Humans and ecosystems

Human interference with ecosystems

Humans have been interacting with ecosystems and modifying them for as long as human life has existed on Earth. The scale, speed and degree of change that is occurring threatens the survival and integrity of many ecosystems and also human life. An ecosystem is a community of species (plant, animal or micro-organism) and their non-living environment working as a functional unit. Ecosystems at risk, like Antarctica and Australia’s Great Barrier Reef (G.B.R) are those that are drastically affected by change and if altered will take a long time to return to their former levels of complexity. Human activities like fishing, tourism and shipping have had major impacts and interference with Antarctica and the G.B.R.

The G.B.R lies along the continental shelf off the Queensland’s East coast. The G.B.R is located at 8’ South latitude and 24’ South longitude. It is the world’s largest reef structure; it extends 2300km from Papua New Guinea (PNG) in the north to just north of Fraser Island in the south. Antarctica is located over the South Pole at latitude 66’30’ south. It is a very rough circular shape with the long arm of the Antarctic Peninsula stretching towards South America. Antarctica’s total surface area is about 14.2 million sq km in summer, which is around two times the size of Australia. In the winter Antarctica doubles in size due to the sea ice that forms around the coasts.

Both Antarctica and the G.B.R are extremely dynamic yet vulnerable ecosystems, which are being altered due to human interference. Fishing impacts on the two ecosystems in both negative and positive ways. In the G.B.R the commercial fishing industry is worth around $400 million annually to the local economy, it is also a huge source of employment for the locals in the area. However, fishing causes many disruptions to the G.B.R’s food chain due to unsustainable over fishing of key species, like the coral trout. Prawn trawling disturbs the sea floor, and catches and removes a lot of other species (by catch) which are needlessly killed in the process. Populations of the endangered dugong in the southern half of the reef have crashed to less than 10% of their original numbers due to commercial gill netting. Fishing has huge effects on the G.B.R because only 4.6% of the park is protected from fishing, and prawn trawling is permitted in 50% of the park, the G.B.R has the largest harvesting activity in a World Heritage Area and its future needs to be based on ecologically sustainable development (ESD).

Fishing is now the only large-scale resource of exploitation that is going on in Antarctica. With most of the other world fisheries being over exploited, even with controls in force, and this is one Antarctica’s main concerns as well as other problems like the over fishing of particular target species, the effects on other species that depend on the target species as a food resource or are eaten by the target species, the killing by-catch and the destruction of habitat by fishing gear. Of the 20,000 species of fish worldwide, there are only about 200 species in the cold Antarctic waters, due to the water being only one degree warmer than the freezing point of most fish, therefore the fish that actually live in the Antarctic waters are quite unique, and need to be sustainable fished to prevent extinction. The Antarctic is classified as a low productivity ecosystem as a result of the extensive seasonal ice cover (low light penetration in winter) and extreme weather conditions. The Antarctic species most significant for fisheries have been considered in three categories: oceanic, demersal and a much smaller percentage of coastal fishes (12%). Species caught are krill, Antarctic cod, ice fish, lantern fish, Antarctic squid, crabs and Patagonian tooth fish . The fishing of krill in Antarctica means that they fisheries are removing the base of the food chain which affects the ecosystem as a whole unit, which is why there has been an annual precautionary catch limit of krill set which is 2,725,000 tonnes. The protection of fisheries is different to other controls in Antarctica in that the target is that of a sustainable exploitation rather than of complete protection. As fisheries protection goes, there is a difference in that not only is the particular target species considered, but the effect of fishing that species on other dependent or associated species is also taken into consideration too. Any fishing boats are required to report their catches so that the stock taken can be assessed. While some nations continue to whale in Antarctica’s waters, today, fish and krill are the only large-scale animal fisheries in the Southern Ocean. Fishing also impacts on seabirds, like albatrosses which get caught and killed in fishing lines. The Antarctic Treaty nations established the Convention for the Conservation of the Antarctic Marine Living Resources, to protect these resources from uncontrolled exploitation. The alterations made by the fishing industry if not controlled in both ecosystems could unbalance natural equilibrium of each ecosystem beyond repair.

