DKCRC Report 52 Economics of Feral Camel Control in the Central Region of the Northern Territory

7/23/2019 DKCRC Report 52 Economics of Feral Camel Control in the Central Region of the Northern Territory

http://slidepdf.com/reader/full/dkcrc-report-52-economics-of-feral-camel-control-in-the-central-region-of-the 1/34

2008

Economics of camel controlin the centra l region

of the Northern Territory

AG Drucker Report

52



Economics of camel control in the

central region of the Northern Territory

AG Drucker

2008



Desert Knowledge CRCII Economics of camel control in the central region of the Nor thern Territory

Contributing author information

Enquiries should be addre ssed to:

Adam G Drucker: School for Environmental Research, Charles Darwin University, Darwin, NT, 0909, Australia.

Desert Knowledge CRC Report Number 52

Information contained in this publication may be copied or reproduced for study, research, information or educational

pu rp os es , su bj ec t to in cl us io n of an ac kn ow le dg em en t of th e so ur ce .

ISBN: 1 74158 099 4 (Online copy)

ISSN: 1832 6684

CitationDrucker AG. 2008. Ec on omic s of ca me l co nt ro l in th e ce nt ra l re gi on of th e No rt he rn Te rr it or y , DKCRC

Research Report 52. Desert Knowledge CRC, Alice Springs. Available at http://www.desert knowledgecrc.com.

au/publications/contractresearch.html

The Desert Knowledge Cooperative Research Centre is an unincorporated joint venture with 28 partners whose mission

is to develop and disseminate an understanding of sustainable living in remote desert environments, deliver enduring

regional economies and livelihoods based on Desert Knowledge, and create the networks to market this knowledge in other

desert lands.

For additional information please contact

Desert Knowledge CRC

Publications Officer

PO Box 3971

Alice Springs NT 0871

Australia

Telephone +61 8 8959 6000 Fax +61 8 8959 6048

www.desertknowledgecrc.com.au

© Desert Knowledge CRC 2008

The project was funded by Australian Government. The views expressed herein do not necessarily represent the views of

Desert Knowledge CRC or its participants.



Desert Knowledge CRC II IEconomics of camel control in the central region of the Nor thern Territory

Contents

Tables............................................................................................................................................................................IV

Figures..........................................................................................................................................................................IV

List of shortened forms ................................................................................................................................................ IV

Acknowledgements ....................................................................................................................................................... V

Executive summary ......................................................................................................................................................VI

Key ndings and recommendations ................................................................................................................VII

Recommendation 1: ........................................................................................................................................VII

Recommendation 2: ........................................................................................................................................VII

1. Introduction ................................................................................................................................................................1

2. Conceptual background and modelling approach ...................................................................................................... 3

2.1 Economics of feral animal control ............................................................................................................... 3

2.2 Model description ......................................................................................................................................... 3

2.3 Cost-Benet analysis .................................................................................................................................... 4

2.4 Population modelling ................................................................................................................................... 4

3. Feral camel control costs ........................................................................................................................................... 5

3.1 Population ..................................................................................................................................................... 5

3.2 Control method ............................................................................................................................................. 5

3.3 Alternative control strategies and target densities. .......................................................................................6

4. Benets of control ...................................................................................................................................................... 9

4.1. Direct economic impacts: cattle production impacts and damage to infrastructure.................................... 9

4.2 Indirect economic impacts.......................................................................................................................... 10 4.3 Total benets .............................................................................................................................................. 11

5. Discussion ................................................................................................................................................................13

6. Sensitivity analysis................................................................................................................................................... 15

6.1 Population growth and carrying capacity cap ............................................................................................ 15

6.2 Aerial shooting costs .................................................................................................................................. 17

6.3 Degree of competition between feral camels and cattle .............................................................................18

6.4 Methane emissions ..................................................................................................................................... 18

6.5 Infrastructure constraints ............................................................................................................................ 18

6.6 Discount rate and time horizon .................................................................................................................. 197. Conclusions ..............................................................................................................................................................21

References .................................................................................................................................................................... 23



Desert Knowledge CRCIV Economics of camel control in the central region of the Nor thern Territory

Tables

List of shortened forms

Figures

AGDCC Australian Government Department of Climate Change

INRM Integrated Natural Resource Management

IPCC Intergovernmental Panel on Climate Change

NPV net present value

NRETAS Natural Resources, Environment, The Arts and Sport (NT Government Department)

NRM Natural Resources Management

NTG Northern Territory Government

PB present benefits

PC present costs

SER/CDU School for Environmental Research, Charles Darwin University

Figure 1: Map of central NT ..........................................................................................................................................2

Table 1: Feral camel population and control costs under an annual removal strategy (1)..............................................7

Table 2: Present benets under Strategy 1 with a 12-year time horizon and a 5% discount rate.................................11

Table 3: Net present value of alternative control strategies..........................................................................................13Table 4: Present control costs and benets under alternative feral camel population growth models

and assumptions..............................................................................................................................................16

Table 5: Total present costs of Strategy 1 under alternative discount rates and time horizons ($m)............................19

Table 6: Net present value of control (Strategy 1) under alternative discount rates and time horizons ($m)..............20



Desert Knowledge CRC VEconomics of camel control in the central region of the Nor thern Territory

Acknowledgements

I should like to thank NRETAS Biodiversity Conservation staff Glenn Edwards, Keith Saalfeld, and

Benxiang Zeng for their assistance in providing the data upon which the model development and

analysis is based. Thanks also to Clive McMahon and Stephen Garnett (SER/CDU) regarding adviceabout population modelling. The model development also benefited from previous work carried out

under the Australian Government–funded NRETAS project ‘Review of threats to biodiversity in the

Northern Territory’.

The work reported in this publication is supported by funding from the Australian Government through

the Desert Knowledge CRC; the views expressed herein do not necessarily represent the views of Desert

Knowledge CRC or its participants.



Desert Knowledge CRCVI Economics of camel control in the central region of the Nor thern Territory

Executive summary

A cost-benefit analysis based on a bio-economic model was carried out to evaluate specific feral camel

control strategies in the central region of the Northern Territory (NT). Based on expert opinion obtained

through a series of workshops and meetings, and with a view to achieving the NT Integrated NaturalResources Management (INRM) Plan goal by 2020, specific control strategies for feral camels in the

central region of the NT were identified.

Two different aerial control strategies were modelled. Strategy 1 involved annual removals, while

Strategy 2 involved periodic removals only when a specific feral camel density was reached. The

direct economic benefits for the pastoral industry of feral camel control were also modelled in terms

of reduced grazing competition together with infrastructure damage. A single environmental service

related to reduced methane emissions was further considered. Although cultural values and other

environmental services are also likely to be important, their modelling was beyond the scope of this

study. Consequently, the analysis carried out in this report does not account for these values.

The total present value of costs of the feral camel control strategies ranged from $5.39m (Strategy

2) to $6.00m (Strategy 1) over a 12-year time horizon (at a 5% discount rate), equivalent to an

annualised present cost of $608 000–$676 000, respectively. Depending on how such a control program

were implemented, these costs could be both public and private in their incidence (i.e. incurred by

government and/or landholders).

Of the $6.00m Strategy 1 costs, $3.74m (62.3% of total) would be spent in year 1; $913 000 (15.2%

of total) in year 2; and $107 000–166 000 in each year thereafter. It is therefore apparent that the vast

majority of the control costs are spent in the first two years of the control program, making the cost-

effectiveness of a go-stop policy low (Strategy 2).

