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Marsupial lawns are portions of land where the soil moisture is much higher than in the vegetation surrounding it. These high moisture levels create lawns that attract a large amount of grazing by marsupials. Commonly found in Tasmania, the lawns function as habitats for local animals.
Similar turfs have been discovered in New Zealand that are maintained by small mammals such as rabbits or sheep. Similar patterns of feeding and use have been recorded in both New Zealand and Tasmania. These lawns are also similar to the famous mammalian lawns of Serengeti. [1] In Tasmania, the lawns form sporadically within woody landscapes [2] as well as sheltered areas along the coast. [3] They are found at altitudes ranging from alpine to coastal, and are often associated with wetlands.
Marsupial lawns are also frequently found behind dunes along the eastern coast. Coastal shores are often lined with tea-tree, banksias, and eucalypts, marshes and marsupial lawns in sheltered areas where mud can slowly accumulate. The lawns can only evolve from constant grazing. [3] The Bay of Fires is a common tourist area for visitors to view the various land structures and forms, including marsupial lawns. [3]
Along with their habitats in woody forests and behind sand dunes, indigenous marsupials patrol domestic lawns nightly. The animals chew off any growth in the grass from the previous night. Fire risk is reduced by this frequent trimming, and the soil remains fertilized and conditioned by fecal matter the marsupials leave behind. Many farmers have found that using the marsupials to aid their plants works great. They allow the marsupials to come in at night and trim grasses in their gardens. This also reveals weeds or other shrubs, making extraction of unwanted plants easier. The marsupials leave vegetables and fruits alone while focusing only on eating grass. While this may be beneficial to crop farmers, others are frustrated with constant efforts to keep marsupials out of their grass cattle pastures. Expensive fencing and repair to keep marsupials out of pastures has caused much controversy. [4]
Marsupial lawns have become home for many of Tasmania's animals, marsupials in particular. [5] The most prevalent of these animals in the lawns are known as the Big Five. They are the forester kangaroo, the Bennett's wallaby, the Tasmanian pademelon, the common wombat, and the Tasmanian devil. [6]
Environmental observations and enclosure experiments have been used to test whether vertebrate grazers are a critical element in maintaining marsupial lawns, or if water inundation played a larger role in formation. Results have shown that both woody and non-woody plants became much taller in the lawns when marsupial grazers were excluded, while the inundation had no effect on woody growth. This shows that marsupials are essential to maintaining lawns, and without them the structure of the lawns would deteriorate. [7]
Local human activity can have a profound influence on the factors affecting marsupial lawn creation and sustainment. In addition to altering these variables, humans also destroy lawn habitat through farming and livestock grazing. In order for these lawns to flourish, natural grazing patterns and fire cycles must be maintained. Humans are encroaching on marsupials’ habitat and altering fire patterns, meaning that Australia's marsupial lawns are under threat.
Land use changes such as farming and grazing are one of the biggest threats for marsupial lawns. These lawns are prime areas for agricultural use because they are naturally located in areas of high soil moisture and nutrient content. This can be attributed to natural topography and rainfall patterns. In contrast, much of the rest of Australia's tropical savannas experience sporadic rainfall, meaning they can support very little vegetation growth. [8] As a result, while marsupial lawns are able to cope with small scale disturbances, such as roads or power lines, when large tracts of lawn are destroyed, there is nowhere for the animals or plants to migrate to. Furthermore, herbivore grazing is essential to prevent the invasion of woody species into the lawns. Therefore, destruction of large herbivorous marsupial habitat will in turn negatively affect lawn growth. [9] Decreased agricultural production in the 21st century has resulted in pressure to develop these economically valuable areas, and it is important that such development is undertaken in a way that acknowledges the value of this unique ecosystem. [10]
With the acceleration of the Australian cattle industry over the past decade, Australian geography has undergone serious environmental changes which have affected marsupial lawns. [11] Australia is the second largest beef exporter in the world and the cattle industry its largest agricultural sector. Increasing beef demand expanded the size of farms and numbers of livestock into areas previously unsuitable for sustained pasture farming. Since Australian farmers use irrigation to water crops and nourish animals, dry landscape can be converted into fertile soil.
Changing the environment from desert to grassland extends fertile land into herbivore habitat. Marsupials that once scavenged the dry deserts for scarce grasses and sparse leafy shrubs now find an abundance of vegetation, particularly in areas being farmed. With this large amount of resources now available, marsupials, have been able to reproduce more than ever before. Most cattle are free range, yet a few are fenced in by a three line barbed wire fence that red kangaroos have no problem jumping over to feed on irrigated grasses. [11] Farmers also erect agricultural settlements near rivers or flood-outs. Although farms may be in the desert, these oases can provide the water for an entire crop or herd if managed correctly. Marsupials use these creeks and flood-outs as natural habitats; however, once farmers irrigate these bodies of water, their habitats are extended. Instead of feeding on dry grass with low nourishment, kangaroos and other marsupials seek the plush grasses growing off irrigated moist soil. As farmers continue to use these methods, the marsupial population will continue to increase.
