Abstract:

What is the natural composition of our east coast hinterland grasslands and do they benefit from grazing?

Rob Scott-Shaw

The discovery of grasslands inaccessible to bulk grazers and areas protected from them for over 80 years and both burnt regularly has enabled studies to enumerate the species composition (graminoid and non-graminoid) and compare them with light and heavily grazed grasslands. A Benchmark percentage composition is required to guide (a) veld management objectives for protected areas and community conservation areas i.r.o. wildlife stocking rates and livestock stocking rates, (b) weighting of species in ecosystem health indices, (c) species selection for rehabilitation programs.
The questions posed are:

  •     What is the natural (true) composition of grassland that is not accessible to bulk grazers (including livestock?)
  •     Is Ngongoni or Wiregrass (Aristida junciformis ) a natural component?
  •     Will these grasslands benefit from grazing?
  •     Is the percentage composition of Red grass (Themeda triandra) positively correlated with plant diversity?

The most significant finding is that the Increaser III grass Aristida junciformis (Ngongoni) is absent in the livestock excluded sites and Themeda triandra (Red grass) maintains a high percentage composition (in the range 45% to 64%) across all plots. The species composition of these grasslands is maintained  by fire alone.
The mean Decreaser species percentage composition for the livestock excluded grasslands is 74% and 0% for the Increaser I & II species. The merits of not using the ecological groups “Decreaser and Increaser” is discussed in the context of grasslands where production is not an objective. Themeda triandra is positively correlated with plant diversity (0.76 for species richness and 0.64 for Shannon Index).
A junciformis has become dominant or co-dominant (highest percentage composition) in most grasslands of South Africa’s east coast. This implies that it has invaded millions of hectares of grassland replacing naturally occurring species such as Themeda triandra, Diheteropogon amplectens, Monocymbium ceresiiforme and Panicum natalense. The study areas fall within the national vegetation types: KwaZulu-Natal Sandstone Sourveld, Moist Coast Hinterland Grassland and Pondoland-Ugu Sandstone Coastal Sourveld parts of Acocks’ Ngongoni Veld.

Presentation Topic

What is the natural composition of our east coast hinterland grasslands and do they benefit from grazing?

 

Contact Mr Scott-Shaw:

Ezemvelo KZN Wildlife, PO Box 13053, Cascades 3202

 

Email Mr Scott-Shaw