Although control costs are large, they are far outweighed by the direct economic benefits to the

livestock industry from reduced competition between livestock and feral camels ($50.68m under

Strategy 1 or 57.9% of total present benefits). The value of reduced methane emissions is also large

($35.24m or 40.3% of total present benefits), while reduced infrastructure damages make a relatively

small contribution to total present benefits ($1.62m or 1.8%). Total present benefits under Strategy 1

are thus $87.54m over 12 years or $9.88m per annum and were larger than those found under Strategy 2

($83.98m).

The difference between the economic benefits under the different strategies suggests that a control

strategy based on annual removals is almost always likely to be preferred. We can therefore conclude

that the magnitude of the benefits arising from a given control strategy should play a key role in

control strategy choice. We also note that approximately 60% of the benefits (i.e. from reduced grazing

competition and infrastructure damage) will accrue privately to pastoralists, while the remaining 40%

(methane emissions avoided) will accrue publicly.

The net present value of control (i.e. total present benefits minus total present costs) is $81.54m

under Strategy 1. Delays in implementation of a control program could, however, reduce this value

significantly. For example, a one-year delay could reduce this value by $7.7m, largely because of

benefits forgone during the delay.

Given the large positive net present value of control and the robustness of the overall findings, there

would appear to be a very strong argument for considering the implementation of a full-scale, long-term

feral camel control program in the near future.



Desert Knowledge CRC VIIEconomics of camel control in the central region of the Nor thern Territory

Key findings and recommendations

Finding 1:The total present value of costs of NT INRM Plan–compatible feral camel control strategies to 2020 in

the central region range from $5.39m (Strategy 2 – periodic removals) to $6.00m (Strategy 1 – annual

removals), equivalent to an annualised present cost of $608 000–$676 000 respectively.

Finding 2:The vast majority (77.6–86.3%) of the total present costs of control are spent during the first two

years. As such, annualised figures tend to significantly underestimate the control agency’s funding

requirement in the first years of a control program.

Finding 3:Although control costs are large, they are far outweighed by the economic benefits to the livestock

industry from reduced competition between livestock and feral camels ($50.68m), as well as to society

as a whole through reduced methane emissions ($35.24m). Including reduced infrastructure damage, the

net present value of control is $81.54m under Strategy 1 and $78.59m under Strategy 2.

Recommendation 1:

The difference between the present value of the economic benefits under the different strategies

suggests that a control strategy based on annual removals should be preferred over a strategy of periodic

removals.

Finding 4:Although cultural values and other environmental services are also likely to be important, their

quantification in economic terms is not required to justify a decision regarding whether to undertake a

control program or not.

Finding 5:The findings were found to be robust under a series of alternative assumptions. The uncertainty

regarding feral camel population estimates needs to be addressed in future years through improved

monitoring and data collection.

Finding 6:Delays in implementation of a control program can reduce the present value of the benefits gained from

a control program significantly.

Recommendation 2:

Given the large positive net present value of control and the robustness of the overall findings, there

would appear to be a very strong argument for considering the immediate implementation of a full-

scale, long-term feral camel control program.



Desert Knowledge CRCVIII Economics of camel control in the central region of the Nor thern Territory



Desert Knowledge CRC 1Economics of camel control in the central region of the Nor thern Territory

1. Introduction

Like other regions of the world, the natural resources of the Northern Territory (NT) face a range of

threats, many of which are costing government, business, and individuals a great deal of money and

effort to counter. The threats include fire regimes that are changing vegetation patterns, introducedanimals that compete with or kill native wildlife, weeds that spread and replace native vegetation, and

land uses that destroy or degrade vegetation (Price et al. 2007).

Exotic pest animals have major economic, environmental, and social impacts across Australia

( Australian Pest Animal Strategy 2007). In a major review of the most significant threats to biodiversity

in the NT (covering fire, feral animals, pastoralism, weeds, and land clearing), one of the highest ranked

threats across all regions was related to the presence of large feral herbivores (Price et al. 2007). There

are 19 species of exotic vertebrate pests in the NT. Arabian camel, donkey, horse, cane toad, pig, water

buffalo, fox, and cat are considered major pests because they have a high level of overall impact at

current densities and distributions. Other species such as the European rabbit, wild dog (excluding

dingoes), and goat are considered to be moderate pests because they have lesser impacts to biodiversity,at current levels. Other species such as the house sparrow, rock pigeon, turtle dove, samba deer, black

rat, brown rat, and banteng are considered minor pests as their overall impact is relatively minor (Price

et al. 2007).

Despite recognising the existence of these threats, their extent and severity is not well understood.

Furthermore, it is unclear whether the funding made available for the control of feral animals (by the

NT and Australian Governments) is either adequate or being effectively targeted. In principle, funding

should be directed to those species and regions where either the most cost-effective outcomes can

be achieved (in terms of reducing population numbers) or the highest net benefits can be obtained

(accounting for a reduction in production and environmental losses). This paper attempts to support

such an analysis by assessing the relative costs and benefits of two feral camel control strategies.In order to carry out such an assessment, a cost-benefit analysis is carried out with regard to the central

region of the NT (see Figure 1) feral camel (Camelus dromedarius) control activities. Based on expert

opinion obtained through a series of workshops and meetings, population data were obtained and, with a

view to achieving the NT Integrated Natural Resource Management (INRM) Plan goal by 2020, specific

aerial control strategies were identified and modelled. The direct economic benefit to the pastoral

industry of feral camel control was also considered, together with the indirect economic benefits

associated with reduced infrastructure damage and reduced methane emissions. Model findings are

subjected to a sensitivity analysis in order to assess their robustness.

The remainder of this report is organised as follows: Section 2 details the conceptual background and

modelling approach, Section 3 details the costs of control, Section 4 details the benefits of control,Section 5 discusses the findings, Section 6 subjects the model findings to a sensitivity analysis and

Section 7 presents conclusions.



Figure 1: Map of central NT

Desert Knowledge CRC2 Economics of camel control in the central region of the Nor thern Territory




2. Conceptual background and modelling approach

2.1 Economics of feral animal control

The management of pests involves making choices that determine how much pest control will cost

and what benefit it will deliver. In order to make informed choices, the effect that alternative coursesof action have on how the costs and benefits of pest control accrue should, ideally, be understood. To

understand how benefits and costs vary between different pest management strategies, the biological

and management components of a pest/resource system must be linked so that its economic inputs and

outputs can be estimated and compared (Choquenot & Hone 2000).

Bioeconomics, that is, the economic analysis of biological systems (Clark 1990), provides a potentially

powerful approach to the analysis of pest management by furnishing a quantitative framework for

considering the benefits and costs of alternative pest control strategies. Bioeconomic models can have

varying levels of complexity, linking economic inputs, such as the costs of feral animal control, with

consequent economic outputs, such as the benefits associated with reduced pest numbers. Economic

inputs and outputs are analysed to identify feral animal control strategies that produce optimal and/orcost-effective outcomes (Choquenot & Hone 2000).

Many feral animals are pests when they impact on grazing capacity and hence the income of

pastoralists. McLeod (2004) notes that, consequently, economic outputs have often been related to

improved agricultural or livestock productivity associated with specific pest species control. In order

to estimate this impact, the distribution of the pest is estimated, the value of agricultural production

within the range of the pest identified, and an assessment of the reduced value of production as a result

of the pest is calculated (for examples see Hone 2006 and Barlow 1987). Any research or management/

monitoring costs associated with the pest may also be accounted for.

