Humanities

Permanent URI for this collectionhttps://repository.chuka.ac.ke/handle/chuka/418

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Browsing Humanities by Author "Eckert, S."

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    Invasion of Savannas by Prosopis Trees in Eastern Africa: Exploring Their Impacts on Lulc Dynamics, Livelihoods and Implications on Soil Organic Carbon Stocks
    (2021) Mbaabu, P. R.; Eckert, S.; Schaffner, U.
    Trees of the genus Prosopis from the Americas, were introduced in Eastern Africa in the 1970s to mitigate land degradation and its associated disservices. However, over time these trees have spread and invaded valuable grasslands and croplands and consequently led to significant land use and land cover (LULC) changes and livelihood stress. Early detection of invasive species is essential for formulating effective management strategies to prevent further spread into non-invaded lands and for monitoring the outcome of management interventions. We mapped the spatio-temporal evolution and dynamics of Prosopis invasion, its impacts on LULC and livelihoods in Baringo, Kenya by applying a Random Forest classifier on Landsat satellite data over seven-year intervals from 1988 - 2016. We then linked the LULC changes to soil organic carbon (SOC) stocks that we had measured for the different LULCs and also to socio-economic data on annual costs of clearing Prosopis from farmlands. By 2016, Prosopis had invaded 18,792 ha of land, spreading at a rate of 640 ha/yr, while all other land uses and land cover declined, each by over 40% of its original coverage in 1988. Through LULC specific SOC measurements, and relating the changes to annual costs of clearing Prosopis, we found that Prosopis removal and restoration to grassland is more effective for climate change mitigation compared to Prosopis ―cultivation‖ while also avoiding trade-offs with other ecosystem services and livelihoods. Therefore, future management of this species in Kenya and Eastern Africa should be based on a more collaborative and integrated approach.
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    Sustainable Management of Rangelands: An Assessment of Invasion Cover Trajectories and Their Contribution to Invasion Management in Marigat Sub-County, Kenya
    (Kenya Agricultural and Livestock Research Organization, 2021) Adoyo, B.; Ehrensperger, A.; Mukhovi, M. S.; Kiteme, B.; Rima, P. M.; Eckert, S.; Schaffner, U.
    Invasive alien species have complex spatiotemporal patterns of spread beyond geographical and jurisdictional boundaries. This calls for a coordinated management approach that is spatially explicit, extends beyond individual plot levels, and incorporates land users’ perceptions and decisions. This study, therefore, aims at assessing spatiotemporal invasion trajectories of the invasive tree Prosopis juliflora in Baringo County, Kenya, and evaluating their possible relation to land users’ management decisions. Pre-classified land cover data over a seven-year time period (1988–2016) were reclassified based on the presence or absence of P. juliflora and integrated into ArcGIS to produce P. juliflora cover trajectories for analysis. The spatiotemporal analysis of Prosopis invasion dynamics yields trajectories that can be linked to underlying land users’ management decisions. Areas that remained free of Prosopis since their first clearance were primarily areas where the invasion would cause the highest loss in terms of income or opportunity costs; areas that were never cleared since they were first invaded tended to be areas where no one could be personally held accountable for their management, while the abandonment of management followed by re-invasion appeared to be linked to different drivers, including diversification of livelihoods and lower market prices for horticultural products. Our findings indicate that invasion trajectories are useful in informing existing management strategies to adopt context-based invasive species management practices. The study recommends scaling up the trajectory analysis approach to be replicated in large-scale invasion management strategies. Since it requires considerable finances and time to conduct such analyses on raw satellite imagery, we suggest further research on how to simplify the approach to make it easily and efficiently replicable for large-scale applications.