Rapid Assessment of Ecosystem Service Values at Yala Wetland, Kenya

(Amayo, O. Justus., Akwany, O. Leonard., Ogoma, O. Maurice)

5th Nile Basin Development Forum, Kigali, Rwanda

Theme: Investing in Nile Cooperation for a Water Secure Future

23rd-25th October, 2017

Presenter

Justus Amayo

Email: justus@ecofinderkenya.org

Introduction and ObjectivesIntroduction

• Wetlands are increasingly underpressure from reclamation foragriculture and overexploitation ofwetland resources

• Safeguarding these ecosystems isregarded as an important means toenhance and maintain andecosystem services

• Improvement on theunderstanding of benefitsdelivered by wetlands undervarious use scenarios

• Governments and other actorsneed information on the relativebenefits of particular actions inwetland areas

Objectives1. To quantify differences in Ecosystem

Services (ES) provision betweenwetland conservation area andwetland area reclaimed for cropproduction

Study Area

• Important riparian and floodplainswamp in LakeVictoria

• IBA and supports communitylivelihoods

• Area of 17,500 ha and comprisesthree satellite lakes

• Increasingly under pressure frompapyrus harvesting, reclamationfor agriculture, hunting of wildanimals including birds

Methodology and Approach

• Rapid appraisal to identify ES delivered by the swamp under current andthe alternative state (L. Kanyaboli N. Reserve) for assessment

• ES identified narrowed down to 5 (global climate regulation, harvested wildgoods, cultivated goods, nature-based recreation and water services)

• Data on the 5 ES collected as follows

1. Global climate regulation

• The site first stratified into 3 main habitats; papyrus dominated reed-bed,cropland and open water

• C stocks in above ground biomass(AGB) , below ground biomass (BGB)and soil organic matter (SOM) were calculated using published literaturevalues for each habitat type

• Carbon storage for papyrus dominated reed-bed

=[(AGB+BGB+SOM)*Habitat area*0.47 (conversion factor for wetlands)]

Methodology and Approach Cont’d

• Carbon storage for cropland

=[(AGB+BGB+SOM)*Habitat area

• Due to lack of standardisation in published literature uncertainty values,errors in C stocks were estimated as 90% of mean values followingstandard guidelines

• We derived upper and lower estimates of net fluxes of CO2 and CH4 fromreed-bed areas

• Emissions of CO2 from soil organic matter oxidation were estimated forarable farmland

• Total carbon stocks and carbon equivalents for each of the gases wereconsidered as the global climate mitigation benefit of the habitats

Methodology and Approach Cont’d

2. Cultivated and Harvested Wild Goods

• The cultivated crops (maize, beans, bananas) and harvested wild goods(grass, papyrus reeds) were characterized at two communityworkshops

• 210 household surveys conducted to obtain the economic values ofboth cultivated and harvested wild goods identified

Methodology and Approach Cont’d

3. Nature-based recreation services

• Values determined using 300 questionnaires for local andinternational visitors over 2 months

• Recorded annual visitor numbers were also used

• The annual value of the recreational benefits provided by the site wascalculated as:

=The estimated annual number of visits * Mean spend per visitor (sum of the cost per visit of travel to the site) + Any additional spend in the

local area (as estimated from responses to the questionnaires)

Methodology and Approach Cont’d

4.Water Services(a) Flood protection services

• Low lying landscapes of villagesaround Yala wetland are at seriousrisks without papyrus vegetation

• Flood protection services wereestimated using household surveysand Costing Nature for a mappedestimate of the flood protectionservices and beneficiaries

• Total benefit of the site wasestimated as the value of avoideddamage to crops and property

(b) Water provisioning services• The quantity of water consumed

per day was determined using 200 household surveys in the alternative site

Results and Discussion• Total C stock in the alternative nature conservation site is estimated

at 139462±125513, of which the highest amount is stored in the SOM

• Under agricultural scenario (current state), total C storage is lessthan half of the alternative site with over 85% stored in SOM

• Net GHG flux at Ouse Fen is 548-5088 and 321-4007 Mg CO2-eq a-1

in the alternative and current sites respectively, and attributableprimarily to CH4 production from anaerobic reed-bed habitats in thealternative state and N2O emissions from mineral fertilisers in thecurrent state (agricultural scenario)

• Approximately 2300 visits were recorded for the site in its alternativestate with a recreational value of $17,200. Under the current state,annual visit numbers were recorded at 280 and an annual recreationalvalue of $1500

Results and Discussion• The alternative site has the potential to protect 1200 ha of cropland, of

which 260 ha would be flooded during a 1-in-20 year flood event

• Over 150 houses would be directly affected by flood.

• The overall damage cost avoided was $30,000 which was then adjusted to$ 1,500 by a factor of 0.05

• No flood protection was provided by the current site

• Average of 40 litres of water used per household per day in the alternativestate. Zero in the current state

• The value of grass in the alternative state is estimated to be $2100 a-1

based on price of grass.The value is zero in the current state

• The value of the three major crops produced is estimated as $100 ha-1yr-1 .The value is zero in the alternative state

Conclusion and RecommendationsConclusion

• Uncertainties with ES measuredbecause of the overlappingboundary of current andalternative sites

• Uncertainties in published valuesof carbon storage underlinedpotential errors hence the needfor site specific data

• Alternative state has capacity toindirectly support agriculturalproduction

• Results provide useful indicationsof the wetland’s capacity toprovide a variety of benefitsdespite the shortcomings

Recommendations

• Need for improved recognitionof wetlands, importance and valueof ES delivered by conservationstrategies to help informconservation

• Need for an extensive ESassessment to include other ESnot considered in the study

• Similar studies should beconducted in the region and inthe Nile Basin to benefit similarwetlands

THANK YOUASANTE SANA