2.2 Model descriptionFollowing this conceptual approach, we apply a simple bioeconomic model in which economic inputs

(costs of control) are integrated into a feral camel population model, leading to economic outputs related

to the present costs and benefits of control. In our bioeconomic model, in addition to the initial starting

population, two factors influence the feral camel population stock: the number of animals removed

each year (subjected to different control strategies) and the population growth rate. The number of

feral animals removed each year is one of the economic components and, together with their density,

determines the control costs of a strategy. The other economic components include the direct economic

benefits of increased cattle production that result from reduced competition with the feral camels that

are removed from the grazing system, as well as the indirect economic benefits associated with reduced

infrastructure damage and reduced methane emissions. Although we recognise that feral camels mayalso have important economic impacts on other environmental services, such as biodiversity, as well as

socio-cultural impacts (e.g. damage to sacred sites, reduced bush-tucker abundance, etc.), we are unable

to quantify such impacts given the current data available. We nonetheless note that where the cattle

production, infrastructure, and methane emission impacts are of sufficient importance to justify a feral

camel control program, valuing other environmental and socio-cultural impacts may not be crucial to

the choice that needs to be made regarding the degree of pest control necessary.




The model developed is in the form of a spreadsheet decision-support tool (the model can be found at

http://www.desertknowledgecrc.com.au/publications/contractresearch.html) that feral camel managers

can use to inform future decision making. To this end, the report directs the reader to specific cells in

the spreadsheet model where the data in question can be found.1

2.3 Cost-Benefit analysisA comparative analysis of the present costs and benefits of control is carried out. The net present value

(NPV) of control is a measure of the financial resources required to reach a target population density of

feral camels relative to the current density. The discounted stream of future costs and benefits associated

with specific control strategies over a given time horizon is calculated as follows:

(1)

where PB and PC are, respectively, the present benefits and present costs of control. The use of adiscount rate r over i years (time horizon) of a control program is used so that future costs and benefits

can be expressed in present value terms. For simplicity, it is assumed that all costs and benefits of a

control program occur at the end of the year in which they are undertaken.

2.4 Population modelling

In the absence of alternative data, a simple growth rate model was used which included a carrying

capacity cap (k). If the feral camel population is below the carrying capacity cap, the population P for

the following year is calculated by:

for all P < k (2)

where i signifies the year and r the growth rate.

The expected feral camel population size in the central region of the NT for the year 2009 (year 1 of

our analysis) was determined by extrapolating from the 2001 aerial survey estimates of Edwards et al.

(2004) using a growth rate r of 10% p.a.

1 Cell references are presente d as superscripts in the following format: where the reader is directed to a cell on the “1. Summary-Input Entry & Results” page of thespreadsheet, only the cell reference is used e.g. “B4”; where the reader is directed to one of the other spreadsheet pages, the cell reference is preceded by the sheet number

e.g. “2B4” for cell “B4” on the “2. Camels CBA Model” page, “3B4” for the equivalent cell on the “3. Initial Population Data” pa ge, etc. For example, the text in section

3.1 below: ‘a natural growth rate of 10%C33 per year’ refers the reader to cell C33 in the spreadsheet, which gives the source of the population growth rate of 10%.




3. Feral camel control costs

3.1 Population

Camels were first introduced into Australia in the 1840s to assist in the exploration of inland Australia.

It is estimated that in the period 1840–1907 between 10 000 and 20 000 camels were imported fromIndia, with an estimated 50–65% landed in South Australia (McKnight 1969). It is not known when

the first feral population established, but some escaped during the Burke and Wills expedition in 1860.

The feral animal population increased substantially after the 1920s when trucks became a widespread

form of transport. Australia now has the largest wild population of camels in the world. In 2001 the

Australian feral camel population was estimated to be in the order of 300 000 (Edwards et al. 2004).

Feral camels are widely distributed across 2.8 million km2, or 37% of the Australian mainland, including

the rangelands of Western Australia (WA), South Australia (SA) and the NT (Short et al. 1988). Feral

camels range in pastoral land in arid and semi-arid Australia, with pastoral areas dominated by Acacia

trees and shrubs particularly well suited to feral camel grazing (Short et al. 1988). In the NT, feral

camels are mainly confined to the southern third of the land area. A 2001 aerial survey indicated thatthere was a minimum of 80 500 feral camels in the NT and that the population was doubling every eight

years (Edwards et al. 2004).

Based on the results of the 2001 census and an assumed actual feral camel population of 120 000 at

that time (i.e. the 2001 NT population estimate of 80 500 was a minimum) and a natural growth rate

of 10%C33 per year, by 2009 (year 1 of our analysis) the estimated feral camel population in the NT

portion of central Australia (262 000C36 km2) will be approximately 257 0003M9. In the absence of control

the population is assumed to increase to 390 000C35 before stabilising as the maximum capacity of the

resource base to support feral camels is reached. Such a hypothetical equilibrium would be reached by

the beginning of year 62I4 (2014).

3.2 Control method

The preferred method of controlling feral camels is shooting by helicopter. Shooting from an aerial

platform (helicopter) – herein referred to as ‘aerial shooting’ – involves the use of a helicopter flying

at low altitudes and low speed to position a marksman relative to the target animals so as to have a

clear and unimpeded shot to obtain a humane kill. Both the helicopter pilot and marksman have to have

undertaken specific training and received recognised accreditation before engaging in aerial shooting

operations (Anon 1991). Aerial shooting has long been recognised as the only practical method of

controlling a number of large vertebrate feral animals, including camels, across large-scale regions,

in inaccessible areas, or to achieve rapid density reductions (Anon 1991, Dobbie et al. 1993, Edwards

et al. 2004, Norris & Low 2005). Norris and Low (2005) identify aerial shooting from helicopters as‘probably one of the best control techniques for large feral herbivores in the Rangelands’. In some

instances control can be assisted through trapping and/or mustering for the purpose of commercial sale

(Dobbie et al. 1993). However, the extent to which trapping and mustering can be used depends on

market demand and the accessibility of the animals under management. In the NT, all three techniques

are used to manage horses and donkeys.

Based on Bayliss and Yeomans (1989), as well as NT Department of Natural Resources, Environment,

The Arts and Sport (NRETAS) data collected from actual control activities, it is recognised that there

is an increasing marginal cost associated with aerial culling as feral animal densities decline. This is

because the labour and helicopter time required to shoot individual animals increases as fewer target

animals can be identified. Thus, at densities of equal to or above 0.25B9

feral camels/km2

, total aerial




control costs are estimated to be $20C9/feral camel. At densities down to 0.15B10 feral camels/km2, these

costs are $40C10/feral camel, increasing to $60C11/feral camel for densities down to 0.1B11 animals/km2.

Below this density, costs increase to $110C12/animal (K Saalfeld 2008, NRETAS, pers. comm.).

In addition to aerial control costs, costs for management and administration of control methods

were estimated based on feral camel density. At densities equal to or above 0.25 feral camels/km2

management costs are assumed to be $60 000C22 per year, falling to $5000C23 at densities lower than this.In addition, status monitoring costs are fixed at $30,000C21 per year regardless of density.

The total present value of the control costs is thus closely related to initial and target feral camel

densities.

3.3 Alternative control strategies and target densities.

Two alternative control strategies are modelled. Both strategies aim to achieve a feral camel density

of 0.25B16/B17 animals/km2 in the first year and then 0.1C16/C17animals/km2 thereafter. The latter target

density is chosen on the basis that, in the view of feral animal control experts, this is the density that is

compatible with the NT’s INRM Plan goal of ‘no deterioration in the extent, condition and functionalityof the native Territory environments’ in which the feral camels are found.

