ADDITIONAL IMPACT ASSESSMENT AND COST BENEFIT ANALYSIS FOR THE GREATER WELLINGTON REGIONAL PEST MANAGEMENT PLAN

1. PURPOSE

This report provides an impact assessment and cost benefit analysis for the inclusion of wilding

conifer and feral deer in the Regional Pest Management Plan (RPMP). It is prepared in accordance

with the requirements of the Biosecurity Act 1993 and the related National Policy Direction for Pest

Management 2015 (NPD).

2. PROPOSED PROGRESSIVE CONTAINMENT PROGRAMME PESTS

2.1 Wilding conifers – European larch, Douglas fir, pine species (Larix decidua, Pseudotsuga menziesii, Pinus spp.)

Description

Wilding conifers are any introduced conifer tree, including (but not limited to) any of the species

listed in Table 1, established by natural means, unless it is located within a forest plantation, and does

not create any greater risk of wilding conifer spread to adjacent or nearby land than the forest

plantation that it is a part of.

For the purposes of this definition, a forest plantation is an area of 1 hectare or more of predominantly

planted trees.

Table 1. Wilding conifer species

COMMON NAME SCIENTIFIC NAME

European larch Larix decidua

Douglas fir Pseudotsuga menziesii

Pine species

Bishops pine Pinus muricata

Contorta or lodgepole pine Pinus contorta

Corsican pine Pinus nigra

Dwarf mountain pine Pinus mugo

Wilding conifers are introduced conifers that have mainly established naturally as a result of natural

seed spread. This process has been exacerbated by landowners failing to take action when wilding

conifers first occur, and much of the ongoing wilding conifer spread in New Zealand is generated

from existing areas of reproducing wilding conifers. Much of the initial wilding conifer spread

originated from a range of sources, particularly historic or ‘legacy’ plantings, such as Crown plantings

for erosion control (as in our region) and research; long-established shelterbelts and amenity plantings

on private and pastoral lease land; and in some locations, from woodlots and forest plantations.

Wilding conifers are produced by many different introduced conifer species. Ten conifer species are

recognised as currently contributing most to the wilding conifer problem in New Zealand. While some

of these species now have little or no commercial value and are no longer planted, or much less

frequently planted than in the past, several of these species, particularly Radiata pine (Pinus radiata)

and Douglas fir (Pseudostuga menziesii), are highly valuable commercially grown species that

contribute significantly to forestry exports.

a. Pest status, attributes and distribution

Status in New Zealand

With the development of the Nation Wilding Conifer Strategy 2015-30, a number of regional

Councils have wilding conifers listed as pests in RPMPs.

Relevant biology

Attribute Description

Form Various forms from evergreen stunted growth forms (eg, contorta

pine) to deciduous (European larch) and tall specimen trees (eg,

various pine species and Douglas fir)

Habitat Range of habitats from open areas to regenerating bush, but most

destructive in the high country at alpine and sub-alpine and/or upper

bush margin zone.

Regional distribution Limited known distribution in Eastern Rimutaka range (Pakuratahi

KNE) and some urban and peri-urban problem sites

Competitive ability Wilding conifers aggressive colonizing characteristics aid their

ability to displace low-level plant communities, especially native

grasslands, and create forests. Also Douglas fir is able to spread into

shrublands, regenerating native forest and mature forest where there

are canopy gaps and a relatively sparse understory.

Maritime pine Pinus pinaster

Mountain pine Pinus unicinata

Ponderosa pine Pinus ponderosa

Radiata Pine Pinus radiata

Scots pine Pinus sylvestris

Reproductive ability Very easily dispersed through wind-blown seeds

Resistance to control A range of effective control methods exist. Control of trees on often

steep terrain pose whole raft of serious health and safety issues

Benefits Minimal, some landowners could have seen wilding conifers as a

resource. Majority of public and landowners see them as a threat to

production and environmental values.

Control programme under the RPMS

Wilding conifers are managed under site–led Key Native Ecosystems, Reserves and Forest Health

programmes under the Regional Pest Management Strategy 2002-2022.

