Status, Impact and Management of Invasive Alien Species in Tanzania

Invasive alien species (IAS) are among the significant drivers of environmental change worldwide and important causes of biodiversity losses. They contribute to economic hardship and social instability, placing constraints on sustainable development, economic growth, and ecological problems in various parts of the world, including Tanzania. This study was undertaken to provide information on the status of invasive species and their management needs in Tanzania. The study used three methodological approaches including documentary search, interviews with relevant stakeholders and limited field visits. Findings from the study have indicated that the awareness, trends, distribution and impacts of the invasive alien species in Tanzania are variable, and similarly are the management and control requirements and practices for these species. Among the major impacts associated with the IAS in the country include loss of biodiversity, where in some cases has caused disappearance of certain species of fauna and flora, social and economic distress to human being due to the disappearance of plants and animal species that are regarded as important sources of livelihoods. The study shows that currently there is limited demonstrated capacity in terms of human and financial resources to address the issue of IAS, except for a few cases such as the water hyacinth (Eichhornia crassipes) in Lake Victoria. In addition, there are no clearly defined long term strategies to address the issue of invasive species in many institutions. Experience shows that many of the legislations and policies dealing with biodiversity and/or resource management in the country do not directly address invasive alien species. This shortfall may be responsible for the inadequate attention being accorded to the management of invasive species. Thus for effective management of invasive alien species, policies and legislations should be encouraged to directly deal with invasive species. Such situation calls for integrated efforts including various institutional frameworks and collaborations.Key words: Invasive alien species, biodiversity loss, management of IAS,sustainable development, Tanzania

Agricultural Commercialisation and Its Implications on Agrodiversity Management in the Drylands of Central Tanzania

The study examines the linkages between agricultural commercialisation and agrodiversity management. It considers agricultural commercialisation an important socio-economic aspect with varied environmental implications, particularly in relation to agro-diversity management. The study was undertaken in Kondoa and Kongwa Districts, in the semiarid central Tanzania. The aim of this study was to examine the implications of agricultural commercialization on agro-diversity management, food security and the environment in general. A variety of methods were used in the study including participatory assessments techniques, field visits and household surveys. Household data was analysed using SPSS. The findings from this study indicate that for decades agricultural production in the semiarid areas of central Tanzania has been centred on production of a diverse number of crops though concentrated on sorghum and millets as the most drought tolerant grain crops. However, from the mid-1980s the balance has shifted in favour of cereal crops like maize, which has become among the major cash-earning crop. Other prominent commercial crops included pigeon peas, sunflower and simsim. Commercial crops appear to be expanding at the expense of traditional drought tolerant crops such as bulrush millet and sorghum, thereby influencing the local agro-diversity. The abandonment of some crops e.g. castor oil plants in favour of market crops also appear to affect the agrobiodiversity in the study areas. It has been found that expansion of farms is a major factor for environmental degradation through deforestation, declining soil fertility due to continuous cultivation and emergence of noxious weeds such as Striga. On the other hand agricultural commercialization appears to have been associated with improvement in food security, household income, housing conditions and education for children. However the emphasis of the less drought tolerant crops like maize in these semiarid areas makes the sustainability of the agricultural system very uncertainKeywords: Agricultural commercialisation, agrodiversity, food security, semiarid Tanzani

Climate change responses benefit from a global food system approach

A food system framework breaks down entrenched sectoral categories and existing adaptation and mitigation silos, presenting novel ways of assessing and enabling integrated climate change solutions from production to consumption.Peer reviewe

Is dry soil planting an adaptation strategy for maize cultivation in semi-arid Tanzania?

Agriculture has the greatest potential to lift the African continent out of poverty and alleviate hunger. Among the countries in sub-Saharan Africa, Tanzania has an abundance of natural resources and major agricultural potential. However, one of the most important constraints facing Tanzania’s agricultural sector is the dependence on unreliable and irregular weather, including rainfall. A strategy to cope with climate uncertainty in semi-arid regions is to proceed with the sowing of the crop before the onset of the rainy season. The advantage is that when the rains start, seeds are already in the soil and can begin immediately the process of germination. The objective of this paper was to assess the effectiveness of dry-soil planting for maize as an adaptation strategy in the context of a changing climate in Dodoma, a semi-arid region in Tanzania. For this assessment, the DSSAT crop model was used in combination with climate scenarios based on representative concentration pathways. A probability of crop failure of more than 80% can be expected when sowing occurs during the planting window (of 21 days) starting on 1st November. The next planting window we assessed, starting on 23rd November (which was still before the onset of rain), presented significantly lower probabilities of crop failure, indicating that sowing before the onset of the rainy season is a suitable adaptation strategy. Results also indicated that, despite not reaching the highest maize grain yields, fields prepared for dry-soil planting still produced adequate yields. The cultivation of several fields using the dry planting method is a strategy farmers can use to cope with low rainfall conditions, since it increases the chances of harvesting at least some of the cultivated fields. We conclude that dry-soil planting is a feasible and valid technique, even in scenarios of climate change, in order to provide acceptable maize yields in semi-arid Tanzania