{"id":319,"date":"2015-09-18T14:29:05","date_gmt":"2015-09-18T14:29:05","guid":{"rendered":"https:\/\/mbgecologicalrestoration.wordpress.com\/?p=319"},"modified":"2015-09-18T14:29:05","modified_gmt":"2015-09-18T14:29:05","slug":"australias-amazing-and-vulnerable-deserts-not-as-pristine-as-they-look","status":"publish","type":"post","link":"https:\/\/nher.blog\/index.php\/australias-amazing-and-vulnerable-deserts-not-as-pristine-as-they-look\/","title":{"rendered":"Australia\u2019s amazing and vulnerable deserts \u2013 not as pristine as they look."},"content":{"rendered":"

In this second\u00a0report from arid Australia, James and Thibaud Aronson discuss the debated roles of fire, cattle and invasive mammals on the native fauna and flora.<\/strong><\/p><\/blockquote>\n

To quote Gary Dinham, director of the Alice Springs Desert Park<\/a>, “although the average annual rainfall in Alice Springs is just 270 mm, [9 in.], it\u2019s erratic. For example, in 2009 the year\u2019s total rainfall at Desert Park was 64 mm. In 2010, it was 990!”<\/em><\/p>\n

Imagine, then, a vast region where almost no rain falls for several years, and then one year, a meter falls in two weeks, causing devastating floods. Despite the aridity, and the unpredictability, there are wooded areas in vast parts of inland Australia with annual rainfall comparable to that of Syria or Sudan! In fact, \u00a0there is such a remarkable diversity of trees and shrubs, and indeed such extensive savanna or woodland tree cover, that it makes perfect sense to speak of desert canopies<\/em> occurring there. However, that stunning first impression does not reveal how much the ecosystems and landscapes have been disturbed, especially in the past two centuries. How? Through severely altered fire regimes, overgrazing by domestic and feral herbivores, open-pit mining, and outrageous numbers of intentional and accidental introductions of exotic species of all sorts that really shouldn\u2019t be there.<\/p>\n

\"Open<\/a>
Open Eucalypt woodland with spinifex grass (Triodia <\/a><\/em>spp.) dominated undergrowth. Karijini National Park, Western Australia.<\/figcaption><\/figure>\n

Because of its inordinately high biomass, the Australian center burns \u2013 or gets burned – every year or every other year\u2026. The 70 species of spinifex grasses present throughout the arid and semiarid areas are in fact some of the most flammable plants on the planet. But that\u2019s just part of the story.<\/p>\n

\"500<\/a>
500 meters away from where the previous photo was taken, this spot had burned six months earlier. The Eucalypts display here the unusual feature of branches resprouting high in a tree with a completely burnt trunk. What makes this possible in some few trees \u2013 including the Mediterranean cork oak – is epicormic buds<\/a>. Taking advantage of the pulse of nutrients released in the soil, annuals have germinated in profusion, and spinifex will come back too, a little slower.<\/figcaption><\/figure>\n

Because European settlers stubbornly tried to import inappropriate farming and pastoral techniques into Australia\u2019s arid center, with its poor soils and unpredictable rainfall, they overstocked and let their cattle roam essentially freely over vast areas. Under these conditions, certain grasses and shrubs are favored, and vegetation is much more fire-prone. this has led to a large increase in the frequency of monster fires, capable of burning vast areas within days or weeks.<\/p>\n

Even today, most landowners with cattle in the outback burn their land every single year. Why? So as to reduce fuel load, as a matter of fact, in efforts – often unsuccessful, as we’ve just said – to reduce the risk of wildfires that might burn down their houses and other infrastructure. But they also are aiming to increase the amount of palatable grasses, including the introduced Buffel grass.<\/p>\n

\"Buffel<\/a>
Buffel grass (Pennisetum cenchroides<\/a><\/em>, more commonly known by its old name Cenchrus ciliaris<\/em>) by a river, showing the worst of its invasive capability, crowding out all native\u00a0understory species under the canopy of red river gums (Euc. camaldulensis<\/a><\/em>). Hardey River, near Paraburdoo, Western Australia.<\/figcaption><\/figure>\n

There is little doubt that this approach could be improved on, but the truly problematic point is whether or not the desert needs to burn. That debate ultimately is rooted in divergent interpretations of the past 100,000 years of Australia\u2019s history.<\/p>\n

