The Effects of African Gamba Grass Invading the Savannas of the Northern Territory in Australia 

Ecosystems are very fragile and finely balanced things. Most ecosystems have achieved a near perfect balance between all of their pieces, but it only takes one small thing to throw an entire ecosystem into disarray. This can be done by putting a species population dip too low, or by having a species into a foreign ecosystem where they take over. This has happened all over the globe, for example, in the 1930s in the United States of America, cougars, and wolves were over hunted.

This caused their population to be extremely low, and subsequently, the deer population was at an all-time high according to the USDA National Wildlife Research Center.

But this can also happen if a species is introduced into an unfamiliar, strange ecosystem. A perfect example of this is the Asian Carp in the Mississippi River, they were initially introduced to the river in the 1970s because they were used in fish farms in the Southern parts of the river and killing and eating most of those native species.

By 1993 the Asian Carp were outnumbering the native species nine to one in the river according to the Upper Midwest Environmental Sciences Center. As I just displayed two different ways an invasive species can affect the native environment it is introduced to. Therefore, I will be discussing the ever so dangerous, and invasive Gamba Grass, or Andropogon gayanus, in the Northern Territory of Australia. Gamba Grass is had invaded this territory and has caused havoc for years in this territory.

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Problem African Gamba Grass is a type of grass that is native to sub-tropical savannas in Africa. It can grow to heights of over thirteen feet, or around four meters tall. Gamba Grass was introduced to Australia in the late 1930s because farmers wanted to see if it could work as a pasture grass for livestock like cattle and sheep. But it wasn’t introduced to the majority of the Northern Territory until 1983. This is when it started to become an invasive species. Because Gamba Grass is such a dominant species over other types of plants there are no other “challengers” to keep its growth in check, so it goes wherever it wants. Since there are no plants to keep the Gamba Grass in check, surely there is an animal that feeds on the grass. Right? Nope. Australia’s largest wild herbivore is the Red Kangaroo, which does eat grass but at only six feet tall, not even half the size of Gamba Grass. So, they have a hard time in their attempts to eat it. Due to these factors, Gamba Grass affects 1.5 million hectares, in the Northern Territory alone, according to the Northern Territory Government, that is around 15,000 square kilometers.

To put that number into perspective the country of the Bahamas is around 13,000 square kilometers, according to the CIA Factbook. That means an invasive species that has not even been in Australia for a century is affecting a chunk of land the size of the Bahamas, in Australia’s Northern Territory. In addition to the ecological problems this grass causes, it is also one of the main reasons for uncontrollable bushfires, in the northern parts of the territory. A study conducted by Samantha Setterfield, an ecologist that has been researching the effects of bushfires and Andropogon gayanus and comparing them to bushfires from native grasses. She concluded that “The Andropogon gayanus (Gamba Grass) invasion resulted in substantial changes in fire behaviour.” She found that the fires from Gamba Grass spread at a rate of .13 m/s−1 (meters per second) faster than bushfires from native grass species. It might not seem like that much but the wind during the observation was 1.3 m/s−1 less for the Gamba Grass bushfires compared to the native bushfires. She examined the difference in the fire-line intensity, which is defined as “The rate of energy or heat release per unit length of fire front, regardless of its depth.” (Byram 1959) She found that the bushfires from Gamba Grass had a fire-line intensity of over 15 and a half, while the fire-line intensity of the native grass did not even reach four.

The final thing she studied was the char height of each type of fire. Char heights are determined by how the fire blackens, or chars trees and other vegetation. While native grasses had a char height of a little over one and a half meters while Andropogon gayanus had a char height of a whopping eight and a half meters. In addition to the sheer difference of these two, bushfires are extremely problematic for the Northern Territory as a whole. In the year 2002 alone over 380 thousand square kilometers was burned. Australia also spends a significant amount of money on bushfires, in both the prevention of them and the control of them. In a study by Brian Ashe, a professor in the Department of Earth and Planetary Sciences at the University of Macquarie, estimated that Australia was spending over eight and a half billion dollars on fire prevention and control, which is around one percent of their countries GDP. Bushfires are a complex thing to try and solve but being able to try and reduce the amount of Gamba Grass could help. Reducing the amount of Gamba Grass would be beneficial to both the environment and communities that have to deal with it. Solution There are two drastically different ways to solve the problem of Gamba Grass, the first way is to try and control the grass by intervention from the Northern Territory’s Government, and Australia’s National Government. This is done in 2 ways.