However, while some agricultural development has enabled kangaroos to expand their population in the harsh conditions of arid Australia, other human developments pose problems to these marsupials. For example, many farmers have reported seeing kangaroos drowning in the watering holes of free-range cattle. As the cows drink and wallow in the ponds, the desert clay becomes an adhesive substance. When kangaroos come to replenish themselves in the ponds they sink into the inescapable goo and die from starvation or heat stroke.
In addition to grazing, fires have a significant effect on the health of marsupial lawns. One of the defining characteristics of lawns is a lack of woody plants. Fires play an important role in the creation and maintenance of these habitats because fires curtail woody plants, and return nutrients to the soil to allow for future growth. Human-caused fires have contrasting effects on marsupial lawns. On one hand, they are often set by indigenous people who use the fires to concentrate marsupials for hunting, which in turn results in lower lawn grazing and more woody plant growth. On the other hand, these fires destroy woody plants and allow grass to grow in its place, which increases potential marsupial lawn area. [12] Consequently, fire suppression efforts may prevent some lawns from getting the woody growth pruning they needs, causing brush buildup. When such areas finally do burn, they can become hot enough to reduce the viability of the soil for years. [13]
In addition to local impacts such as land use and fire management, global issues such as climate change also have the potential to impact marsupial lawn ecosystems. Because of the scope of the predicted changes, global warming has the ability to affect precipitation levels, temperature, and fire cycles in Australia. This in turn will alter where and to what extent marsupial lawns can exist. However, currently it is not possible to predict whether or not climate change will increase or decrease the total acreage of marsupial lawns.
Climate models predict that northern Australia may see slightly increased rainfall in the coming decades. [8] However, the precipitation may be less reliable, and as a result there may be long periods of drought or at the very least a longer dry season each year. [8] In addition, climate change will bring with it higher overall temperatures, as well as continually elevating levels of carbon dioxide (CO2). Preliminary research shows that higher temperatures, higher rainfall, and elevated CO2 levels may lead to increased woody plant growth. This in turn would decrease marsupial lawn habitat. However, higher temperatures and a long dry season mean increased fire frequency, which could serve to offset the new woody growth. [14] To further complicate matters, it is possible that the higher levels of evaporation brought on by increased temperatures could compensate for the increased rainfall. However, research has not been done to determine whether higher precipitation or higher temperatures will have a greater effect on water availability in the region.
The overall effect of climate change on marsupial lawns, and the greater northern Australia area, is needed to be studied in greater detail. Currently the counteracting and overlapping effects make it difficult to discern the overall impact human induced climate change will have on marsupial lawns.
Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature reserves. It can also be caused by immobile, travel restricted populations of native or non-native wild animals.
Sclerophyll is a type of vegetation that is adapted to long periods of dryness and heat. The plants feature hard leaves, short internodes and leaf orientation which is parallel or oblique to direct sunlight. The word comes from the Greek sklēros (hard) and phyllon (leaf). The term was coined by A.F.W. Schimper in 1898, originally as a synonym of xeromorph, but the two words were later differentiated.
A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area.
A savanna or savannah is a mixed woodland-grassland ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. According to Britannica, there exists four savanna forms; savanna woodland where trees and shrubs form a light canopy, tree savanna with scattered trees and shrubs, shrub savanna with distributed shrubs, and grass savanna where trees and shrubs are mostly nonexistent.
A meadow is an open habitat or field, vegetated by grasses, herbs, and other non-woody plants. Trees or shrubs may sparsely populate meadows, as long as these areas maintain an open character. Meadows can occur naturally under favourable conditions, but are often artificially created from cleared shrub or woodland for the production of hay, fodder, or livestock. Meadow habitats, as a group, are characterized as "semi-natural grasslands", meaning that they are largely composed of species native to the region, with only limited human intervention.
In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible cellulose within grass and other forages into meat, milk, wool and other animal products, often on land unsuitable for arable farming.
Rangelands are grasslands, shrublands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, savannas, chaparrals, steppes, and tundras. Rangelands do not include forests lacking grazable understory vegetation, barren desert, farmland, or land covered by solid rock, concrete and/or glaciers.
