Deer Management in New Zealand
An introduction to deer management in New Zealand
Deer Management refers to the regulation and management of all deer species in an attempt to limit the impact that deer are having on native wildlife and plant life.
Deer were introduced into an ecosystem that had no mammals, except for three species of bats. After being introduced in Nelson in 1854, they rapidly spread to multiple points within New Zealand.
By the 1920's concerns, were being expressed about their impacts on vegetation, particularly in alpine grasslands and forests. From the 1930's, all protection for deer was removed and eradication of deer was attempted. There have been ongoing conflicts between conservationists, recreational hunters and commercial users over deer and deer control.
Deer abundances increased in the early 2000's following a soften of the markets for deer products, leading to a reduction in commercial harvesting.
This webpage will first offer figures and information on New Zealand's deer abundance, deer species and specific case studies where deer have had a detrimental impact on a local ecosystem. Following this, attention will be turned to current means of prevention, which will be analysied for their individual merits and downfalls. With all this information gathered from local authorities and what current prevention attempts have shown, this webpage will attempt to make its own recommendation surrounding deer management.
For centuries New Zealand’s forests, tussock grasslands, alpine habitats and wetlands grew and evolved with no mammalian herbivores grazing and shaping their composition. Species of Moa, a large herbivorous bird, evolved and diversified to fill the ecological niches that mammals filled in other countries (Forsyth et al 2009).
However, this changed with the arrival of Māori. By the time of European settlement it is believed that the Moa were extinct. Since their arrival, Europeans have introduced over 25 species of mammals, including deer. These combined influences have caused changes to New Zealand’s ecosystems.
Introduction of deer
A private individual introduced red deer for sport in 1854, with more released throughout the North and South islands from 1863 onwards. Between 1861 and 1919, more than 250 red deer (Cervus elaphus) were released in New Zealand for sport. They were either brought directly from the UK or came via Australia. Acclimatisation Societies formed throughout New Zealand to facilitate the introduction of exotic species.The animals were originally protected and managed by the Protection of Certain Animals Act (1861). Since then, tension has existed between the desire to protect indigenous species and environments while at the same time exploiting socio-economic value of the deer. Attitudes toward deer have varied over three distinct eras—the 'secure era' of the 1850s, the 'open era' that began in 1930, and the 'economic era' that has occurred from the 1950s (Figgins and Holland 2012).
In the secure era, Europeans introduced species to ‘civilize’ the landscape. This led to the formation of regional Acclimatization Societies throughout NZ to facilitate the introduction of exotic species. The introduction of deer was justified as a way to provide egalitarian recreational hunting opportunities, as they were introduced as game animals. The Protection of Certain Animals Act 1861 protected the introduced species by imposing strict hunting bans to allow an increase in population. By the early 20th century, institutional restrictions on recreational hunting, lack of competition, absence of predation and rapid population growth caused red deer numbers to increase, which led to environmental damage and grazing resource competition between the deer and the sheep and cattle (Figgins and Holland 2012).
In the open era, a 'deer menace' conference organized by the Department of Internal Affairs devised a plan to best carry out deer destruction. This led to all legal red deer protection being repealed and allowed nationwide recreational hunting. Recreational hunting (deerstalking) thus became a popular activity, as well as a form of environmental hunting. In 1930, deer became considered pest animals, meaning they were to be eradicated when possible. Government cullers shot 1,953,670,000 deer between 1930-1953 (Figgins and Holland 2012).
In the economic era, the Wildlife Act (1953) enabled unrestricted commercial, environmental and recreational hunting of red deer. It banned hunting in areas that would hinder government control measures. Commercial hunting expanded, and hunting for tourism re-emerged as well. Current legislation, such as the Wild Animal Control Act (1953) gives the Department of Conservation a framework for managing New Zealand's wild animals. It does not refer to deer as pests, but rather classifies them as 'wild animals' to give DoC overall management responsibility (Figgins and Holland 2012).
