Veld Assessments
Key questions
Why should we assess the condition of the rangeland
What Parameter of Vegetation can we measure?
Why is it important to assess these parameters?
Important ref:
Anon., 1995b. New concepts for assessment of rangeland condition. Journal of Rangeland
Management. 48: 271 -282.
Friedel, M.H. 1991. Range condition assessments and concept of thresholds: a view point.
Journal of Rangeland. Journal of Range Management 44:422-426.
Tainton, N.M, Edwards, P.J and Mentis ,M.T. 1980. Arevised method for assessing veld
condition. Proceding of Grassland Society of Southern Africa. 15:37-42.
Westoby, M., Walker, B and Noy-Meir,I. 1989. Opportunistic management for rangelands not at
equilibrium.
Chapter will:
Describe various methods used to assess the condition of rangelands
Why it is important to conduct veld condition assessment
Effect of management on rangeland health status
Review the concept of rangeland
Chapter objectives
Describe and conduct practical veld condition assessment
Describe the importance of veld condition assessment in grazing management
Develop an appropriate veld monitoring procedure factoring Clements ‘s theory of plant
succession and equilibrium and non-equilibrium theories
VELD CONDITION
Veld condition refers to the state/health of the veld in relation to its position in plant succession
as modified by some disturbance e.g. herb ivory
Measurement and interpretation of parameters like species composition, basal area etc is termed
veld condition assessment.
VELD DETERIOTION PATTERNS
1. Species Composition changes
2. Reduced plant Vigour
3. Reduced soil cover and protection
4. Increased bare areas
5. Increased erosion
6. Severe run-off
7. Desert formation
Listed above- Continuum of succession- measure of this referred as veld condition assessment
Causes of veld deterioration
1.
2.
3.
4.
Incorrect stocking rate
Incorrect utilisation of grazing
Incorrect use of fire
Drought
Purpose of Veld condition assessment
1.
2.
3.
4.
5.
To assess present condition
To monitor changes in condition
To determine effects of present management practises
To determine –what management practises need changing
To assess grazing capacity and hence recommend stocking rates
VELD CONDITION ASSESSMENT METHODS
Do we measure plant or soil condition?
Examples of veld condition methods based on succession model
Dyksterhuis (1949) USA
Ivy (1969) Zimbabwe
Tainton, Mentis and Edwards (1980) South Africa
PARAMETER TO BE MEASURED
 Species Composition
 Basal cover
 Litter cover
 Soil erosion and compaction, and
 Plant vigour
Each parameter is scored out of 10, 10 being excellent condition and 1 very poor condition
On adding score:
40-50 Excellent condition
30-40 Good
20-30 Fair
10-20 Poor
0-10 Very poor
Species Composition
Succession
Decreaser species- Species which predominate in good condition but whose abundance declines
when condition deteriorates through over or under utilisation
 Most climax grasses will be classified in this group
Invader species- These are plants which are foreign to a given plant community where they occur
but in only in small numbers. Veld dominated by this group is considered to be in very poor
condition.
Increaser species 1- Species not abundant in good condition veld but whose abundance increases
when veld is under utilised.
Increaser 11- Species not abundant in veld in good condition but whose abundance increases
when veld is over utilised.
Increaser 111- Species which are not abundance in veld in good conditions but whose abundance
increases when veld is selected.
Assess the proportion of decreaser and increaser species, High score is given for high proportion
of decreasers and desirable increaser;
Basal cover
Basal cover: actual basal cover and how close this is to the ideal for the site, and the extent and
evenness of distribution of living plants, high scores given for evenly distributed high basal
covers from small tufts
Litter cover
Actual litter cover and its composition and the extent and evenness of distribution of living
plants, with high scores given for evenly distributed high levels of litter and mostly of grass
debris
Soil erosion and compaction
Soil erosion and compaction- evidence of current soil movement and stability of previously
eroded areas. High scores for no erosion.
Plant Vigour
Health status of the plants, extent of plant vigour and productivity in relation for the potential for
the site, high scores for productivity and vigour
Assess plant size, leaf colour, number and size of flowering heads, number and type of
seedlings, vigour of seedlings, age of seedlings, Age of distribution of plants, die back of tufts,
bush encroachment.
Equilibrium and non equilibrium communities
Communities highly organises assemblages of co-evolved species
Each species is competitively superior in its own niche in the habitat
Competitive interactions among these species maintain state of equilibrium and diversity without
continual change in species composition. After a disturbance the species eventually re occupy
their former positions; the community arrives at equilibrium or some degree of stability
New ecological thought- communities seldom attain equilibrium. Disruptions are common,
preventing species assemblages from reaching any highly ordered state. Contrary to equilibrium
theory, community exist at some level of no-equilibrium, held in state by environmental
disturbance .e.g. state and transition model (Westoby et.al )-proposes a multi directional change
in community composition rather than a unidirectional changes. Depending on the transition or
process bringing about change in the vegetation community, there can be several end results or
states. Examples of transition are overgrazing, moderate grazing, light grazing and drought or
that for any given site, there is a possibility of not one but many climaxes possible, depending on
biotic and abiotic factors coming into play