Tana Delta Irrigation Project, Kenya: An Environmental Assessment

Rehabilitation of the Tana Delta Irrigation Project, Kenya: An Environmental Assessment.
Exotic and Invasive species
TARDA has so far relied on 4 exotic tree species for its woodlot programme:
a) Azadirachta indica. As stated previously (4.5), the invasive nature of Neem disqualifies
this as a suitable species for reforestation and, unless it is found that the primates utilise
the leaves or fruits, a programme of removal of the existing trees and seedlings should be
planned.
b) Pithecellobium dulce has not been very successful in the woodlots but was seen growing
very well as individuals in the villages. It is probably a potential food species for the
Mangabeys and perhaps more work is needed to determine whether this is a tree valued
by local communities and whether establishment can be improved.
c) Senna (Cassia) siamea. This widely used species probably has its value in further
reforestation efforts but should be evaluated against other species.
d) Eucalyptus camaldulensis. It is not known how successful this species has been,
however, with the worldwide advances made in selecting new and better Eucalypt
hybrids, their pole wood and firewood values cannot be discounted and they should
continue to be evaluated within the woodlot programme.
An additional species that has shown great promise further south, in Malindi District, is Albizia
lebbeck. This should be included with any other novel species suggested by KEFRI or ICRAF
in trials.
The Prosopis problem is now countrywide and cannot be solved by TDIP alone. However,
every effort should be made to remove it where feasible and to persuade local pastoralist
communities to stop feeding pods to their livestock which assists greatly in spreading
« Mathenge ». Innovative ideas must be sought to at least tame this weed even if there is
little hope of eradication.
Strengthen/establish Village Environment Committees
As the first stage in moving towards some form of village management of the forest or PFM,
the village committees need to be strengthened and an environmental subcommittee created
where none exist. In a similar manner to the approached used by CFCU in Kwale and Kilifi
Districts (now also Malindi District), these village committees should be encouraged to
appoint Forest Guards or Wardens that draw some honoraria, initially from the donor project,
but eventually from committee funds raised from sale of wood products and from fines.
Village Guards/Wardens
These should be appointed by the Village Committees on the following basis:
i. Must be local resident of village
ii. One guard or warden per 10 Ha (with obviously a minimum of 1 guard for forests less
than 10 Ha). Thus Forest 48 with its reported size of 30 Ha would initially have 3,
increasing as necessary with expansion and corridor creation).
iii. The ‘honorarium’ should not be considered a salary. This needs further discussion as
to whether the « Kaya system » is workable, but a possible combination of nursery
contracts with these ‘honoraria’ should be explored.
Riverbank Strip Forest Development
Two of the most striking facts about the primates’ habitat preferences are that they like
riverine forest and that they like the forest perimeter. One of the most effective ways of
creating new habitat is thus to utilise the riverbank and the protection this is afforded by
Kenyan legislation. Prior to the enacting the Environment Management Act, it was standard
that 30m on either side of a river should NOT be cultivated. Although this was often
contravened with impunity, it is probable that it is enforceable using the new legislation. With
the advantage of the high water-table, it should be the quickest and easiest place to establish
a forested strip using fig stakes of Ficus sycomorus. Overtime a more generous strip can be
negotiated with the village committees, extending it to perhaps 100 metres (Appendix 6).
The use of this strip to interplant mango trees will be beneficial to both the villagers and the
endangered primates.
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