Tracking Invasive Tree Species in South Africa


Usually, a species that turns out to be invasive does not intend to be that way. In the case of the Honey Mesquite, or Prosopis tree in South Africa, it was introduced into that region to provide shade, wood for fuel, and seed pods for livestock. But good intentions sometimes go awry.

Prosopis groveOf the 750 introduced tree species in South Africa, most are fine. Only a few become invasive like the prosopis. This invasive tree found a fertile breeding ground in the northern parts of South Africa, where it and its hybrids became invasive because of their adaptability to the harsh climate, vigorous growth, high seed production, efficient seed dispersal mechanism and the absence of natural seed-feeding insects. It now poses significant threats to biodiversity and ecosystem services in South Africa – especially in tree communities near riverbanks. These invasions reduce water yields and suppress indigenous vegetation, as well as cause drastic soil erosion. This can also impact grazing areas for livestock and reduce the productivity of croplands.

In part due to species like the Prosopis, the national Agricultural Research Council (ARC),  needs to leverage geospatial solutions to better understand the Prosopis invasion and to identify potentially high-risk ecosystems.

Invasive ProsopisFaced with this task, the ARC turned to Hexagon Geospatial and ERDAS IMAGINE. Using IMAGINE to classify imagery for landcover data, calculate vegetation indices and identify seasonal spectral signatures for the vegetation, they were able to map out the invasion of the prosopis across 30 years. They then used the Spatial Modeler to identify areas that might be susceptible to future invasions.

Read this case study to find out more.


About Author

Jay Pongonis

A 15 year veteran of Hexagon Geospatial, ERDAS, and Intergraph, including 7 years as a Senior Technical Instructor, I have a lot of hands-on experience with the wide product portfolio offered by Hexagon Geospatial. In my current role in Product Marketing, I parlay that customer-facing experience into creating compelling, useful, informative documents and multimedia assets.

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