Mbekuzeni (Mbekuzeni) Veld Condition Assessment Report

Introduction

Grassland health in Mbekuzeni (Mbekuzeni), uMfolozi-uMhlatuze Catchment has been monitored using Veld Condition Assessments (VCAs). There are several ways that VCAs can help us understand the current ecological condition, which is important because this provides a clue into what the historical grassland management has been like and what we can do to improve the functioning of the system.

Here’s a map of the VCA sites within the Mbekuzeni (Mbekuzeni) boundary.

Many grass species may be present in the landscape, which we call Species Richness. We recorded a total of 20 in these VCAs, but there are probably many more that we didn’t come across! Generally, the greater the diversity of species, the better, but it also matters what kind of species are present. If you have a high richness of pioneer species with low grazing value, for example, that would be less valuable for livestock production than fewer species that are more palatable. Generally, the more palatable species are also deep-rooted perennial grasses that are efficient at regrowth after disturbance from well-managed grazing. So good grasses for grazing are often also good grasses for ecosystem functioning, water infiltration, and carbon sequestration!

All of the grass species we assessed have been categorised based on how they respond to disturbance and what they can tell us about the management history of the site. These are represented by the following four categories:

  1. Increaser 1 = Grasses that are abundant in underutilised veld. These are usually unpalatable, robust climax species that can grow without any defoliation.
  2. Decreaser = Grasses that are abundant in well managed veld, but decrease in number when overgrazed or undergrazed. These are usually palatable climax grasses preferred by grazing animals.
  3. Increaser 2 = Grasses that are abundant in overgrazed veld. These grasses increase due to the disturbing effect of overgrazing and include mostly pioneer and sub-climax sources.
  4. Increaser 3 = Grasses that are commonly found after an extended period of overgrazing or selective grazing. Unlike Increaser 2 grasses, however, these are usually unpalatable, dense climax grasses. These grasses often increase in abundance for the same reasons as Increaser 2 grasses, but they require management responses that are more similar to Increaser 1 grasses. Treating them like Increaser 2 grasses by protecting them from disturbance (applying rest) won’t reduce their number.

The condition of the veld isn’t necessarily related only to the number of animals, but to their behaviour. If grazing practices are unmanaged (no predators, no herding, no fences etc), then they will usually result in selectively grazed or overgrazed conditions. Without careful time control of disturbance from fire and grazing, it is unlikely that well-managed conditions will result. “Disturbance intensity”, therefore, shouldn’t be confused with “stocking rate”!

Depending on the abundance of species from each category, we can make some conclusions about the ecological condition of the site. This can help inform the management actions that are required to a well managed state that favours productive and palatable Decreaser species. The following criteria has been applied to categorise the veld condition in this report:

It’s important to note that how we define these conditions is a bit subjective and an over-simplification for us to make broad generalisations about how one site compares to another. If we look at the grazing value of each individual grass species (quality and quantity of leaf production) as well as how frequently we came across that species in our assessment, we can calculate how well livestock are being nourished by the health of that site. We call this the Veld Condition Score, which is expressed as a % relative to benchmark, well managed sites in the region.

Another key indicator that we’re interested in is the Basal Cover. This is a measure of the % if the site that is covered by grass. If this number is low, then there is a lot of exposed soil that is very easy to erode from wind and rain, will get harder and hotter in the sun, and can be an opportunity for invasive plants, including wattle, to establish. If the number is high, however, then water infiltration is better, soil moisture is higher and more stable, the soil is able to support more biological activity, this generally improves the health of the soil and makes it more resilient to the impact of dry spells.

Summary Results

Site Information

Here’s a summary of the site-level results:

Mbekuzeni (Mbekuzeni) Site Information Summary
Site ID Date Condition Veld Condition Score (%) Basal Cover (%) Species Richness Grass Biomass (kg/ha) Observer Description Lat Lon
DH14A01 2023-01-11 Selectively Grazed (Disturbed) 40.7 30.2 12 1,315.46 Thamsanqa Shezi Burnt last season. Termite mounds. Heavily grazed. Short savanna trees both burnt and new resprouting ones. -28.1482 31.1424
DH14A03 2023-01-11 Overgrazed 35.8 30.3 11 2,030.17 Thamsanqa Shezi Not heavily grazed. Few sedges and forbs. -28.1500 31.1333
DH14A02 2023-03-01 Selectively Grazed (Disturbed) 45.8 30.9 11 1,939.15 Thamsanqa Shezi Close to a water point. Lantana camara species is a problem. few rocks around. -28.1519 31.1594
DH14A04 2023-03-01 Overgrazed 29.9 36.0 14 1,719.28 Thamsanqa Shezi In the middle of Lantana camara. rocky. -28.1513 31.1500

Abundance of Grass Species Categories

The ecological composition of the grass layers are presented for each of the VCA sites below. The best case scenario here is a lot of Decreaser species with only a few Increaser 1 and 2 species. Ideally, there should be very little to no Increaser 3 species!

Veld Condition Indices

The other key ecological indices are presented below as horizontal lines on top of the distribution of results from similar communal grassland sites. For all three indicators, the higher the values, the better.

Grass Species Composition

Species Abundance

Details of the grass species composition are presented below. Here is a summary of the abundance of each species, grouped by ecological category. A colour scale has been applied to the data to highlight the more abundant values in a darker purple so that they can be easily identified. If you have a lot of low-value grasses present, then the grazing potential of the site will be limited.

