Reining in the brumbies

Forest and Bird, Volume 22, Issue 4, 1 November 1991, Page 37

Reining in the brumbies

Protected feral horses threaten the North Island’s best remaining area of tussock grassland. Forest and Bird’s Conservation Director, Kevin Smith, makes the case for the protection of the grasslands rather than the horses.

a HE SIGHT OF HORSES running free across open country has universal appeal. Film producers used the imagery to good effect in countless movies of the wild west. It is not surprising therefore that a lobby has developed in New Zealand to champion the cause of a herd of feral horses found in the central North Island. What is surprising is that the feral horses enjoy protected status under the Wildlife Act a privilege otherwise reserved only for indigenous wildlife. Roaming over 70,000 hectares of montane to subalpine tussock grassland in the southwestern KaimanawaMoawhango area, the feral horses were granted absolute protection within this area by an order in council in 1981. Their grazing, trampling, campsites and dung heaps threaten the survival of the last extensive area of tussock grassland in the North Island. A number of rare or special native plants and special habitats may be eliminated by the horses with one species of native grass, Deschampsia caespitosa, having already disappeared. The 1981 protection order has resulted in burgeoning horse numbers. In 1990 they numbered 1102, increasing at 16.7% per annum from 174 in 1979. In the last two years they have increased at 20% per annum, a doubling time of 3.43 years. The estimate after this current breeding season is 1490 horses. In August this year, a public discussion document on the future of the horses was produced by the Department of Conservation. The document put forward three

options now being considered by the Minister of Conservation, Denis Marshall. These included the "do nothing" option, a reduction in horse numbers and on-going management, or the uplifting of the protection order and removal of horses from the area. The 1981 protection order marked the end of a successful campaign by a small group of horse lovers who persuaded the New Zealand Forest Service to establish the Kaimanawa Wild Horse Committee in 1978. Comprised of horse lovers, army officers, a Forest Service ranger and an animal physiologist from Massey University, the committee was concerned at the loss of feral horses from the central North Island. In 1981, when the horses were protected, there were only about 170 remaining in the Kaimanawas. Feral horses were once common in many areas of the North Island in the late 1800s and early 1900s. Since then, land development, wild animal control programmes and commercial exploitation have caused their range and numbers to shrink rapidly. The only remaining feral horses, or brumbies, in the North Island are the Kaimanawa horses and a few horses in Aupori forest in Northland. Feral horses first originated from deliberately released domestic horses, escaped cavalry horses and Maori horses. These were supplemented by the liberation of horses belonging to the Mounted Rifles near Waiouru at the end of World War II and from the escapes or releases of farm horses from nearby sheep stations.

The reduction in the range of feral horses has been matched by a more dramatic reduction in the area of tussock grassland and low monoao (Dracophyllum) shrublands in the North Island. These grassland/shrubland communities developed mostly from Maori fires that deforested the extensive central North Island plateaux. Once widespread across the volcanic plateau, the tussock has given way to pine forests and farmland. The last stronghold is on the army land of the Waiouru Military Reserve east of the Desert Road and Waiouru. For the travelling public, the wild open landscapes of the Desert Road provides one of the few natural scenic highlights in the drive from Auckland to Wellington. Only 20 years ago, uninterrupted vistas of tall red tussock land also flanked the Taihape-Napier highway just to the southeast; but subsidised agricultural development of these marginal lands in the 1970s and early 1980s eliminated vast areas of tussock. Ironically, the KaimanawaMoawhango tussock was spared because of its ownership by the Army who value the open landscape for military manoeuvres. Under the control of the New Zealand Forest Service or Department of Lands and Survey — departments that ostensibly had nature conservation responsibilities — the tussock would probably have been cleared for some foolish forestry or land development programme.