Current situation

Wilding conifers has been identified as being in the Wellington Region. Due to the limited known

infestation, the progressive containment programme is proposed as:

The species is limited in distribution in the Wellington Region.

b. Impact assessment

Land use/habitats

Land use type Current land use

infested

Potential land use

infested

Pest significant

problem on this

land type

Dairy - Low No

Sheep and beef - Low No

Forestry - - No

Horticulture - - No

Native

bush/conservation

Low Medium Yes

Coastal - - No

Estuarine and marine - - No

Freshwater/wetland - - No

Urban/non productive - Low No

Water bodies occupied

Water Body Type Current water body

infested

Potential water body

infested

Lakes - -

Rivers & Streams - -

Wetlands - -

Ponds & dams - -

Drains & canals - -

Troughs - -

High = Most infested/preferred Low = Less infested/preferred

How is it a problem?

Category Current Potential Comment Source

Production

Dairy - - Description

Sheep and beef - -

Forestry - -

Horticulture - -

Tourism - -

International trade - -

Other - -

Environment

Soil resources - Low Alters decomposition

rates and nutrient

cycling. Can raise

soil levels through

sedimentation.

Water quality Low Moderate Can cause lowering

of the water table.

Threatened species Low High Significant threat to

indigenous

biodiversity as it can

form dense stands of

monoculture

replacing alpine and

sub alpine

ecosystems.

Species diversity High Dense stands

compete with

indigenous species

and prevent native

recruitment.

Social/cultural

Human health - -

Recreation - Moderate Forms dense and

impenetrable stands

that obstruct access

and changes general

landscape feel of the

area.

Māori culture Low Can impede or

restrict access to

cultural sites

Options to respond to Wilding conifers

1. Do nothing: In this scenario, no control of Wilding conifers is undertaken, and the assumption is

made that the species continues to establish in new areas and no attempt is made to control

infestations.

2. Progressive containment: In which the intermediate outcome for the programme is to contain or

reduce the geographic distribution of the subject, or an organism being spread by the subject, to an

area over time.

Level of analysis

In relation to the NPD considerations (section 6(1) outlines four criteria) a low-level analysis was

deemed appropriate for Wilding conifers.

c. Cost-benefit analysis

Benefits of each option

Benefit Option

No regional intervention

(do-nothing approach)

Progressive containment

To reduce the

geographic

distribution or extent

Low – limited to alpine and

subalpine terrain in the

Medium – High as wilding pines

can have significant adverse impact

on land production, landscape,

of Wilding Conifers

to protect the

Wellington Region’s

indigenous

environmental

values, specifically

alpine and sub-

alpine habitat

biodiversity.

Wellington region. environmental and native

biodiversity values. Also wilding

conifer control reduces risk to Māori

losing access wahi tapu sites and

loss of taonga species.

Costs of each option

Option

Programme costs No regional intervention

(do-nothing approach)

Annual cost (excl GST)

Progressive containment

Annual cost (excl GST)

Council costs

Control

Surveillance

Administration

Education/awareness

- $20,000

Land occupier costs - -

Total ($) - $20,000

Costs of effects on

values

Medium – very few known sites

and limited natural habitats that

would be adversely affected by the

spread of wilding conifers

Low - a progressive containment

programme would reduce the

impact on the environment for a

modest cost of control.

CBA assumptions and inputs

Pest assumptions Values Programme assumptions Values

Current area

infested:

800ha Proposed programme: Progressive

containment

Maximum potential

area infested:

5,000ha Proposed annual

expenditure by Council:

$20,000

Time to reach

maximum extent:

75 (5) Repeated inspections and

works required:

Inspect and control by

service delivery

annually.

Current impacts ($): Unknown Discount rate: 4%

d. Risks to success

Risk that each option will not achieve the NPD objective 6(2)(g)

Risk type

Option

No regional intervention

(do-nothing approach)

Progressive containment

Outcome risk

(technical and

operational risks)

Medium - infestations would

increase. Voluntary control by

landowners likely to have little

impact.

Low – some risk if using chemical

control due to the potential for non-

target damage.

Regulatory Risk Low Low – some risk if using chemical

control but known infestations are

not in an area easily accessible to

public.