Deer abundance and population dynamics
Deer populations followed a general trend after release in an area. There was a rapid buildup to very high densities, often refered to as a population explosion. It was during this overpopulation phase that significant deer impacts on the ecosystem were first noted. At this stage, most of the palatable species of plants had been significantly reduced and deer were affecting the abundance of even the least palatable species, including saplings of canopy species.
Following the population explosion, there was a rapid decline in abundance due to inadequate food availability, associated with reports of starving deer and of even "blankets of dead dear" (Caughley 1983, Yerex 2001). After this there was a consolidation phase in which plant abundance recovered, and deer abundances stabilized with the available food supply. It is during this phase that shifts in plant species composition occurred with less palatable species surviving and deer preferentially browsing the remaining palatable species.
As the deer populations expanded outward, the general pattern was repeated as deer colonized each new valley or range.
There was no single peak in deer abundance, but it was thought that deer abundance reached its highest point sometime in the 1930's to 1950's, after which there followed a decline in abundance due to both environmental and hunting pressures. Deer numbers continued to decline through to the 1980's, when the commercial deer harvesting was at its peak. Since the 1980's, deer abundance has been increasing over most of New Zealand (Forsyth 2011). The deer markets improved in 2006, thus resulting in a reduction of deer abundances in some areas.
Types of deer
Seven taxa of deer exist in New Zealand:
- Red Deer (Cervus elaphus scoticus)
- Wapiti (C. elaphus nelson)
- White-tailed deer (Odocoileus virginianus)
- Sambar deer (C. unicolor)
- Sika deer (C. nippon)
- Rusa deer (C. timorensis)
- Fallow deer (Dama dama)
Red deer are most common throughout the country and have colonized much of New Zealand's habitat. Wapiti primarily reside in Fiordland. White-tailed deer live mainly on Steward Island, and in a small area near Lake Wakatipu. The sambar deer is present southeast of Rotorua and in coastal Manawatu. The sika deer maily lives in central North Island. Many of the rusa deer live southwest of Rotorua. The fallow deer is the second most widespread species, with habitats on both the North and South Islands (Department of Conservation).
Deer in New Zealand have no natural predators, which has allowed their population to rapidly expand. Their numbers will continue to increase until they deplete their food resources. The deer feed primarily on understory vegetation, which has led to a reduction in the abundance of seedlings and saplings and threatens to change the forest composition. They preferentially browse certain species, which alters forest composition and allows only the least favorable plants to recover. Therefore, the introduction of deer has caused a serious decline in the abundance of palatable understory herbs and shrubs. Because they use virtually all of New Zealand's vegetated habitats (including coastal dunes, lowland swamps, forests, and alpine grasslands) and contribute to ecosystem degradation, the Department of Conservation now considers them to be a serious threat to forest conservation (Forsyth et al 2009).
Case study: Secretary Island
Up until the early 1960’s, Secretary Island was one of the only places in New Zealand that had zero impact from grazing or browsing mammals, which saw its fragile and native ecosystem flourish. However, by 1975 the small number of deer that naturally reached Sectary Island had expanded their population to the point where grazing and trampling caused by deer impacted the ecosystem's structure.
The small five-finger tree, or Pseudopanax colensoi var fiordensis, formed most of the sub-canopy layer on the island prior to the arrival of the deer. However, selective grazing saw nearly the complete eradication of this base layer. (Mark and Baylis, 1982). This essentially opened up the forest floors, exposing root systems of the many beach trees on the island and encouraging erosion.
Measurements of the permanent forest plots on Secretary Island, dating from 1975 to 2003/04 noticed significant changes in forest composition and structure, especially in that of the understory. There was a dramatic decline in the deer’s preferred species to eat, i.e. the five-finger, but close to no change in the less palatable plant species. (Monks et al., 2005).
Since 2006, the Department of Conservation has removed 686 deer from Secretary Island. Since the eradication began, the forest understory has been recovering and is now dense. However, they estimate that there are still between 16-18 deer left on the island, which DOC plans to effectively target during the final stages of eradication [(DOC)].
