Accounting for recorder effort in the detection of range shifts from historical data

Christopher Hassall, David J. Thompson
  • Methods in Ecology and Evolution, June 2010, Wiley
  • DOI: 10.1111/j.2041-210x.2010.00039.x

Accounting for recorder effort in the detection of range shifts from historical data

What is it about?

I analysed a series of different methods that have been used to control for the effects of recorder effort bias in the detection of range shifts. This recorder effort bias occurs when there are far more recorders looking for animals in a later period and so the chance of discovering those extreme populations increases. Thus range shifts could simply be an artefact of increased sampling. I demonstrate that the methods that have been used before vary in the detection of range shifts and that some make more sense than others. I follow this up with a case study on range shifts in British Odonata and make recommendations concerning the most appropriate methods.

Why is it important?

Climate change is an important issue and we need cutting-edge analytical tools if we are to properly assess its impacts on the world. This paper has contributed to the validation of these statistical techniques to make our detection of climate change more sophisticated and robust.


Dr Christopher Hassall
University of Leeds

Climate change is causing a range of effects in plants and animals. One of the most noticeable is the colonisation of new areas as the environment warms to a point where animals are able to persist where once they could not. However, the sources of data used to detect these kinds of patterns tend not to be systematically collected and so present unique challenges during analysis. In particular, a lot of existing data on sightings of animals that are used to detect trends under climate change originate from enthusiastic amateurs who make a note of which species they see and where.

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