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Articles | Volume XLIII-B3-2021
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLIII-B3-2021, 335–340, 2021
https://doi.org/10.5194/isprs-archives-XLIII-B3-2021-335-2021
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLIII-B3-2021, 335–340, 2021
https://doi.org/10.5194/isprs-archives-XLIII-B3-2021-335-2021

  28 Jun 2021

28 Jun 2021

INVASION OF SAVANNAS BY PROSOPIS TREES IN EASTERN AFRICA: EXPLORING THEIR IMPACTS ON LULC DYNAMICS, LIVELIHOODS AND IMPLICATIONS ON SOIL ORGANIC CARBON STOCKS

P. R. Mbaabu1,2,3, U. Schaffner4, and S. Eckert5,6 P. R. Mbaabu et al.
  • 1Faculty of Humanities and Social Sciences, Chuka University, P.O. Box 109-60400, Chuka, Kenya
  • 2Kenya Forestry Research Institute (KEFRI), Baringo Sub-Centre, P.O. Box 57-30403, Marigat, Kenya
  • 3Institute for Climate Change and Adaptation, University of Nairobi, P.O. Box 30197-00100, GPO, Nairobi, Kenya
  • 4CABI, Rue des Grillons 1, 2800 Delémont, Switzerland
  • 5Centre for Development and Environment (CDE), University of Bern, Mittelstrasse 43, CH-3012 Bern, Switzerland
  • 6Institute of Geography, University of Bern, Hallerstrasse 10, CH-3012 Bern, Switzerland

Keywords: Prosopis invasion, grassland restoration, Landsat; random forest, Land Use Land Cover Change, Soil Organic Carbon, climate change mitigation, Kenya

Abstract. 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.