Impacts
Indicator:
This indicator assesses the combined impact of all invasive species at a particular site on the delivery of selected ecosystem services, or on biodiversity. It should have a focus on those ecosystem services that are important in the context of the site concerned (for example on water resources in dry regions, livestock production in rangelands, or biodiversity in protected areas) and can be used to prioritise sites for management interventions. At a more advanced level, the value of impacts can be expressed in monetary terms and so used for calculations of costs and benefits of control.
Source data:
Le Maitre et al (2019) calculated the impacts of different degrees of alien plant invasion on yields from the the Western Cape Water Supply System
Ntshidi et al. (2018) concluded that the water use of poplar invasions is significantly lower than that of other riparian invasions
Dzikiti et al. (2018) demonstrated that deep rooted indigenous trees growing in arid to semi-arid environments are equally likely to use as much or more water per plant than invasive alien plants.
Preston et al. (2018) investigated the impact of invasive alien plants on water provision in selected catchments
Le Maitre et al. (2016) estimated the impacts of invasive alien plants on water flows in South Africa
Dzikiti el at. (2016) quantified the savings from clearing invasive alien Eucalyptus camaldulensis using in situ and high resolution remote sensing data in the Berg River Catchment
Meijninger & Jarmain (2014) assessed the impact that invasive alien plants, and the clearing thereof by Working for Water, has on the availability of water resources in the Western Cape and KwaZulu-Natal provinces
Hope (2009) investigated the viability of relating annual river yields to remotely sensed changes in vegetation cover in a large mountainous fynbos catchment
Van Wilgen et al. (2008) conducted a biome-scale assessment of the impact of invasive alien plants on ecosystem services
Dye and Jarmain (2004) reviewed relevant available information on rates of evaporation from black wattle and from grasslands and fynbos shrublands
Dye et al. (2001) concluded that the removal of riparian wattle and its replacement by indigenous herbaceous plants may result in significant reductions in annual evapotranspiration, and could very likely lead to streamflow enhancement
Le Maitre et al. (2000) conducted a preliminary assessment of the impact of invading alien plants on surface water resources
Prinsloo and Scott (1999) describe the changes in streamflow following the removal of invasive wattle from riparian zones during the dry summer months in three small catchments in the Western Cape
Dye and Poulter (1995) conduced a field demonstration of the effect on streamflow of clearing invasive pine and wattle trees from a riparian zone