It is generally agreed that humans arrived on the island continent approximately 50,000 years ago. What is unclear is what lasting impact the first immigrants had, and on what scale. The suggested date for their arrival roughly coincides with the extinction of all animal species weighing more than 100 kg, similar to what happened later in the Americas and even later in Madagascar. Therefore, some argue that humans must have driven the megafauna to extinction. Others say that Australia had been getting progressively hotter and drier for 20 to 50 thousand years prior<\/em> to the arrival of humans, and that large animals could not cope with the new climate. If that\u2019s true, at most the earliest Australians hunted out only tiny remnant populations of these large animals (including giant kangaroos, rhinoceros-sized wombats, a lizard twice the size of a Komodo dragon, giant turtles, marsupial lions, and some of the largest birds that ever lived on Earth).<\/p>\n

\"Beaten<\/a>
Beaten only by the ostrich, the emu (Dromaius novaehollandiae<\/em>) is the second largest living bird, standing as tall as an average person. However, it is small compared to the now extinct mihurung or thunder bird (Dromornis stirtoni<\/em>), that was nearly twice its size and weighed half a ton!<\/figcaption><\/figure>\n

Through the use of \u2018fire-stick farming\u2019 (the practice of setting fires in patches to stimulate new tender shoots on grasses and other plants, and thereby attract game), the Aborigines \u2013 according to some scholars – gradually transformed most of Australia\u2019s landscapes from fire-sensitive thickets, woodlands, and forests, to spinifex grasslands and Eucalypt woodlands highly tolerant of this kind of fire regime.<\/p>\n

Others counter that the earliest humans in Australia in fact stayed at low population densities until the arrival of Europeans and that their nomadic societies could not possibly have transformed landscapes at any meaningful scale. To date, no clear consensus has yet emerged.<\/p>\n

What is beyond question is the enormous impact that Europeans have had since 1788, when the first English settlers drove in their tent pegs and set up corrals for their sheep and cattle. \u00a0The introduced livestock were the first animals with cloven hooves ever to walk on Australian soil. As a direct result, the biocrust, that is the beneficial communities of lichens, mosses, and bacteria which form on undisturbed soils in many arid lands, and indeed the top profiles of the soils themselves were quickly eliminated.<\/p>\n

European settlers also cleared vast areas of land for grazing and crop lands, and introduced rabbits, cats, foxes, rats, mice, donkeys, camels, and other exotic animals\u00a0 which have had horrific impact on small marsupials, birds, and reptiles of the island, not to mention the complex ecological networks and community dynamics in which those animals occurred. Sad to say, Australia has the worst record of any country for recent animal extinctions.<\/p>\n

\"Cattle<\/a>
Unsupervised cattle at a waterhole. Cockatoo Creek, Willare, Western Australia.<\/figcaption><\/figure>\n
\"Cleared<\/a>
Cleared and overgrazed land on a cattle station in Western Australia. The ribbon of woodland in the background provides a reference for what the whole area once looked like.<\/figcaption><\/figure>\n

Of the 60 mammal species that\u00a0have gone extinct<\/a>\u00a0worldwide, in the last 200 years, 30 were Australian \u2013 and most inhabited\u00a0the arid and semi-arid zone. Besides, a further 6 formerly widespread mammals\u00a0are on the brink of extinction today, surviving only on handkerchief-sized, fenced off reserves<\/a> or offshore islands inaccessible to feral cats and foxes.<\/p>\n

While that is a terribly bleak legacy, promising steps are now being taken to limit the damage going forward, and ensure that the history of massive human-caused extinctions is not repeated. In our third and fourth blog posts from Australia we will discuss the obstacles to restoration, and then some of the encouraging endeavors underway.<\/p>\n","protected":false},"excerpt":{"rendered":"

James and Thibaud Aronson discuss the debated roles of fire, cattle and invasive mammals on Australia’s native fauna and flora.<\/p>\n","protected":false},"author":1,"featured_media":320,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"_wpas_customize_per_network":false,"jetpack_post_was_ever_published":false},"categories":[6,9,14],"tags":[61,166,283,284,321,339,340,348,365,431,495,671,839,877,942],"class_list":["post-319","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-arid-and-semi-arid-ecosystems","category-australia","category-desert-trees","tag-alice-springs-desert-park","tag-buffel-grass","tag-dromaius-novaehollandiae","tag-dromornis-stirtoni","tag-emu","tag-eucalyptus","tag-eucalyptus-camaldulensis","tag-extinctions","tag-firestick-farming","tag-hardey-river","tag-karijiini-national-park","tag-pennesitum-cenchroides","tag-spinifex","tag-thunder-bird","tag-western-australia"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/nher.blog\/wp-content\/uploads\/2015\/09\/dsc029811-scaled.jpg?fit=2560%2C1703&ssl=1","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/posts\/319","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/comments?post=319"}],"version-history":[{"count":0,"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/posts\/319\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/media\/320"}],"wp:attachment":[{"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/media?parent=319"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/categories?post=319"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nher.blog\/index.php\/wp-json\/wp\/v2\/tags?post=319"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}