Comments on: Biodiversity Pt. 1: Richness vs. Evenness or What Kinds Of Beer Are In My Refrigerator

By: Anatomy of an ecological catastrophe: what to expect in the deep Gulf of Mexico | Deep Sea News

Sat, 22 May 2010 20:09:01 +0000

[...] Pollution throughout marine communities is associated with a loss of biodiversity both in terms of species richness and evenness. Although natural sedimentation occurs, the type, amount, and density of sedimentation occurring [...]

By: semih

semih — Wed, 16 Sep 2009 23:04:41 +0000

That’s an interesting calculation. I had never heard a formul like that before I read this.

By: Matt H.

Matt H. — Tue, 05 May 2009 22:40:46 +0000

Oooo Entropy. Where all the beer in the Universe slowly disappears until the Universe gets crunked.
Man why couldn’t my college professors used analogies like these. My GPA would’ve been so much better.

By: Dr. M

Dr. M — Wed, 29 Apr 2009 18:43:39 +0000

Both are special cases of a general entropy index (so in sense the both can measure the same thing). Now the form of these equations can be different so that Simpson’s is more sensitive to evenness and Shannon’s is more sensitive to richness. Of course, what your bartender says is right they differ and as such can yield different patterns. I would not advocate one over the other. Although I could play devil’s advocate and mention that misleading results can be obtained with Simpson’s at low numbers. Of course, I prefer measuring richness and evenness separately instead of lumping them. One should simply realize that both measure different things as does Chao, Ice, and other diversity indices giving greater weight to rare or dominant species. All that is important is to not blindly apply anything and understand how an index, or any statistical method, fundamentally works and what exactly it is measuring. I simply mentioned Shannon-Weiner as a specific example and because it is older by on whole year.

By: Peter

Peter — Wed, 29 Apr 2009 15:40:21 +0000

My bartender told me that the Shannon index of beer diversity is a relic of the Stone Age with no real ecological underpinnings. Rather, Shannon is a measure of uncertainty, designed to crack codes.

He favors Simpson’s index, which calculates the probability that two beers drawn from an infinitely large population will be the same brand. My bartender considers the Simpson index the most appropriate measure of diversity, and won’t permit me to use the Shannon, as not to propagate the myth of its utility. Yet, Dr. M is a beer scholar of good repute, and he invokes the Shannon. How could this be?

By: Mike Haubrich, FCD

Mike Haubrich, FCD — Wed, 29 Apr 2009 10:49:08 +0000

jebrynes: My guess is that depleting beer diversity has a negative impact on ecologist functionality.

By: jebyrnes

jebyrnes — Wed, 29 Apr 2009 05:54:02 +0000

But how does beer diversity influence ecologist function? My guess is that it is a negative relationship. But clearly, experiments must be conducted! And we really need to try both an additive and replacement design here.

By: Eric

Eric — Wed, 29 Apr 2009 04:17:27 +0000

So I am one who loves to sample rare beers often, and I believe they are critically important to the design of my Maximum Party Area MPA (critical habitat for some professors). At the same time for some I need to make sure that the MPA includes enough bottles of the most popular beers at all times too. Which index can capture both ends of the curve with equal sensitivity so I can properly design my MPA to protect both?

By: Peter

Peter — Wed, 29 Apr 2009 03:51:13 +0000

abundance of beer should be positively correlated with richness

By: Jim Lemire

Jim Lemire — Wed, 29 Apr 2009 02:56:16 +0000

from my calculations…you’re in need of more beer