forests are vulnerable to climate-change representing a risk for indigenous peoples and forest-dependent communities. Mechanisms to conserve the forest, such as REDD+, could assist in the mitigation of climate change, reduce vulnerability, and enable people to adapt. Ninety-eight interviews were conducted in three countries containing the Congo Basin forest, Cameroon, CAR, and DRC, to investigate perceptions of decision-makers within, and responses of the institutions of the state, private sector, and civil society to the challenges of climate change. Results indicate that while decision-makers' awareness of climate change is high, direct institutional action is at an early stage. Adaptive capacity is currently low, but it could be enhanced with further development of institutional linkages and increased coordination of multilevel responses across all institutions and with local people. It is important to build networks with forest-dependent stakeholders at the local level, who can contribute knowledge that will build overall institutional adaptive capacity

Profiling climate change vulnerability of forest indigenous communities in the Congo Basin

The livelihood strategies of indigenous communities in the Congo Basin are inseparable from the forests, following their use of forest ecosystem goods and services (FEGS). Climate change is expected to exert impacts on the forest and its ability to provide FEGS. Thus, human livelihoods that depend on these FEGS are intricately vulnerable to climate impacts. Using the livelihood strategies of the two main forest indigenous groups; the Bantus and Pygmies, of the high forest zone of southern Cameroon; this paper examines the nature and pattern of their vulnerability to different climate risks as well as highlights how place of settlement in the forest contributes to the vulnerability of people in forest systems. Forests provide different capitals as FEGS and make direct and indirect contributions to livelihoods which are exploited differently by the two indigenous groups. The results show that vulnerability of forest communities is structured by lifestyle, culture and the livelihood strategies employed which are largely shaped by the place of settlement in the forest. The Pygmies living within the forests are engaged in nomadic gathering and foraging of non-timber forest resources. The Bantus prefer forest margins and are mostly preoccupied with sedentary farming, using the forest as additional livelihood opportunity. The contrasting lifestyles have implications on their vulnerability and adaptation to climate impacts which need to be taken into considerations in planning and implementation of national climate change adaptation strategies

Implications of meltwater pulse events for soil biology and biogeochemical cycling in a polar desert

The McMurdo Dry Valleys are one of the most arid environments on Earth. Over the soil landscape for the majority of the year, biological and ecosystem processes in the dry valleys are constrained by the low temperatures and limited availability of water. The prevalence of these physical limitations in controlling biological and ecosystem processes makes the dry valleys a climate-sensitive system, poised to experience substantial changes following projected future warming. Short-duration increases in summer temperatures are associated with pulses of water from melting ice reserves, including glaciers, snow and permafrost. Such pulses alter soil geochemistry by mobilizing and redistributing soil salts (via enhanced weathering, solubility and mobility), which can alter habitat suitability for soil organisms. Resulting changes in soil community composition or distribution may alter the biogeochemical processes in which they take part. Here, we review the potential impacts of meltwater pulses and present new field data documenting instances of meltwater pulse events that result from different water sources and hydrological patterns, and discuss their potential influence on soil biology and biogeochemistry. We use these examples to discuss the potential impacts of future climate change on the McMurdo Dry Valley soil ecosystem