hey guys.
this probably wont help but may be able to guide your response. this is like an 8 mark part of my yr 11 assignment on bicentenial park which i got 8 for.
Discussion of Human Impact
There are several ways in which humans have impacted on the local ecosystem through waste disposal, overfishing, littering, contamination, pollution and construction.
Originally, 40 years ago, the southern end of the mangrove ecosystem was used for waste disposal for Strathfield Council and as a dumping ground for city rail. The landfill was then covered in soil, tarpaulin and turf in an attempt to avoid the harmful chemicals (leachate) seeping out. However, this was unsuccessful and in recent times, oil and other harmful chemicals have seeped through the soil and has run-off into the wetlands. These chemicals kill the organisms and pollute the creek, leading to a loss of biodiversity and an incredible negative impact on the fishing industry. As a management strategy, a solar powered leachate drain has been installed which traps contaminated water. This water is then transported to a nearby water recycling plant that also uses solar energy where the chemicals are removed but the water is still retained. Consequently, this would reduce the contaminated substances entering the waterways protecting the organisms and the traditional site itself, in conjunction with recycling water by using an environmentally friendly energy source. Another management strategy has been to install a layer of clay above the waste but under the tarpaulin. This could cause temporary relief to certain areas but it is a very expensive strategy which could erode away.
Litter is a major issue caused by humans significantly impacting on the mangrove ecosystem. Generally, litter is introduced from stormwater canals, however also from people’s scraps that dropped in the water and blown by the wind into the waterways. This litter can kill aquatic life, increase the pH of the water through the oily chemicals and is aesthetically unpleasant. A floating litter boom effectively traps the litter however there are limitations to the management strategy. Firstly, some rubbish can manoeuvre under the boom completely avoiding it. Secondly, the strategy is subjective to the size of the litter as the tube is only 25cm in diameter. Thirdly, the boom doesn’t stop the oily chemicals of the waste escaping into the water shown in the picture below thus not managing the increased pH levels. The oily chemicals clump around the boom limiting abiotic factors such as light availability to aquatic organisms. Also, booms are only located in certain areas of the ecosystem, not the whole environment and rubbish could be spread to other areas. The filters need to be manually emptied requiring constant maintenance. Evidently, the floating litter boom is a provisional management strategy however is not full-proof in protecting the ecosystem.
More suitable strategies could be to raise awareness to the observers through signs and posts. Also, educating the public of the implications the litter has on the ecosystem. This would stop the litter at first hand eliminating the source altogether.
Overfishing has a direct impact on the abundance of aquatic life. It contributes to a loss of biodiversity, and also disrupts the natural food web which disrupts the whole ecosystem. E.g. Brim may feed on tadpoles but if the tadpoles are overfished, the brim will also die. Overfishing can also be environmentally taxing as boats use fuels that lead to high enhanced greenhouse emissions. Restrictions can be put into place to stop this loss of biodiversity however this can impact on the fishing industry and lead to a loss of jobs. This is where the issue of “conflict of interest” comes into place, where differing groups (such as environmentalists and fishermen) causes disagreement about the overall well-being of the ecosystem. The conflict of interest can alter the overall effectiveness of management strategies when only one parties view is respected. Ultimately, ecological sustainable development must be reinforced for the overall well-being of the ecosystem; that is, balancing the economical, environmental and social factors to meet the needs of the present state of the ecosystem without endangering it to meet its needs in the future. For example, fisherman must catch enough fish to keep the fishing industry running without causing a loss of biodiversity so it won’t affect the whole ecosystem in the future.
The introduction of exotic species on the mangrove ecosystem has a central impact on the ability of other organism’s survival. Plants such as lantana have a prolific nature and try to take control of the original species such as the Saltmarsh by competing for nutrients, space, shelter and sunlight exposure. These species have several negative impacts including the fact they take control over the creek bed, disrupting natural processes such as the creek flow. They cover the creek, altering the abiotic factors on the aquatic life, such as sunlight exposure. This causes interspecific competition and an aesthetically unpleasant look. These species have been manually removed in the past however in terms of prevention, restrictions and laws must be put in place to stop people from introducing new species.
Humans impact by the trampling of vegetation in the ecosystem. This has several impacts including the disruption of natural processes within the ecosystem, the inevitable extinction of sacred species and the loss of habitats for many animals. Thus, animals would either die or migrate affecting the distribution of organisms. Boardwalks have been introduced in an attempt to stop these negative impacts. An advantage to this is it prevents devegetation, however still allowing sightseeing and allowing humans to observe the natural beauty of the ecosystem. A disadvantage is that, organisms tend to clump around resources including shelter (e.g. boardwalks), this would increase the intraspecific competition around the boardwalk which could lead to the area becoming “aesthetically unpleasant”.
The development or construction nearby the ecosystem affects the abiotic factors of the ecosystem. E.g. Sunlight Availability. The outskirt of the mangrove ecosystem has concentrated development nearby. This also changes the ecosystem’s access to natural forces such as wind as the built structures prevent it. This can have negative impacts in the ways it is disrupting natural processes altogether and nature has its way of working things out with out the interference of humans. However, positive impacts in the ways it prevents destabilizing of vegetation, trees and habitats. A management strategy is “council buyback” where the government buys the land back and demolishes it however this is extremely expensive. A prevention strategy is to restrict further construction been built.
Contamination through oil leaks and sewerage leaks have impacted on the mangrove ecosystem previously. The chemicals can both kill plants and animals and destroy the creek flow thus stop the functioning of the whole ecosystem. As the sewerage line is nearby, it is vital to secure the pipes to assure no leakages. This is the only real solution apart from moving the transporting system. As for oil leaks from boats, awareness and education of the implications of their actions and how to prevent oil leakages on boats.
Finally, noise and air pollution from near-by factories and industry’s can have harmful effects on the environment and the mangrove ecosystem. Air pollution includes the high emissions of enhanced greenhouse gases which inevitably causes indirect erratic climatic conditions. Thus, causing varied abiotic factors for the mangrove ecosystem leading to the death of organisms that can’t adapt to the different features. Directly, the toxins from the emissions can be harmful for the terrestrial fauna. (E.g. crabs and waterbirds). Noise pollution in the mangrove ecosystem is also represented by the fact it is located in an industrial, metropolitan area. A management strategy would be restrictions on the time of production and also the amount of emissions released. To combat this, they could employ more environmentally friendly energy sources such as solar energy using wind turbines.
