Assessment

Problem:
 
 
“Currently the main limitation to designing a control strategy is the lack of comprehensive
mapping of aliens at national, regional and quaternary scales. Until spatial information covers the full extent of South Africa it will not be possible to evaluate completely whether the programme is indeed focussing on the most important areas from a species perspective.– WfW External Evaluation (2003)
 

 Solutions:
 
  • Gairola (2016) classified woody invasive plant species in a moderately invaded coastal belt valley on the east coast of South Africa using WordView-2 satellite imagery
  • Main et al. (2016) conducted an assessment of remote sensing techniques in the mapping of invasive alien plant distribution, tree cover and biomass, in the Agulhas plains
  • Le Maitre et al. (2016) estimated the impacts of invasive alien plants on water flows in South Africa
  • reviewed the information on the impacts of invasions on surface runoff and groundwater resources at stand to catchment scales and covering a full annual cycle
  • Van den Berg (2013) investigated the detection, quantification and monitoring of Prosopis spp. in the Northern Cape province using remote sensing and GIS (click here for data)
  • Kotze et al. (2010) established and implemented a cost effective, objective and statistically sound invasive alien plant monitoring system at a quaternary catchment level
  • De Lange & Van Wilgen (2010) found that although an estimated R6.5 billion was lost every year due to invading alien plants, this would have amounted to an estimated additional R41.7 billion had no control been carried out
  • Poona & Shezi (2010) investigated the use of different satellite remote sensors and techniques to identify, map, monitor and predict the spread and distribution of some of the major current and emerging invasive alien plant species in the KwaZulu-Natal province
  • Pretorius (2009) evaluated the feasibility of mapping certain invasive alien plant species using colour infrared (CIR) orthophotos, SPOT 5 and Geoeye satellite imagery
  • Foxcroft et al. (2009) found the selection of the appropriate scale of resolution to be crucial when evaluating the distribution and abundance of alien plant invasions, understanding ecological processes, and operationalizing management applications and monitoring strategies
  • Van Wilgen et al. (2008) conducted a biome-scale assessment of the impact of invasive alien plants on ecosystem services
  • Henderson (2007) provided an overview of the species identity, invasion status, geographical extent, and abundance of alien plants based on field records from 1979 to 2000
  • McNaught et al. (2006) developed a field manual for surveying and mapping invasive alien plants
  • Cobbing (2006) investigated the use of LANDSAT ETM imagery as a suitable data capture source for alien invasive Acacia spp.
  • Rouget et al. (2004) assessed the climatic correlates of distribution of 71 important invasive alien plants, and analysed the implications of these findings for future invasions in different vegetation types in South Africa, Lesotho and Swaziland  ver the next few decades
  • Gibson & Low (2003) conducted a survey and audit of available data sets of invading alien plant distribution
  • Hulme (2003) recommended the repeat sampling of specific points across large geographic areas for monitoring invasions and targeting management.
  • Le Maitre et al. (2000) conducted a preliminary assessment of the impact of invading alien plants on surface water resources
  • Stow et al. (2000) investigated the potential of airborne colour-infrared digital camera imagery for inventory and mapping of alien plant invasions in fynbos
  • Rowlinson et al. (1999) compared remote sensing data sources and techniques for identifying and classifying alien invasive vegetation in riparian zones