Legal risk Low Low

Socio-political risk Medium – if left uncontrolled it

could extend its range and become

a nuisance to the public of the

region. Under a do-nothing

approach there would be a

moderate to high risk of public

and political criticism of Greater

Wellington for not being more

proactive over wilding conifer

management, as it is done in

neighbouring regions.

Medium – high - if no prevention,

this plant could expand its range

which could become a nuisance and

be noticed by the general public in

future.

Other risks - -

e. Who should pay?

Matters for consideration in allocating costs for proposed Wilding Conifer plan

Legislative rights and responsibilities None known.

Management objectives Progressive containment.

Stage of infestation Very few known infestations and all are under

control

Most effective control agents Greater Wellington control is likely to be more

effective due to the limited number of known

sites and the potential of infestation.

Urgency Moderate

Efficiency and effectiveness Greater Wellington owns or administers land

with known infestations. Greater Wellington

control is the most effective option

Practicality of targeting beneficiaries The main beneficiaries are the wider community

for biodiversity benefits and this group can be

readily targeted through the General Rate.

Practicality of targeting exacerbators Exacerbators other than Greater Wellington are

currently unknown.

Administrative efficiency General rate is highly efficient for addressing

community benefits related to biodiversity.

Security Rating mechanisms are generally secure.

Fairness Fair as only known infestations are on the

publically owned land

Reasonable Yes.

Parties bearing indirect costs None known.

Transitional cost allocation arrangements None required.

Mechanisms available General rate is the most readily available

mechanism. Levies are expensive to establish and

administer.

Beneficiaries and exacerbators

Group Beneficiary Exacerbator Change

behaviour

Benefits

exceed costs

Control cost

effectively

Land

occupiers

Minor Minor Yes Yes Yes

Regional

community

Major Major No Yes No

Proposed allocation of costs

The proposed programme costs are to be 100% Council costs, allocated across the various rating

districts used in the Wellington Region under the Local Government (Rating) Act 2002.

f. Preferred option

Progressive containment is the preferred option and is realistic given the distribution of the species.

Greater Wellington will undertake direct control (through its service delivery programme) of Wilding

conifers at all known sites. The control costs involved under a progressive containment programme

are relatively minor compared to the benefits to the regional biodiversity and natural environments.

3. PROPOSED SITE-LED PROGRAMME PESTS

3.1 Feral deer (Cervus elaphus)

Red deer were liberated in Wairarapa in the 1800s and were well established by early 1900s. Fallow

and sika were illegally released in the Wellington region in more recent times for recreational hunting.

Red deer still remain the most common species in the region. Feral deer frequent native bush,

regenerated scrubland, exotic forestry and rough grassland in the region.

Any deer which is not held behind effective fences or otherwise constrained, and identified in

accordance with a recognised identification system, is considered to be feral by GWRC.

a. Pest status, attributes and distribution

Status in New Zealand

Naturalised. Under the Wild Animal Control Act 1977, any deer that is not -

(A) held behind effective fences or otherwise constrained; and

(B) identified in accordance with an animal identification device approved under the National Animal

Identification and Tracing Act 2012 or in accordance with an identification system approved under

section 50 of the Biosecurity Act 1993 and approved by the Director-General for the purposes of this

Act,

is recognised as a “wild” or feral deer.

Relevant biology

Attribute Description

Form Fallow are a small deer, with a coat that is

either black, brown with spots, or

occasionally, white. Adults weigh between

30 and 85kg.

Red deer are a medium sized deer with a

reddish brown coat and a creamy coloured

rump patch. Adults weigh between 80 to

200kg. They are the largest and most

common deer in the region.

Sika are a small deer, chestnut coloured in

summer with spots , and dark coloured in the

winter, When alarmed, sika display a white

rump patch, and make a piercing whistle.

Adults weigh between 45 and 85kg.

Habitat Generalist herbivore that browses a wide

variety of plant species but often concentrates

the majority of feeding on a small number of

favoured species. They are able to stand on

two legs to reach higher vegetation, and will

eat fresh leaf litter as well as live vegetation.