Strategy 1 aims to attain this level as quickly as possible and then maintain that level through annual

removals. By contrast, Strategy 2, while also aiming to attain the 0.1 animals/km2 goal as quickly as

possible, permits densities to rise to 0.25E17 animals/km2 before ‘triggering’ a further round of removals

to reduce feral animal densities down to 0.1/km2. A priori, it is expected that the latter strategy may be

cheaper as there are increasing marginal costs of removing feral animals as densities decline.

Based on the above population figures, where control Strategy 1 is used (Table 1), the initial density of

0.98I39 animals/km2 means that approximately 191 7002D53 feral camels need to be removed (almost 75%

of the current population). Taking into account the natural growth rate of feral camels (10% per year),

the population at the beginning of the second year will have reached approximately 72 0002E44 and afurther 45 8502E53 feral camels need to be removed to reach the target density of 0.1 animals/km2. Total

population will then be 26 2002E57 feral camels and the 10% natural increase of 26202F53 will need to be

removed each year thereafter.

Table 1 also presents the control costs that occur in each year under an annual feral camel removal

strategy. Given that marginal control costs increase as densities decline, it is assumed for simplicity’s

sake that the cost level to be applied is that which is related to the density at the beginning of each year.

Although costs per animal removed increase with declining density, the absolute number of animals

removed declines rapidly, leading to a fall in total control costs from $3.92m2D64 in year 1 to $1.0m2E64 in

year 2 and $192 0002F64 thereafter.

Given that the control costs presented in Table 1 occur in different years, in order to determine their

total present value it is necessary to discount them to a present value. Using a typical real discount

rate of 5%C58 (based on an approximate capital opportunity cost of 9% and an inflation rate of 4%) and

assuming a 12C56-year time horizon (i.e. covering the period 2009–2020), it can be seen that a feral

camel control program would cost approximately $6.00mD69, which is equivalent to an annual present

cost of approximately $676 000D70.

A similar analysis under a density sensitive control strategy (2) reveals total present costs of

approximately $5.39mD104 over 12 years, which is equivalent to an annualised present cost of

approximately $608 000D105. Strategy 2 control costs are lower as removals are only carried out in

years 1, 2, and 12 when feral camel densities are above the trigger density of 0.25 animals/km2. Feral




camel numbers removed in years 1 and 2 are identical to those under Strategy 1. In subsequent removal

years (years 12 and every 10 years thereafter 2) approximately 41 750O88 feral camels would have to be

removed, compared with 2620 per year under Strategy 1.

Table 1: Feral camel population and control costs under an annual removal strategy (1)

Parameter Year 1 Year 2 Year 3 and

thereafter

Total

Feral camel population including natural growth 257 231 72 050 28 820

Total area (km2) 262 000 262 000 262 000

Feral camel density/ km2 0.98 0.28 0.11

Target density/km2 0.25 0.10 0.10

Feral camels to be removed to achieve target

(number)

191 731 45 850 2 620

Total animals remaining at end of year after

removals

65 500 26 200 26 200

Control costs (Strategy 1: annual removals)

Ae ri al shoo ti ng cost ($ /anima l) $20 $20 $60

Total cost of aerial shooting $3 834 613 $917 000 $157 200

Status Monitoring $30 000 $30 000 $30 000

Management of control program $60 000 $60 000 $5 000

Total control cost in each year (Aus$) $3 924 613 $1 007 000 $192 200

Total present costs of control (over 12 years @

5% discount rate)

$5 997 244

Annual ised presen t cost s of cont ro l (ove r 12 -yea rtime horizon @ 5% discount rate)

$676 641

2 Note that the latter do not play a role in the current 12-year analysis.







4. Benefits of control

The benefits of feral animal control can be understood in terms of costs avoided as a result of the

implementation of a given control strategy. Costs avoided can be categorised as environmental, cultural,

and economic.

EnvironmentalIn general, feral camels are known to have negative impacts on sensitive and threatened plants and plant

communities through grazing and trampling in areas where they occur. They contribute to soil erosion,

damage vegetation, and foul waterholes (Dörges & Heucke 2003, P Latz, Ecological consultant, pers.

comm.). Feral camels are also considered to have a direct impact on sensitive and threatened animals

through habitat modification and competition for food and other resources where they occur at moderate

to high densities. Grazing and trampling also lead to a direct impact on landscape function. Camels are

responsible for methane emissions as a by-product of their digestive process.

CulturalFeral camels have negative impacts on Aboriginal cultural values. Impacts occur through habitat

modification, damage to culturally important sites including waterholes, damage to cultural resources

such as bush foods and trees used for artefact production, and the loss of totemic animal species (refer

to Edwards et al. 2008 for more details).

EconomicIn terms of production, there is a direct impact through competition for food and habitat modification

in areas where feral camels overlap with pastoralism, agriculture, and bush food production. In times of

scarce forage, and particularly in arid areas, feral camels are likely to compete for herbage with sheep

and cattle. This competition inflicts a direct cost on Australia’s grazing industries (McLeod 2004) while

indirect negative impacts (e.g. through damage to infrastructure and the spread of weeds) also occur on

production.

The magnitude of all the above impacts is assumed to increase with the feral camel density.

While the economic impact of feral camels in all three of these categories may be significant, as noted

above, due to data availability constraints we are only able to focus on the direct economic costs in

terms of the forgone (private) income from cattle production and the costs of infrastructure damage. A

single indirect cost associated with an environmental service – methane emissions avoidance – is also

considered. Assessing the economic values of the other environmental and cultural values is beyond the

scope of this study.

4.1. Direct economic impacts: cattle production impacts anddamage to infrastructure

Pastoralism is the predominant land use in the NT in terms of area, with approximately 55% of the land

under some form of pastoral management (pastoral leases plus pastoral operations on some Aboriginal

land tenures) (NTG 2008). Pastoral land use spread through most suitable areas of the NT during the

1870s–1890s. The industry is now primarily based on breeding and turning off cattle for live export or

fattening elsewhere in Australia. Grazing is generally based on native pastures, although introduced




species are used in some areas, and property and paddock sizes are generally very large (Oxley et al.

2005). Currently, increasing demand and rising costs, as well as high land values, are placing pressure

on pastoralists to increase productivity, leading to further intensification of pastoral use through infra-

structure development, increased stocking rates, and greater use of exotic pastures (Ash et al. 2006).

We assume a negative relationship between yields from cattle production and feral camel density.

Reducing the numbers of feral camels hence has potential benefits for the pastoralist industry.

We conservatively estimate the net income forgone per annum to the pastoralist from each head of cattle

that is replaced by feral camels to be $100C42. The magnitude of the production loss avoided depends on

a number of factors. These include:

The current feral camel population. This is extrapolated to the present from the most recent census

data that is available and varies in future years according to natural growth rates and removal efforts.

The proportion of the total feral camel population that is found on pastoral stations. This is estimated

as 20%.C45

The proportion of pastoral properties that provide good grazing and where competition with feral

camels actually takes place. This is estimated as 62%C44

. Combined with the previous assumption thismeans that 12.4% (0.62 x 0.2) of feral camels are directly competing with cattle.

The degree to which feral camels are considered to compete with cattle for scarce grazing resources.

The degree of competition is expressed as a proportion of the feral camel feed requirements to cattle.

This is assumed to be 1.5C43 times higher, that is, 1 feral camel = 1.5 cows.