Current state of environment
Deer are highly destructive grazers that target specific plant species, often to the point of localized elimination that changes the composition of forests, eg Asplenium bulbiferum on Secretary Island (Mark etal 1991).
Many cases of this have been seen throughout New Zealand forests. Some favourite foods that have seen a dramatic decline include Broadleaf (Griselinia littoralis), Mahoe (Melicytus ramiflorus) and Pate (Schefflera digitata). By targeting specific species of plants, deer can change the composition of not only the forest understory and canopy, but the wildlife as well.
Deer will graze any favoured plant species that grows below six feet in height; this includes seedlings and saplings of the larger canopy tree populations which have a far more long-term effect on forest regeneration, as these are often the pioneer species. Epiphyte, or plants that can grow on other trees, seem to be able to maintain their presence in the forest by staying out the deer's reach, but they become uncommon on the forest floor.
Another common issue seen throughout heavily deer scavenged forests is the influx of plant species that deer do not like to eat, as they may get an advantage because there is less competition for light or nutrients from palatable plants. A New Zealand forest case study from 1963 carried out on the Fiordland coast demonstrates how picky deer can be. Only five plant species were targeted by the introduced deer, and nearly all to extinction. This affected the composition of the Fiordland forests as well the wildlife present there.
The five plants the deer targeted are:
• Three-finger (Pseudopanax colensoi var. ternatum),
• Five-finger (P. colensoi var. fiordense),
• Lancewood (Pseudopanax crassifolium),
• Hen and Chicken fern (Asplenium bulbiferum)
• Coprosma (foetidissima)
Another more recent New Zealand forest case study of the Waihaha Ecological Area, part of Pureora Forest Park, outlined the importance of protecting pioneer canopy species when they are in their vulnerable seedling states. Trees which make up the canopy play a very large role in controlling what else can live at the site. They create the structure of the forest, and if deer eat too many young trees from one of the canopy populations, the future structure of the forest might change in a negative way.
Plants that live under these canopy trees and in the gaps made by the death of a canopy tree often have shorter lifespans, and may be rather patchy in their distribution in the forest. They come and go, without changing the essential character of the forest. However, their leaves and fruit are food for forest animals, including birds. If deer eat any of these under storey plants, it could change the biomass of food available for animals. At Waihaha, Putaputaweta (Marble leaf) is an important food plant for deer and seldom grows as an epiphyte. Birds like kokako eat the leaves as well as the fruits.
Monitoring of deer
Until recently there has not been any widespread systematic monitoring of deer abundance in New Zealand. In 2012 the Department of Conservation (DOC) initiated the use of a Faecal Pellet index (FPI) as a measure of relative deer abundance on DOC land as part of its state of the environment reporting. The FPI method consists of random transects with plots where faecal pellet groups are recorded, which is described in detail in Forsyth 2005.
Prior to this, the monitoring of deer abundance has been undertaken for a range of different management reasons, and has tended to occur sporadically on differing timescales (Forsyth et al 2011).
Two other methods that have been used to look at deer impacts are browse sign, or percentage of plants browsed, and absolute abundance. One of the key problems with browse sign is the level of knowledge needed to be able to preform it accurately. Both a knowledge of plant species identification and what deer browse sign on different species looks like is required. The problem with absolute abundance is the nature of deer makes it very difficult to get an accurate count, and other methods of estimation, such as mark recapture, are difficult and costly to undertake.
Faecal pellet counts
Faecal Pellet count methods have been used in New Zealand since the 1950's as a relative measures of deer and goat abundance. But the methodologies used have varied significantly and are not directly comparable. Forsyth etal 2011 provides a summary of trends in relative deer abundance since the 1950's, drawing from the literature and unpublished sources of information using the most commonly used method, a presence/absence of faecal pellets.
Attempts have been made to calculate absolute abundance from faecal pellet counts, but without accurate information on local decay rates and species specific defecation rates, which is costly and difficult to collect, its accuracy is in doubt.
