Scenario description

Scenarios were formulated bearing in mind the global changes and issues on food production and population growth (e.g. Angelsen, 2010; Godfray et al., 2010b), globalisation and land scarcity (e.g. Lambin and Meyfroidt, 2011), impacts of climate change in semi-arid areas (MEA, 2005), liberalisation of markets (including land) and the rapid increase in foreign direct investment in the agricultural sector (Zoomers, 2010). The global changes and issues will lead to an accelerating expansion of agricultural land at the expense of natural ecosystems, including marginal lands. Such changes will result in detrimental environmental impacts (Foley et al., 2005; MEA, 2005), asserting the need for sound policies and innovation to reconcile ecosystems conservation with food production. Four scenarios were developed and analysed for each of the four wetlands. These scenarios were based on land use drivers, current uses and farmers’ livelihood strategies, the production constraints that experience farmers, and the effects of land use on wetland ecosystems (Figure 3). At a farm type level, variables were related to available cropland and the extent of area converted for cultivation (e.g. upland per capita and wetland field: farm size ratio). Variables for WCGs and wetland were more related to the biophysical characteristics (available land, carrying capacity, and flooding patterns) and socio-economic conditions of their environment (i.e. market access).

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Changes in the state of the wetland •Decrease in wetland natural area; •Depletionof available soil nutrients, leading to land degradation; •Sedimentation of watercourses; •Soil compactionowing to over-grazing; •Lowered water table and dryingup of springs; •Loss of biodiversity (natural vegetation and fauna); •Pesticidepoisoning; •Loss of wetland; •Increased conflicts (farmer-farmer,farmer-herder, and farmer-wildlife)over land and water resources; •Displacementof land use within the wetland location via conversion of ranch land for high-value crop production; •Increased pressure on upland ecosystems (cut-flower farms).

Production constraintsLand-usedrivers Biophysical characteristicsof the field: wetland resources •Land suitability for cash crops (rice and vegetable) production •Soil fertility •Water soil/moisture availability Climate change/variability •Drought occurrence •Rainfall scarcity •Unreliable rainfall patterns Cultural, political, and institutional conditions •Agricultural development policy •Improved market access for farm inputs and ouputes •Land availability in and access to the wetland •Population resettlement policy Personal and socio-economic characteristics of farmers •Needfor food •Income generation opportunity Upland resources •Cropland scarcity •Land degradation

Abiotic •Flood •Seasonal drought •Soil acidity / salinity Biocticfactors •Weeds •Pests and diseases •Nematodes Conflict •Farmer-farmer •Farmer-herder •Farmer-wildlife Market policy •High input prices •Non-regulated output pricing policies Poor access to technology •Limited access to certified seeds •Poor transportation infrastructure •Inadequate access to fertiliser Socio-economic characteristics •Labour shortage •Lack of capital •Remoteness of wetland field

Non-agriculturalservices •Waterfor domestic use; •Thatching material (e.g. Cyperusand Typhaspp.); •Wild vegetables; •Medicinal plants; •Fish; •Land for settlement; •Habitat for wildlife.

Crop and livestock production •Cropland; •Grazing pasture and animal watering point; •Food; •Cashfrom crop or livestock sale; •Crop diversity; •Water for upland irrigation; •Forage resources enhanced (cut- and-carry, crop by-products)

•Improved food security (food crops production or purchase of foodstuffs from vegetable sale); •Improved household income (cash availability for school fees, farm inputs); •Diversification options (off- farm employment,crop- livestock integration) Figure 3: Land use drivers, current uses and farmers’ livelihood strategies, and the production constraints used in the scenario development. Drivers and constraints were listed by farmers during field surveys conducted in two inland valleys and two floodplains in Kenya and Tanzania.

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Scenarios and the entry points in the model are summarised in Table 5.

Scenario Entry point(s) Driver(s) in the model Baseline

(business-as-usual trend)

Wetland, wetland cluster group, and/or farm type

Upland per capita, wetland area, market and wetland accessibilities, and land uses

‘Upland’ Increasing

land scarcity on uplands Farm type Upland per capita, wetland dependency ratio, rates of conversion and fallow, wetland field size, household distribution within farm types, and land uses

‘Market’ Improved

Market access, rates of conversion and fallow, household distribution within farm types, farm type distribution within and between wetland cluster groups, and

Flooding regime and duration, rates of land conversion and fallow, and land uses within farm types and of farm types within and between wetland cluster groups, rates of land conversion and fallow, and land use

Upland per capita, flooding regime and duration, proportional distributions of households within farm types and of farm types within and between wetland cluster groups, rates of land conversion and fallow, and land uses access, rates of land conversion and fallow, and land uses

Table 5: Description of scenarios for wetland uses based on current development and future uses. Entry point(s) and driver(s) used in the model are specified for each scenario

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2.4.1 The business-as-usual scenario (Baseline)

The (Baseline) scenario is the status quo policy in the situation in 2009. The scenario envisions a continuation of the current trends on land conversion in the wetland for agricultural production in the study area. Historical analyses on wetland use suggest a recent expansion of cropland and land use intensification. Wetland conversion for cultivation is assumed to be maintained or increase unless appropriate measures are taken with all stakeholders.

2.4.2 Increasing land shortages on upland (i.e. ‘Upland’) scenario

The scenario of increasing land shortages on upland examines the impacts of further increase in cropland shortages on uplands. The scenario is based on reports from previous studies on the upland-based traditional agriculture in sub-Saharan Africa (Thenkabail and Nolte, 1996; Wakatsuki and Masunaga, 2005). Therefore, the increasing population growth-induced land shortages are expected to lead to increasing expansion of production on marginal lands and wetlands. Five levels of land shortage were implemented based on empirical analyses. The levels are upland075, upland05, upland025, upland0125, and upland00625, where the figures indicate the corresponding value of land per capita.

2.4.3 Economic development policy improved market network infrastructure (i.e. ‘Market’) scenario

The ‘Market’ scenario describes a situation of market-driven economic development. Previous studies in the region have confirmed the substantial influencing capacity of improved market networks on the production orientation among wetland-dependent households (Wood and Halsema, 2008; Chapter 3). We defined three scales of market access based on the physical market proximity and the available infrastructure (number and roads condition) to the market: low, medium, and good access. We assume that establishing new or improving existing roads opens new areas, reduces transport costs, provides market access, and thereby creating incentives for an input and output markets. Roads can further assist in land use intensification and economic development.

2.4.4 Agricultural development policy via the establishment of an irrigation scheme (i.e. ‘Irrigation’) scenario

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The (Irrigation) scenario was defined during focus group discussions held with lowland rice farmers in Malinda floodplain in Korogwe. Malinda floodplain is located in the sub-humid area and rural households rely mainly on rain-fed farming for food and their livelihoods. Rice is primary grown to generate cash while complementing the upland farming that mainly source for grains. This scenario is further supported by the National Irrigation Policy and Strategy that targets poverty reduction and the agricultural sector development programme (National Investment Brief-Tanzania, 2008). The scenario suggests a lowland development via the establishment of a small surface irrigation scheme based on the Mkomazi River diversion or by a dam. The scenario examines how possible changes in flooding patterns of the wetland will affect land uses made by rice farmers.

2.4.5 Combined scenarios

Besides these four main scenarios also three combined scenarios were explored. These were:

(i) ‘Upland’ with ‘Market’ scenario: Market responses with land scarcity are likely to stimulate land conversion of existing natural area, or land use intensification, or even their combination. It is expected that it will lead to improve rural livelihoods (food and incomes), changes in agricultural systems, and to exacerbate pressure on the wetland;

(ii) ‘Upland’ with ‘Irrigation’ scenario: allows multi-cropping (i.e. more than one crop per year) by landless farmers and hence brings a new dimension for food security and even diversity for rural livelihoods; and

(iii) ‘Irrigation’ with ‘Market’ scenario: wetland development is often accompanied by market proximity and the availability of road infrastructure is seen as crucial for agricultural and economic development. It is expected to bring along the appropriate technology, required for the development of irrigation scheme. Changes in the extent, diversity, and intensity of lowland use are among expected outcomes. It will create sources of activities for the rain-fed-based rural poor. It will open widows for livelihood diversification and hence poverty reduction, whereby improving food security.

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3. Results

Given the different trends in the scenarios for each of the four sites, four cases are presented in this Chapter to cover: (i) the contrasting features of the sites;

(ii) the heterogeneity of the wetland systems; and (iii) the diversity of agrowetland households and their land use decisions. The case studies were selected because they show the most important effects of the scenarios. In all scenarios, there are changes in the proportional distributions of farm types, land development, and land uses and/or the combination of those. Changes in the probabilistic distribution of households within farm types for the selected scenarios are presented in Table 6. The effects of all simulated scenarios across the wetlands are summarised at the end of the results section (see Table 7).

3.1 Highland humid inland valley under increasing upland scarcity