Vegetation Assessment Flip

8/6/2019 Vegetation Assessment Flip

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Data collection: vegetationData collection: vegetat ion

Flip Breytenbach

LADA Regional Training Workshop

Pumulani Lodge5 Aug 2010


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INTRODUCTIONINTRODUCTIONINTRODUCTION

Vegetation degradation is an important aspect of land degradation.

Vegetation degradation can occur in:

Grasslands and rangelands

Forests and woodlands

Croplands


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More emphasis is placed on assessing vegetation degradation in grasslands

and rangelands.

Detailed assessments of forests and woodlands are not covered though can be

added if important at an assessment site.

Detailed tools are not provided for assessing crops or other vegetation incroplands can be visually assessed using Tool 15 (Part 2: Page 112)


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INDICATORSINDICATORSINDICATORS

The most important indicators of vegetation degradation are (Part 1: Page 29):

Reduced vegetation cover

Changes in vegetation structure and plant community composition

Decline in species and habitat diversity

Changes in abundance of indicator species

Land productivity in terms of biomass, quality of products and livestock

production


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Plant and litter cover

Directly affects:

Infiltration

Runoff rate

Erosion rate

Soil organic matter and nutrient

restoration


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Vegetation structure and composition

Multi storey system (trees, shrubs, dwarf shrubs,

grasses) better use of rainwater and higher

protection against erosion

Wooded savanna provide shade and a cooler

microclimate


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Vegetation diversity

Biodiversity degradation can be assessed at three levels:

Reduced habitat diversity

Loss of or reduced species diversity

Loss of or reduced varietal/land-race diversity


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Vegetation quality and productivity

Pasture and rangelands direct linked to livestock productivity

After assessing vegetation degradation in rangeland and pasture it is important

to look at the effects of this degradation on livestock productivity

(Tool 13.2- Part2: Page 90)


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Seasonality and inter-annual variability

Vegetation growth is dynamic (meteorological, geological, topographical)

Good understanding is required of variation in plant growth and characteristics

between seasons, months and years will influence data recorded


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Assessment indicators and methods are described in:

Tool 4 Part 2: Page 22

Tool 13 Part 2: Page 87


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VEGETATION ASSESSMENTVEGETATION ASSESSMENTVEGETATION ASSESSMENT

There are two stages of vegetation assessment namely:

A rapid assessment of vegetation and land use

More detailed vegetation assessment at selected sites in

the study area


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Assessment of the overall state of the vegetation (Tool 4.B.

Part 2: Page 23)

A rapid assessment of:

vegetation type

vegetation cover

Structure

species composition

Undertaken through the reconnaissance visits.

Table 3 Page 24 can be used as a basis for the vegetation overview


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Part 2: Page 87

The following tools provide a rapid assessment of vegetation.

Tool 13.1 Interviews and focus group discussions on vegetation resources

Tool 13.2 Visual assessment of vegetation status, quality and trends in

pasture/rangeland

Tool 13.3 Assessing vegetation status, quality and trends in

forests/woodland

Tool 13.4 Assessing vegetation condition in croplands


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VISUAL ASSESSMENTVISUAL ASSESSMENTVISUAL ASSESSMENT

Changes in species composition combined with decline in plant vigour leading

to lower forage biomass production, will result in the affected rangeland

having a reduced livestock carrying capacity.

A set of proposed indicators is outlined in Table 15 (Part2: Page91)

Once the rapid assessment has been conducted the vegetation condition can

be scored (Table 16 Part 2: Page 93)

Scoring should be accompanied by a description of reasons for the current

vegetation status management practices


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Rapid assessment of the vegetation status, quality and trends in

forest/woodlands (Tool 13.3) indicators Table 18 on Page 96: Part 2

Rapid assessment of vegetation condition in croplands (Tool 13.4) -

indicators Table 19 on Page 98: Part 2


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Further information on vegetation assessment methods (Annex 2 Part 2:Page

118)

Vegetation cover

Basal cover

Folial cover

Canopy cover

Plant residues and litter amount


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Method: 200m line transect. At each metre a hit or a miss is recorded.

Number of hits divided by 2 percentage basal cover.


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ADDITIONAL DETAILADDITIONAL DETAILADDITIONAL DETAIL

Species composition

How to determine the species composition of veld

At each sample site a 200-point survey method is applied.

Working downslope.


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At each metre the hit of a species or the

nearest plant species is recorded. If it is a hit on

the base of a species, it is recorded as such.

No plant species in a radius of 50cm bare

soil is recorded.


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CARRYING CAPACITYCARRYING CAPACITYCARRYING CAPACITY

Potential of an area to support livestock through grazing/browsing production

over an extended number of years without deterioration to the overall

ecosystem. (Part 2: Page 119)

Determining the carrying capacity

It must be repeated over time to obtain a proper norm.

Dry material production is determined via harvesting (clipping 1m2 quadrates,

weighing the dried grass and converting the obtained production to kg/ha) or

by using a disc pasture meter.


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The following formula is then used:

CC = 365 / {(Production X Utilisation factor) / Daily intake}

Where : 365 = days/year

Production = production of palatable species (kg/ha)

Utilisation factor = 35% = 0.35. (Only 35% of all grass is considered to

be utilised. The rest is wasted).

Daily intake = 3% of body weight = 10 -12 kg/day


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VELD CONDITIONVELD CONDITIONVELD CONDITION

Determination of veld condition (Part 2; Page 120)

To conserve our grasslands, we must know in what condition it is.

Different methods are described to determine veld condition. Some of these

methods have a difficult scientific basis, while others are easy to use.


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Visual, subjective methods

Veld is evaluated by using pre-determined characteristics listed on a form,

which is completed while walking through the veld. These methods are

totally subjective, the accuracy depending on the judgement of the operator.

These methods need no in-depth knowledge of the veld and is easily applied.

They are scientifically inaccurate.


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Ecological classification methods

These are the most general methods used to determine veld condition.

The veld condition of a camp is compared with that of a benchmark, which is

a similar veld type taken to be in a good condition. The benchmark is chosen

by the operator and remains the same for future comparisons. On the basis

of botanical surveys, comparisons are made between different camps,

relative to the condition of the benchmark, by determining a veld condition

index for the benchmark and each camp. The surveys are repeated over time

to give an indication of veld condition trend.


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THANK YOU

Vegetation Assessment Flip

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