Strengths and Weakness of Faecal Pallet counts
- Readily repeatable
- Little training or experience need to undertake
- Cost effective
- Compatible with other methods used in pest reporting and monitoring
- Good for general longterm trends in relative abundance
- Is not sensitive enough to detect small changes or early changes in relative abundance, due to persistence of faecal pellets in the environment
- Pellet counts are affected by the species present, and differences in species biology
- Affected by differing degradation rates of pellets in different environments and following storm events
- Cannot reliably differentiate between species in the field, eg red deer and goats pellets were they co-occur. Accurate differentiation requires additional testing to identify species eg DNA, which is costly
- Needs further research in different ecosystems to see how well it relates to deer impacts, particularly habitat use and selective browsing impacts
Department of Conservation
DOC advocated for deer control and management, with selective eradication in Northland. It views the deer as introduced pests that cause environmental damage, and hope to reduce the deer population in an effort to protect New Zealand's native ecosystems. DOC recommends that efforts be made to improve hunting opportunities so that hunting does not harm indigenous biodiversity. It also proposes simplifying the hunting permit system and considering the wider use of deer repellent to reduce deer by-kill during aerial 1080 poisoning. DOC hopes to see an increase in public participation in conservation management (DOC).
New Zealand Forest and Bird
The lack of effective deer control in the past several decades is a cause for concern. Deer populations remain virtually untouched, even with the use of commercial hunting. The helicopters were able to control deer in the more open country, but struggled in the denser forest areas. Forest and Bird Advocacy Manager Keven Hackwell compares walking into New Zealand forests to walking into an empty cathedral. "While there may be a fine canopy overhead, below there is just empty space," he says. Deer have already caused total forest collapse in some areas. Damage to the canopy and understory puts the land at risk for floods and erosion, and offers little protection from heavy rain and run-off. Therefore, New Zealand Forest and Bird advocates for deer control as a means to achieve forest recovery (Forest & Bird magazine article, 2008).
Regional Councils believe DOC should hold overall administrative authority. The majority support place-based management that would allow for the protection of indigenous biodiversity. They think the management of resources should be confined to private land, and that commercial hunting is more effective than recreational hunting. Because recreational hunting is a less cost-effective pest control method than using professional cullers, Regional Councils suggest accommodating hunting to minimize environmental damage but believe in creating a new strategy to appease the hunters and DOC (DOC).
Hunters are pro-conservation. They prefer private hunting over state-employed culling. Both recreational and commercial hunters do not wish to see the deer population exterminated, as they view the deer as a valuable resource for both pleasure and financial revenue. Hunting on private land is seen as a staple egalitarian pleasure in New Zealand. Recreational hunters now account for a majority of the national deer kill (DOC).
Commercial hunters view the industry as the predominant force historically controlling these animals. However, the boom/bust nature of the industry limits its ability to provide stable sustainable control at a minimal government cost. Some believe the Department of Conservation should be more more proactive in managing competition within the industry, and should avoid the use of 1080. They see the deer as a renewable resource worthy of sound management. Commercial hunters oppose eradication, and would rather see the deer classified as “big game animals.” They do not want seek greater numbers, but rather a greater proportion of stags and improved trophies. They also would like to see habitat sustainability and the protection of indigenous fauna and flora in key areas, which would require the management of hunters and hunting (DOC).
Recreational hunters want deer managed as a social and economic resource. However, they all all accept the need to protect native biodiversity, and recognized their adverse environmental effects. Yet they still view eradication as not feasible. Most think recreational hunting should be preferred over commercial hunting, but agree that commercial harvesting and professional culling are still needed in areas with unavoidable damage. Recreational hunters want to see legislative changes that represent their interests (DOC).
Farmers view deer as pests and give priority to indigenous biodiversity. They generally prefer more effective management to keep numbers low to achieve conservation benefits. However, they also recognize deer as part of New Zealand's cultural and economic heritage. They acknowledge that recreational hunters have good access to farmland but cannot always control the wild deer population, creating a need for other control methods. They consider deer farming and guided hunting in game estates and on unfenced farms to have provided farmers with important diversification opportunities other than traditional sheep and cattle farming. Some farmers think the Wild Animal Control Act is outmoded and want a change in designation of 'farmed deer' to 'farmed game' (DOC).
