An alternative approach to

determining appropriate stocking

rates for wildlife

Mike Peel, Rina Grant, Pete Zacharias & Izak Smit

Approach

• Sustainability - using energy flow

approach – context systems – describe

their ability to provide goods and

services to achieve land user objectives;

• Promote - proactive adaptive

management (SAM) approach;

• Using Thresholds of Potential Concern

(TPCs) as end-points – effective

management

From the above to

Land-use development – shaping savannas in the eastern Lowveld of South Africa

Man induced re-scaling • Areas - re-scaled – fences and artificial water points -

animals cannot migrate

• Eruption of ‘sedentary’ water dependent species - increased animal concentrations

• Altered utilisation patterns both in time (continuous) and space (limited)

• AND ultimately system functioning

– water infiltration - runoff

– Changes in grass cover/ composition

– Altered tree:grass interactions

– Altered ‘biodiversity’ and ‘ stocking capacity’

The study area

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40 0 40 80 120 160 Kilometers

NVegetation Monitoring sites

KNP Boundary

Private Reserves

NP Farms

$T Study sites

Rivers

Issues relating to area size – OR why we

manage different size areas differently

Objective

Relevance- Large Natonal Parks e.g. Kruger

Relevance- Small areas e.g. game ranch

- Maintain essential

Ecological processes and life support systems

- Preserve genetic diversity

- Sustainable utilisation of species and ecosystems

High High Moderate-Low

Moderate Moderate High

The Wildlife Economy • South Africa’s wildlife - high value both regionally

and globally;

• Value - underplayed - difficult to quantify -

depletion of wildlife and natural resources – often

not seen - economic cost to society;

• The value of wildlife is not fully represented -

economic decisions - often viewed - less profitable

than activities that generate more easily

quantifiable benefits and outputs to society;

• By demonstrating - wildlife values and expressing

them in monetary terms - wildlife - equal footing -

other sectors of the economy

The Wildlife Economy cont’d

• We explore ways of justifying and financing

wildlife conservation, for using wildlife as a

means of economic development, and for

setting in place economic activities that

promote sustainable resource use.

Objectives driven management – Why?

• Smaller Protected Areas

– Important role in the management and

conservation – natural resources;

– Not enough to just “manage”;

– Management activities - long-term ecological

and economic objectives in mind;

– Effective wildlife management - multi-faceted

plan that is objectives driven.

We have looked at

• Value and costs of wildlife

• Vegetation types - ecological potential

• Review models – animal numbers and

stocking rates/densities

• Management regimes – spatial scales

• Predictive understanding - vegetation –

dynamics - Proactive management

• Small/intermediate size properties

• Management challenges

• Sustainability vs. biodiversity

Challenges relating to size

Thresholds of Potential Concern

• TPC – envelope – flux acceptable -

manager’s/scientists – vision/objectives

• TPC width – risk

• Management – administered – system state –

acceptable range – objectives

Sustainability

• Multi-faceted –

social/economic/environment –

objectives – manage:

– Productive systems – outputs

– Manage system contexts - many attributes

– competitive/resilient – able to exploit

opportunities

– Identify – dysfunctional systems lack –

supply

– Ecological processes – subsidise

management

Sustainability

• System knowledge

– High quality – long term - current

– Respond quickly – apply management

• Sustainability - cost and cost/benefit

considerations (ecological, economic and

social) - need to determine whether

sustainability within a system is in fact

achievable

We look at:

• Two declining wildebeest populations

• Ability – system - stabilise – population

metabolism

• Resource requirements – spectrum of

grazer species

• Useful energy flows – internal

overheads – external overheads – cost

of diet

Data - predict sustainable wildlife densities

• Population size of various grazers;

• Energy requirements;

• Time available to convert food into

energy – potential activity;

• Potential activity time minus overheads;

• Rest

• Maintenance

• Reproduction;

• Actual activity time – satisfy energy

requirements – grazer species (single

and multiple species)

Data - predict sustainable wildlife densities

• Amount of grass available;

• Energy provided by the grass sward;

• Energy required by the grazer

population;

• Grass required to supply - required

energy - sustain the population

Small Protected Areas - Sustainability

• Two small fenced adjacent PA’s of similar size;

• (<10km2)

• Decline in the wildebeest population from 135 to 10

in a drought situation – one PA

Results – Sustainability – Multiple species

Energy

required

(1)

14335

MJd-1

Potential

activity (2)

6000600

h

Rest

Overhead

(3)

47%

Actual

available

activity (4)

3180318

h

Maintenance/

reproduction

overhead (5)

11%

Available

activity

Food (6)

2520252

h

Grass

required (7)

498322

kg y-1APPA-1

Energy

required (8)

5232385

MJd-1

Grass available minus EL = 151305 kg y-1APPA-1 Resource limiting - high

mortality in selective

feeders

Results – Sustainability –Wildebeest only

Energy

required

(1)