Each feral camel can therefore be considered to cause an annual financial loss to cattle producers

through increased grazing competition of $18.60 (0.124 x 1.5 x $100), equivalent to $4.78m for a herd

of 257 000 feral camels.

According to a pastoral property survey data (refer to Zeng & Edwards 2008 for more details) covering

infrastructure damage during the previous two years, damages to fences, yards, and water points

occurred on two-thirds of pastoral properties. Such damage was estimated by the landholders as

totalling $132 500 per year; assuming that the amount of damage is directly proportional to feral camel

densities, we extrapolate this to $160 000C49 per year at 2009 predicted densities. We also recognise that

this figure is at best a lower-bound estimate of infrastructure damage as the survey excluded a number

of other types of infrastructure, as well as some Aboriginal managed lands and conservation areas.

4.2 Indirect economic impacts

Methane is a greenhouse gas 21 times more powerful than carbon dioxide. Methane is produced in

herbivores as a by-product of enteric fermentation, a digestive process by which carbohydrates are broken down by micro-organisms into simple molecules for absorption into the bloodstream. Both

ruminant animals (including cattle and sheep) and some non-ruminant animals produce methane,

although ruminants are the largest source since they are able to digest cellulose, a type of carbohydrate,

due to the presence of specific microorganisms in their digestive tracts. The amount of methane that is

released depends on the type, age, and weight of the animal, the quality and quantity of the feed, and the

energy expenditure of the animal (IPCC 1997).

According to the IPCC (1997, p 4.10), camels’ enteric fermentation emissions are 46 kgs/animal, which

is equivalent to 0.97 t/animal4A7 of CO2e per year.

•

•

•

•




The existence of approximately 257 000 feral camels in the central region of the NT thus generates

approximately 248 5003 tons of CO2e per year, equivalent to 1.6% of total NT emissions (Garnett et al.

2008). Removing feral camels can therefore make a contribution to NT emission-reduction strategies

insofar as only a small proportion of removed feral camels are replaced by cattle, which have slightly

higher emissions (1.31 t/animal4A22 per year for rangeland beef cattle: AGDCC 2008). Helicopter CO2e

emissions resulting from removal activities are taken into account and are found to be relatively low at0.014 t4A16 CO

2e per feral camel (Garnett et al. 2008).

Following estimates by Hatfield-Dodds et al. (2007, p.8)4, which focus on the prospects for rural

Australians becoming valued service providers in Australia’s low carbon future, we assign a

conservative value of $15C52 per ton of CO2e emitted.

At the 2009 estimated feral camel population level, the value of CO2e emissions is thus approximately

$14.50/animal per year, equivalent to $3.73m4A35.

4.3 Total benefits

Given the above, the total present value of feral camel impacts (i.e. as a result of grazing competition,infrastructure damage, and methane emissions) in the absence of any control program is $100.79mI9

over 12 years. This is equivalent to $11.37m per year. Under control strategies 1 and 2 these impacts

would be reduced to $13.25mI13 and $16.81m I24, respectively, over 12 years.

Consequently, as can be seen in Table 2, the total present benefits of control strategy 1 are $87.54mI17

($100.79m - $13.25m) over 12 years at a 5% discount rate (equivalent to an annualised value of

$9.88mI18), of which $50.68m (57.9%) is related to reduced grazing competition, $1.62m (1.8%) is

related to reduced infrastructure damage, and $35.24m (40.3%)5 is related to the value of reduced

methane emissions. As can be seen, the values of reduced grazing competition and methane emissions

are both large, and individually several times greater than the $6.00m costs of control.

Table 2: Present benefits under Strategy 1 with a 12-year time horizon and a 5% discount rate

Type of benefit Present benefits ($) Proportion of total present benefits (%)

Present benefits from reduced grazing

competition 50 675 922 57.9%

Present benefits from reduced infrastructure

damage 1 619 305 1.8%

Present benefits from reduced methane

emissions 35 242 741 40.3%

Total present benefits 87 537 968 100%

Annual ised presen t bene fi ts 9 876 507

A similar analysis for Strategy 2 reveals $83.98mI28 ($100.79m - $16.81m) of economic benefits,

equivalent to an annualised value of $9.48m I29.

3 For simplicity, it is assumed that the camel population is made up largely of adults emitting methane at the levels stated above.

4 Hatfield-Dodds et al. (2007, p.8) present a range of estimates of the Australian carbon price a ssociated with steady action to achieve significant reductions in emissions

from 1990 or 2000 emission levels, along with a mid-range estimate of international carbon prices associated with feasible global action to avoid dangerous levels of climatechange. While these different estimates reflect different levels of annual and cumulative emissions, they suggest a likely price range of $15–$65 in 2020 and $20–$75 in

2025, and an effective mid-term ‘price floor’ of $15–$20 even with a very modest long-term emissions target or with offset sales targeting only overseas markets.

5 To generate these numbers, set two of the three values in C42, C49, and C52 to zero and then look up the result in I17.







5. Discussion

As can be seen in the summary presented in Table 3, the costs associated with the density sensitive

Strategy 2 ($5.39m) are lower than those of Strategy 1 ($6.00m). The slightly higher cost effectiveness

of Strategy 2 is related to the fact that control costs increase exponentially and, therefore, it is cheaperto only remove animals at higher densities (i.e. when their population reaches a density equal to, or

greater than, 0.25 animals/km2). This is in contrast to removing animals when they are always close to

0.1 animals/km2, as is the case under Strategy 1. Nevertheless, the difference between the two strategies

over 12 years is small.

By contrast, the difference in the benefits of control between the two strategies is much larger. Total

present benefits are $87.54m for Strategy 1 and $83.98m for Strategy 2. Benefits are lower under

Strategy 2 as higher feral camel populations are tolerated between removal years.

Under both strategies it is clear that the total present benefits far outweigh the total present costs of

control. While infrastructure damage avoided represents a relatively small proportion of the benefits

(1.8%), reduced grazing competition and reduced methane emissions are individually several times

greater than the control costs. Hence, we observe a high net present value for both control strategies

($81.54m I20 for Strategy 1 and $78.95mI31 for Strategy 2, over 12 years). This is equivalent to an

annualised value of $9.20m and $8.87m respectively. The benefit-cost ratio is greater than 14 in both

cases.

Table 3: Net present value of alternative control strategies

Strategy 1 $ Benefit-cost

Total present costs 5 997 244

Total present cenefits 87 537 968

Net present value 81 540 724

Annual ised ne t presen t va lu e 9 199 866

Benefit-cost ratio 14.6

Strategy 2

Total present costs 5 391 893

Total present benefits 83 983 961

Net present value 78 592 068

Annual ised ne t presen t va lu e 8 867 182

Benefit-cost ratio 15.6

Despite the fact that Strategy 2 was slightly more cost effective, given that the net present value6 of

Strategy 1 is larger than that of Strategy 2, it is clear that the former would be the preferred control

strategy. As such, the remainder of the analysis in this report focuses only on Strategy 1.

We now subject the above findings to a sensitivity analysis.

6 Although the benefit-cost ratio of Strategy 2 is larger than that of Strategy 1, the actual choice criterion should be based on the net pre sent value figures.







6. Sensitivity analysis

The control costs and benefit estimates derived above are entirely dependent on the data provided by the

relevant experts. Insofar as the results obtained can provide useful ‘ball park’ figures upon which policy

recommendations and future research priorities can be defined, it is useful to assess their robustness byexploring the degree to which the model results are driven by and sensitive to particular assumptions.

