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:

Empire State Invasives

Well, blogcentral managed to survive the deluge last Friday relatively unscathed. Today drips of brown water continue to inundate the kitchen area of the lab. I am trying very hard to convince myself that the fetid water is simply laden with rust, but I must admit that my overactive imagination is causing me much concern.

New York State Invasive Species
Anyway, we were chatting about invasive species last Friday, specifically the red lionfish. Sometimes it’s hard to understand the impacts of invasive species until you’ve seen it firsthand in your local environment. So I thought it’d be neat to take a peek at some other invasive species that are impacting the New York Region. The Department of Environmental Conservation lists a number of invasive species that are a major threat to agriculture and the environment in New York State. Today we will focus on three, Zebra Muscles, Chinese Mitten Crabs and Gypsy Moths.

Zebra Muscle


Perhaps the most famous invasive species in New York State, the Zebra Muscle has major impacts on the local ecology as it is able to out-compete native benthic organisms. It also impacts human activities directly by being quite adept at clogging intake pipes for industry, including power plants.


The map shown here courtesy of the USGS shows that Zebra Muscles are present in every major New York State water body from Lake Champlain, to the St. Lawrence River, Lake Ontario, the Erie Canal and the Hudson River.




Chinese Mitten Crab



The DEC states that it is the most recent invasive species to strike the state. It has been spotted primarily in the lower Hudson River, and has slowly been moving northward (reaching as far north as Dutchess County). Chinese Mitten Crabs compete with the endemic Blue Crab, whom may be adversely affected by this invasive species.

The Mitten Crab has long been a problem along the West Coast, more recently it has moved into the Chesapeake and appears to have moved north into New York waters only in past years. The species has been unable to thrive in the St. Lawrence waterway, despite being introduced, but may have more luck in the warmer waters of the Hudson Estuary.

Photo credit: http://www.invasivespeciesinfo.gov/aquatics/mittencrab_child.shtml

Gypsy Moths


Yuck. You’ve no doubt seen their rather unattractive nests in trees in your own back yard. The success of this invasive species varies greatly from year to year. Sometimes their presence is not noticeable, other times they decimate the canopy in localized regions.

In addition to the seemingly omni-present Gypsy Moth, New York State has also been stricken with two other species of moths, the Forest Tent Caterpillar and Eastern Tent Caterpillar, both of which have caused major damage to native trees in past years.

Photo credit: USGS, http://www.invasive.org/images/768x512/2652087.jpg

Other Transport Mechanisms
We had also talked a bit about methods of introduction of invasive species. One I didn’t mention, but that is getting a lot of attention in New York State is the transport of firewood. Wood is home to many species of burrowing insects. When transported from region to region, we may accidentally be transporting non-native species and introducing them to new habitats, where they may negatively affect local tree populations. Many tree species aren’t able to adapt quickly enough to fight off infestation with recently introduced insects. Many formerly common tree species in New York such as the American Chestnut and the White Birch have in recent years been decimated by invasive species.

In New York State a major concern is transport of insects in firewood into the Catskill and Adirondack State Parks. Many campers bring with them firewood from home, and in the process may be rapidly spreading these invasive bugs.

Here is the Department of Environmental Conservation’s poster asking people to take care with their firewood:

Red Lionfish Invasion!

It’s raining so hard here at blogcentral, that the roof is leaking. While a few drops of water may not mean a lot to most, when you are working in a room with machines using tens of thousands of volts of electricity, this becomes a real threat. Thus, this first post may be our last.

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I read an interesting article by Daniel McFadden of the Associated Press earlier this week about invasive species in the Gulf of Mexico. I think invasive species is an extremely ambiguous term that no doubt is confusing to many, and it’s worth clarifying our terminology before moving onward.

An invasive species, is by most definitions, a species that is not native to its current habitat that is some how harmful to the habitat it has come to reside in. By not native we mean that it is not traditionally found in its new ecosystem, and has by some manner only recently arrived. Today when we talk about invasive species we most often mean introduced species, and that is to say species that we as humans moved into their new habitats.

There are a number of invasive species that are likely familiar to Americans including zebra muscles in the Great Lakes, “flying” carp in the Misssissippi River and Kudzu in the Southeastern United States. The focus of the quoted article, the red lionfish, is looking likely to become a prime example of invasive species in a major vacation hotspot, the Caribbean.

Introduction of new marine species by humans can be done in a number of ways, most often by maritime vessels releasing ballast water. Ballast water in water that ships take in at one location to stabilize the vessel, and often release it far away areas where they are docking. This ballast water often contains fish and other aquatic animals larvae and eggs that may not be native to a region.

Other major methods of introduction of invasive species include accidental transport on ships and airplanes, and intentional transport of species for domestication or for pleasure viewing (e.g. zoos and aquariums).

Today’s example of an invasive species was transported by way of pleasure viewing.

“The red lionfish, a tropical native of the Indian and Pacific oceans that probably escaped from a Florida fish tank, is showing up everywhere - from the coasts of Cuba and Hispaniola to Little Cayman's pristine Bloody Bay Wall, one of the region's prime destinations for divers.”

….

”Researchers believe lionfish were introduced into the Atlantic in 1992, when Hurricane Andrew shattered a private aquarium and six of them spilled into Miami's Biscayne Bay, according to the National Oceanic and Atmospheric Administration.”

Yikes!

The lionfish in coral reef ecosystems represents a perfect storm. The lionfish is an aggressive animal that is able to out-compete native species. The lionfish is a voracious consumer of native species. And lastly, the lionfish has been introduced to an ecosystem that already under a great deal of stress.

Lionfish are likely to get a lot of attention in the upcoming years because they are both visible to tourists and somewhat hazardous to swimmers. But the real threat they pose is in terms of damage to the already fragile ecosystem they are invading.

“Wherever it appears, the adaptable predator corners fish and crustaceans up to half its size with its billowy fins and sucks them down in one violent gulp.
Research teams observed one lionfish eating 20 small fish in less than 30 minutes.
This may very well become the most devastating marine invasion in history," said Mark Hixon, an Oregon State University marine ecology expert who compared lionfish to a plague of locusts. "There is probably no way to stop the invasion completely."

In addition to its voracious appetite, the fish has shown a surprisingly large range for a tropical fish, being spotted as far north as Rhode Island. According to my diving buddies, they have been seen in the waters of the south shore of Long Island as well.

The red lionfish represents a real challenge to marine planners trying to manage the delicate coral reefs. The effects of this species will be felt over a large latitude range from the Caribbean all the way into the Northeastern United States. Of course, this is only one of the many many species we have introduced and are in some way responsible for.