Cervus canadensis
(wapiti)

Cervus canadensis is a large deer native to eastern Asia and North America. Populations of C. canadensis have been introduced into the wild in New Zealand and Italy. The New Zealand population has thrived and spread over 2000 km² of mountainous habitat in the Fiordland region; however, this range was colonised by red deer (C. elaphus) from the 1950s and hybridization means that no pure C. canadensis are now present. A hunting organization culls red deer and obvious hybrids in this area in an attempt to keep the wapiti phenotype. C. canadensis (or their hybrids) affect the structure and composition of the forests and alpine grasslands in Fiordland, and helped cause the Endangered status of the herbivorous bird Porphyrio hochstetteri, the takahe (although the deer population in the remaining takahe range consists only of C. elaphus). The status and origin of the small Italian population are unknown. C. canadensis and their embryos or semen continue to be transported internationally for the improvement of farmed C. elaphus herds.

The native range of C. canadensis extends from central Asia, south to Bhutan and east to south-east Russia in a series of patchy populations, across the Bering Strait and from southern Canada to the borders of Mexico, with a population stronghold in the Rocky Mountains. C. canadensis were extirpated from the eastern states of the USA by the beginning of the 20^th century (O’Gara and Dundas, 2002) but have been reintroduced to many states in recent decades (O’Gara and Dundas, 2002; Anderson et al., 2005). Feasibility studies to reintroduce the species to additional eastern states are being conducted; it is likely that these and natural spread of the earlier reintroductions will allow much of the former range that is still suitable habitat to be reoccupied.

Introduced populations of C. canadensis occur in New Zealand (now all hybrids with red deer, C. elaphus, but retaining much of the phenotype of C. canadensis – Fiordland Wapiti Foundation, 2017) and in one small area of northwest Italy. C. canadensis (including semen and embryos) are widely imported to countries outside their natural range where red deer are farmed or ranched to increase the body size of the farmed stock (Moore and Littlejohn, 1989).

In many places where C. elaphus are farmed or ranched outside their native range, C. canadensis bulls or their semen or embryos are introduced to increase the size of offspring from the red deer hinds, allowing higher stocking rates of the smaller C. elaphus hinds but larger offspring for venison production (Moore and Littlejohn, 1989). Wapiti, or red deer with wapiti genetics, can then escape and join wild red deer populations, as has for example happened in many places in New Zealand (C. Speedy, Fiordland Wapiti Foundation, New Zealand, personal communication, 2018). Even when no animals are imported, the introduction of genetic material and subsequent escape of offspring is introducing C. canadensis genes (and occasionally phenotypes) into wild populations of Cervus in countries such as Argentina.

In its native range, C. canadensis lives in open deciduous woodland, boreal forests, mountainous areas and upland moors, grasslands, pastures and meadows. It is generally found in hilly or mountainous regions (IUCN, 2017)

In New Zealand, the wild population lives in indigenous forest and alpine grassland in Fiordland National Park in South Island. The forests are wet (up to 7 m of rainfall per year), and temperate with winter snow. They are dominated by southern beech (Nothofagus spp.), podocarps such as rimu (Dacrydium cupressinum) and a variety of hardwoods. The alpine grasslands above 900 m altitude are dominated by snow tussocks (Chionochloa spp.). The terrain is mountainous, and steep-sided from past glaciations; it extends from fiords in the west up to about 2000 m altitude towards the east.

Genetics

In New Zealand, hybridisation between C. elaphus and C. canadensis in Fiordland began about 70 years ago, as C. elaphus began to invade the C. canadensis range. Early evidence of hybridisation in the wild was provided by morphometric studies on the skulls of deer shot within the area (Caughley, 1971) and later confirmed by genetic studies (Randi et al., 2001). A random sample of 156 young deer shot in the area in 2015 showed that all were now to some extent hybrids (Fiordland Wapiti Foundation, 2017).

Reproductive biology

In New Zealand, the rutting season is between mid-March and the end of April, with calves born from late November to mid-December. This is a displacement of 6 months compared to the northern hemisphere ancestors of these deer, a transition that took place within two years of the establishment of a wild population (Logan and Harris, 1967).The females have single calves (rarely twins). The age at which females first breed depends on the physical condition of the population – they breed as yearlings when conditions are good and as 3-year-olds when they are poor (Smith, 1974).

Longevity

The natural lifespan of C. canadensis is about 17-18 years (IUCN, 2017).

Population size and density

In North America, the population of C. canadensis in the late 1990s was estimated at about one million. Typical population densities range from 2 to 10 individuals per km² (density can reach about 25 per km², higher figures in the literature almost certainly refer to fed populations) (IUCN, 2017). See IUCN (2017) for population figures in other parts of the native range.