Sensitivity analyses are thus carried out covering a range of factors, including feral camel population

growth rates, aerial shooting costs, the degree to which feral animals compete with livestock for grazing

resources, methane emission values, infrastructure constraints, discount rates, and time horizons.

6.1 Population growth and carrying capacity cap

The rate at which the natural population growth of feral camels takes place is an important factor in

determining total present control costs in the model. The annual natural population growth rate applied

to the 2001 aerial survey population was 10% and a maximum central region carrying capacity of

390 000 feral camels was assumed.

We note that the model findings appear to be robust even under much higher population growth rates.

For example, as can be seen in Table 4 (Model 1b), a 50% increase in the growth rate (i.e. to 15% per

year 7) would lead to an increase in Strategy 1 total present costs of only $2.7m (from $6.00m in Model

1a to $8.70m). In addition to the fact that modelling such a 50% increase might lead to projected species

growth occurring beyond maximum population growths observed in practice, we also note that such an

increase in control costs of $2.7m would still be small relative to the estimated direct economic benefits

of control. This finding holds true even at very low rates of feral camel population growth, and with

both high and low carrying capacity caps.

In addition, the baseline model (Model 1a) has been adapted to incorporate some of the main population

data parameters and models analysed by McLeod and Pople (2008). Model 1c uses the parameters

provided by McLeod and Pople’s exponential model, while Model 1d uses the parameters provided

by their logistic model. Models 2, 3, and 4 incorporate McLeod and Pople’s exponential, logistic, and

theta-logistic models, respectively, in place of the simple population model used in Model 1a. The

population parameters used in the McLeod and Pople models are also used.

As can be seen in Table 4, the alternative assumptions and underlying population models do have a

large influence on present control costs and the net present value of control. Strategy 1 present costs

of control vary from $3.67m (Model 4) to $4.95m (Model 2), while the respective net present values

of control decline to $35.66m and $75.22m.8 Relative to the Model 1a baseline, these reductions

occur principally through the large changes in the estimated 2009 initial feral camel population (under

156 000 in Model 4) and the estimated maximum carrying capacity (262 000 under Model 3).

Despite the sensitivity of the findings to the underlying assumptions made regarding feral camel

population growth, and the clear need for improved monitoring and population data collection (Clive

McMahon 2008, Research Fellow, Charles Darwin University, pers. comm.), it is apparent that the

finding that the net present value of control is large (benefit-cost ratio larger than 10, even under Model

4) is robust.

7 To generate the numbers below, adjust C33.

8 To generate these numbers use the alternative spreadsheets provided and adjust C32, C33, and C35.






6.2 Aerial shooting costs

Aerial shooting costs were assumed to increase in inverse proportion to the density of feral camels

being removed. The cost levels used in this report are based on those for actual control programs

conducted in different environments and at different target animal densities (refer to Saalfeld & Zeng

2008). These were estimated as $20/animal at densities of equal to or above 0.25 feral camels/km2, $40/animal at densities down to 0.15 feral camels/km2, $60/feral camel for densities down to 0.1 animals/

km2, and $110/feral camel below 0.1 animals/km2.

We note that in our model, aerial shooting cost levels are determined by the feral camel density at the

beginning of each year. Given the non-continuous nature of the cost function used, this means that under

Strategy 1 control costs in the first two years are at the $20 level and at the $60 level thereafter. This is

because although in year 1 densities are brought down from 0.98 to 0.25 animals/km2, by the beginning

of year 2 natural growth rates have lifted the density back to 0.28 animals/km2. Similarly, years 3 and

onwards always start off with a density of 0.11 animals/km2. As the target density is 0.1 animals/km2

(achieved at the end of each year, year 3 onwards), no removals ever take place at the $110 level.

It is therefore worth exploring the degree to which varying control costs and minimising the

discontinuous nature of our cost curve might affect our overall findings.

In the case of buffalo in Arnhem Land, Baylis and Yeomans (1989) argued that control costs increase

exponentially according to the following formula:

(3)

where C is the cost per kill and D is the density/km2.

On the basis of this model, and taking into account that helicopter flying costs per hour appear to haveincreased substantially9, aerial shooting costs would thus now be in the region of $92–$148 per animal

killed at a density of 0.12 animals/km2. This would be equivalent to a cost 1.5–2.5 times greater than we

have currently modelled.

Accounting for an across-the-board increase in aerial shooting costs of 2.5 times10 increases the total

present cost of Strategy 1 to $14.37m (2.4 times that of our baseline). However, given that total present

benefits are $87.54m, it is apparent that even much larger increases in aerial shooting costs will not

have a significant effect on the large and positive net present value of control.

Adjusting the target density downwards has a similar effect to increasing control cost levels. At levels

that do not allow natural population growth to result in densities at a different cost level at the beginning

of the following year, we can also smooth the discontinuous nature of our cost curve. At our baseline

cost levels (i.e. $20, $40, $60, and $110), reducing the first year target density to 0.2211 animals/km2 and

subsequent year targets to 0.0512 animals/km2 would increase Strategy 1 total present control costs to

$7.00m, which is only $1.00m more than under our baseline assumptions. This result occurs as the vast

majority (77.6%) of feral camel removal still takes place in year 1 at $20/feral camel. While removals in

year 2 do take place at $60/feral camel and in year 3 at $110, relatively few camels are being removed.

Total present costs of control are thus particularly sensitive to the cost levels at the initial very high

9 Bayliss estimated that helicopter costs in 1989 were approximately $220 per hour, which is equivalent to $500 in 2007 dollars. Given that helicopter costs are currently

approximately $800, it appears that such costs have increased much faster than suggested by the ABS consumer price index for transport in general.

10 To generate the numbers below, adjust C9–C12.

11 Adjust B16.

12 Adjust C16 and D16.




densities and the degree to which the $110 cost level becomes an underestimate at very low densities

(i.e. far below 0.1 animals/km2. Nevertheless, as noted previously even under significant increases in

these costs net present values of control are likely to remain large and positive.

6.3 Degree of competition between feral camels andcattle

As noted in Table 2, the total present benefits arising from feral camel control under Strategy 1 are

large ($87.54m over 12 years). The amount attributable to reduced grazing competition was based

on a number of assumptions regarding the current feral camel population size, the proportion of that

population that can be found on pastoral properties (20%), the proportion of good grazing land on

pastoral properties where such competition actually impacts cattle significantly (62%), a measure of the

amount of pasture consumed by feral camels relative to cattle (150%), and the value of cattle off-take

($100/animal). These assumptions led us to conclude that $50.68m (57.9% of the total present benefits)

could be associated with reduced grazing competition as a result of Strategy 1.

The above assumptions lead us to effectively assume that 12.4% (0.2 x 0.62) of the feral camel population are directly competing with cattle. It can be shown that the proportion of feral camels found

on pastoral properties would need to be less than 2.4%13, such that only 1.5% (0.024 x 0.62) – similar

to McLeod’s 2004 assumption – would be effectively competing with cattle, for the net present value of

control to fall to zero in the absence of infrastructure and methane benefits. A similar switching point

(at the original 20% rate) for cattle values can be found at approximately $11.8514/animal.

Given the fact that both the proportion of feral camels found on pastoral properties and the value of

the cattle would have to be extremely low to reduce the net present value of control to zero, the model

results are robust with regard to the potential net benefits that can be generated through a control

program even without accounting for infrastructure and methane emissions.

