Friday, March 8, 2013

Ancient Insects Confirm Biodiversity Hypothesis

This is a little unexpected but worth noting. It also suggests that coming out of the Ice Age, there has been an additional change in seasonality that may not yet be accounted for in terms of local diversity. Certainly that is true in terms of the vegetation as a review of post Ice Age flora would suggest. There may be merit in establishing unoccupied niches and then setting out to fill them if it is beneficial. At least such a strategy would be superior to accidental release.

We should at least establish the likelihood of such unoccupied niches.

From that perspective, the introduction of the python into Florida is not such the disaster it appears, although I certainly do not welcome its presence. On the other hand I also suspect that we should get into the business of harvesting surplus carnivores like alligators on an ongoing basis. Humanity was in the business of harvesting surplus game and that role in the environment needs to be restored before it really causes us serious grief. I prefer to not use hyenas or wolves for that matter.

Ancient insects shed light on biodiversity

by Staff Writers

Burnaby, Canada (SPX) Feb 14, 2013

Simon Fraser University evolutionary biologists Bruce Archibald and Rolf Mathewes, and Brandon University biologist David Greenwood, have discovered that modern tropical mountains' diversity patterns extended up into Canada about 50 million years ago.

Their findings confirm an influential theory about change in modern species diversity across mountains, and provide evidence that global biodiversity was greater in ancient times than now. The scientific journal Palaeogeography, Palaeoclimatology, Palaeoecology has published their research.

About 45 years ago, an evolutionary biologist at the University of Pennsylvania theorized that change in species from site to site across mountain ranges in the tropics should be greater than in temperate latitudes.

Daniel Janzen reasoned that the great difference between summer and winter in temperate latitudes (high seasonality) offers a wide window to migrate across mountainous regions. The small difference in the tropics (low seasonality) allows a very narrow opportunity, annually. Consequently, communities across tropical mountains should have fewer of the same species. Many studies examining modern communities support this theory.

Archibald, Mathewes and Greenwood realized that fossil beds across a thousand kilometres of the ancient mountains of British Columbia and Washington provided a unique lens through which to deepen evaluation of this theory.

Fifty million years ago, when these fossil beds were laid down, the world had low seasonality outside of the tropics, right to the poles. Because of this, if Janzen's theory is right, the pattern of biodiversity that he described in modern tropical mountains should have extended well into higher latitudes.

"We found that insect species changed greatly across British Columbia's and Washington State's ancient mountain ranges, like in the modern tropics," Archibald says, "exactly as Janzen's seasonality hypothesis predicted.

This implies that it's the particular seasonality now found in the modern tropics, not where that climate is situated globally, that affects this biodiversity pattern." He adds: "Sometimes it helps to look to the ancient past to better understand how things work today."

The findings also bolster the idea that ancient Earth was a much more diverse world than now with many more species.

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