Tana Delta Irrigation Project, Kenya: An Environmental Assessment

The major perceived causes of forest decline include:
Rehabilitation of the Tana Delta Irrigation Project, Kenya: An Environmental Assessment.
• Increased community demand;
• Lack of seasonal flooding due to the change in the course and flooding regime of the Tana River and
• Poor enforcement of use regulations.
Communities believe the most effective solutions for forest conservation lie in increased community
management allied to appropriate technical assistance.
The ‘headline’ recommendations are that:
• The proposed rehabilitation should attempt to redress the TDIP communities’ state of livelihood
vulnerability and lack of development options, which will also serve to reduce pressure on the
declining natural resource base.
• Appropriate design and implementation must engage the communities as partners, and be
characterised by information sharing, consultation and collaboration.
• Participatory forest management (PFM) be piloted and based on the twin goals of indigenous forest
conservation, and forest expansion (both indigenous and exotic).
• Community-related interventions – whether concerning forest or livelihoods – are implemented
through mutually agreed agencies and processes.
Botanical/Ecological Study
The forests of the Lower Tana River are of great importance for the conservation of biodiversity for there are
many species of plants and animals that are dependant upon these forests, including several endemic,
threatened species. This study has identified 320 plant taxa in the area; 58 of them tree species, of which
two can be considered Critically Endangered in a global sense. Twenty one per cent of the plants are of
conservation concern. All of these threatened species need to be taken into account in designing the
programme to re-establish that Irrigation Scheme.
The most significant find is that the forest cover has declined by 37% over 10 years with a related reduction
in the quality of the cover. Past interventions have aggravated the situation by the introduction of invasive
plants and the exacerbation of community differences and conflict.
The impact on these critically important forests of the Lower Tana River has been devastating; both by the El
Nino weather event of 1997/8 and the increasing human pressure. The latter is due directly to the lack of
livelihood alternatives as promised at the inception of this donor funded Tana Delta Irrigation Scheme.
Assessment of the current size, composition, health and conservation status of these forest fragments shows
an urgent need for bold and innovative intervention if the habitat of two of the world’s most threatened
primates, and the livelihoods of the local communities, are to be protected and improved.
Opportunities for practical actions to achieve positive change both in primate habitat and in the lives of the
local people are many. These include: an increase in environmental awareness; the full involvement of the
people in participatory forest management (PFM) and design; the immediate start of nurseries for selected
indigenous and exotic species; the linking of existing forests by corridors; the establishment of woodlots; and
the initiation of simple, effective community income generating ventures.
Primate Study
The most fundamental finding of the primate study is a decrease from the 2001 group numbers for both the
red colobus and mangabeys, as well as changes in distribution of these primates in the forests of the survey
area.
The total number of red colobus has declined significantly from the 1994 census, decreasing from 260 to
127. Mangabey individuals have stayed stable (144 in 1994, >149 in 2005).
This study found approximately 20 groups of red colobus in 11 forests (46 per cent of the forests surveyed)
and 14 groups of mangabey in nine forests (38 per cent of forests surveyed). As illustrated in the table
below, there is a direct relationship between the size of the forest and the number of primate groups present.
Red colobus were observed in varying forest sizes while mangabeys appear to have favoured the larger
forests, as they were found only in the six largest forest blocks censuses and two small isolated patches.
Forests with one or more groups of red colobus and mangabey
iv