Assignment Part 1

Tropical forests are iconic for both their biodiversity and ecosystem function. But it is not clear if biodiversity drives ecosystem function, or if the two simply co-occur in this biome as a result of climate, evolution or other factors. For this assignment, you will analyze a dataset on tree species richness and ecosystem processes or properties that I have compiled from tropical forests. I began with data from Averill et al. 2014, a paper that explored the role of mycorrhizal identity of ecosystems and patterns of soil carbon and nitrogen storage. Many of the sites in Averill et al.’s dataset are part of the Center for Tropical Forest Science – Forest Global Earth Observatory (CTFS-ForestGEO) network (www.forestgeo.si.edu), which provides information about species numbers. For some sites, I found published reports of tree species numbers. For other sites, I could not find species numbers. In teams of two, you will explore the relationship between biodiversity and ecosystem function. There are many ways that you can achieve this goal, the approach and specifics are entirely up to you.

However, you will:

1) state a question and hypothesis

2) define an analytical approach

3) analyze data

4) present your results in a figure or figures

5) interpret your findings

Metadata bef.data

Site ID – defined by Averill et al. 2014

site.name- guessed, described by Nina

c50 – total soil carbon content 0-50 cm (kg C/m2)

n50 – total soil nitrogen content to 0-50 cm (kg N/m2)

sand50 – sand content of soil 0-50 cm (%)

silt50 – sand content of soil 0-50 cm (%)

clay50 – sand content of soil 0-50 cm (%)

latitude

longitude

c – total soil carbon content 0-1m (kg C/m2)

n – total soil nitrogen content 0-1m (kg N/m2)

ph – soil pH 0-1 m depth

sand – sand content 0-1m (%)

silt – silt content 0-1 m (%)

clay – clay content 0-1m (%)

em – mycorrhizal dominance of ecosystem (0 = arbuscular, 1 = ectomycorrhizal)

npp – estimate of net primary productivity (10 year average of MODIS NPP product) (kg C/m2 yr)

mat – mean annual temperature (°C), estimated from WorldClim

map – mean annual precipitation (mm), estimated from WorldClim

tree.spp – species number for site or location

panama.plot.spp – tree species number measured in 1 ha plot across the Panamanian isthmus

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Assignment Part 2

Many experiments are inspired by patterns (or the lack of pattern) from previous observations or experiments. Using your findings/results/questions from part 1, design an experiment, observational study (or some kind of hybrid) to address your original question or address a new question that arose during the course of your study. This experiment can be as elaborate and complex as you’d like it to be, as long as it *could* be achieved and allows you to address the question you pose. Consider that experimentation in forest ecosystems might require many years for a productivity response to manifest, or hundreds of years for a soil carbon stock response to manifest. Consult the literature to see what kinds of experiments already exist and what evidence may already exist to support your hypothesis.

6) describe the knowledge gap or surprise (i.e. what your analysis did or did not show, or what the literature lacks)

7) state (or restate) your question and hypothesis

8) design and experiment or study to address this question

Add these components to Part 1 and turn in one final paper (~3 pages), and give one presentation (5-10 min) of your journey of discovery.

Due on the Oct 3rd.