5036

MJd-1

Potential

activity (2)

1182600

h

Rest

Overhead

(3)

53%

Actual

available

activity (4)

555822

h Maintenance/

reproduction

overhead (5)

14%

Available

activity

Food (6)

402084

h

Grass required

(7)

175044

kg y-1APPA-1

Energy

required (8)

1837958

MJy-1

Grass available minus EL = 151305 kg y-1APPA-1

Resource limiting

resulting in population

mortality

Results – Two small PA’s

• Energy flow model resources limiting – both PA’s

• Reserve 1 no game removal - Reserve 2 active

animal

Parameter/Reserve 1 2

Pre and post drought perennial grass percentage

60 - 24 52 - 12

Impala removed 0 35

% mortality 81 <5

Wildebeest removed 0 28

% mortality 93 35

Income/Loss (Rands)

-296 200 -27 600 +50 750

Nett + 23 150

Results

• Land-use - economically viable (marginal) – size;

• Non-viable - large inputs implemented - bush

control;

• Sustainability issues important – live game removal;

• Consolidation of properties improves viability

Intermediate sized Protected Area -

Sustainability

• Intermediate sized unfenced reserve adjacent to

KNP - top end paying guests

• ≈600km2

• Wildebeest 203 109

0

100

200

300

400

500

600

700

800

900

79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13

Wild

eb

eest

Wildebeest trends - Intermediate sized area

Wildebeest

600 wildebeest re-introduced x 3 and 400 in 2007, 600 2009

Results – Sustainability – Multiple species

Energy

required

(1)

168401

MJd-1

Potential

activity (2)

97647720

h-1

Rest

Overhead

(3)

47%

Actual

available

activity (4)

51753292

h-1 Maintenance/

reproduction

overhead (5)

11%

Available

activity

Food (6)

41012042

h-1

Grass

required (7)

5853940

kg y-1APPA-1

Energy

required (8)

61466365

MJd-1

Grass available minus EL = 189297698 kg y-1APPA-1 Resource not limiting yet

population declined

Results – large intermediate sized PA

• Energy flow model - resources NOT limiting –

population declined;

• Classic predator prey graph - wildebeest in a

predator pit – not good for tourism.

Wildebeest and lion trends in the Sabi Sand Wildtuin

0

100

200

300

400

500

600

700

800

900

1000

19

90

19

91

19

92

19

93

19

94

19

95

19

96

19

97

19

98

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99

20

00

20

01

20

02

20

03

20

04

20

05

20

06

Year

Wil

deb

eest

nu

mb

ers

0

10

20

30

40

50

60

70

80

90

100

Lio

n n

um

bers

Wildebeest numbers Lion numbers Poly. (Lion numbers) Poly. (Wildebeest numbers)

Why has this happened? Some thoughts

Broad-leafed woodland e.g.

Combretum spp

Terminalia fringe - contour

seepline grassland Microphyllous woodland

Terminalia fringe -cleared - shelter gone

Homogenised by bush

clearing

Results

• Supplementing prey species such as wildebeest

– ensures visitor satisfaction – high occupancy

rates

• This form of land-use is economically viable –

the profitability of these operations – good

Systems creeping into risky areas

0

100

200

300

400

500

600

700

800

900

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

03

04

05

06

07

08

09

10

11

12

13

An

imal

bio

mass (

kg

km

-2)

Herbivore Biomass/Rainfall/ - KGR

Stocking Rate Coe upper New guideline Agric. Rainfall

0

500

1000

1500

2000

2500

3000

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

03

04

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11

12

13

An

imal

bio

mass (

kg

km

-2)

Herbivore Biomass vs Grass Standing Crop - KGR

Stocking Rate Prey Only Coe upper

Systems creeping into risky areas

1323 1200 1100 1000 900 800 700 600 500 400 300

Surplus/Deficit

Standing Crop

At current game numbers a year yielding around 600kgha-1 would result in food shortage

• Translated - buffalo - satisfy the requirements of

a 500kgha-1 season (414mm followed by 398mm

year yielded 207 kgha-1 year)- mean a

reduction/loss – 230 animals - logistics

Usefulness - Smaller National Parks and

PA’s

• Question in PA adjacent KNP – Do we manage

buffalo to reduce risk of die-off in drought? -

movement

• Different - clear usefulness for some

smaller/intermediate sized National Parks

• Illustrate - different to expected - management

options in intermediate sized PA’s vs small

National Parks

Embedded in well-articulated TPCs, the

sustainability approach provides strong

pointers for proactive management actions in

savanna systems aimed at ensuring that the

management of the particular ecosystem can

deliver the defined objectives sustainably

Synthesis and Applications

Research/Monitoring/Management

Interface