Tasmania, the largest island of Australia, has a landmass of 68,401 km2 (26,410 sq mi) and is located directly in the pathway of the notorious "Roaring Forties" wind that encircles the globe. To its north, it is separated from mainland Australia by Bass Strait. Tasmania is the only Australian state that is not located on the Australian mainland. About 2,500 kilometres south of Tasmania island lies the George V Coast of Antarctica. Depending on which borders of the oceans are used, the island can be said to be either surrounded by the Southern Ocean, or to have the Pacific on its east and the Indian to its west. Still other definitions of the ocean boundaries would have Tasmania with the Great Australian Bight to the west, and the Tasman Sea to the east. The southernmost point on mainland Tasmania is approximately 43°38′37″S146°49′38″E at South East Cape, and the northernmost point on mainland Tasmania is approximately 40°38′26″S144°43′33″E in Woolnorth / Temdudheker near Cape Grim / Kennaook. Tasmania lies at similar latitudes to Te Waipounamu / South Island of New Zealand, and parts of Patagonia in South America, and relative to the Northern Hemisphere, it lies at similar latitudes to Hokkaido in Japan, Northeast China (Manchuria), the north Mediterranean in Europe, and the Canada-United States border.
Fire ecology is a scientific discipline concerned with the effects of fire on natural ecosystems. Many ecosystems, particularly prairie, savanna, chaparral and coniferous forests, have evolved with fire as an essential contributor to habitat vitality and renewal. Many plant species in fire-affected environments use fire to germinate, establish, or to reproduce. Wildfire suppression not only endangers these species, but also the animals that depend upon them.
Páramo may refer to a variety of alpine tundra ecosystems located in the Andes Mountain Range, South America. Some ecologists describe the páramo broadly as "all high, tropical, montane vegetation above the continuous timberline". A narrower term classifies the páramo according to its regional placement in the northern Andes of South America and adjacent southern Central America. The páramo is the ecosystem of the regions above the continuous forest line, yet below the permanent snowline. It is a "Neotropical high mountain biome with a vegetation composed mainly of giant rosette plants, shrubs and grasses". According to scientists, páramos may be "evolutionary hot spots", that meaning that it's among the fastest evolving regions on Earth.
Themeda triandra is a species of C4 perennial tussock-forming grass widespread in Africa, Australia, Asia and the Pacific. In Australia it is commonly known as kangaroo grass and in East Africa and South Africa it is known as red grass and red oat grass or as rooigras in Afrikaans. Kangaroo grass was formerly thought to be one of two species, and was named Themeda australis.
Cytisus proliferus, tagasaste or tree lucerne, is a small spreading evergreen tree that grows 3–4 m (10–13 ft) high. It is a well known fertilizer tree. It is a member of the Fabaceae (pea) family and is indigenous to the dry volcanic slopes of the Canary Islands, but it is now grown in Australia, New Zealand and many other parts of the world as a fodder crop.
The Australian environment ranges from virtually pristine Antarctic territory and rainforests to degraded industrial areas of major cities. Forty distinct ecoregions have been identified across the Australian mainland and islands. Central Australia has a very dry climate. The interior has a number of deserts while most of the coastal areas are populated. Northern Australia experiences tropical cyclones while much of the country is prone to periodic drought. This dry and warm environment and exposure to cyclones, makes Australia particularly vulnerable to climate change -- with some areas already experiencing increases in wildfires and fragile ecosystems.
The Ord Victoria Plain, an interim Australian bioregion, is located in the Northern Territory and Western Australia, comprising 12,540,703 hectares.
The shortgrass prairie is an ecosystem located in the Great Plains of North America. The two most dominant grasses in the shortgrass prairie are blue grama and buffalograss, the two less dominant grasses in the prairie are greasegrass and sideoats grama. The prairie was formerly maintained by grazing pressure of American bison, which is the keystone species. Due to its semiarid climate, the shortgrass prairie receives on average less precipitation than that of the tall and mixed grass prairies to the east.
Land clearing in Australia describes the removal of native vegetation and deforestation in Australia. Land clearing involves the removal of native vegetation and habitats, including the bulldozing of native bushlands, forests, savannah, woodlands and native grasslands and the draining of natural wetlands for replacement with agriculture, urban and other land uses.
Grazing pressure is defined as the number of grazing animals of a specified class per unit weight of herbage. It is well established in general usage.
Alpine vegetation refers to the zone of vegetation between the altitudinal limit for tree growth and the nival zone. Alpine zones in Tasmania can be difficult to classify owing to Tasmania's maritime climate limiting snow lie to short periods and the presence of a tree line that is not clearly defined.
The ecology of the Great Plains is diverse, largely owing to their great size. Differences in rainfall, elevation, and latitude create a variety of habitats including short grass, mixed grass, and tall-grass prairies, and riparian ecosystems.
Eragrostis setifolia, commonly known as neverfail grass, is a species of perennial grass in the family Poaceae native to Australia, where it is widespread and common throughout the range lands and is commonly utilized as a pasture grass. According to IUCN classification it is listed as a least concern species throughout most of its range with the exception of Victoria where it is classified as vulnerable. It is capable of C4 photosynthesis.