Mathew Mpanda

Greenhouse gas fluxes from agricultural soils of Kenya and Tanzania

Knowledge of greenhouse gas (GHG) fluxes in soils is a prerequisite to constrain national, continental, and global GHG budgets. However, data characterizing fluxes from agricultural soils of Africa are markedly limited. We measured carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) fluxes at 10 farmer-managed sites of six crop types for 1 year in Kenya and Tanzania using static chambers and gas chromatography. Cumulative emissions ranged between 3.5–15.9 Mg CO2-C ha−1 yr−1, 0.4–3.9 kg N2O-N ha−1 yr−1, and −1.2–10.1 kg CH4-C ha−1 yr−1, depending on crop type, environmental conditions, and management. Manure inputs increased CO2 (p = 0.03), but not N2O or CH4, emissions. Soil cultivation had no discernable effect on emissions of any of the three gases. Fluxes of CO2 and N2O were 54–208% greater (p < 0.05) during the wet versus the dry seasons for some, but not all, crop types. The heterogeneity and seasonality of fluxes suggest that the available data describing soil fluxes in Africa, based on measurements of limited duration of only a few crop types and agroecological zones, are inadequate to use as a basis for estimating the impact of agricultural soils on GHG budgets. A targeted effort to understand the magnitude and mechanisms underlying African agricultural soil fluxes is necessary to accurately estimate the influence of this source on the global climate system and for determining mitigation strategies.

IMPACT OF FORESTLAND TENURE CHANGES ON FOREST COVER, STOCKING AND TREE SPECIES DIVERSITY IN AMANI NATURE RESERVE, TANZANIA

ABSTRACT The aim of the present study was to evaluate the impact of changes from private to state tenure on forest resources for three blocks in Amani Nature Reserve. The resource changes were determined in terms of forest cover, forest stocking and tree species diversity over a period of six to eight years. when considering the three blocks as one entity one may in general maintain that there have been positive changes regarding forest cover. There were differences between the blocks, however. the proportions of dense and semi-closed forest increased by around 14% in the former tea company block, remained unchanged in the former farmland and decreased by around 12% in the former sisal company block. the changes in stocking parameters and tree species diversity were mainly positive, but none were statistically significant. Although the results were somewhat ambiguous evidence of positive impacts as a result of the tenure changes was identified. This is in line with the main aim of establishing nature reserves focusing on conservation values. More research, however, is required regarding impacts of tenure changes on livelihood for those living adjacent to the nature reserve.

Allanblackia, butterflies and cardamom: sustaining livelihoods alongside biodiversity conservation on the forest–agroforestry interface in the East Usambara Mountains, Tanzania

Win–win outcomes for biodiversity conservation and poverty reduction are the holy grail of integrating conservation and development and are rarely met. Domestication of valued local species and introduction of high valued crops can help prevent depletion of wild resources. We compared three commodities from the forest–agroforestry interface of the East Usambara Mountains in Tanzania at different stages of domestication: (a) Allanblackia stuhlmannii, a local tree with valuable edible kernel oil; (b) butterflies, with an international market chain for pupae sold to butterfly gardens and (c) cardamom (Elettaria cardamomum), an introduced shade tolerant spice from India with established global markets. Data on production systems, institutional set-up and profitability were collected through focus group discussions, interviews with key individual informants and literature review. Cardamom has become a major support for rural livelihoods, generating 9 million USD for 750 tons of product in the area, or 850 USD per year for 10,600 households. Allanblackia and butterflies generate only 1% of that income for the landscape. For Allanblackia (around 20 USD per year for 5000 households), the transition from a forest product collected from the wild to being an agroforestry commodity is in an early but critical stage, where the slow growth of the trees and inadequate research attention to production systems, as well as modest farm gate price, currently limit farmer interest but are the focus of ongoing research. Butterflies (approximately 200 USD per year for 350 households) have had the fastest domestication pathway, with continuous innovation into new products and use, linked to international markets. There is gender-sensitive integration with household tasks and compatibility with homegarden agroforestry systems, while due attention is given to institutional arrangements of its local business scheme. Cardamoms economic success has made it a ‘villain’ to forests conservation, as forest transformation to cardamom agroforestry retains only half of the forest trees, and is a step towards further change. Differences in institutional settings of these three domestication pathways relate to their potential to reconcile biodiversity and livelihood concerns and suggest that a socio-ecological system approach to domestication is a prerequisite for a biological–technical one to achieve societal goals.