Correlations, Shifting Baselines and Lupus

A few quick hits today.

Correlation is NOT Causation

So after winning the softball championship last night the only thing left to do was celebrate. So after the game the team full of scientists and our scientist friends came over to the house and we grilled up plentiful quantities of hot dogs, burgers of all varieties and consumed an equally plentiful quantity of ice cold brews. Needless to say after seeing this news from the New York Times, I’m sure everyone in attendance may have second thoughts on the latter half of our consumption last evening.

The more beer scientists drink, the less likely they are to have a paper published or cited, according to a new study by Thomas Grim, an ornithologist at Palacky University, Czech Republic.
Grim surveyed the behavior of Czech scientists and found a correlation between amount of beer consumed and papers published.

Something that one needs to remind your audience in any publication relying on a correlation study is that correlation is not causation. To anyone who has taken a class in statistics, no doubt the instructor repeated this saying ad nauseum – but it is worth repeating.

The study demonstrates a mathematical relationship between the number of publications a scientist has made and the quantity of beer consumed. The study does not however, explain the “physics” of the problem; do scientists who fail more turn to beer to ease their pain or do scientists who drink more tend to produce lousy results? This study does not answer this question, thus the findings are quite limited.

I have quite a bit of anecdotal evidence that suggest those scientists who enjoy a good brew publish okay in the United States.

Shifting Baselines
Resident zoologist and sole blog reader Mikey P brought up a good point in the comments on Monday:

Did you know that many of today's household pests are invasive or non-endemic species?

From what I remember, these include but are not limited to:
- House Sparrows (among other sparrows)
- Rats (both black and brown rats, aka "roof" rats and Norway rats, respectively)
- Cockroaches (German and American are the most common, non-native)
- Pigeons

Most of these actually came over during colonial periods.

Thanks for the knowledge Mikey! In addition to what Mikey listed, you can consider any wild formerly domesticated animal such as feral cats and wild dogs to be invasive species as well. In fact domesticated cats cause very high mortality in birds in suburban and urban areas.

These species aren't traditionally thought of as non-native, presumably because they've been here so long and that we've either adapted to having them around or are just used to dealing with them in our societal memory.

Societal memory is a serious issue in environmental science. What one generation considers to be “natural” may be radically different from what three generations previously considered “natural” to be. An excellent example of this, and one purported by Daniel Pauley of the University of British Columbia, is how the size of fishes caught by fishermen has changed the way we look at fish.



The image shown above (thanks Lyndie) demonstrates both “societal memory” and “shifting baselines.” In each image the people catching the fish are quite proud of their “large” catch. The difference is that in older days catchers were indeed bigger than they are today. Trends have been observed by fisheries biologists showing that as humans selectively remove the largest of each species, the gene pool of the fish species becomes dominated by smaller sized fish, thus fish shrink.

But the concept of “shifting baselines” applies to more than just fisheries. It applies to what a generation considers to be “virgin forest” or what a generation considers to be “pristine water quality.”

Last Hit
Today’s picture of the day from national geographic is can’t miss: