Invasive Futures

Traditional rangeland management and livelihoods in Kenya, particularly in the Baringo County basin, are slowly changing due to environmental pressures as well as system-immanent drivers such as rangeland degradation and changing aspirations of land users. Invasive plant species are spreading rapidly, taking over pastoral communal lands and hindering livestock mobility. In response, households are transitioning to arable farming to adapt to the invasion. However, as arable farming expands, the seasonal availability and quality of pasture decrease, further negatively impacting agro-pastoral livelihoods. Furthermore, cropping systems are themselves susceptible to the spread of new invasive plant species. Ecological shocks, such as plant invasions, thus become key elements in future-making, as they accelerate social-eco­logical transitions and livelihood transformation processes in future rangelands.

• What are the spatial-temporal patterns of land-use transitions in the Baringo region?
• How do soil fertility and land use change after Prosopis invasion and clearing?
• What is the effect of agricultural management on Parthenium invasion, soil water dynamics, and crop performance?
• How do aspirations, invasive spread, and soil fertility change households’ resilience to future shocks?

Interview, socio-economic randomized controlled trial, household survey, statistical and econometric analysis, physical and chemical soil analysis

a) Prosopis spread, soil fertility, and coping strategies: Prosopis has been established in the area since the 1980s. It is mostly found in the seasonally inundated plains, where 65% of households report infestation. Grazed pastures show much higher infestation levels than frequently cropped farmlands. Semi-nomadic pastoralists and agro-pastoralists are more affected by Prosopis infestation than arable farmers. Prosopis stand densities in Baringo County were mapped using ground-truthing and remote sensing, and their relationship with soil fertility was analyzed. Prosopis obtains about 15-20% of its nitrogen from the atmosphere through biological nitrogen fixation and significantly increases carbon (C), nitrogen (N), phosphorus (P), and calcium (Ca) levels in the topsoil.

Economic incentives, such as better market access for hybrid maize, forage seeds, and high-value vegetables, have encourgaed mechanical clearing of Prosopis, driving a shift from pastoralism to crop farming and the development of new livelihood strategies. Other strategies include charcoal production and beekeeping. Data from 530 smallholders show that positive perceptions of Prosopis are linked to charcoal production but negatively associated with beekeeping and eradication efforts; income also increases with charcoal production. A video-based randomized control trial (RCT) with 653 agro-pastoralists demonstrated that showcasing role models enhanced community aspirations and cooperation in Prosopis management, raising willingness to participate in management programs to over 70%, promoting labor exchange, and reducing reliance on paid removal strategies.

b) Parthemium spread and control: Parthenium, likely introduced through wheat seeds from Australia, has rapidly spread across crop- and rangelands over the past five years, negatively impacting crops and animal health. The shift from pastoralism to crop farming, along with mechanized tillage and irrigation, has accelerated the spread of parthenium, especially during fallow periods, which boost the soil seed bank. Dispersal occurs through irrigation canals, road traffic, farm machinery, and manure application. Relatedly, Parthenium is more prevalent in irrigated than in rainfed areas and is influenced by soil and water conditions. Farmers mainly rely on hand weeding, while using herbicides and soil-based control strategies is positively associated with access to extension services, membership in organizations, and the educational level of household heads. However, herbicide use remains largely limited to larger, market-oriented farms.

c) Impact on households and livelihoods: An economic survey collected information on 530 households, including data on farmer and (agro-)pastoralist aspirations in the face of invasive species and related livelihood threats. Households generally aspire beyond their current status regarding income, assets, livestock, and social status. However, ecological shocks such as the widespread invasion of Prosopis and the emerging spread of Parthenium negatively affects these aspirations, particularly those related to income and assets. Similarly relevant for future making, non-cognitive skills such as self-efficacy and locus of control are negatively associated with ecological shocks. Individuals are less likely to believe they have control over life outcomes and tend to judge their capabilities lower when faced with such shocks. Education, access to agricultural extension services, and household wealth are additional determinants of aspiration formation. Cooperative membership contributes positively to the formation of income and asset aspirations. The RCT on community management of Prosopis shows that targeted video interventions signficantly boost aspirations related to community, environment, and social support. Aspirations also shape future-oriented behavior: livestock investments increase with the aspiration gap up to a certain point before declining, indicating aspiration failure. While internal locus of control is positively associated with livestock investment, this relationship weakens as the aspiration gap widens. Additionally, higher aspirations gap is linked to a higher and more sustained livelihood diversification, particularly among the poorest and smallholder households. However, excessively high aspirations relative to current status reverse this effect, particularly among women-headed households, providing evidence of gendered aspirations failure

d) Response strategies and land-use patterns: Coping with risks and uncertainties entails changes in livelihood strategies and shifts in production systems. Observations indicate that practices of future-making appear to be dominated by shifts from pastoral land use towards agro-pastoralism or even intensive crop farming and non-farm livelihoods. However, the extent of these livelihood shifts appears to depend on resource endowments and access to physical, social, and educational infrastructure, with better-off actors acting as pacemakers. Male-headed households are observed to engage more and sustain their engagement in diversified livelihoods, specifically intensive crop farming and agro-pastoralism with larger livestock, while a substantial number of female-headed households (mainly widows) remain in single livelihoods, such as small-scale livestock raising and forest-based activities including charcoal and honey production. Differences in aspirations, with women tending to have lower absolute aspirations, are associated with these different livelihood transitions. While women may aspire to shift to invasion-adaptive livelihood strategies, they are unable to translate their aspirations into actions due to their poor endowments.

With A01 on soils potential to store carbon under different management practices. With B02 and Z02 on mapping Prosopis and Parthenium spread in the Baringo region and with B02 also on the availability of breeding and feeding sites for mosquitoes linking management practices, Parthenium abundance, and soil properties relevant for soil water dynamics. With C08 on aspirations and livelihood choices. Contribution to the geospatial database for the Baringo region (Z02), the Kenya part of the central survey (Z03), the exhibition project (Z05), and CRC228 policy-dialogue activities.

Publications:

• Bacud, E.S.T., Heckelei, T., & Ihli, H.J. ‘Beyond capital assets: Evidence of gendered aspirations failure in rural livelihood diversification’ (under review).
• Becker, M., Biber-Freudenberger, L., Börner, J., & Heckelei, T. ‘Land system transitions in rural Africa: Validating the middle-range theory of change’ (submitted).
• Ihli, H.J., Rommel, J, Bacud, E.S.T., Baylis, K., & Heckelei, T. ‘Community aspirations and voluntary provision of public goods: Evidence on cooperative management of invasive species in Kenya’ (under review).
• Mutuku, D.M., Becker, B., Behn, K., & Kamiri, H. ‘The role of Parthenium invasion on agricultural land use change in the Njemp Flats: A change detection analysis’.
• Sainepo, M.B., Behn, K., and Becker, M. (2024). Contextualizing Parthenium abundance with hydro-edaphic conditions and native plant species in different land systems in Baringo, Kenya. Biological Invasions. DOI  (pre print)

Master's Theses:

• Akindipe, A. Aspirations and Agricultural Investments: Insights from a Two-Wave Panel Study in Rural Kenya. Master thesis (ongoing), University of Bonn, Germany
• Asiyo, S.P. Impacts of invasive weed Parthenium hysterophorus (Asteraceae) on native plant diversity in Baringo lowlands, Kenya. Master thesis (ongoing), Karatina University, Kenya
• Issaka, F.C. Land Tenure’s Influence on Invasive Species Control Strategies in Kenya. Master thesis (ongoing), University of Bonn, Germany
• Momanyi, E.R. Effects of Invasive Weed Parthenium hysterophorus on Growth of Selected Field Crops and Pasture Grass in the Njemps Flats, Baringo County, Kenya. Master thesis (ongoing), Karatina University, Kenya