RHP South African
River Health Programme 		State of the Rivers Report
Crocodile, Sabie-Sand & Olifants
River Systems
go back to RHP homepage Table of Contents introduction/background overview of study area indicators and indices list of infoboxes with links
ecoregion 4.03 in Sabie-Sand Catchment Crocodile River System Sabie-Sand River System Olifants River System summary ecoregion 4.03 in Sabie-Sand Catchment

The Importance of Riparian Vegetation

The riparian zone is the area adjacent to
the river or water body. It forms part of the
river ecosystem and is characterized by
inundation or flooding sufficiently frequently
to support vegetation distinct from
surrounding areas. The riparian zone plays
many essential roles in the functioning of the
river ecosystem, including:
  • Flow regulation: the riparian vegetation
    slows the flow of water, both by physically
    blockingthe passage of water, and by
    absorbing the water into its root systems.
    This moderates the impacts of flooding on
    surrounding areas.
  • Water quality regulation: the riparian
    vegetation acts as a buffer or filter between
    nutrients, sediments,contaminants, and bacteria
    from the surrounding land and air, and the river
    channel itself. The riparian vegetation therefore prevents
    soil, pesticides, fertilizers and oil from entering the river
    and impacting on in-stream communities.
  • Habitat provision: The riparian zone is an important habitat
    for many plants and animals, because it is an area of transition between the land and the river. These relatively steep environmental gradients (moisture, temperature, topography, and soil) generally support higher levels of biodiversity than more homogeneous areas.
  • Corridor functions: because it follows the river, the riparian zone serves as a corridor, connecting two or more habitats that may otherwise be isolated by land transformation of areas in between. Many species of animals use corridors to disperse, and find food and mates.

    Riparian zones are particularly vulnerable to invasion by alien vegetation (because they are good dispersal routes for seeds) and this is becoming a huge ecological problem in South Africa. Alien vegetation is a problem because:

  • it takes up more water than indigenous vegetation (which may impact on the river’s flow regime)
  • it takes up habitat for indigenous vegetation (which support a greater variety of flora and fauna)
  • it changes the aesthetic characteristics of the riparian zone and
  • it damages buffering capabilities of the riparian zone.

    • Back to RHP homepage back to table of contents back to top of page The Importance of Wetlands information box Environmental Flow Requirements information box