6.4 Methane emissions

As noted in Table 2, the present benefits arising from reduced methane emissions as a result of feral

camel control under Strategy 1 are $35.24m over 12 years, which is equivalent to 40.3% of total present

benefits. This value was based on an assumption of a $15/ton CO2e price and that feral camels emit 0.97

tons of CO2e per year, cattle 1.31 tons, and that helicopter shooting emits 0.014 tons/feral camel. In the

absence of reduced grazing competition and infrastructure damage benefits, CO2e values would have to

be below $2.5615/ton before the net present value of control would become negative.

Given that at even very low CO2e prices feral camel control can generate positive environmental

benefits, it can be argued that the results of the model are robust.

Furthermore, we note that while the benefits of reduced grazing competition and infrastructure damage

would accrue largely to pastoralists (i.e. be captured privately), the benefits of reduced methane

emissions could be captured by Australian society as a whole, assuming that such CO2e emission

reductions can be marketed.

13 Adjust C45 and set C49 and C52 to zero.






6.5 Infrastructure constraints

K. Saalfeld (2008, NRETAS, pers. comm.) notes that a helicopter has a maximum endurance for a single

flight of three hours, and three flights can be carried out per day (9 hours flying + 1.5 hours refuelling

time = 10.5 hours). A minimum of 10% (maximum 25%) of flying time needs to be allocated to transit

to and from the shooting area, and of the remaining time, a minimum of 30% (up to maximum of 50%)

should be allocated to search for targets. Out of three hours of flight time this leaves 108 minutes

(180 - 18 - 54) of actual shooting time. Of the shooting time, a competent shooter could be reasonably

expected to shoot 200–250 animals with check time (after shooting each group of animals the shooter

has to fly back over and check that all animals have been killed – this can take as long as the actual

shooting) taken into account. For a single helicopter this would give daily totals of 600–750 animals.

This could be slightly higher with a very high density of animals and much lower with low densities, as

considerable time is spent searching and flying between groups.

Using the 600 animals/day figure, and noting that approximately 192 000, 46 000, and 2600 feral camels

need to be removed respectively in years 1, 2, and 3 onwards (see Table 1), it is apparent that 320, 76,

and 4 helicopter days are required, respectively.

Even considering that removal rates might be lower at lower densities and more helicopters days might

be spent travelling to particularly remote locations targeted for a control effort, the amount of helicopter

time, shooters, and pilots required for such a control strategy does not seem to be unfeasible.

6.6 Discount rate and time horizon

The choice of discount rates and time horizons can play an important role in determining the magnitude

of the overall figures. While the actual choices of a specific discount rate and time horizon are

somewhat arbitrary, the use of a real discount rate between 3–10% is common in many analyses, and the

use of a 12-year time horizon seems reasonable given the long-term effort that needs to be put into feral

animal control and the 2020 NT INRM plan goal.

Tables 5 and 6 present the total present cost and net present value of control estimates for Strategy 1

under a range of discount factors and time horizon assumptions.16 As can be seen, total present control

costs vary between $4.80m ($1.27m) and $12.03m ($307 000 per year), while net present values vary

between $24.95 ($6.6m per year) and $427.52m ($10.9m per year). Hence neither the choice of discount

rate nor the time horizon affect our overall finding that the net present value of feral camel control is

large and positive.

Table 5: Total present costs of Strategy 1 under alternative discount rates and time horizons ($m)

Years

5 12 20 50

Discount rate

10% 4.80 5.38 5.70 5.97

5% 5.13 6.00 6.69 7.80

1% 5.43 6.66 7.96 12.03

16 Adjust C56 and C58.




Table 6: Net present value of control (Strategy 1) under alternative discount rates and time horizons ($m)

Years

5 12 20 50

Discount rate

10% 24.95 59.57 79.04 95.09

5% 29.62 81.54 122.76 189.10

1% 34.24 107.55 185.30 427.52

It is nonetheless interesting to note that wherever the natural population growth rate is higher than the

discount rate (as it is in our baseline case), delaying the implementation of a control program will result

in higher present costs. Lower benefits also occur regardless of the discount rate–population growth

relationship. For example, delaying the implementation of Strategy 1 for even one year increases total

present costs to $6.16m and reduces the net present value of control to $73.84m.17

17 To generate these values, adjust the B16 target density to larger than the current density (e.g. 1) and C16 to 0.25.




7. Conclusions

A cost-benefit analysis is carried out with regard to feral animal control activities and the potential

benefits associated with such control activities. Based on expert opinion obtained through a series

of workshops and meetings, and with a view to achieving the NT INRM Plan goal by 2020, specificcontrol strategies for feral camels in the central region of the NT were identified.

Two different aerial control strategies were modelled. Strategy 1 involved annual removals, while

Strategy 2 involved periodic removals only when a specific feral camel density was reached. The direct

economic benefits for the pastoral industry of feral camel control were modelled in terms of reduced

grazing competition and infrastructure damage. A single environmental service related to reduced

methane emissions was also considered. Although cultural values and other environmental services are

also likely to be important, their modelling was beyond the scope of this study.

While the control program costs and benefit estimates derived above are entirely dependent on the data

provided by the relevant experts in this field, it is argued that the results obtained provide useful ‘ball

park’ figures upon which policy recommendations and the identification of future research priorities

can be identified. The robustness of the findings were explored through a number of sensitivity analyses

covering such factors as feral camel population growth rates, aerial shooting costs, the degree to which

feral animals compete with livestock for grazing resources, methane emission values, infrastructure

constraints, discount rates, and time horizons. Overall findings were found to be robust under a series

of alternative assumptions related to existing feral camel population estimates, the degree of effective

competition between feral camels and cattle, the value of cattle, and the value of reduced methane

emissions. The uncertainty regarding feral camel population estimates needs to be addressed in future

years through improved monitoring and data collection.

The total present costs of the feral camel control strategies ranged from $5.39m (Strategy 2)–$6.00m

(Strategy 1) over a 12-year time horizon (given a 5% discount rate) and are equivalent to an annualised present cost of $608 000–$676 000 respectively. Depending on how such a control program were

implemented, these costs could be both public and private in their incidence (i.e. incurred by

government and/or landholders).

Of the $6.00m Strategy 1 present costs, $3.74m (62.3% of total) is spent in year 1, $913 000 (15.2%

of total) in year 2, and $107 000–$166 000 in each year thereafter. It is therefore apparent that the

vast majority of the control costs are spent in the first two years of the control program. As such, the

annualised figures presented in this report, which represent the total 12-year cost smoothed over all 12

years, tend to significantly underestimate the control agency’s funding requirement in the first years of a

control program.

Furthermore, it can be shown that if funding for aerial shooting were made available only for the first

year (but assuming monitoring costs continued to be incurred), then by year 12 $3.98m would still have

been spent, while the feral camel population would have recovered to 72.7% of its initial level. Despite

the fact that total present benefits would still have been significant (see below), it is clear that the cost

effectiveness of a ‘go-stop’ policy is low.

Although control costs are large, they are far outweighed by the direct economic benefits to the

livestock industry from reduced competition between livestock and feral camels ($50.68m under

Strategy 1 or 57.9% of total present benefits). The value of reduced methane emissions is also large

($35.24m or 40.3% of total present benefits), while reduced infrastructure damages make a relatively

small contribution to total present benefits ($1.62m or 1.8%). Total present benefits under Strategy 1 are

thus $87.54m over 12 years or $9.88m per year and were larger than those under Strategy 2 ($83.98m).The difference between these economic benefits suggests that a control strategy based on annual




removals is almost always likely to be preferred. We can therefore conclude that the magnitude of the

benefits arising from a given control strategy should play a key role in control strategy choice. We also

note that approximately 60% of the benefits (i.e. from reduced grazing competition and infrastructure

damage) will accrue privately to pastoralists, while the remaining 40% (methane emissions avoided)

will accrue publically.