The first way is to try to limit and control the sale of Gamba Grass. This would be done similarly to how the Queensland Government classified Gamba Grass as a “restricted invasive plant under the Biosecurity Act 2014.” This means that the people of Queensland cannot buy or sell Gamba Grass without a permit. This controls the initial distribution of the grass into the environment. The Biosecurity Act 2014 also “requires everyone to take all reasonable and practical steps to minimise the risks associated with invasive plants (Gamba Grass) under their control.” They encourage this by suggesting ways for citizens to deal with the already existing Gamba Grass, these ways include, by just simply pulling or digging the grass up. The other ways include creating controlled fires, but not during times of drought or no rain fall. But burning patches of Gamba Grass that have developed seeds could be counter- intuitive because of the fact that fire updrafts may carry the seeds great distances. The second step is for Australia’s National Government to do their part for every single territory and not just see it as the territories problem. This can be done by having the government try to develop and create a type of weed killer, that is specifically designed to kill the Gamba Grass.

They can definitely afford this since the government spends, “approximately AUD $8,500 million per year or approximately 1.15% of the country’s Gross Domestic Product” (Ashe). The government uses “55% of the total is allocated to costs in anticipation.” (Ashe) That 55 percent rounds out to around 4.675 billion Australian dollars, which is more than enough to try and develop some type of chemical that will affect the grass. The second solution is a lot more extreme, and fun than the first. This solution is to send large foreign herbivores to Australia. Australia’s lack of large herbivores helps contribute to the growth of Gamba Grass. Since there are no native animals that can eat it, it continues to grow and spread in areas like national park. For example, in Litchfield National Park, Gamba Grass has grown into over 20 percent park according to the National Parks Services of Australia. So, if there are no animals that are able to try and naturally control the grass. Why shouldn’t they introduce an animal that can in fact, eat it. Gamba Grass is a great meal specifically for African elephants and black rhinos. The general idea of bringing these animals to Australia may seem outrageous but using these animals may be more cost-effective and practical compared to the alternatives.

This solution will be difficult to start, but it would not all be at once, there would be a slow supply of elephants being introduced to Australia. The effect would be monitored closely, and if it is successful then they would continue to introduce elephants to the wilderness. Aside from the beginning stages one of the greatest challenges would be controlling the populations so that their need for resources would not negatively affect the environment. To prevent that, they could adopt a type of wildlife reserve where they build fences, monitor the availability of water and food, and control the breeding. I know this sounds kind of out there, but if the current solutions to control Gamba Grass are not being as effective as they should be, why not try an idea that has never been done instead of being stuck in a constant loop of ineffective methods. These are the two best solutions to try and combat Gamba Grass in the Northern Territory. Effects Out of those two solutions, one seems more extreme than the other, but it isn’t that insane. People might think that the beginning of this paper contradicts the introducing species into the environment solution.

But the example of the Asian Carp, and of the Gamba Grass are whenever species are introduced to an ecosystem by careless citizens for “easier, or quicker” solutions to the status quo. The introduction of these large herbivories would be done by the government and would be closely monitored. Everything would be monitored, from the amount they ate of Gamba Grass, and native grasses, to the way it was affecting the local wildlife, all of the way to how it affects tourism. It would also benefit the elephants, and rhinos in several ways, it would help to conserve their populations because they would be out of their native environments where they are constantly being hunted. Australia is also a lot better equipped to try and deal with the declining population of these animals. Unlike the current countries that these animals are living, Australia is not a third world country, so they have better resources and better conservation programs.

Australia also does not have as major things to focus on like the Sub-Saharan African nations, where the elephants and rhinos live. If just one of these solutions would be put into place it would create a more balanced ecosystem on the Australian savannas. It would also help reduce the intensity of bush fires by a significant amount. If these were not put into place the Gamba Grass will continue to grow and according to the Northern Territory’s Government Gamba Grass has the potential to affect more than 38 million hectares, that is around 380,000 square kilometers. That is slightly larger than the entire land mass of Japan, according to the CIA World Factbook. If that much land is covered in Gamba Grass it will be a ticking time bomb, just waiting for a bush fire that could possibly decimate the landscape. It could possibly become one of the largest bush fires that Australia has ever seen. So, it is indicative that the Australian Government, or at least the Northern Territory takes initiative similarly to how the Queensland Government has dealt with Gamba Grass, or they can do something completely different and never tried before.