Coastal Wetlands Research Papers - Academia.edu (original) (raw)

This report provides a synthesis of the scientific literature on communicating background information for a climate vulnerability assessment in the Rufiji-Mafia-Kilwa (RUMAKI) Seascape, Tanzania. The objective of this assignment was to prepare a review document summarising available information, data and references relevant to assessing climate vulnerability in the RUMAKI seascape. The report is divided in five major sections:

• Trends in the status of ecosystems, natural resources and natural resource-based livelihoods
• Major development issues affecting the above
• Climate trends and projections for the area
• Vulnerability and resilience of ecosystems and livelihoods to climate change
• Extent to which climate change adaptation is addressed in relevant (natural resources) management policies and strategies

Ecosystems, natural resources and natural resources based livelihoods

The RUMAKI seascape is characterised by a wide diversity of biotopes and species that are predominantly utilized by surrounding local communities. The fact that different habitats support different species, there is disproportionate distribution of natural resources as well as economic activities. Artisanal fisheries is concentrated in productive areas which include estuaries, mangrove forests, coral reefs flats, sandy beaches, cliffs, sea grass-beds and muddy tidal flats. Agricultural activities are concentrated in the floodplains.

Coastal forests are a source of valuable timber and non-timber forest products, which are vital to the livelihoods of local communities. They provide timber for boat building, fuel wood for dry processing of fish, charcoal, building poles and woodcarvings. The value of non-marketed forest products is immense. Non-timber forest products from coastal forests, which are traded by local communities, include bee products, food, fruits, medicines, and natural dyes and fibres, among others. Due to their low cost and wide availability, plant-based traditional medicines are more popular in Rufiji, Mafia and Kilwa districts. However, overexploitation and clearing for other uses has led to a reduction of these important forests. In many areas forests have been cleared for agriculture, firewood and charcoal. Clearing of coastal forests poses a threat to mangroves because local communities shift from the use of coastal forest to mangroves for fuel wood, timber and charcoal making. Cutting of mangrove poles is a major activity in the delta. A mangrove management plan has been put in place to control the harvest of mangrove products, but effective enforcement of this plan has been far from reach. Because of the capital required for permits, most permits are in the hands of traders from large centres outside the Rufiji Delta. These external traders employ local people to do the cutting. Nonetheless, most harvesting is reported to be illegal, unselective and unsustainable. The future trends of this trade are likely to be influenced by demographic changes in the delta as well as its growing external demand.

Agriculture is one of important economic activities in the RUMAKI area despite the fact that marine resources are taken as the core livelihood activity. Major crops grown in the three districts of Rufiji, Mafia and Kilwa are rice, maize and cashew nut. Agriculture in these districts like in most of rest of the country is whether dependent and therefore trends in agricultural production varies between years and seasons, where good years are related good whether (timely and enough rainfall) and increased crop productions. Bad years are mainly associated with extreme whether events (droughts and floods) where crop production is jeopardized. In the past agricultural production in most villages produced beyond self-sufficiency to create surplus for export outside their local boundaries. Currently, the old crop production trend has significantly changed. The present agricultural production in Rufiji is not even enough for subsistence. Despite the declining trends in agriculture, various studies indicate that it is still the main livelihood occupation of many households in the lower Rufiji.

Major development affecting ecosystems and natural resources in the RUMAKI seascape

Tanzania has recently made natural gas discoveries in coastal regions, and is expected to be one of the largest gas producers in Eastern Africa. Songo Songo off the eastern coast, and Mnazi Bay in southeast Tanzania - are in production with an estimated gas potential ranging from 2 to 3 trillion cubic feet. Although the discovery of gas in the coast region is very potential for the economy of the country, activities associated with exploration, extraction, transport poses threats to ecosystems and livelihoods. In general the nature of mining sector in the RUMAKI area is very limited and small compared to large inland mining operations. Lime mining for cement production is done in Kilwa. Illegal coral mining is done mainly in Mafia district.

The proposed future impoundment of the Rufiji River at Stiegler’s Gorge was planned during the late 1970s. The Stiegler’s Gorge project is envisaged as a multipurpose project with several expected long-term benefits, of which two are considered to be the most important: 1) its high hydropower potential (2100 MW) would facilitate the pursuit of Tanzania’s policy for industrialization and further electrification and 2) flood control. A number of studies have shown that the implications of implementing the proposed project will not be realized without some environmental impacts, the major one being the degradation of the river bed and river main channel, leading to disruption of the natural flooding pattern of the river and sedimentation pattern. All these will in turn lead to disruption of livelihoods and ecosystems depending on the Rufiji Delta and its floodplain.

Climate trends and projections in the RUMAKI seascape

A number of studies projecting the impact of climate change on water resources in Tanzania have been undertaken, using multiple General Circulation Models have generally concluded that while future rainfall patterns were uncertain, the RUMAKI area may receive more rainfall under various climate change scenarios. Some of these studies have suggested that there would be a seasonal shift in rains, with less rainfall early in the season and stronger rains later in the season. In terms of temperature (air and sea surface) increases, all studies concluded that these would be in the range of 1.5°C - 2°C for the first half of this century and around 2°C - 4°C for the second half. These findings from local studies are within the range predicted for East Africa by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.

In terms of the impact of climate change on water flows in the Rufiji River Basin, studies predict increased flows in the Rufiji Basin; as it is predicted in the Great Ruaha Basin. A country-wide projections indicate a rise in perennial drainage to a total of 136% in central Tanzania and 125% in northwest Tanzania by the end of this century. There are also suggestions that by mid-century, national basis stream flows will be between 80-100% of 1961-1990 flows and only 80-90% of the base period flows by 2100. Historical trends and projections on sea level rise indicate increases in sea-level rise. However, these results are blanketed with large uncertainty due to lack of gauged long-term sea-level rise data. Same trends have also been observed in wind speed and direction, as well as in ocean salinity and pH.

Vulnerability and resilience of ecosystems and livelihoods in the RUMAKI seascape

The concept of vulnerability and resilience address the degree to which at a given point in a time a society is adapted to the hazards of its environment. However, it should be noted that the relationship between vulnerability and resilience is not linear but rather dialectical such that lowering vulnerability may not necessarily increase resilience but it may also create other forms of vulnerability. In Tanzania, there have been efforts in analysing the vulnerabilities of sectors to the impacts of climate change; however, there has been a bias towards the agricultural sector and semi-arid lands. For the RUMAKI seascape, there is no a comprehensive analysis of climate observations, impacts and response options, but rather some few insights of the vulnerability and resilience of ecosystems to climate change impacts. Moreover, a number of studies have been carried out at a smaller scale across coastal regions.

Coastal areas are already affected by extreme events. Both ecosystems and livelihoods are exposed to the future impacts of climate change. Sea level rise and the associated shoreline change are uncertain, however, increased floods and environmental degradation will exacerbate erosion and sedimentation. Coastal ecosystems such as coral reefs, sea turtles, sea grasses are extremely vulnerable because they have already been significantly altered by human activities. The Rufiji Delta and floodplain is expected to suffer further losses of productivity and services that they provide. Manmade components such as the proposed Stigler’s Gorge dam are also vulnerable to climate change due to the projected increase in precipitation, which might lead to changes in dam operations. Therefore, as the climate continues to change, repeated disruptions of lives, infrastructures and economic activities will pose challenges to the RUMAKI ecosystems and livelihoods. Further, it is anticipated that after the construction of the dam, the frequency of low flow discharges will be significantly reduced.