Rare plant habitat

The ecological importance of the Kaimanawa tussock grassland has only been appreciated in recent years, both as the best surviving example of a oncecommon ecosystem, and as the habitat of a number of rare or unusual plants. Botanical surveys of the area by Dr Geoff Rogers of the Forest Research Institute have shown the area to be of outstanding biogeographic significance. It contains 32 native herbs and grasses with important

biogeographic limits whose distribution coincides with the feral horse range and another three species just south of the horse area. These include two plants Ranunculus recens var and Logania depressa (probably extinct) -- found nowhere else; the southern limit of five plants endemic to the central North Island; ten species of montane herbs that occur only in the Kaimanawa grasslands in the North Island but are present in the South Island; and the North Island southern limits of sixteen species that re-occur in the South Island. Dr Rogers describes the area as having the highest national concentration of biogeographically special plants in one area. He believes the Moawhango region

south of the Kaimanawas and north of the Ruahines is an ancient centre of biotic survival. Parts of this area escaped the marine innundation of the lower North Island in the late Miocene-Pliocene (8-12 million years ago) and the tectonic upheaval resulting in the uplift of the Tararua and Ruahine Ranges that started less than one million years ago. This geological upheaval would have wiped out the habitats of these old land mass plants elsewhere in the lower North Island (see Forest & Bird, November 1986).

Protection plea

Rogers makes a plea for the protection of the Kaimanawa-Moawhango grassland both as an ancient refugia of immense

botanical significance and as the last significant example of the natural grasslands that once stretched from Rotorua in the north to the northern Ruahine Range in the south. Only 10% of the 660,000 hectares of natural grassland present in 1840 remains today. Maori fires removed the original forest cover of the upland plateaux of the Moawhango area. Relict pockets of beech (mainly mountain beech with some red and silver) and kaikawaka survive on south facing sites and in damp valleys. In areas burnt in early European times, shrublands of manuka and monoa prevail at lower altitudes and, at higher altitudes, the shrub species Dracophyllum recurvum, Brachyglottis bidwillii, and Hebe tetragona. Extensive tussock grasslands comprising red and hard tussock cover areas burnt more recently. In the floors of the basins in this undulating terrain are hard tussock grasslands. These basin floor sites have probably never supported forest since the

last glaciation and are centres of outstanding conservation value because they were the sites from where the tussocks dispersed when fire deforested the region.

The Department of Conservation discussion document on the horses notes that: "The wild horse range encompasses a unique range of basin floors, wetland and flush zone habitats and contains many outstanding botanical and ecological features. The high fertility flushes fed by ground water seeping from the underlying marine sediments, the extensive blanket bogs capping rounded greywacke ridges and the extensive

basin bogs support many of the at least 32 plant species, with important biogeographic limits, present." Trampling and grazing by the burgeoning horse population is seriously degrading these natural plant communities. The heavy grazing of the hard tussock grassland in the basins is gradually eliminating the hard tussock and favouring the spread of weeds such as Hieracium and exotic grasses. The DoC report summarises Dr Rogers’ conclusions of the environmental impact of horses as follows: "The northern Moawhango is the only example of undulating ridge and basin topography in the North Island. The region supports by far the highest concentration of biogeographically significant plants in New Zealand. Five species are suffering damage by horses that, in

the long term, threatens their survival. Because of intensive grazing pressure, many tussock communities about water courses have been severely modified or eliminated. Furthermore, many mires, seepages, and other riparian microhabitats are being severely damaged by trampling and grazing. The spread of weeds, mainly Hieracium, heather and exotic grasses is enhanced by all facets of horse disturbance including grazing, trampling and the creation of dung heaps. Unique flush zones also suffer gross modification by trampling and grazing." Dr Rogers points to the intermontane basin floor of the Argo Valley as an area where horse and stock grazing has eliminated the hard tussock. Basins to the north will suffer a similar fate if horse grazing continues. The natural wildlife values of the tussock grasslands are unknown and are not mentioned in the DoC discussion document. Evidence from elsewhere suggests that the tussock grasslands and shrublands will be just as important for invertebrate conservation as they are for botanical conservation. They are likely to contain the best remaining populations of insects associated with scrubland and tussock grassland vegetation that characterised wide areas of the North Island during cold, glacial periods in the past. Native birds present include pipit, paradise duck, banded dotterel, blue duck and the New Zealand falcon, a declining species. In summary, the Moawhango Ecological District has botanical, scientific and landscape values of outstanding national significance warranting their total protection. Many of these features are unique to the area. The values are such that the Moawhango grasslands would be a worthy addition to the Tongariro World Heritage Area, which presently covers only the Tongariro National Park, or to the Kaimanawa Conservation Park.

These natural heritage values are threatened by feral horses, by the spread of exotic weeds including heather, Hieracium and contorta pine, and by physical damage from heavy machinery used in army manoeuvres. Of these threats, the most pressing is the rapidly increasing horse population. Horses directly foster the spread of Hieracium and create disturbed sites for the spread of contorta and heather.

