Hello, my name is Mr. Schaefer. Join me as I travel to New Orleans to study Climate Change and Caterpillars!

Tuesday, September 28, 2010

Sample Data Types (for science teachers following this blog)

September 28th, 2010
So, in conversations with Jim Merritt, he wanted some data that he can use with his students after I Skype to his classes. The data they have collected here over the past 14 years is simply enormous. Today, to enter the data into the computer, we had to know:
  • Plot details - each plot is a circle with radius of 5 meters. Each plant in the plot must be listed by type, number of leaves up to 7 feet or so, total number of leaves, and a percentage of leaves that have been eaten.

  • Caterpillar details - each found caterpillar must be ID'd by family, genus, and species, as well as given an "Instar number" (essentially, the number of times it has molted, although frankly, that's a guess based only on size of the caterpillar), and what type of plant species it was found on

  • Data details - such as date collected, person collecting, and individual caterpillar number.

I can only imagine just how much data they have. It's a monumental task that Rebecca and Mark, our fearless leaders, should be running as soon as we leave, ad nauseum, to get correlation between several factors involving caterpillar development.

Those factors, however, seem critical for the work I am doing. Let's examine them below:

  • SPECIES RICHNESS - a strict measure of the number of species of caterpillars or flora found in a single plot. This can change drastically based on invasive species entering an ecosystem, or massive environmental degredation (the last here were the hurricanes that blew through). People here are looking at something called parasitoids - organisms that lay their eggs in caterpillars, which later hatch, destroying the host. How this relationship has changed is a focs of the researchers, over a VERY long haul.

  • SPECIES DIVERSITY - a measure that combines species richness with species abundance. Invasive species and environmental change also alter this data.

  • TROPHIC LEVELS - as a canopy opens up, the ground clutter changes significantly. That usually has a negative impact on species diversity. Opening of a canopy happens, once again, during severe weather, or human influences. A trophic cascade can have a change that carries an affect far beyond its initial level. Increasing biodiversity can have a cascade affect on additional biodersity as well! (as it was explained to me, like "steps on a waterfall")

So which is better? A plot with 10 species, and 5 individual members of each species in that plot, or a plot with 25 species, one member being represented by 100 individuals, and the other species with 2 or fewer representatives?

The answer seems obvious to me.

So, begins a series of hypothetical data points for this experiment. Use any of them as you see fit.

CHINESE FALLOW - data set one

A very invasive species, brought here originally to make candles out of it.

Plot # # of plant species # of caterpillar species # of individual tallow samples









More (hypothetical) data tables to come...

No comments:

Post a Comment