1 Tahrcountry Musings: Ecosystem collapse- The importance of regular monitoring

Friday, April 29, 2011

Ecosystem collapse- The importance of regular monitoring

I was fascinated to read in today’s Science daily about ecosystem collapse and how regular monitoring can be used to predict the collapses.

An experiment in Peter Lake, in Wisconsin, US headed by Dr Stephen Carpenter has come up with the finding that ecosystem collapses could be predicted with the right type of monitoring. 

Researchers changed the structure of the food web in Peter Lake, by introducing a predatory fish.
In the food web of the lake insects such as fleas ate tiny water-borne plants, small fish such as golden shiners ate the fleas, and much bigger largemouth bass ate the little fish.
In a matter of three years, the introduced fish was running all over the place. This produced a decline in tiny water plants and an explosion of water fleas.
Sensing the threat from the new predators, the golden shiners of the lake began to spend more time in the shallows. They also went in for shelter under floating logs. Larger fleas moved in and started eating the phytoplankton. Wildly varying numbers of fleas and phytoplankton were seen at different times.
After a series of flip flops by late 2010, the ecosystem appeared to have stabilised its transition from one stable state to another.

The researchers say the change was preceded by signals that could be used to predict similar collapses elsewhere. This is the first time that this phenomenon has been demonstrated experimentally.
The researchers add that that isolating these signals from the ecosystem is not only useful for predicting environmental catastrophes, but they can also be used to determine which habitats are most likely to respond to conservation


panek said...

A nice example confirming concepts of ASS, biomanipulation, trophic cascades etc., but what are these very signals you mention?

Petter said...

Very beautiful experiment.
It has always been argued that this is the case but rarely shown.

Mohan Alembath said...

Hi Panek,
For three years, all the chemical, biological and physical vital signs of the lake were continuously monitored as biota were manipulated to track "regime shift"

It was in these massive sets of data that Carpenter and his colleagues detected the signals of the ecosystem's impending collapse.

panek said...

OK - you mean phosphorus, Secchi depth, pH, nitrogen, oxygen and rest of all the stuff combined? Thanks. I've got no subscription to Science, but I hope I'll get this article somehow. I understand it is this article: DOI:10.1126/science.1203672
Well, three years is a good period for a grant, but ecological shifts usually need more time. It makes it more exciting (as Petter said), but AFAIK some biomanipulation experiments in Polish lakes were very promising in first years, but the results reversed eventually. I hope it won't be that in this case.

BTW, is it this Carpenter? http://rs.resalliance.org/2011/03/22/steve-carpenter-wins-stockholm-water-prize/

Mohan Alembath said...

Hi Panek,
Yes, it is the same Carpenter