The abundance and distribution of different animal and plant species was consistently measure and recorded throughout the field study at Homebush Bay Mangrove Ecosystem. The mangrove trees, salt marsh, casuarina, crab holes and seedling were just few of the different organisms that were observed. Besides this, students also interpreted factors that impacted on the growth of these species.
Different sampling techniques were trailed throughout the day, including the use of quadrats and a transect line.
ABUNDANCE- QUADRATS:
Quadrats are portable frames in which have an internal grid. They are used by scientists to estimate the abundance of species in a particular area. At this excursion, students were required to record the number of seedling and crab holes that they saw within 10 separate quadrats that were placed at 5 metre intervals. The plants with small leaves on the stem as well as crab holes (which were filled with water due to previous weather) were counted, displaying evidence of mangrove crab and plant numbers as the distance from the creek increased.
The quadrats used were 1 m by 1 m, and all organisms within and on the border were counted.
Different sampling techniques were trailed throughout the day, including the use of quadrats and a transect line.
ABUNDANCE- QUADRATS:
Quadrats are portable frames in which have an internal grid. They are used by scientists to estimate the abundance of species in a particular area. At this excursion, students were required to record the number of seedling and crab holes that they saw within 10 separate quadrats that were placed at 5 metre intervals. The plants with small leaves on the stem as well as crab holes (which were filled with water due to previous weather) were counted, displaying evidence of mangrove crab and plant numbers as the distance from the creek increased.
The quadrats used were 1 m by 1 m, and all organisms within and on the border were counted.
OBSERVATIONS:
- The number of seedlings increase as the quadrats are placed further aways from the creek. This is due to the fact that there is a greater chance of survival when the plants are not covered by much water
- There are a greater number of crab holes closer to the creek, but not when a quadrat is placed in the water. This is a consequence of more availability of food for the mangrove crabs (such as algae and plankton) near the water.
DISTRIBUTION- TRANSECT LINE:
A transect is a line or narrow section through an area of the ecosystem, along which observations are made and measurements are being recorded. Students were required to estimate the height of three different plant species (mangrove, salt marsh and casuarina) along different intervals of the transect. Recording them on a graphed timeline, students acknowledged the changes in size and amount of organisms.
- The number of seedlings increase as the quadrats are placed further aways from the creek. This is due to the fact that there is a greater chance of survival when the plants are not covered by much water
- There are a greater number of crab holes closer to the creek, but not when a quadrat is placed in the water. This is a consequence of more availability of food for the mangrove crabs (such as algae and plankton) near the water.
DISTRIBUTION- TRANSECT LINE:
A transect is a line or narrow section through an area of the ecosystem, along which observations are made and measurements are being recorded. Students were required to estimate the height of three different plant species (mangrove, salt marsh and casuarina) along different intervals of the transect. Recording them on a graphed timeline, students acknowledged the changes in size and amount of organisms.
OBSERVATIONS:
- as the mangroves got smaller, salt marsh appeared
- once the mangroves decreased in height, it was then replaced by the salt marsh
- the casuarina trees eventually replaced the salt marsh
- as the mangroves got smaller, salt marsh appeared
- once the mangroves decreased in height, it was then replaced by the salt marsh
- the casuarina trees eventually replaced the salt marsh