Rainforest Riddles
Background: 70% of the biomass of a tropical rainforest is in its canopy. The complex 3D structure, warm, sunlit conditions and no shortage of water combine to create ideal conditions for life to flourish. Many plants gain access to this utopia by hitchhiking on more structurally robust plants (some small plants even hitchhike on sloths; Pauli et al., 2014). These are epiphytes . One challenge facing rainforest epiphytes is that the lack of soil in the tree tops means that although it rains regularly, the water becomes inaccessible very quickly once the rain stops and the sun beats down. In the neotropics, bromeliads have evolved specialised whorls of leaves that fit tightly together, forming a living vase or tank in which water collects.
These bromeliad "tanks" are relatively long-lasting and so become colonised by a range of aquatic organisms. Araujo et al. (2007) investigated whether bromeliad tank volume might predict the invertebrate biodiversity (Figure 1).
Q1. Which statistical tests would be most appropriate for the data in figure 1? (I.e. Which tests are reported?)
Q2. What criticism can be made about the presentation of the statistical analyses in Figure 1? (hint: read the legend thoroughly).
Q3. Assuming the data were checked thoroughly for their accuracy, and it was kept in because it was a real measurement, propose a possible explanation for the bromeliad that contained >150ml.
More Background: A dissertation student went on a tree climbing course and raised enough money to join a team and go to Trinidad to try to repeat and expand on Araujo et al's (2007) study. They wanted to investigate whether theories of island biogeography (that larger "islands" support greater species richnesses) hold true for bromeliad tank "islands". The team of three spent two months in the summer of 2008 climbing into the rainforest canopy, measuring and collecting bromeliads of a variety of species into large plastic bags, then dismantling them leaf by leaf to identify and catalogue all the invertebrates (and the occasional golden tree frog or fer-de-lance). You have been given a subset of their data in Blackboard (Assignments/Tuesday Case Study). Using this data answer the following questions.
Q4. Identify a statistical, null hypothesis to test the question in bold above using this data.
Q5. Draw an appropriate graph to illustrate the data. Make it look nice (professional) and label it. Export it to a MS Word document for submission to BB. Make sure the axes are labelled correctly and the legend is appropriately detailed.
Q6. Carry out the most appropriate statistical test to test your null hypothesis and report the results.
Q7. What, if anything, can you conclude about the relationship between epiphytic bromeliad plants and the animals that live in them?
Q8. Suggest an additional set of measurements or observations that could be made to help develop your understanding of the bromeliad ecosystem.
Need all questions answered in detail.
Attachment:- Assignment Files.rar