Feral deer are able to occupy a wide variety

of climates and habitat types, and are able to

survive in the absence of a permanent water

source.

Regional distribution Widespread

Competitive ability Efficient in digestion of plant and leaf

material, facilitating the use of a wide variety

of plant species. Palatable bush plant species

such as pate, broadleaf, three-finger,

lancewood, and hen and chicken fern can be

all but removed from the ground tier.

Browsing reduces vegetation cover and

density and causes the loss of plant species

richness and altered community composition

in favour of unpalatable species. Pest plant

invasion can occur under these

circumstances. Deer also damage vegetation

planted on land retired for soil conservation

purposes and newly planted or young trees in

exotic forests.

Reproductive ability Polygynous mating system (one male with a

group of females) with high reproductive

success. One offspring produced per year.

Juveniles stay with the mother for about 6

months.

Resistance to control No natural predators in New Zealand.

Controlled by shooting and high-quality

fencing.

Benefits High recreational hunting values and also

limited wild meat exports

Control programme under the RPMS

Feral deer are controlled under site–led Key Native Ecosystems, Reserves and Forest Health

programmes under the Regional Pest Management Strategy 2002-2022.

Current situation

Feral deer are widespread throughout the region, however high numbers are localised. Control

programmes are maintained by service delivery in several Key Native Ecosystem sites in the region

by Greater Wellington and hunted by the recreational and professional hunters.

b. Impact assessment

Land use/habitat types

Land use type Current land use

infested

Potential land use

infested

Pest significant

problem on this

land type

Dairy - Low No

Sheep and beef Low Moderate Yes

Forestry Low Moderate Yes

Horticulture Low Low No

Native bush /

conservation

High High Yes

Coastal Low High No

Estuarine and marine - - No

Freshwater / wetland - - No

Urban / non productive Low Low No

How is it a problem?

Category Current

Potential Comment

Production

Dairy - Low Competes with stock for pasture and

reduces pasture productivity. May

spread livestock diseases.

Sheep and beef Low Moderate Removal of vegetation through

browsing and trampling can cause soil

erosion, particularly in the eastern hill

country.

Forestry Low Moderate Can cause severe damage to young

trees in plantation forests by

trampling seedlings, browsing young

trees and stripping bark from older

trees.

Horticulture - Low Can cause damage to fruit trees and

crops.

Tourism - - Resource - can be seen as a tourist

attraction, also hunting tourism

International trade - - Resource - modest exports of wild

venison to overseas markets

Environment

Soil resources Low Moderate Removal of vegetation through

browsing and trampling can cause

erosion.

Water quality Low Moderate Erosion of soil can lead to increased

sedimentation in waterways.

Threatened species Low Moderate Eats a wide variety of plant species

and can eliminate preferred

(palatable) species, leading to changes

in plant species composition, and

preventing forest regeneration and

succession.

Species diversity High Eats a wide variety of plant species

and can eliminate preferred

(palatable) species, leading to changes

in plant species composition, and

preventing forest regeneration and

succession.

Social / cultural

Human health Low Damages and eliminates palatable

native plant species and alters

structure of native forest, which can

affect recreational experiences.

Viewed as a recreational resource by

hunters.

Recreation Low Destroys native forests and damages

peri-urban gardens.

Māori culture Moderate Destroys native forests and eats

culturally important plants.

Options to respond

1. Do nothing: In this scenario, no control of feral deer is undertaken, and the assumption is made that

the species continues to establish and no attempt is made to control the population.

2. Site-led: In which the intermediate outcome for the programme is that the subject, or an organism

being spread by the subject, that is capable of causing damage to a place is excluded or eradicated

from that place, or is contained, reduced or controlled within the place to an extent that protects the

values of that place.

Level of analysis

In relation to the NPD considerations (section 6(1) outlines four criteria) a low-level analysis was

deemed appropriate for feral deer.

c. Cost-benefit analysis

Benefits of each option

Benefit Option

No regional intervention (do-

nothing approach)

Site-led

Protect the cultural

and economic values

of KNE areas and on

TA reserves in the

region.

Council avoids the costs of an

intervention approach.