New Zealand Fish and Game
New Zealand Fish and Game was established to manage game animals on behalf of hunters. It replaced the acclimatization societies the early colonists formed to introduce animals for sport. It was established under the Conservation Act (1987) to manage, maintain and enhance game resources with regard to the recreational interests of hunters. Although Fish and Game oversees introduced fish and game birds they hold no responsibility to deer under the current legislation. NZ Fish and Game also works toward habitat conservation initiatives, causing them to value both the interests of hunters as well as habitat conservation. (DOC).
Māori see deer as both harmful and as resources. They do not approve of the impact that the animals have on the life-force of ecosystems, but also dislike the impacts of some pest control tools and the threat of professional and recreational hunters disrespecting sacred places. Some Māori gain revenue from the sale of deer-hunting rights, causing them to see them as a commercial resource (DOC).
The Animal Health Board shares similar views to the Department of Conservation. They view the wild deer as pests that should be managed, and want to see their numbers controlled. They cite a need to protect indigenous biodiversity and fears about the spread of Tb as their main concerns (DOC).
Current means of prevention
In New Zealand, the Department of Conservation has responsibility for the management of deer. Currently hunting—in the form of commercial deer recovery, recreational and DOC funded—is the primary means of controlling deer.
DOC funded hunting:
- Is expensive
- Often referred to as search and destroy
- Is only used in specific areas with defined goals
- The development of helicopter deer recovery in 1960-70's resulted in a significant reduction in deer abundance across New Zealand
- Helicopter hunting is most effective in open areas, such as grassed valley floors and alpine areas. It is not effective in densely forested areas
- Commercial Hunting pressure is variable and subject to periodic fluctuations in the market. In the early 2000's the market softened and deer abundance increased until 2006 when the market improved and subsequently deer abundance was reduced. As a result it cannot be relied upon to control deer
- Contributes to deer control in New Zealand
- Recreational hunting pressure is concentrated in areas near major population centers
- Key factors influencing recreational hunting pressure are time and access
- Generally recognized that it is not useful for achieving specific goals
- There are many reasons for people to go hunting, and they are as varied as the hunters themselves
Poison has been used to control deer in the past. It was used on Secretary Island in Fiordland, after deer became established there. The method used was to put 1080 gel on broadleaf (Griselinia littralis) foliage. This resulted in a significant reduction in the deer population, but was not successful in eradicating deer, as was the hope. Foliage 1080 poison was included as a tool in the latest attempt to eradicate deer from Secretary Island, which started in 2006.
The use of aerial poison drops to control deer is controversial. Currently, only 1080 laced carrot baits are approved for use in aerial control operations against deer, but this is not currently undertaken. Deer are a known by-kill in 1080 poisoning operations when it is used to target possums. The by-kill rates of deer are highly variable (30-95%), and as a result it is not considered a reliable means of deer control (Brown 2005). The addition of a deer repellant to baits has been agreed to when used in Recreational Hunting areas.
What is being done
The Department of Conservation's policy is to prevent the spread of deer into areas not currently occupied and to control deer in other areas.
Currently DOC is under taking the following control measures:
- Eradicating deer from Northland
- Removing some recently introduced deer from Egmont National Park
- Preventing deer from dispersing through parts of Taranaki
- Controlling deer in Kaweka Forest Park to let mountain beech seedlings recover
- Controlling deer in the Murchison Mountains to prevent deer from damaging plants that takahe eat.
