1 a) The ecosystem which we studied on our field trip was a paperbark swamp.
b) Two abiotic factors which control the development of the ecosystem are water and soil. Water makes up a large part of all living organisms and is needed for the growth and survival for all flora and fauna. Without water in the environment the animals and plants within the ecosystem would not be able to survive. Animals like the short-finned eel, frogs and turtles require water as it is their habitat. Frogs lay their eggs in the water so without water there would be no frogs. The short finned eels live in the water all their lives so if there was no water then there would be no short finned eels as they will all be dead. Water is also required for plants to photosynthesise. If there were to be no water there wouldn’t be any plants which would then affect the whole food chain.
Another abiotic factor which controls the development of the ecosystem is the soil. Soil is needed for plants to grow. Without soil the plants will have nothing to get their nutrients from and will have nowhere to place their roots and grow. The pH of the soil is also a large factor which effects the development of the ecosystem. If the soil is too acidic, plants will not be able to grow in it. The soil at Centennial park is sandy and quick to drain of water and low in nutrients, so the plants which are in the ecosystem have adapted to the environment. Animals also need soil to gather food from or lay their eggs in. The Sydney basin turtle and the snake-necked turtle both lay the eggs in the ground. Birds also need the soil as it is the habitat for earthworms which they eat.
2) Sun ; Plants ; Insects ; Blue Tongue Lizard ; Kookaburra ; Foxes
3) Two types of biotic interactions which are seen the park is predation and parasitism. Predation is where an organism consumes another living organism for energy. This biotic interaction is only beneficial for one organism, the predator. An example of predation is the grey-headed flying fox eating insects. Parasitism is where an organism feeds off another organism. This biotic interaction is beneficial for the parasite and harmful to the host. An example of parasitism as seen in the Centennial Park ecosystem is the mistletoe which attaches itself to the Casuarina trees.
4) Casuarina trees and the Grey-Headed Flying fox have both adapted to the ecosystem they are in. The Casuarina trees have adapted with their leaves being very small. This minimises water loss through transpiration. Twigs of the Casuarina tree perform all of the photosynthesis. The twigs also hide the stomata in the grooves which further protects it from water loss.
The Grey-headed Flying fox also has adaptations which make it suitable to live in the environment. They have very good eyesight and smell which helps them locate seeds, fruit and nectar which they mostly eat. They do not use echolocation as their strong sense of smell helps guide them towards their food. It’s hooked feet also help it to hold onto the branch whilst eating as they do not remain airborne while they eat. Clawed thumbs on each of their wings also help with holding onto the food.
5) An animal which is not native to Centennial Park is the fox. Foxes were first introduced to Australia to hunt but now, they are killing a lot of the native fauna. Foxes breed once a year in late winter. Every summer they will disperse to find new areas which mean that they will then be very widespread killing many of our native fauna. The fox problem is being managed through use of fences, shooting of foxes on sight and den destruction. Some of these methods however are not that very effective. Destroying a foxes’ den is not a major problem to the fox as it will migrate to a new area and quickly build a new one. Fencing off areas from foxes is only effective for small areas. It costs up to $20,000 for a kilometre and requires regular maintenance and service. Shooting of foxes is helpful but it is only going to control a small part of the fox population. Only foxes which are seen can be shot which is not a feasible way to estimate fox numbers.
Impact on Ecosystem
Rubbish and Wastes
-Animals getting caught in plastic bags.
-Non-biodegradable things take a long time to decompose.
-Interferes with animals habitats.
-Rubbish brought by people.
-Nocturnal Animals effected.
-Ducks over breeding
-Large congregations of ducks at certain ponds
-Due to the large number of ducks it pollutes the water in the pond from their droppings.
-Reducing animal’s habitat.
-Air pollution from exhaust fumes
-Roots of trees grow into roads which will get run over by cars.
-Animals crossing roads may be run hit.
b) Rubbish and Wastes
Rubbish and wastes is a large problem affecting the ecosystem of Centennial Park. If there is a large amount of rubbish, it will contaminate the soil and water which will result in loss of flora and fauna. The park attempts to manage the rubbish problem through these ways:
– Having Bins throughout the park
– Supplying plastic bags for dog walkers
– Having rangers who patrol the park for rubbish
– Having a waste water catchment to reduce the ecosystem’s exposure to contaminants.
Having bins throughout the park is an obvious way to try to manage the amount of rubbish. Without bins, people will be more inclined to throw their rubbish on the ground. Having bins around will encourage people to go to the bin to dispose of their rubbish. This method is not absolutely reliable because it is up to the individual to decide whether he will put his rubbish in the bin and bins cannot be everywhere in the park.
Supplying plastic bags for dog walkers is an effective way to reduce the amount of dog poo around the park. Many people go to Centennial Park to walk their dogs, which will eventually expel some waste. If the owner of the dog did not bring a plastic bag, they will most likely leave it there. The plastic bags being at the park will help with the problem but again it is up to the individual to decide whether or not to dispose of it properly.
Rangers who patrol the park regularly are another way which tries to manage the rubbish problem. This method is fairly effective but as the park is quite large there will be areas which will be unchecked and rubbish may build up there. This method requires the rangers to be vigilant in their patrols for it to be effective.
The waste water catchment is a good way of keeping out the large bits of solid rubbish out of the park’s water which is inhabited by animals. This method is only effective in filtering out the solid waste. Chemical wastes are not covered in this method.