Mbekuzeni (Mbekuzeni) Grass Species Abundance (DH14)
From veld condition assessments conducted between
2023-01-11 and 2023-03-01.
Scientific Name VCA Site
DH14A01 DH14A03 DH14A02 DH14A04
Increaser 3
Sporobolus africanus 8 12 12 3
Rendlia altera 4 — — —
Aristida junciformis — — — 1
Sub-Total 12 12 12 4
Increaser 1
Hyparrhenia hirta 17 6 4 7
Cymbopogon caesius 3 — 12 11
Sub-Total 20 6 16 18
Decreaser
Digitaria eriantha — — 2 —
Sub-Total 0 0 2 0
Increaser 2
Paspalum dilatatum 7 3 12 1
Heteropogon contortus — — 3 4
Eragrostis curvula — 8 — —
Eragrostis superba 5 — — —
Eragrostis plana 3 18 29 7
Eragrostis chloromelas 17 11 16 36
Eragrostis racemosa 1 — 2 2
Eragrostis capensis 1 — — 2
Sporobolus stapfianus 29 7 — —
Digitaria monodactyla 6 28 — 4
Microchloa caffra — — 5 —
Melinis repens — — — 8
Pennisetum clandestinum — 1 — —
Sporobolus fimbriatus — — 3 13
Sub-Total 69 76 70 77

Species Descriptions

The same groupings have been applied in the below description table. A colour scale was used on the Grazing Value column to highlight the more valuable species for grazing in green and the less valuable ones in red.

Grass Species Descriptions
Scientific Name Common Name Grazing Value Perenniality Description
Increaser 3
Sporobolus africanus Ratstail Dropseed 3 Perennial Tough, strong leaves with low yield makes this a poor grazing grass. It can be an important nutrition source in the absence of more palatable grasses. Dominance is an indicator of overgrazing.
Rendlia altera Mahems Crest 0 Perennial Hard grass with low leaf production. Often found on slopes.
Aristida junciformis Ngongoni Three-awn 0 Perennial Invasive with very low grazing value. Animals will overgraze most other species before utilizing this grass, increasing its abundance. Once dominant, it is very difficult to eradicate.
Increaser 1
Hyparrhenia hirta Common Thatching Grass 6 Perennial Popular thatching and weaving grass. Good early season grazing, but unpalatable when it matures.
Cymbopogon caesius Broad-leaved Turpentine Grass 1 Perennial Very unpalatable with bitter, turpentine taste.
Decreaser
Digitaria eriantha Finger Grass 5 Perennial Palatable grass and regarded one of the best natural pastures in southern Africa. Dominance is an indicator of well managed veld conditions.
Increaser 2
Paspalum dilatatum Common Paspalum 7 Weak perennial Considered a weed in gardens and cultivated lands, especially fruit orchards.
Heteropogon contortus Tangleshead 6 Perennial Relatively palatable, but low leaf production. The awns penetrates the wool of sheep, which decreases it's quality. Can also penetrate skin and cause irritation or sores. Associated with frequent burning.
Eragrostis curvula Weeping Love Grass 5 Perennial Palatability is low, but leaf production is high. Makes very good hay, and early spring grazing. Can become moribund and very unpalatable if under-utilized.
Eragrostis superba Saw-tooth Love Grass 4 Weak perennial Good early season grazing, but loses nutrition as it matures. Drought resistant.
Eragrostis plana Tough Love Grass 3 Perennial Low palatability, but often utilzed late in the season because it remains green for long. Dominance indicates overgrazing or too frequent burning.
Eragrostis chloromelas Narrow Curly Leaf 2 Perennial Palatable in early growing season, but then leaves roll and become unpalatable.
Eragrostis racemosa Narrow Heart Love Grass 2 Perennial When abundant, indicator of disturbance. Well grazed, but low leaf production.
Eragrostis capensis Heartseed Love Grass 2 Perennial Poor leaf production limits the grazing value, but it sprouts early, especially after fire, and can therefore be valuable until more palatable grasses emerge.
Sporobolus stapfianus Fibrous Dropseed 1 Perennial Relatively palatable, but very low leaf production.
Digitaria monodactyla One-finger Grass 1 Perennial Relatively palatable, but low leaf production. Important role in soil stabilization in mountainous regions with high rainfall.
Microchloa caffra Pinchusion Grass 1 Perennial Low leaf yield, but possibly slightly palatable. Indicator of shallow and gravelly soils, often in overgrazed veld.
Melinis repens Natal Red Top 1 Weak perennial Relatively palatable, but very low leaf production. Indicator of disturbance.
Pennisetum clandestinum Kikuyu Grass 0 Perennial —
Sporobolus fimbriatus Dropseed Grass 0 Perennial —

Acknowledgements

The veld condition assessments that inform this report where collected by the Meat Naturally Rangeland Restoration Associates identified in the first summary table with the support of Mbekuzeni (Mbekuzeni) Ecoranger Trainees.

The ecological theory and principles applied in interpreting this data were derived from generous converstations, research and literature from the following ecologists:

  • Francois de Wet
  • Alan Short
  • Winston Trollope
  • Frits Van Oudtshoorn
  • Neil Tainton
  • J.E. Danckwerts