The C. canadensis herd in Fiordland, New Zealand, increased after its spread into the wild in 1905 in a typical irruptive fluctuation (Caughley, 1970; Forsyth and Caley, 2006), reaching peak densities in around 1930. The expected decline and stabilisation of the population predicted by these models was confounded by official culling which began in the 1930s, more intensive recreational hunting from the 1950s, commercial exploitation from the 1960s, and current culling of C. elaphus and non-typical C. canadensis phenotypes. The density of deer (red and hybrids) within the C. canadensis range was about 2 animals/km² in 1989 (Nugent and Sweetapple, 1989).

Nutrition

C. canadensis are highly adaptable and both graze grasses and browse herbs and woody plants (Poole, 1951).

C. canadensis in North America suffer predation from large predators such as wolves (Canis lupus) and bears (Ursidae), where they are present.  Reintroduction of wolves into Yellowstone National Park in 1995/96 reduced wapiti densities and changed the behaviour of the deer, allowing deer-preferred plants such as aspens to increase (Fortin et al., 2005).

New Zealand C. canadensis have no natural predators other than humans. The wild animals in New Zealand are generally healthy with few ectoparasites (the louse Damalinia longicornis was found once) but share several endoparasites with C. elaphus. One significant endoparasite is the nematode Elaphostrongylus cervi, which was first found in deer in Fiordland and since then has been found in farmed animals throughout New Zealand (Nugent, 2005). The wild herd in Fiordland has not been exposed to bovine tuberculosis.

General

• Sport (hunting, shooting, fishing, racing)

Human food and beverage

• Meat/fat/offal/blood/bone (whole, cut, fresh, frozen, canned, cured, processed or smoked)

Materials

• Horn
• Skins/leather/fur

Medicinal, pharmaceutical

• Source of medicine/pharmaceutical

The genus Cervus forms a ring of sub-species and species around the Northern Hemisphere. Deer at the western end of this ring (red deer, C. elaphus) have a wide phenotypic variation in body size and antler conformation, but are generally distinguished from the eastern and North American species (wapiti, C. canadensis) and southern species (sika, C. nippon) of the ring by differences in pelage and antler form. Generally, there is an increase in body size and lighter pelage across the genus from west to east. Wapiti are typically the largest species in the genus. Both sexes have a lighter coloured body and larger cream-coloured rump patch (but with dark head, neck and legs) than red and sika deer. Wapiti calves are brown with a dark dorsal strip and may have a pattern of indistinct light spots for the first few months – red deer fawns also have white spots with a distinct double row along their back that are more distinct than those in wapiti.  There are differences in antler conformation between the three species, with wapiti sur-royals (the top tines in adults) sweeping backward, while those in red deer stay in the same plane as the lower tines, as do those for sika deer.  Sika deer (Cervus nippon) retain the juveniles’ distinct white spots as adults, especially in their summer pelage. See King (2005) for more detailed descriptions of the three species.

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

In New Zealand, the Fiordland herd is managed by a cooperative programme between the New Zealand Department of Conservation (who manage the National Park) and the Fiordland Wapiti Foundation (a non-government organisation of those with an interest in recreational hunting). The aim is to keep the total number of deer in the area to levels at which sensitive plants can persist and to maintain the high proportion of C. canadensis phenotypes in the otherwise hybrid population. In the area of Fiordland where the proportion of C. canadensis alleles in animals is highest, all red deer (C. elaphus) are shot and significant numbers of young (<3 years) and older (>9 years) females culled, but all young males that are clearly hybrids are left until they grow old enough to show clear phenotypic characters. Outside this area, all C. elaphus, most obvious hybrids, older C. canadensis-type males with poor antlers and many females are culled to help manage herd size and structure and to help maintain C. canadensis phenotypes. Most of the hunting is done by shooting from helicopters. Between 900 and 1200 deer are culled per year, suggesting a total deer population of about 4000. The recreational hunting season is during the ‘bugle’ when 400 or more hunters gain access to trophy C. canadensis in hunting blocks allocated under a ballot system (Nugent, 2005; C. Speedy, Fiordland Wapiti Foundation, New Zealand, personal communication, 2018).

In the past C. canadensis were culled as pests, exploited for venison recovery and captured alive for the New Zealand deer farming industry (Nugent, 2005).

New Zealand: Department of Conservation, Whare Kaupapa Atawhai / Conservation House, PO Box 10420, Wellington 6143, www.doc.govt.nz

New Zealand: Landcare Research, Gerald St, Lincoln, www.landcareresearch.co.nz

19/12/16 Original text for Invasive Species Compendium sections by:

John Parkes, Landcare Research/Kurahaupo Consulting, New Zealand