The net present value of control (i.e. total present benefits minus total present costs) is $81.54m underStrategy 1. We also note that total present benefits are likely to be only a lower-bound estimate, as in

some cases alternative control methods (e.g. ground shooting) may be cheaper than aerial shooting,

direct economic benefits could be generated from control programs (e.g. use of removed animals for

pet meat or human consumption), and cultural and additional environmental values could be taken into

account.

At the same time, a further implication of such findings is that even though the unquantified cultural

and many additional environmental benefits of a control program may be large, their valuation will not

affect the overall finding resulting from this cost-benefit analysis, that is, that the net present value of

control is large and positive.

Finally, we note that given the natural population growth rates and the large potential benefits of

control, delay in control program implementation can have a significant impact. Under current

assumptions, even a one-year delay in implementation can result in a decrease in net present value of

$7.7m (($81.54m– $73.84m).

There would therefore appear to be a very strong argument for considering the implementation of a full-

scale, long-term feral camel control program in the near future.




References

AGDCC––see Australian Government Department of Climate Change

Anon. 1991. Culling of Large Feral Animals in the Northern Teritory. Report by the Senate Select

Committee on Animal Welfare. Commonwealth of Australia.

Ash AJ, Hunt LP, Petty S, Cowley R, Fisher A, MacDonald N and Stokes C. 2006. Intensification

of pastoral lands in northern Australia. In 14th Biennial Australian Rangelands Conference.

Renmark, SA. pp. 43–46. Australian Rangeland Society, Brisbane.

Australian Government Department of Climate Change (AGDCC). 2008. Austral ian Greenhouse

Emissions Information System http://www.ageis.greenhouse.gov.au/GGIDMUserFunc/

QueryModel/Ext_QueryModelResults.asp#resultStartMarker

Australian Pest Animal Strategy: a national strategy for the management of vertebrate pest animals in

Australia. 2007. Natural Resources Ministerial Council, Canberra.

Barlow ND. 1987. Pastures, pests and productivity: simple grazing models with two herbivores. New

Zealand Journal of Ecology 10: 43–55.

Bayliss P and Yeomans KM. 1989. Distribution and Abundance of Feral Livestock in the ‘Top End’ of

the Northern Territory (1985–86) and Their Relation to Population Control. Australian Wildlife

Research 16(6) 651–676.

Choquenot D and Hone J. 2000. Using bioeconomic models to maximize benefits from vertebrate pest

control: Lamb predation by feral pigs. University of Nebraska, Lincoln. http://digitalcommons.

unl.edu/nwrchumanconflicts/8

Clark C. 1990. Mathematical bioeconomics . Second edition. John Wiley and Sons, New York, USA.

Edwards GP, Zeng B, Saalfeld WK, Vaarzon-Morel P and McGregor M (Eds). 2008. Managing

the impacts of feral camels in Australia: a new way of doing business. DKCRC Report 47.

Desert Knowledge Cooperative Research Centre, Alice Springs. Available at http://www.

desertknowledgecrc.com.au/publications/contractresearch.html

Dobbie WR, Berman DMcK and Braysher M. 1993. Managing Vertebrate Pests: Feral Horses. Bureau

of Resource Sciences, Commonwealth of Australia.

Dörges B and Heucke J. 2003. Demonstration of ecologically sustainable management of Camels on

Aboriginal and pastoral land , Final report on project no. 200046 of the Natural Heritage Trust,

Canberra, Australia.

Edwards GP, Zeng B and Saalfeld WK. 2008. Evaluation of the impacts of feral camels. In: GP Edwards

et al. (Eds), Managing the impacts of feral camels in Australia: a new way of doing business.

DKCRC Report 47. Desert Knowledge Cooperative Research Centre, Alice Springs. pp 133–

182. Available at http://www.desertknowledgecrc.com.au/publications/contractresearch.html

Edwards GP, Saalfeld K and Clifford B. 2004. Population trend of camels in the Northern Territory,

Australia, Wildlife Research 31: 509–511.

Garnett S, Altman J, Ansell S, Cooke P, Drucker A, Hamilton R, McMahon C and Zander K. 2008.

Feral animals, climate change and Indigenous employment in the NT. 14 th Australasian

Vertebrate Pest Conference, Darwin 10–13 June.




Hatfield-Dodds S. Carwardine J. Dunlop M. Graham P and Klein C. 2007. ‘Rural Australia Providing

Climate Solutions’. Preliminary report to the Australian Agricultural Alliance on Climate

Change. CSIRO Sustainable Ecosystems, Canberra.

Hone J. 2006. Linking pasture, livestock productivity and vertebrate pest management. New Zealand

Journal of Ecology 30(1), 13–23.

Intergovernmental Panel on Climate Change. 1997. Revised 1996 IPCC Guidelines for National

Greenhouse Gas Inventories. Reference Manual (Volume 3). http://www.ipcc-nggip.iges.or.jp/

public/gl/invs6.html

IPCC––see Intergovernmental Panel on Climate Change

McKnight TL. 1969. The Camel in Australia. Melbourne University Press. Melbourne.

McLeod R. 2004. Counting the Cost: Impact of Invasive Animals in Australia 2004. Cooperative

Research Centre for Pest Animal Control. Canberra.

McLeod SR and Pople AR. 2008. Modelling management options for management of feral camels in

central Australia, DKCRC Research Report 48. Desert Knowledge CRC, Alice Springs. Norris A and Low T. 2005. Review of the management of feral animals and their impact on biodiversity

in the Rangelands: A resource to aid NRM planning . Pest Animal Control CRC Report 2005.

Pest Animal Control CRC, Canberra.

Northern Territory Government. 2008. Portrait of the NT . DPIFM. http://www.nt.gov.au/dpifm/

Primary_Industry/index.cfm?newscat1=Portrait%20of%20the%20NT&newscat2=&header=Port

rait%20of%20the%20NT

NTG––see Northern Territory Government

Oxley TJ, Leigo S, Hausler P, Bubb A and Macdonald NM. 2005. Pastoral Industry Survey NT 2004 .

Department of Primary Industry, Fisheries and Mines, Darwin.

Price, O, Drucker A, Edwards G, Fisher A, Woinarski J and Saalfeld K. 2007. ‘Review of threats to

biodiversity in the Northern Territory’. Draft Final Report for NHT Project 2005/043, NRETA.

Saalfeld WK and Zeng B. 2008. Review of non-commercial control methods for feral camels in

Australia. In: GP Edwards et al. (Eds), Managing the impacts of feral camels in Australia:

a new way of doing business. DKCRC Report 47. Desert Knowledge Cooperative Research

Centre, Alice Springs. pp 185–220. Available at http://www.desertknowledgecrc.com.au/

publications/contractresearch.html

Short J, Caughley G, Grice D and Brown B. 1988. The distribution and relative abundance of camels in

Australia. Journal of Arid Environments (15) 91–97.

Zeng B and Edwards GP. 2008. Key stakeholder perceptions of feral camels: pastoralist survey. In: GP

Edwards et al. (Eds), Managing the impacts of feral camels in Australia: a new way of doing

business. DKCRC Report 47. Desert Knowledge Cooperative Research Centre, Alice Springs.

pp 35–62. Available at http://www.desertknowledgecrc.com.au/publications/contractresearch.

html



DKCRC

Partners

Documents

DKCRC Report 52 Economics of Feral Camel Control in the Central Region of the Northern Territory