20 June 2010

Island snails

Since about 2000, we’ve been surveying the land snails of a group of small islands in Turkey. In preparation for my current trip there, recently I tallied up the species we have so far collected. Here is a graph showing the number of species found on each island as a function of island surface area (km2).


These types of graphs are customarily done using log units, but our data come closer to a straight line when plotted in ordinary numbers. Island C is clearly an outlier. The main reason for the smaller than expected number of species on island C is probably that I was the only one who collected there on one occasion, while at least 2 people have collected on each of the other islands on multiple occasions.

Revisiting island C to add 4 or 5 more species to its snail fauna is on top of my list of things to do in Turkey.

3 comments:

Lisa M. said...

It would be cool to do the same graph, but using only the number of species detected on the first visit. Then you could assess how much of an outlier island C is. [and if there were 10 or more visits (say) to all of the islands, then you could do accumulation curves, and then plot the relevant parameters of the accumulation curves vs. area. but that is a graph for the future, obviously.]
Lisa

Paul said...

How do you find snails? I live in an area where there should be lots of them, but I never see any!

Kevin Bonham said...

What is the area of island A?