Organismal Ecology: Ecosystem Report- Report Writing Assignment

Internal Code: MAS670

Report Writing Assignment:

Introduction: You have learnt during lectures that there are multiple levels to the field of ecology, starting from the study of individual organisms (organismal ecology) through to populations, communities and ecosystems. There is also a branch known as landscape ecology and finally, global ecology. There can sometimes be confusion among some ecological levels, particularly habitat, ecosystem and biomes. Typically, habitats are smaller components of an ecosystem (e.g. seagrass beds within a marine ecosystem) and you typically find many habitats within an ecosystem, but not the other way around. In contrast, biomes occur at a much broader scale and can consist or more than one ecosystem (e.g. tropical forest biomes can consist of both rainforest and dry forest ecosystems). Question: Part 1. Recording species richness and percent cover of primary producers in your two areas 1. Start by selecting a random point in your first area (you will repeat this for the second area). From this point, mark out a rectangular quadrat of 1 x 1 m with pegs. Please not that a quadrat is an area used for sampling and is usually square, rectangular or circular. It is not the same as a quadrant, which is a segment of a circle. 2. Search carefully within the quadrat and count and record each different species of plant that you can find. You will not necessarily know the common names (or scientific names) of these plants, but you can give them descriptive names to recognise that they are different (e.g. Grass species A, Grass species B for two grasses that differ in their morphology such as leaf shape or seed heads). You can take photos of these as a reference for your remaining quadrats because you need to be consistent with your records as you move from one quadrat to the next. Enter the data from your first quadrat into Table 1 (see results section below). 3. Now estimate the percentage cover of your two most abundant primary producers in your quadrat. This will be explained to you during tutorials and we have provided a schematic diagram to assist you with this (Appendix 1). You should enter these data into Table 2 (see results section below). 4. Now repeat this procedure (counts of species richness and estimates of percentage cover) so that you have records for a total of 5 replicate 1m x 1m quadrats in your first chosen area. 5. Once you have completed your first 5 quadrats, move to your next area and repeat steps 1 - 4 so that you now have another set of 5 1m x 1m quadrats in area 2. Part 2: Observing the heterotrophs : Biotic components of the ecosystem 1. Comment on any differences in the number or types of primary producers that were present in your 2 ecosystems. 2. Provide at least 2 abiotic factors and 2 biotic factors that might be influencing these differences in primary producers between your two ecosystems. If you didn’t find major differences, you should still comment on two abiotic and biotic factors that you think are having a significant influence on the primary producers in this system. 3. Think about any differences you have found and how these might influence the types of niches available for other plants and animals (e.g. how much structural complexity occurs in your 2 ecosystems and why might this be important 4.For each of your ecosystems, describe one example of how: A.the abiotic environment affects living things in each ecosystem; B.living things can change or modify the abiotic environment in each ecosystem over time. 5. Other than feeding, what types of biotic interaction did you observe or would you expect to observe at other times (i.e. just those interactions among heterotrophs)? Primary producers (or autotrophs) 6. What were the two most common primary producers, based on percent cover, in each of your ecosystems ? 7. From what you can recall,were these species also the most abundant within your ecosystem Remember, percentage cover and abundance are two very different measures of how ‘common’ particular species might be. 8. Why do you think these species were more common than other primary producers in these ecosystems? 9. What other primary producers might be present in your ecosystem that you could not observe? Primary consumers (heterotrophs) 10. What were the two most common primary consumers in each of your two ecosystems? 11. Were they consuming primary producers while you were observing them, and if so, what were they consuming? 12. If these primary consumers were not observed feeding, then how can you be sure that they are primary consumers? Secondary consumers 13. What were the two most common secondary consumers that you observed in each of your two ecosystems? 14. If feeding, what were these secondary consumers eating during your observations? 15. If these secondary consumers were not observed feeding, then how do you be sure that they are secondary consumers? Tertiary consumers 16. Can you identify any tertiary consumers in this ecosystem? Tertiary consumers are often harder to find. If not, describe at least one tertiary consumer that could potentially occur, even if you have not observed any? Hint: you may have observed evidence of tertiary consumers in your area, such as feathers, dropping, bones, etc. 17. Explain why tertiary consumers usually occur at a low density in ecosystems (hint: think in terms of availability of energy). Food chain 18. Based on your observations, present a simple food chain for each of your two ecosystems (up to the level of tertiary consumer). Give the name of the organism at each trophic level and use arrows to indicate the direction of energy flow. You should provide references that support the trophic status of each level in your food chain. Chemical cycling in the ecosystem 19. What kinds of detritus or carrion can you observe in this ecosystem? Is there any evidence that scavengers, detritivores or decomposers are utilising this decomposing organic matter? If yes, describe what you observed. 20. If you cannot directly see any decomposers, please describe the broad kinds of organism that are typically involved in the processing of detritus and carrion in an ecosystem?