Around 2.4 million people visit the G.B.R each year with an economic value of $1.5 billion per year. The impacts caused by tourism vary according to the intensity of the tourism in focus. Tourists trample the reef, remove corals and shells while undertaking activities like fishing, diving, snorking, reef walking and cruise boat visits, the boats used to carry tourists around also cause localised destruction to the reefs when they drop there anchors out. Sewerage from resorts is pumped into the reef, which damages coral, encouraging the growth algae and sea grasses around the reefs. The facilities like marinas, harbours and boat channels that have been built for the use of tourists have also affected the reef by localising traffic to certain areas of the reef. The frequently visited reefs close to the shore can experience over fishing through tourists recreational fishing. The controversial road near cape tribulation, built in 1982, which caused sediment runoff to blanket and kill the unique fringing reefs in the area.

There is a concern that the increasing number of tourists to Antarctica might damage the environment. There is no doubt that Antarctica is an incredible tourist destination, it is a magnificent and largely uninhabited wilderness with mountains, glaciers, icebergs and abundant wildlife, inaccessibility and severe climate add an element of adventure to invite tourists to Antarctica. Over the last few decades tourist numbers have increased rapidly. During recent summer seasons about 8009-9000 tourists visited Antarctica, compared to less than 2000 15 years ago. Due to the increasing number of tourists the Antarctic Treaty countries established guidelines and regulations to minimise the impact of these visitors on this remarkable environment. Although remoteness and lack of development make Antarctica a difficult and expensive place to visit, there is no shortage of people wanting to make the trip-tourist numbers now exceed the number of scientists and support staff who work there, and are increasingly steady. The majority of tourists come from Germany, Britain and Australia. Tourist visits can cause damage to slow growing moss beds, disturb wildlife and take historic items or geological souvenirs. Rubbish and wastes from ships have also been a problem, as have unplanned visits to scientific bases. Visits are becoming much better regulated, and impact has reduced in some areas. But accidents can occur, with major consequences for the environment, such as the oil spill after the grounding the tourist and supply ship Bahai Paraiso on the Antarctic Peninsula. Other large cruise ships have also run aground, requiring expensive rescue and repair operations. Tourisms impacts on the ecosystems are not always bad as tourists can bring more awareness from there experiences, which means that ESD can be established through this awareness.

Shipping and oil spills are a huge concern for both the G.B.R and Antarctica as both ecosystems have shipping routes passing through them. The G.B.R is impacted upon by the commercial routes that pass through the G.B.R as the ships cause a lot of damage to the corals and habitats of unique and precious animals to the G.B.R. There have been 2 groundings of large container vessels over the past few years due to negligence, when there are groundings there is even more damage caused to the reed in trying the get the ship out of the area. The antifouling agent used in the paint on the ships is quite toxic and harmful to the ecosystem, the more the G.B.R is exposed to this chemical the greater the effect it has on the ecosystem. Oil spills from ships are an increasing form of pollution in Antarctica due to the shipping activity in the area. While ships often have facilities to contain waste oil and separate oil from water which is then taken out of Antarctica for disposal, an ever increasing presence of ships is bound to lead to more accidents which do happen. Recently there have been a number of groundings of tourist ships in shallow, poorly chartered waters and also accidents involving fishing boats in pursuit of the Patagonian tooth fish. These accidents in Antarctica like the G.B.R impact upon the ecosystem tremendously, and negligence is a huge part of why these accidents with ships happen.

Humans have modified natural ecosystems in many ways. The number of human-induced modifications to ecosystems has increased as humans numbers and technology has increased. Natural ecosystems are increasingly being modified, cultivated, exploited through tourism, built on and degraded. This has impacts on the functioning and dynamic equilibrium of ecosystems. ESD is an important factor in maintaining ecosystems for future generations for many reasons, but there also has to balanced practices implemented so the human population can use the resources provided by the ecosystem but not exploiting the ecosystems in questions.