Removal of horses sought

New Zealand has national and international responsibilities for the protection of its endemic flora and fauna. It is clear that the ongoing presence of feral horses in the Kaimanawa area is not compatible with the protection of the natural plant and animal communities. Accordingly, the Forest and Bird Executive have called on the Minister of Conservation, Denis Marshall, to rescind the protection order on the horses and to remove them from areas of public land with natural vegetation. | Supporting Forest and Bird in this call have been ECO (Environment and Conservation Organisations), Federated Mountain Clubs and the Tongariro-Taupo Conservation Board. The Board chairman, Mr John Ryan, said groups which wanted to maintain the herd were welcome to take horses from the Kaimanawa Forest Park and from important areas south of the park because the horses were doing as much damage to the environment as rabbits in Central Otago. The Board is also concerned that the horses will keep increasing their range and spread into Tongariro National Park or further areas of the Kaimanawa Forest Park. Maori members of the Board were concerned at their spread onto Tuwharetoa land adjoining the

Kaimanawa Conservation Park. Feral horses were removed from Tongariro National Park in the 1960s and 1970s through live capture and shooting by private operators. In light of the current environmental crisis caused by the expanding horse population, it is worth revisiting the reasons advanced for their protection in the first place. The most extraordinary argument advanced at the time was that the animals lived in ‘unique conditions.’ (The uniqueness of the conditions, of course, relates to the presence of endemic flora and fauna which is being eliminated by the horses). The existence of the feral horses would enable ‘scientifically valuable’ comparisons with other wild or feral equids such as zebra. The animals may have physiological, anatomical or behavioural differences from other horses (emphasis added). The herd may be of future value as a genetic source of traits associated with ‘hardiness’.

e The only honest arguments were those not based on pseudo-science but on the horses’ intrinsic aesthetic value and historical value as a remnant of once larger feral horse groups. No attempt was made to balance these values against the aesthetic values of a wild natural tussock land ecosystem free of domestic animals or the historical values of flora and fauna that evolved over millions of years. There was no evaluation of the environmental impacts of a protection order, nor was there any opportunity for public comment. Botanists and natural history scientists in the DSIR were not consulted. It remains a mystery why the former Wildlife Service, with its proud record in the conservation of native wildlife, went ahead with the protection proposal. It must be remembered that not only are horses a recent introduction to New Zealand, but

that they are not wild horses at all, merely feral domesticated horses. The domestic horse (Equus caballus) is derived from the extinct wild tarpan, first tamed sometime between 5000 and 3000 BC. An article on horses in the ‘Handbook of New Zealand Mammals’ notes that: "Over the centuries many national varieties of domesticated horses have developed and been taken to all continents and to a very large number of oceanic islands. Escaped or unwanted horses have established feral populations in many parts of the world including Asia, Europe, North and South America and Australia." So much for the scarcity value of feral horses. However, there are those who refuse to accept that the Kaimanawa horses are just feral domestic animals and insist they represent relict genetic material. Forest and Bird joins the Tongariro-Taupo Board in inviting these people to remove the horses — and most could be easily rounded up and driven into corrals — and care for them on lands of no conservation value, such as marginal farmland of which there are vast areas nearby. The genetic stock could be maintained and the horses left to run free for those who wish to view them. However, few people seem to have this ambition with only six parties a year at most requesting permission to view the horses. A concessionaire has extensively advertised horse viewing trips but has not had any takers yet. Ongoing culling of the feral horses to maintain a reduced herd in the more modified areas in the south of the range is an option canvassed by DoC in its discussion paper. Forest and Bird does not support this proposal (though it finds favour with our Rangitikei branch) because degradation of the natural areas will continue, albeit at a slower rate; DoC will be committed to spending scarce conservation dollars on feral horse management forever when there are other pressing conservation priorities in the Kaimanawa area; and DoC will be forced to kill horses on a regular basis and leave itself open to continued criticisms from the people concerned with the ethics of killing horses. And then where would it end? Similar arguments could be advanced and sometimes are — to maintain feral populations of other domestic animals including sheep, cattle, goats or cats. The native flora and fauna of New Zealand evolved in isolation over millions of years. It is unique in the world and we have an international obligation to ensure its survival. Sentiment and emotion should not allow introduced animals, which are wrecking New Zealand's natural ecology, to be placed on a pedestal above these island’s original inhabitants. &