- Hunters working on foot remove deer from the mainland islands at Otamatuna (Te Urewera National Park) and Hurunui (north Canterbury)
- A research program is underway to learn how forests respond to deer control in two North Island and two South Island study areas
- Running a three-year trial, by contracting a helicopter deer control operator to focus their venison recovery operations within Raukumara Forest Park
- DOC encourages people to hunt by issuing free permits
- Allowing some commercial operators to harvest deer for the export venison trade [(DOC)]
The effectiveness of current deer control is debatable and depends on the desired outcome. In areas where deer management has well-defined, measurable goals, such as in the Murchison mountains, it is effective. However, there are only a few of these areas and they only cover a very small proportion of the deer's range. Over most of the deer's range in New Zealand has no clearly defined goals or standards to measure the effectiveness of deer management against. Therefore, deer management cannot be said to be effective.
Due to the presence of other pests, eg possums and stoats, deer management needs to be considered in an integrated management regime where the combined impacts of all the introduced pests are managed together to achieve the desired outcomes.
There is a need for more research into the deer's impacts, and how differing deer management regimes interact with the various environments, other pests and the species of deer present in New Zealand.
Proposed means of management
Ideally this proposed deer management plan will cater to the needs of more than a single stakeholder. By meeting the needs of one stakeholder (recreational hunters) obtaining trophy stags and venison for personal consumption, the concerns the Department of Conservation (Stakeholder 2) has surrounding the deer impact on the environment should be addressed, if managed correctly.
Currently, recreational hunting of deer is relatively unorganized and sporadic as most hunters are independent, meaning targeting areas for eradication/management purposes and information on deer populations, locations and kills are unseen, even though the benefits of having these records would help hunters and the Department of Conservation alike.
By minimizing the number of independent hunters, through registering with a club or group to aid in the gathering of records and using the club/group as a hub to share ideas goals and knowledge. These hubs can then be contacted by the Department of Conservation and aid them in the conservation and protection of deer-affected environments.
It is accepted that the eradication of deer is not technically or economically feasible, even if it was desirable, which for many it is not. Therefore, we are looking at long-term management options.
The primary aim of deer management, under current legislation, is the protection of the indigenous biodiversity, on Department of Conservation land.
This does leave options open for improving recreational hunting and safari hunting experience on private land. But suitable regulations and controls must be in place to ensure that these areas are well managed and minimise the risk of damage to any surrounding private and Government land. Hunting groups and Private Forest owners could co-operate under such a scheme, to the benefit of both. An example is the Tokoroa Pig Hunting Club, which has developed a hunting system for 120,000 ha of plantation forest with the co-operation of the forest owners.
The 2013 restructuring of the Department of Conservation, and the mandate to engage with community groups and others in partnership, provides significant opportunities for commercial and recreational hunting groups to become actively involved in deer management in their local area. Because of the differing local issues, local engagement is likely to be more effective than national. The NZ Deer Stalkers Association and hunting clubs should look to actively engage with the department of conservation's partnership section in dialogue and offering management options. The existing Recreational Hunting areas would be one place that recreational hunters and DOC could actively co-manage. The establishment of a local plan, similar to the Tahr management plan, where goals and densities are set out as well as management if certain thresholds are exceeded, is one blueprint that could be followed. The Kaimanawa RHA and the specific issues of Sika deer and mountain beech regeneration might be a good place to start and to build dialogue and trust. Hopefully, this would lead to a better understanding on both sides and co-operation that has benefits to biodiversity and hunting.
Commercial deer recovery operators must not be excluded from this process, as they do a valuable job that would be very costly to replace if the industry fails. The trial under way in the North Island of contracting a deer recovery operator to target a specific area has potential benefits to both DOC and the operator. If the early trial results are promising then additional trials in other areas should follow.
However, deer management cannot be looked at in isolation, due to the complex interactions between pest species. Therefore, any deer management plan must form part of an integrated pest management plan to maximise the benefits for indigenous biodiversity. Targeting only one species will not completely protect the native forest. For example, the Department of Conservation found that translocating the kōkako to Secretary Island was unsuccessful, potentially because of a stoat plague. This case shows that integrated pest management is essential when working toward long-term recovery and restoration [(DOC)]. To this end it is important that DOC continues state of environment monitoring and consistently monitors deer populations and trends over the whole of New Zealand.
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