The environmental issue of livestock in national parks is on the agenda again in Australia.
It is a simple enough decision: to graze livestock in areas gazetted as national park or not.
And in most parts of the world the decision is easily made. Livestock live on rangeland, whilst parks and reserves are for wildlife.
But in Australia there are no great herds of native grazing animals. Kangaroos and wallabies are everywhere of course and mostly they are plentiful so the national parks are not really for their benefit.
Parks are more about preserving habitat types and vegetation for plant species and a host of smaller creatures. Particularly forest types that were extensively cleared for grazing and agriculture since European settlement and are now rare or isolated.
And grazing actually performs a useful management function. Grazed forests have lower fuel loads and so burn less violently during the inevitable wildfires — and wildfire can be severe enough to destroy forest structure and even species.
This creates a challenge because maybe there could be a choice.
The cattlemen claim that there is no environmental impact of livestock grazing, ignoring or denying significant scientific evidence to the contrary.
They talk up grazing as essential to reduce the fuel load and so avoid catastrophic wildfire. The implication is that that heavy fuel load results in wildfire more damaging to the habitat than the presence of hoofed herbivores.
In the alpine national parks that are the focus of the current environmental issue livestock grazing also has a tradition and powerful folklore that the pro-grazing lobby are swift to mention.
Conservationists take the usual default position that national parks are just for wildlife — there is no cost-benefit analysis necessary.
Alpine habitats are a mixture of robust grasses that tolerate cold and dry alongside less robust annual plans that thrive briefly in the summer. The last thing these habitats need are heavy hooves.
Plus, once the battle to designate an area with National Park status, the job of conservation should be done. National parks and reserves are designated because the rest of the landscape is open for primary production.
Herbivores are everywhere and all plants will lose some biomass to the attentions of insects, mammals and birds.
In Australia this used to include marsupials the size of rhinoceros [Diprotodon] and a host of kangaroos. Today the mega herbivores have gone and for perhaps 50,000 years only smaller kangaroos, possums and rodent sized marsupials have joined the insects to eat the vegetation.
The continent is dry and pulsed growth after rain makes the vegetation prone to wildfire. It is likely that the dominance of eucalypt species is because they tolerate fire better than other types of tree.
Then it all changed.
200 years ago cattle and sheep arrived in Australia along with horses, pigs, goats, camels, foxes, cats and of course rabbits and steadily spread throughout the continent.
Before we proceed with the story of livestock in national parks, here’s an idea of what 200 years is relative to 50,000 — the red section of the bar represents roughly 1,000 years
Except camels that do very nicely in the dry, and rabbits that do nicely everywhere, the imported livestock have hard hoofs and tend to herd. They gather at water points and make a mess of the wet soil and the same happens away from water during wet periods.
Goats eat just about anything and pigs can make quite a mess of the undergrowth.
Livestock are a disturbance event, a shock to the system.
Nature is still responding and re-balancing from this shock. Nature is resilient of course, and will respond through adaption and a reshuffling of the species pack.
This readjustment process takes time and may not return to the previous condition or compliment of species. Indeed some species may be lost altogether.
So letting livestock in national parks is not a simple decision.
Livestock will always be a shock to alpine systems until they cope with the effects of grazing and hard hooves. It will take time for them to rebalance, far longer than there has been since cattle were first introduced.
Meantime environmental values will be eroded until new ones appear.
Just letting livestock in is enough to do this.
So here is one solution.
It would be interesting to see what the adversaries are prepared to pay given this solution preserves both conservation and folklore values but would not be economic.
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