Using razors for simplicity

It’s weird the things you remember from school.

I remember Occam’s razor: when competing explanations are otherwise equal, the simplest one is often the most likely, until evidence proves it otherwise. I also know that this wise philosophy is often misinterpreted to mean that the simplest solution is often the best.  Also committed to memory are the orders of the first ten elements in the periodic table and of the planets in the Solar system based on their distance from the Sun.  I know that the size of a turning effect or moment is dependent on the size of the force applied and on the perpendicular distance from the pivot, and that it is impossible to fold a piece of paper in half more than 7 times, irrespective of its size or thickness.

There is no doubt that at some point in my life, I will find a use for all of these nuggets of classroom-gained gold.  The first of these (the more commonly misinterpreted version, obviously) proved its worth not long after I started my KTP.

 

At a Plants for Bugs project meeting, the team were discussing the importance of quantifying the density of vegetation on the plots. What was needed was a method which could estimate, in such a heterogeneous habitat (comprising climbers, shrubs and low growing vegetation), how the structure of the vegetation varied from the ground to the canopy, throughout the year. This is important as a plot with lots of high-level canopy cover but little in the way of low-level ground cover is likely to support a different suite of invertebrates to one displaying the opposite trend. If invertebrate abundance and/ or diversity is influenced by plant origin, vegetation density may play some part in explaining the direction of this effect.

The idea was brainstormed and a number of options trialled. We dangled plumblines from clothing frames and toyed with the use of lasers to record the distance to ‘first vegetation’. Ultimately, we had to select the method which would provide a good estimate of vegetation density in a sensible amount of time.  We decided that simplest was best on this occasion, and adopted an idea involving the use of a checkerboard backdrop to record the number of squares obscured by vegetation at multiple height classes.

 

Monitoring vegetation density using a checkerboard composed of 20cm and 5cm squares (June and September 2011)

 

As estimates of vegetation density using this method will vary depending on the observer’s line of sight, it is important that the same person is involved in the recording throughout the experiment.  So, for two days this week, I’ll be out of the office and in the garden, monitoring this covariate on the Plants for Bugs plots.  I expect many of you may well be spending at least some of this time attempting to get eight folds from a sheet of paper.

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