Shifting baseline

Shifting baseline (also known as sliding baseline) is a term used to describe the way significant changes to a system are measured against past baselines, which themselves may represent significant changes from the original state of the system.

The term was first used by the fisheries scientist Daniel Pauly in his paper "Anecdotes and the shifting baseline syndrome of fisheries". [Pauly (1995) ] Pauly developed the term in reference to fisheries management where fisheries scientists sometimes fail to identify the correct "" population size (e.g. how abundant a fish species population was "before" human exploitation) and thus work with a shifted baseline. He describes the way that radically depleted fisheries were evaluated by experts who used the state of the fishery at the start of their careers as the baseline, rather than the fishery in its untouched state. Areas that swarmed with a particular species hundreds of years ago, may have experienced long term decline, but it is the level of decades previously that is considered the appropriate reference point for current populations. In this way large declines in ecosystems or species over long periods of time were, and are, masked. There is a loss of perception of change that occurs when each generation redefines what is "natural".

The concept was further refined and applied to the ecology of kelp forests by Paul Dayton of Scripps Institution of Oceanography, who used a slightly different version of the term in his paper, "Sliding baselines, ghosts, and reduced expectations in kelp forests". [Dayton (1998)]

The term has become widely used to describe the shift over time in the expectation of what a healthy ecosystem baseline looks like.

Broadened definition

In 2002, filmmaker and former marine biologist Randy Olson broadened the definition of shifting baselines with an op-ed in the "Los Angeles Times". He explained the relevance of the term to all aspects of change, and the failure to notice change in the world today. He and coral reef ecologist Jeremy Jackson (of Scripps Institution of Oceanography) co-founded "The Shifting Baselines Ocean Media Project" in 2003 to help promote a wider understanding and use of the term in discussions of general conservation.

A conceptual metaphor for a shifting baseline is the price of coffee. A cup of coffee may have only cost a $0.05 in the 1950's, but in the 1980's the cost shifted to $1.00 (ignoring inflation). The "current" (21st century) coffee prices are based on the 1980s model, rather than the 1950s model. The point of reference moved.

ee also

*Bias of an estimator
*Observer effect

Notes

References

* Dayton, Paul (1998) "Sliding baselines, ghosts, and reduced expectations in kelp forests."
* Pauly, Daniel (1995) [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VJ1-40W0T2R-7Y&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=313bda126ec2c8cba56b51a0c83d6e6d "Anecdotes and the shifting baseline syndrome of fisheries."] Trends in Ecology and Evolution 10(10):430.
* Pauly, Daniel (2001) [http://www.fisheries.ubc.ca/members/dpauly/chaptersInBooksReports/2001/ImportanceHistoricalDimensionPolicyMngtNaturalResourceSystems.pdf "Importance of historical dimension policy management in natural resource systems."] ACP-EU Fisheries Research Report No 8.

External links

*http://www.shiftingbaselines.org
*http://www.scienceblogs.com/shiftingbaselines