Provides for a rule for the control

of feral deer. Mitigates adverse

impacts of feral deer in high

value native biodiversity areas by

maintaining low deer numbers.

Costs of each option

Programme Costs Option

No regional intervention (do-

nothing approach)

Annual cost (excl GST)

Site-led

Annual cost (excl GST)

Council costs

Control

Surveillance

Administration

Education /

awareness

$5,000 – mostly staff time

responding to public enquiries

$13,500 – contact management

and control work.

$5,000 – mostly staff time

responding to public enquiries

Land occupier costs $- $-

Total ($) $5,000 $18,500

Costs of effects on

values

High - Due to feral deer having

a large home range, no respect

for boundaries, and can re-

invade areas from long

distances, control efforts can be

short lived if constant control is

not maintained. Feral deer occur

throughout some rural and semi-

Low - Costs to values are

reduced. Ongoing costs of a

control programme.

rural areas of the Wellington

Region. Environmental impacts

are recognised as being severe

where no control is undertaken.

d. Risks to success

Risk that each option will not achieve the NPD objective 6(2)(g)

Options

Risk type No regional intervention

(do-nothing approach)

Site-led

Outcome Risk (Technical and

operational risks)

Medium –Control of

individuals in the wild can be

difficult due to the animal

intelligence and wariness;

access to all land types, and

therefore may not be

successfully implemented by

the public in the absence of

regionally coordinated

management by Council.

Inadequately contained

farmed deer and illegal

releases represent an on-

going source of reinvasion of

high biodiversity value areas.

None identified.

Regulatory Risk None identified. Medium - Potential for

deliberate releases to

establish or supplement wild

populations as a hunting

resource.

Legal risk None identified. None identified.

Socio-political risk None identified. Medium - Valued by iwi

and some sectors of the

public as a cultural,

recreational and/or food

provisioning resource.

Other risks None identified. None identified.

e. Who should pay?

Matters for consideration in allocating costs for proposed feral deer plan

Legislative rights and responsibilities Responsibilities under the Wild Animal Control

Act 1977

Management objectives Site-led.

Stage of infestation Established throughout the region.

Most effective control agents Greater Wellington to undertake direct control by

service delivery in Key Native Ecosystems and in

actively managed Territorial Authority reserves.

Urgency Low.

Efficiency and effectiveness General rate is highly efficient for addressing

community benefits related to biodiversity.

Practicality of targeting beneficiaries Individual beneficiaries cannot be easily targeted

at a regional level other than through a levy. The

majority of benefits are for the public of the

region as a common good through maintained or

improved native biodiversity values. Wider

beneficiaries can be targeted through general rate.

Practicality of targeting exacerbators Feral deer are highly mobile so difficult to target

exacerbators.

Administrative efficiency General rate is highly efficient where common

good and wider public benefits are addressed.

Security Rating mechanisms are generally secure.

Fairness Moderate. Wider community covering costs for a

pest which may not currently affect them

directly.

Reasonable Given the moderate funding requirements and

difficulty of alternative approaches the general

rate is a reasonable approach.

Parties bearing indirect costs Hunters experience some loss of value associated

with perceived reduced hunting opportunity.

Transitional cost allocation arrangements None required.

Mechanisms available General rate is the most readily available

mechanisms. Levies are expensive to establish

and administer.

Beneficiaries and exacerbators

Group Beneficiary Exacerbator Change

behaviour

Benefits

exceed costs

Control cost

effectively

Land occupiers

(Crown and

Private)

Major Major Yes Yes Yes

Regional

Community

Major - No Yes Yes

Proposed allocation of costs

The proposed programme will be funded through the general rate allocated across the various rating

districts used in the Wellington Region under the Local Government (Rating) Act 2002, and cost

recovery.

f. Preferred option

Site-led Key Native Ecosystem and TA Reserves programme is the preferred option and is realistic

given the region wide distribution of feral deer. Greater Wellington will undertake direct control

(through its service delivery programme) of feral deer on selected KNE sites. The control costs

involved under site-led programme are relatively minor compared to the benefits to the regional

biodiversity and natural environments.