The loss of biodiversity, a loss that is both quantitative and qualitative, in Rufiji Delta and Bagamoyo is driven by strong local dependence on natural resources, particularly for cash needs. This study was unable to gauge the actual quantitative extent because of the lack of baseline data. Extinction was not observed. However, certain sizes of mangrove trees and fish are not easily available.
Major direct causes such as commercial harvesting of mangroves for poles, charcoal, and firewood lie behind this loss of biodiversity. Expansion of rice farms is another direct cause. Similarly, salt-making and construction of ponds for prawn-farming in Bagamoyo leads to habitat loss in deltas.
The main influencing factors or root causes that trigger biodiversity loss in the Ruvu, Wami, and Rufiji Deltas can be traced to national and international policies and programs. Commercial harvesting of mangrove poles, which is prompted by lack of alternatives and opportunities, accounts for most of the loss occurring in the deltas. Many people are involved in commercial harvesting of mangroves as a means of livelihood because other sources, such as agriculture and fishing, are inadequate and are affected by poor roads, unreliable markets, and inefficient supply of equipment.
Issues related to legal and institutional frameworks as well as institutional functions constitute formidable problems. For example, the participation of local governments and the local people in the management of the mangrove forests is inadequate. Only a few villages have formed Village Natural Resources Committees, charged with sustainable management of mangroves, under the auspices of the mangrove project. Laws regarding management of forest reserves were enacted in 1957 and revised in 1997. Most of them were inadequate and outdated, and penalties did not reflect the actual value of the degraded areas. Although revised, the laws still give the judges freedom to issue lower penalties. Conflicting government policies also contribute to the loss of biodiversity in the deltas.
Increasing world demand for prawns and liberalization of the fishing sector has brought private fishing vessels to Tanzania’s waters. International fishing vessels draw close to the inshore waters where small fishermen fish, denying them their opportunity to fish freely and affecting the nets they set. Also, international fishing vessel practice trawling, which destroys the seabed and marine organisms.
These processes are not taking place in isolation from international influences. Since 1986, Tanzania has been implementing macro-economic policy reforms. These reforms are influenced by international financial institutions. One of the key features of the reform programs is reduction of government expenditure and an increased role for the private sector. These policies have had the effect of diminishing the enforcement capability of the regulatory agencies. Monitoring and patrol against illegal harvesting has been critically affected. The vast mangrove area of the Rufiji Delta has only three staff and one boat and often funds are lacking to buy fuel. In Ruvu Delta, likewise, patrols are rare.
International influence is also seen in the role of the international private sector. The proposed Rufiji prawn farm is a case in point. This aquaculture project is likely to lead to the extensive felling of mangrove trees during the construction phase, and pose further threats of pollution and increased demand for food and poles in future as the workers begin to arrive in the Delta. Increased private investment may push the destruction of the mangrove forests even further because of inappropriate government policies, which would allow large-scale prawn farming to take place in an ecologically sensitive area, and because of weak monitoring, management, and law enforcement.
The future of these deltas is precarious. Assuming that the current situation and weaknesses continue, the loss of biodiversity will be very high. Current harvesting trends are likely to continue or even increase as long as new alternatives and opportunities are not found, and as far as ineffective management regimes are still in place. New threats such as large-scale prawn farming, salt-making, population growth, and expanding tourism will pose further challenges in future. The future scenario may change for the better if sustainable approaches are adopted. The introduction of the Integrated Coastal Zone Management Project is likely to help improve the situation if well-implemented.